Evs Book

Environmental Science and Engineering

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Environmental Science and Engineering As per latest ANNA UNIVERSITY Syllabus Syllabus (2013 Regulation) Regulation)

For III Semester Civil, EEE, EIE, CSE, IT and Bio-Tech For IV Semester Mech, Chemical For V Semester ECE, Auto For VI Semester BME

Dr. Arun Luiz T

(Ph.D, IIT Madras)

S. CHAND CHAND & COMPANY COMPANY PVT. PVT. LTD. LT D. (AN ISO 9001: 2008 COMPANY)

RAM NAGAR, NEW DELHI-110055

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S. CHAND & COMPANY PVT. LTD.

(An ISO 9001 : 2008 Company)

Head Ofce : 7361, RAM NAGAR, NEW DELHI - 110 055

S. CHAND CHAND

Phone: 23672080-81-82, 23672080-81-82, 9899107446, 9911310888 9911310888 Fax: 91-11-23677446

P U B L I S H I N G

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© 2015, Dr. R.L. Madan All rights reserved. No part of this publication may be reproduced or copied in any material form (including photocopying or storing storing it in any medium in form of graphics, electronic electronic or mechanical mechanical means and whether or not transient or incidental to some other use of this publication) without written permission of the copyright owner. Any breach of this will entail legal action and prosecution without further notice. Jurisdiction : All disputes with respect to thi s publication shall be subject to the jurisdiction of the Courts, Tribunals and Forums of New Delhi, India only. First Edition 2015

ISBN : 978-93-854-0199-2 978-93-856-7603-1

Code : 1004 1010000663 359

This book is for Sale in India & other SAARC Countries only. PRINTED IN INDIA

By Nirja Publishers & Printers Pvt. Ltd., 54/3/2, Jindal Paddy Compound, Kashipur Road, Rudrapur-263153, Rudrapur-263153, Uttarakhand and published by S. Chand & Company Pvt. Ltd., 7361, Ram Nagar, New Delhi -110 055.

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PREFACE

As per the directions from The Supreme Court of India, UGC has made mandatory a course of Environmental science for undergraduate students in Indian universities. This book has been written to cater the needs of B.E./B.Tech B.E./B.Tech students according to the new new syllabus prescribed by Anna Universtiy (Regulation 2013). This book comprises of five units which covers the entire syllabus. Topics like ecosystems and biodiversity, environmental pollution, natural resources, social issues and human population and environment. This book has been written in a simple and lucid manner. Most of these topics are traditionally taught in environmental science and engineering in several universities and institutes. Figures and tables are incorporated wherever necessary to make the concept clearer. This book also contains short questions with answers, review questions and university question paper. Author hopes that this book will be useful for both students and faculty alike. Despite all precautions and care, some error or misprints might have been left inadvertently. The author welcomes comments, suggestions and criticisms for the improvement of the book. Kindly mail your comments to [email protected] Dr. Dr. Arun Luiz T

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ACKNOWLEDGEMENTS

Author would like to extend special thanks to my father, my brother, my friends, students and department colleagues for their constant encouragement. This book would have never been published without my mother’s blessings. I dedicate this book in her memory. SSN Management is acknowledged for the support. Author thanks Chand and Company Pvt. Ltd, New Delhi for fast efficient publishing.

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ABOUT THE AUTHOR

Dr. Arun Luiz is currently working as Assistant Professor, Department of Chemistry in SSN College of Engineering, Kalavakkam. He completed his Master in Science from St. Mary’s College, (University of Calicut), Sulthan Bathery, Kerala in 2002. He stood first in his college for BSc and MSc (Chemistry). He received his PhD in Inorganic Chemistry from IIT Madras in the year 2010. His research interest includes phosphorus based ligands in synthetic inorganic chemistry and organometallic chemistry. He has published two books on engineering chemistry and has many research papers in reputed national and international journals. He has a great passion towards towards teaching.

About The Book • • • • • •

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The contents of of the book has been written according to latest latest syllabus of Anna University University Chennai (2013 Syllabus). Study material is simple on explanation and guide guide to further information. Correct and updated information is furnished. Figures, diagrams diagrams and tables tables are given to explain explain concepts clearly. clearly. Objecitve type, short answer answer and essay essay types questions are included. Latest Anna University University questions have been mentioned. Solved question question paper is given.

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SYLLABUS

GE6351 Environmental Science and Engineering UNIT I Environment, Ecosystems and Biodiversity Definition, scope and importance of Risk and hazards; Chemical hazards, Physical hazards, Biological hazards in the environment – concept of an ecosystem – structure and function of an ecosystem – producers, consumers and decomposers-Oxygen cycle and Nitrogen cycle – energy flow in the ecosystem – ecological succession processes – Introduction, types, characteristic features, structure and function of the (a) forest ecosystem (b) grassland ecosystem (c) desert ecosystem (d) aquatic ecosystems (ponds, streams, lakes, rivers, oceans, estuaries) – Introduction to biodiversity definition: genetic, species and ecosystem diversity – biogeographical classification of India – value of biodiversity: consumptive use, productive use, social, ethical, aesthetic and option values – Biodiversity at global, national and local levels – India as a mega-diversity nation – hot-spots of biodiversity – threats to biodiversity: habitat loss, poaching of wildlife, man-wildlife conflicts – endangered and endemic species of India – conservation of biodiversity: In-situ and ex-situ conservation of biodiversity. Field study of common plants, insects, birds Field study of simple ecosystems – pond, river, hill slopes, etc.

UNIT II Environmental Pollution Definition – causes, effects and control measures of: (a) Air pollution (Atmospheric chemistryChemical composition of the atmosphere; Chemical and photochemical reactions in the atmosphereformation of smog, PAN, acid rain, oxygen and ozone chemistry;- Mitigation procedures- Control of particulate and gaseous emission, Control of SO2, NOX, CO and HC) (b) Water pollution: Physical and chemical properties of terrestrial and marine water and their environmental signicance; Water quality parameters – physical, chemical and biological; absorption of heavy metals - Water treatment processes. (c) Soil pollution - soil waste management: causes, effects and control measures of municipal solid wastes – (d) Marine pollution (e) Noise pollution (f) Thermal pollution (g) Nuclear hazards–role of an individual in prevention of pollution – pollution case studies – Field study of local polluted site – Urban / Rural / Industrial / Agricultural.

UNIT III Natural Resources Forest resources: Use and over-exploitation, deforestation, case studies- timber extraction, mining, dams and their effects on forests and tribal people – Water resources: Use and overutilization of surface and ground water, dams-benefits and problems – Mineral resources: Use and exploitation, environmental effects of extracting and using mineral resources, case studies – Food resources: World food problems, changes caused by agriculture and overgrazing, effects of modern ag riculture, fertilizer-pesticide problems, water logging, salinity, case studies – Energy resources: Growing energy needs, renewable and non renewable energy sources, use of alternate energy sources. Energy Conversion processes – Biogas – production and uses, anaerobic digestion; case studies – Land resources: Land as a resource, land degradation, man induced landslides, soil erosion and desertification – role of an individual in conservation of natural resources – Equitable use

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Syllabus xi

of resources for sustainable lifestyles. Introduction to Environmental Biochemistry: Proteins– Biochemical degradation of pollutants, Bioconversion of pollutants. Field study of local area to document environmental assets – river/forest/grassland/hill/mountain.

UNIT IV Social Issues and the Environment From unsustainable to sustainable development development – urban problems related to energy – water conservation, rain water harvesting, watershed management – resettlement and rehabilitation of people; its problems and concerns, case studies – role of non-governmental organization- environmental ethics: Issues and possible solutions – 12 Principles of green chemistry- nuclear accidents and holocaust, case studies. – wasteland reclamation – consumerism and waste products – environment production act – Air act – Water act – Wildlife protection act – Forest conservation act –The Biomedical Waste (Management and Handling) Rules; 1998 and amendments- scheme of labeling of environmentally friendly products (Ecomark). enforcement machinery involved involved in environmental legislation- central and state pollution control boards- disaster management: floods, earthquake, cyclone and landslides. Public awareness.

UNIT V Human Population and the Environment Population growth, variation among nations – population explosion – family welfare programme– environment and human health – human rights – value education – HIV/AIDS – women and child welfare –Environmental impact analysis (EIA)- -GIS-remote sensing-role of information technology in environment and human health – Case studies.

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CONTENTS

Preface Acknowledgements Acknowledgements About the Author Syllabus

v vii ix x

1. Environment, Ecosystems Ecosystem s and Biodiversity 1.1 Environment Studies: Definition, Scope and Importance 1.2 Hazard and Risk 1.3 Ecosystems 1.4 Structural Aspects of Ecosystems 1.5 Function of Ecosystems 1.6 Major Ecosystem Ecosyste m Types 1.7 Biodiversity 1.8 Levels (Types) (Types) of Biodiversity Biodiversi ty 1.9 Values (Importance) of Biodiversity 1.10 Classification of Species 1.11 Hot Spots of Biodiversity 1.12 Red List of Threatened Species (Red Data Book) 1.13 India As a Mega Diversity Nation 1.14 Biogeographical Biogeographical Classication of India 1.15 Threats to Biodiversity 1.16 Conservation of Biodiversity Anna University Questions

1 1 2 6 6 7 15 22 22 22 24 25 26 27 28 30 31 34

2. Pollution 2.1 Introduction 2.2 Atmosphere 2.3 Oxygen and Ozone Chemistry 2.4 Air Pollution 2.5 Smog 2.6 Acid Rain 2.7 Particulate Pollution 2.8 Air Pollution Control Devices 2.9 Emission Control of NOx, CO, HC 2.10 Indoor Air Pollution 2.11 Air Pollution – Case Study 2.12 Water Pollution 2.13 Waste Water Treatment 2.14 Water Pollution – Case Studies

35 35 36 38 40 42 44 45 46 48 48 49 49 54 56

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xiv Contents

2.15 2.16 2.17 2.18 2.19 2.20 2.21 2.22

Soil Pollution Solid Waste Management Marine Pollution Noise Pollution Thermal Pollution Nuclear Hazards Nuclear Hazards – Case Studies Role of an Individual In Prevention of Pollution Anna University Questions

3. Natural Resources 3.1 Introduction 3.2 Forest Resources 3.2 Water Resources Resourc es 3.3 Mineral Resources 3.4 Food Resources 3.5 Land Resources 3.6 Energy Resources 3.7 Equitable Use of Resources for Sustainable Lifestyles 3.8 Environmental Biochemistry Anna University Questions 4. Social Issues and the Environment 4.1 Sustainable Development 4.2 Urban Problems Related to Energy 4.3 Water Conservation 4.4 Watershed Management 4.5 Resettlement And Rehabilitation Issues 4.6 Role of NGO 4.7 Environmental Ethics—Issues And Possible Possible Solutions 4.8 12 Principles Of Green Chemistry 4.9 Climate Change 4.10 Waste Land Reclamation 4.11 Consumerism And Waste Products 4.12 Environmental Legislation 4.13 Enforcement Machinery Involved Involved in Environmental Legislation 4.14 Environmental Impact Analysis/Assessment Analysis/Assessment 4.15 Ecomark 4.16 Diaster Management 4.17 Floods 4.18 Earth Quake 4.19 Cyclones 4.20 Tsunami

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57 58 60 61 62 65 66 68 69 71 71 72 74 81 83 87 92 100 100 102 103 103 104 104 106 107 108 108 109 109 111 112 113 118 119 120 120 122 123 125 126

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Contents xv

4.21 Landslides 4.22 Public Awareness Anna University Questions 5. Human Population and the Environment 5.1 Population 5.2 Population Characteristics 5.3 Variation of Population Among Nations 5.4 Population Explosion 5.5 Environment and Human Health 5.6 Family Planning 5.7 Women and Child Welfare elfar e 5.8 HIV / AIDS 5.9 Human Rights 5.10 Value Education Educati on 5.11 Environmental Impact Analysis/Assessment Analysis/Assessment 5.12 Role of Information Technology in Environment and Human Health Anna University Questions Appendix

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128 128 129 131 131 132 134 137 138 139 140 142 144 145 146 146 149 151

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Unit

1

ENVIRONMENT, ECOSYSTEMS AND BIODIVERSITY

SYLLABUS Definition, scope and importance of Risk and hazards; Chemical hazards, Physical hazards, Biological hazards in the environment – concept of an ecosystem – structure and function of an ecosystem – producers, consumers and decomposers-Oxygen cycle and Nitrogen cycle – energy flow in the ecosystem – ecological succession processes – Introduction, types, Characteristic features, structure and function of the (a) forest ecosystem (b) grassland ecosystem (c) desert ecosystem (d) aquatic ecosystems (ponds, streams, lakes, rivers, oceans, estuaries) – Introduction to biodiversity definition: genetic, species and ecosystem diversity – biogeographical classification of India – value of biodiversity: consumptive use, productive use, social, ethical, aesthetic and option values – Biodiversity at global, national and local levels – India as a mega-diversity nation – hot-spots of biodiversity – threats to biodiversity: habitat loss, poaching of wildlife, man-wildlife conflicts – endangered and endemic species of India – conservation of biodiversity: In-situ and ex-situ conservation of biodiversity. Field study of common plants, insects, birds Field study of simple ecosystems – pond, river, hill slopes, etc.

1.1

| ENVIRONMENT STUDIES: DEFINITION, SCOPE AND IMPORTANCE

The word Environment is derived from the French word “Environ” which means “surrounding”. Environment is the sum total of inter relationships that exists among living organisms and non living things like air, water and land. Environmental science is an interdisciplinary area that integrates physical, chemical and biological sciences. It deals with the study of the environment, problems faced by the environment and their solutions. Rapidly growing human population, technological development development and indiscriminate use of natural resources have resulted in the degradation of environment. Thus, the need and scope of environmental studies have become more significant in the current scenario due to the following reasons: ·

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Environment issues being of international importance Environment issues like global warming and ozone depletion, loss of biodiversity etc are not merely national issues but are international issues. International efforts and cooperation are required to address these problems.

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Environmental Science and Engineering 2 Environmental ·

Problems associated with industrialization and development Rapid growth of science and technology resulted in industrialization. This rapid industrialization has caused severe environmental damage due to its activities.

·

Population explosion Total world population has crossed 7 billion. This population explosion will cause depletion of all natural resources.

·

Natural resources: Conservation and management Due to over exploitation, many natural resources are being depleted at an alarming rate. Proper steps have to be taken for their preservation.

·

Ecology and Biodiversity Diverse ecosystem of earth is affected by human activities. Environmental education helps to create awareness among people.

·

Environmental pollution and control Human activities have resulted in wide spread pollution of land, water and air. Irrecoverable damage to environment can happen if pollution is not checked.

Methods to propagate environmental awareness Among students through education: Schools, colleges, universities etc Among people through mass-media: Through articles, environmental rallies, movies, documentaries, street plays, TV serials. Among the planners, decision-makers and leaders: Orientation, training through workshops and training programs. Publication of environment-related resource material: in the form of books, booklets or pamphlets. World Environment Day is celebrated every year on June 5th to create a global awareness for environmental protection. The United Nations Conference on the Human Environment was organized from 5–16 June 1972 in Stockholm, Sweeden. This was the first attempt made by global community to deliberate on environmental protection. Since 1972, World Environment Day is celebrated on June 5th. Name

1.2

Date

World water day

March 22

Earth day

April 22

World environment day

June 5

World population populati on day

July 11

| HAZARD AND RISK

Hazards and risks are often mentioned in relation to occupational safety and health. These are defined as the following. A Hazard is a potential source of harm or adverse health effect on a person or persons. Hazard can be an object or a situation which may cause harm. Improper earthing or wiring, non-uniform pavements, unguarded machinery, a fire, an explosion and a sudden escape of toxic gas etc are hazards.

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Environment, Ecosystems and Biodiversity 3

Examples of Hazards and Their Effects:

Workplace Hazard

Example of Hazard

Example of Harm Caused

Thing

Knife

C ut

Substance

Benzene

Leukemia

Material

Asbestos

Mesothelioma

Source of Energy

Electricity

Shock, electrocution

Condition

Wet floor

Slips, falls

Process

Welding

Metal fume fever

Practice

Hard rock mining

Silicosis

A risk is is chance or probability that a person may be harmed or suffers adverse health effects if exposed to a hazard. Risk can be high or negligible. Factors that influence the degree of risk include: · · ·

The amount of exposure of a person to a hazardous thing or condition, The way person is exposed (e.g., breathing in a vapour, skin contact), and The severity of the effects under the conditions of exposure. Risk = hazard + exposure

Though, the terms Hazard and Risk are often used interchangeably, they are not essentially the same. For example, water spill in a room can result in a slipping hazard to people who enters the room. If access to that area is prevented by a physical barrier (or wet floor board) then the hazard would remain though the risk would be minimised.

Types of hazards Environmental hazards are of the following types 1. Chemical hazards 2. Physical hazards 3. Biological hazards or bio-hazards

1. Chemical hazards in the environment A chemical hazard is any substance that can cause harm, primarily to people. It includes chemical accidents like explosions, leakage, fire etc. Severity of the chemical hazard depends upon: · · ·

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Concentration of the chemical. Physical state of the chemical (solid, liquid, gas). Mode (inhalation, swallowing, skin contact etc) and duration of exposure.

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Environmental Science and Engineering 4 Environmental

Classification of chemical hazards a) Explosives: Explosive are chemicals that result in a sudden, instantaneous release of pressure, gas, and heat when subjected to sudden shock, pressure, or high temperature. Examples of explosive and potentially explosive chemicals include: ·

Compounds containing the functional groups azide, nitro, peroxide etc. Eg: Nitrocellulose, Trinitrotoluene (TNT).

b) Flammable and Combustible Liquids: Flammable Liquid: A liquid having a flash point below 100°F (38°C) Eg: Acetaldehyde, ethyl ether, acetone, benzene, ethyl alcohol. Combustible Liquid: A liquid having a flash point above 100°F (38°C). Eg: Kerosene, nitrobenzene. c) Poisons: A poison is a substance that is capable of causing the illness or death of a living organism if swallowed, breathed in, or absorbed through the skin. Some poisons causes instantaneous harm while some other poisons (heavy metals, pesticides) accumulate inside the body or a period of time and can result in “slow death” Eg: Potassium cyanide, methyl alcohol, carbon monoxide. d) Corrosive: A corrosive is a chemical that can result in visible destruction of living tissues (often irreversible destruction) by chemical action at the site of contact. Eg: Concentrated mineral acids, bases etc.

Suggestions to minimize risks due to chemical hazards · ·

·

· ·

Use the smallest quantity of the chemical possible (explosives, poisons etc). Always Always wear appropriate gloves, lab coat or apron, safety goggles or explosion-proof shields when working with potentially explosive chemicals. Corrosive chemicals should be handled in a fume hood to avoid breathing corrosive vapors and gases. Inflammable liquids when used, keep containers away from open flames. Properly dispose of any hazardous waste according to the instructions.

2. Physical hazards in the environment A physical hazard is defined as some factor present in the environment that can cause harm to the body without necessarily touching it. They can be detected through your sense of touch or sight. These hazards arise at work due to the influence of various forms of energy. They include noise, temperature, lighting, vibration and radiation. These also include natural disaster events such as earthquakes, tornadoes, volcanoes, blizzards, landslides and droughts. Physical hazards and their health effects

Sl No

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Physical hazard

Health effect

1.

UV radiations

Can damage DNA and can cause skin cancer and cataract.

2.

Noise

Painful and ir reparable damage to ear. Can cause elevation in blood pressure, heart beat etc.

3.

Temperature

High temperature can lead to dizziness, dehydration, head ache etc.

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3. Biological Biologi cal hazards in the environment Biological hazards are of biological origin. It includes organisms, or products from an organism, that could be harmful to humans. They include pathogenic bacteria, viruses and parasites, and also toxins (poisons) that are produced by organisms. Biological hazards are the cause of the majority of human diseases. Bacteria: Cholera, tuberculosis, leprosy and many diarrhoeal diseases

Hepatiti s B and C, HIV, HIV, measles and polio Viruses: Hepatitis Parasites: Lice, worms etc Biological agents enter the body when they are inhaled, eaten (ingested) or absorbed. Once inside the body, these infectious agents can multiply quickly and may be passed from one person to another.

Controlling biological hazards The best way to prevent illness is to reduce or eliminate exposure to biological agents. Some methods to reduce biological hazards are · · · ·

Practice good personal hygiene (e.g. regular hand washing) Have properly sterilized food, water etc. Clean and disinfect work surfaces often. Injury and wounds must be given first aid and given immediate medical attention to minimize the chance of infection.

Examples of Environmental Health Hazards by type of Agent

Physical

Chemical

Biological

Noise

Solvents

Animals (rodents, wild

Lighting

Acids/bases

animals, pets)

Radiation

Metals (Pb, Cd, Hg)

Bacteria

Vibration

Poisons

Vir uses

Temperature

Dusts (asbestos, silica, wood)

Spores/fungi

Electricity

Pesticides

Pests

Air pollutants/particulates

Insects

Principles of hazard management · · · · · ·

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Establish the context and identify the hazard Hazard/risk analysis and evaluation Communicate and consult Treat the hazard/risk Monitoring and reviewing Record keeping

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1.3

| ECOSYSTEMS

The term Ecology is derived from the Greek words Oikos (home) + logos (study). Ecology deals with the study of organisms in their natural habitat and their interactions with their surroundings. The surroundings consists of other living organisms (biotic) and physical (abiotic) components. Ecology: The study of plants and animals in their relation to each other and with their environment. Ecology is the study of ecosystems. Ecosystem: An ecosystem is a group of biotic communities or species interacting with one another and with their non-living environment exchanging energy and matter. Types of Ecosystem: a) Natural Ecosystems: These ecosystems are capable of operating and maintaining themselves under natural conditions. A classification based on their habitat can further be made: ·

·

Terrestrial ecosystems: This ecosystem is related to land and the type of vegetation. Eg: forest, grassland and desert. Aquatic ecosystems: This ecosystem is related to water. It is further classified into two types based on salt content. a) Fresh water ecosystem: Running water ecosystem. Eg: River, streams. Standing water ecosystem: Eg: Pond, lake. b) Marine ecosystem: Eg: ocean, sea or estuary.

b) Artificial Ecosystem: These are maintained by man. These are manipulated by man for different purposes, e.g., croplands, artificial lakes and reservoirs, townships and cities.

1.4

| STRUCTURAL ASPECTS OF ECOSYSTEMS

Two major structural components of ecosystem are (i) Abiotic components (ii) Biotic components i) Abiotic components Non-living components (physical and chemical) of an ecosystem collectively collectively are called abiotic components.

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Main abiotic factors of the ecosystem are include · · ·

Climatic factors: solar radiation, temperature, wind, water currents, rainfall. Physical factors: Light, fire, pressure, geomagnetism Chemical factors: Acidity, inorganic salts.

ii) Biotic components Living organisms or living members in an ecosystem form biotic components. It includes plants, animals and microorganisms present in an ecosystem. These consists of three types (a) producers, (b) consumers, and (c) decomposers or reducers (a) Producers Producers are mainly the green plants, which can synthesize their own food by the process of photosynthesis. In the presence of sunlight and chlorophyll, green plants covert covert CO2 and water into starch (food). They are also known as photo autotrophs..

Certain microorganisms produce food by the oxidation of certain chemicals in the absence of sunlight. They are known as chemosynthetic organisms or chemo-autotrophs . (b) Consumers Consumers are organisms which cannot prepare their own food but depend on producers or other organisms for food. Primary consumers or Herbivores: They feed directly on green plants. They are also known as plant eaters. Eg. rabbit, deer, sheep, insect Secondary consumers or carnivores: They feed on herbivores, hence called secondary consumers. Eg. small fish, frog. Omnivores feed on both plants and animals. Eg. humans, rat, fox, many birds. Tertiary consumers: They feed on secondary consumers Eg. big fish, snake. Detritivores (Detritus feeders or Saprotrophs): They feed on dead organisms, plant or animal matter. Eg. Earth worms, fungus, termites, ants etc (c) Decomposers Decomposers derive their nutrition by decaying dead plants and animals. They break down the complex organic molecules to simpler molecules. Eg: Various bacteria and fungi

1.5

| FUNCTION OF ECOSYSTEMS

Major functions of ecosystems are the following: (i) (ii) (iii) (iv) (v)

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Food Food chain, chain, food webs and trophic structure (Ecological (Ecological pyramids) Energy flow in ecosystem Cycling of nutrients nutrients (Biogeochemical (Biogeochemical cycles) Primary and Secondary production production Ecosystem development development and regulation

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1.5.1

Food chains, food webs and ecological pyramids

FOOD CHAIN The transfer of energy within the ecosystem (among various levels) by a sequence of eating and being eaten is known as food chain. Some common examples of simple food chains are: (i) Grass ® grasshopper ® Frog ® Snake ® Hawk (Grassland ecosystem) (ii) Phytoplanktons ® Zoo plankton ® small fish ® Large fish (Marine ecosystem)

Some features of food chain: · · ·

· · ·

Involves nutritive interaction between the various biotic components of an ecosystem. A food chain is always straight (unidirectional flow of energy). Usually 80 to 90% of potential energy is lost as heat when energy is transferred from one level to another. Shorter food chains provide greater available energy and vice-versa. Most food chains have no more than four or five links. If any of the intermediate steps in the food chain is removed, other succeeding links of food chain will be affected.

Types of food chain I. Grazing food chain: Here, green plants (primary producers) are eaten grazing animals and they are further eaten by carnivores. This type is food chain is found common in grassland ecosystem and grassland ecosystem. Eg: Grass ® Rabbit ® Fox Fox II. Detritus food chain: It starts with dead organic matter. Organic matter is broken down into simple nutrients by bacteria and fungi. Eg: Leaf litter ® algae ® crabs ® small carnivorous fish ® large carnivorous fish (Pond ecosystem) Eg: Dead organic matter ® fungi ® bacteria (Forest ecosystem) III. Parasitic food chain: In parasitic food chain, producer or consumer has parasites. These parasites extract food from them. However However,, the energy transfer through this kind of food chain is not significant.

Producer Trees

Herbivores

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Fruit eating birds

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Parasite

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Hyperparasites

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Lice and bugs

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Bacteria and fungi

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FOOD WEBS Many organisms will depend upon more than one source of food. Most consumers feed on more than one type of organism and most organism are eaten by more than one type of consumer. A network of food chains which are interconnected is called food web. This is also called the ‘web of life’ as it shows many interrelationships in nature.

Significance of food chain and food web ·

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Food chain/web explains the feeding relationships and interaction between organisms in any ecosystem. To understand the energy flow mechanism and matter circulation in ecosystems. To track movement of toxic substances and the problem of ‘Biological magnification’ in the ecosystem. To analyse the link between biological diversity and stability of an ecosystem.

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Food Chains and Food Webs- A Comparison

Food Chain

Food Web

1. Simple structure

1. Quite complex structure

2. Unidirectional

2. Multi directional

3. N um umber of organisms are less

3. N um umber of organisms are large.

4. Food chain is a single strand of different levels of energy transfers.

4. Food web web will show many food chains in a particular ecosystem

Ecological Pyramids Ecological pyramid is a graphic representation of trophic levels and functions of an ecosystem. Ecosystem characteristics such as number, energy and biomass show a regular decrease as it moves to next trophic level and the figure obtained is a pyramid. Most ecological pyramids begin at the bottom with the producers and proceed through different trophic levels.

Typical ecological pyramid

Ecological pyramids are of three general types as under: (i) Pyramid Pyram id of numbers: It shows the number of individual organisms at each trophic levels. (ii) Pyramid of energy: It shows the rate of energy flow and/or productivity at successive trophic levels. (iii) Pyramid of biomass: It shows the total biomass present in each tropic level in the food chain.

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10 Environmental Science and Engineering

i) Pyramid of numbers Pyramids of numbers show the relationship between producers, herbivores and carnivores at successive trophic levels in terms or their numbers. Shape of the pyramid varies from ecosystem to ecosystem as the number of organisms at each level is variable. Upright, partly upright and inverted are the three types of pyramid of numbers. An aquatic ecosystem is an example of an upright pyramid where the number of organisms becomes lesser and lesser higher up the pyramid. A forest ecosystem is an example of a partially upright pyramid, as fewer producers support more primary consumers, but there are less secondary and tertiary consumers. An inverted pyramid of numbers is one where the numbers of organisms are higher on the top of the pyramid. Parasitic food chain shows inverted pyramid of number.

Pyramid of numbers in grassland ecosystem ii) Pyramid of energy Pyramid of energy represents graphically the amount of energy consumed by each tropic level. It shows the energy flow in the ecosystem. An energy pyramid is always upright. In accordance to second law of thermodynamics, no organism obtains 100% of energy from the plant or animal that it eats. Infact, there is a huge loss of energy (about 90%) in the form of heat, respiration etc. Only 10% of the energy passes on to the next higher level. Features: · Pyramid of energy is always upright and vertical. · Energy flow in different trophic levels can be easily understood with the help of an energy pyramid. · From the energy pyramid it is clear that the total energy is minimum at the highest trophic level and is maximum at the lowest trophic level. · A lot of energy is lost in the form of heat and respiration etc between energy levels.

Pyramid of energy

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iii) Pyramid of biomass Biomass is renewable organic (living) material. A pyramid of biomass is a graphical representation of the amount in biomass at different trophic levels. It is measured in grams per meter 2, or calories per meter 2. It shows the decrease in biomass in each tropical level from base to apex. There are two types of biomass pyramids: upright and inverted. An upright pyramid is one where the combined weight of the producers is larger than the combined weight of consumers. An example is a forest ecosystem. An inverted pyramid is one where the combined weight of producers is smaller than the combined weight of consumers. An example is an aquatic ecosystem.

Pyramid of biomass 1.5.2

Energy flow in the ecosystem

Energy is the most essential requirement for all living organisms. Sun is the primary source of energy. Producers convert a part of solar energy into chemical energy which is stored in plant tissues. Herbivores consume plants and a part of energy is transferred to their body. Later, secondary consumers obtain a part of this energy when they feed on primary consumers. On the death of organism, decomposers act on the dead bodies and recycle the essential nutrients. As energy flows through the food chain, lot of energy is lost at every trophic level. The loss of energy takes place through respiration, loss of energy in movement, hunting and other activities. It is estimated that nearly 90% energy is lost at every energy level. That is, the energy transferred from one trophic level to the other is only about 10% (10% law).

The flow of energy in an ecosystem is always unidirectional. This means that it flows from the producer level to the consumer level and never in the reverse direction. This flow of energy is governed by two laws of Thermodynamics. Ist law of Thermodynamics states that energy can neither be created nor be destroyed but it can be transformed from one form to another.

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IInd law of Thermodynamics states that a part of energy is lost when it is transferred from one level to another. 1.5.3

Nutrient cycles (Biogeochemical cycles)

Elements that are essential for survival of both plants and animals are called nutrients. 1. Macronutrients: Macronutrients : Elements that are required in large amounts Eg: Carbon, Oxygen, Calcium, Magnesium, Phosphorus 2. Micronutrients: Micronutrients : Elements that are needed in small amounts Eg: Zinc, Copper, Cobalt, Selenium Nutrients are always always circulated to and fro within the environment. This cyclic exchange of nutrient material between the living organisms and their non-living environment is called biogeochemical cycle. The common biogeochemical cycles are Hydrological cycle or water cycle, Carbon cycle, Oxygen cycle, Nitrogen cycle, Phosphorus cycle. Some are gaseous cycles like carbon (as carbon dioxide), oxygen, nitrogen, etc. A few are sedimentary cycles like sulphur, phosphorus, etc.

Oxygen cycle Atmospheric oxygen is the major source of oxygen (21% of air). Oxygen is taken up by plants and animals from the air during respiration. The plants return oxygen to the atmosphere during photosynthesis. So equilibrium is maintained. Oxygen Cycle and Carbon Cycle are related.

Oxygen removal: · Respiration by producers, consumers and decomposers remove oxygen from the atmosphere. · Oxygen gets removed from the atmosphere chemically by reacting with rocks and minerals exposed by weathering. · Oxygen is also removed during the formation of ozone in the upper atmosphere.

3O2

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2O3

Oxygen supply: · Oxygen is released into the atmosphere during photosynthesis.

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Oxygen is formed in the atmosphere during the decomposition of ozone 2O3 ® 3O2

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Nitrogen cycle Nitrogen is present in the atmosphere as N2 (78% volume) which acts as the reservoir of nitrogen. Atmospheric nitrogen cannot be used by plants and animals directly. It has to converted to salts like nitrates or ammonium for absorption. This is known as nitrogen fixation. This happens by the physical process of lightening or biologically by some bacteria and/or cyanobacteria (blue green algae). Nitrogen compounds are used for the biosynthesis of amino acids, proteins, vitamins etc. and passes through the food chain. When the organism dies, the organic nitrogen in dead tissues are decomposed by ammonifying and nitrifying bacteria which convert them into ammonia, nitrites and nitrates, which are again used by plants. Certain bacteria convert nitrates into molecular nitrogen.

Various steps in nitrogen cycle Atmospheric nitrogen fixation by lightning : Due to high temperature developed due to lightning, nitrogen to combine with oxygen in the air forming oxides of nitrogen. These dissolve in rain water, forming nitrates reaching earth. Biological nitrogen fixation by certain microbes: Certain micro organisms converts atmospheric nitrogen into ammonia by using enzyme nitrogenase. This is known as biological nitrogen fixation. Eg: Rhizobium and Nitrogen-fixing c yano bacteria Industrial Fixation: Use of nitrogen rich fertilizers Ammonification: Bacteria, or fungi, convert the organic nitrogen (dead remains of organisms) into ammonium (NH 4+). Eg: Bacillus Nitrification: Biological oxidation of ammonia with oxygen into nitrite (NO 2 – ) followed by the oxidation of these nitrites into nitrates (NO3 – ). Eg: Nitrobactor Denitrification: Denitrification is the reduction of nitrates back into nitrogen gas (N 2) by bacteria. Eg: Pseudomonas and clostridium.

1.5.4

Ecosystem productivity

Primary production Primary productivity of an ecosystem is defined as the rate at which incident solar energy is converted into food (starch) by photosynthesis. To a lesser extend primary production can happen in the absence of sunlight by chemosynthesis.

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Secondary production The amount of food stored by the consumers is known as secondary production. A part of this energy stored is transmitted to the next trophic level. 1.5.5

Ecological succession

Ecological succession is defined as the orderly changes that happens in a community structure and function over a period of time. Quite often it is observed that one type of community is totally replaced by another over a period of time. In other words, a community evolves slowly from a simple community to a much complex community. The community which established first is known as pioneer community. The communities which are transitory and undergoing changes are known as Seral stages or seres. The final and mature community established at the end is known as climax community .

Types of ecological succession Primary succession: It involves involves the gradual establishment of biotic communities on a lifeless ground. a) Hydrach: Establishment starts in a water body like pond or lake. This type of succession begins with the formation of colonies of phytoplankton. phytoplankton. b) Xerach: Establishment starts in dry area where soil is devoid of water and minerals. Usually this begins with the formation of lichen on the surface of rocks. Secondary succession: This involves the establishment of biotic communities in an area, where some type of biotic community is already present. Process of Succession The process of succession takes place in a systematic order of steps as follows: (i) Nudation: It is the formation of a bare area without any life form. This bare area may be created due to landslides, volcanic eruption, overgrazing, agricultural/ industrial activities etc. (ii) Invasion: Nudation is followed by invasion. It is the successful establishment of one or more species on a bare area. Seeds, spores etc are carried by wind, water, insects or birds. These seeds germinate and small s mall plants begin to grow. grow. Slowly, Slowly, these pioneer species increase in number and form groups. (iii) Competition: Competition results when the number of individuals increases. Competition can be between different species or within the same species. Competition happens for space, water and nutrition. Survival of the fittest takes place. (iv) Reaction: Due to the influence of the environment, some modification in the existing species will be created. The available resources are suitable for certain species and unsuitable for some other species. This reaction will result in the replacement of some species by another leading to several seral communities. (v) Stabilization: This is also known as the climax where the final stable community is formed. It may take several years to attain a stable community.

Importance of ecological sucession ·

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It provides information, how smaller community develop into a climax community. Growth rate of one or more species can be suitably checked by adjusting various environmental parameters. It helps in afforestation and forest management programs.

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1.6

| MAJOR ECOSYSTEM TYPES

The major types of ecosystem are a) Terrestrial ecosystem: ecosyst em: This is an ecosystem found only on landforms. Example: Forest, grassland, desert ecosystem. b) Aquatic ecosystem: It is an ecosystem in a body of water. Example: Fresh water ecosystem (pond, lake, stream, river etc), marine ecosystem (estuartine, ocean etc) 1.6.1

Forest ecosystem

Forest ecosystem predominantly consists of trees, along with herbs, shrubs, creepers, mosses, lichens, bacteria etc. Wide variety of animals and birds are also seen. Depending upon the prevailing climatic conditions forests can be of various types a) Tropical Rain Forests: Forests: They are evergreen forests found near the equator (tropics). These forests are found in areas which are characterized by high temperature, high humidity and high rainfall. b) Tropical Tropical deciduous forests: These forests are found a little away from the equator and are characterized by a warm climate the year round. Different types of deciduous trees are found here, which lose their leaves during dry season. c) Tropical scrub forests: They are found in areas where the dry season is even longer. Here there are small deciduous trees and shrubs. d) T Temperate emperate rain forests: They are found in temperate areas with adequate rainfall. These are dominated by coniferous trees like pines, firs, redwoods etc. e) Temperate Temperate deciduous forests: They are found in areas with moderate temperatures.

1. Abiotic components (Non-Living Components) Abiotic components of forest eco system include basic inorganic and organic compounds of the environment or habitat of the organism. a) Inorganic Components: Inorganic components of an ecosystem are carbon dioxide, oxygen, water, nitrogen, calcium etc. Most of them are involved in matter cycles (biogeochemical cycles). b) Organic Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids, amino acids etc. All of these are synthesized by the biota (flora and fauna) of an ecosystem and are reached back to ecosystem as their wastes, dead remains, etc. c) Other physical factors: Climate, temperature, light, soil etc., are other abiotic components of the eco-system.

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2. Biotic Substances (Living Components) Components) a) Producers Producers include green plants like herbs, shrubs and trees. They prepare food (starch) from water and CO2 in presence of sunlight and chlorophyll. Nature and number of plants associated may vary according to the location. Examples: Grass, trees etc. b) Consumers A) Herbivores (plant eaters): Herbivores feed directly on producers and hence also known as primary consumers. Examples: rabbit, deer, squirrel, insects. B) Carnivores (meat eaters): They feed on other herbivores. If they feed on herbivores they are known as secondary consumers. Example: frog, fox. If they feed on other secondary consumers they are known as tertiary consumers. Example: snake, lion, tiger. c) Decomposers Decomposers break down complex compounds present in dead tissues of producers and consumers into simple substances. These simple compounds can be easily consumed by green plants. Example: earthworms, bacteria, fungi etc. 1.6.2

Grassland ecosystem

In Grassland ecosystem, the vegetation is dominated by grasses. Grasslands are distributed all over the globe. It occupies 20% of earth’s surface. Grasslands often occur in areas with annual precipitation between 60 cm and 150 cm and average mean annual temperatures ranges from −5 and 20°C. Tropical grassland in Africa: Savannah. Temperate grassland: US and Canada – Prairies, South America – Pampas, Africa – Velds, Europe and Asia – Steppes.

1. Abiotic components (Non-Living Components) Abiotic components of grassland ecosystem include basic inorganic and organic compounds of the environment or habitat of the organism. (a) Inorganic Components: Inorganic components of an ecosystem are oxygen, carbon dioxide, water, nitrogen, calcium, phosphate etc. (b) Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids and amino acids. (c) Phyical factors: Climate, temperature, sunlight, soil etc. form other abiotic components of the eco-system.

2. Biotic components (Living Components) a) Producers Primary producers are herbs and shrubs. Isolated trees are also found. They prepare food (starch) from water and CO2 in presence of sunlight and chlorophyll. Food production is much less when compared to a forest ecosystem. b) Consumers A) Herbivores (plant eaters): Herbivores feed directly on producers and hence also known as primary consumers. They include small insects, deer, rabbit, hare etc. B) Carnivores (meat eaters): Carnivores feed on other herbivores. If they feed on herbivores they are known as secondary consumers. These are lizards, snakes, fox, jackal etc. Tertiary consumers like eagles, vultures are also found in grasslands.

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c) Decomposers Decomposers break down complex organic compounds present in the dead organisms to simple substances which are easily absorbed by green plants. Decomposers include earthworms, bacteria, fungi etc. A typical grassland food chain:

Grass (producer) 1.6.3

Rabbit (herbivore)

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Jackal (carnivore)

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Desert ecosystem

A desert biome is one that receives less than 25 cm of annual precipitation. Nearly a third of the earth’s surface (land) are covered by deserts Deserts are classified into two. a) Hot and dry: Temperature exhibit daily extreme because. Days are too hot and nights are cold. Example: Sahara. b) Cold: Cold deserts are covered in snow or ice. Example: Antartica

1. Abiotic Substances (Non-Living Components) Abiotic substances of desert eco system include basic inorganic and organic compounds of the environment or habitat of the organism. (a) Inorganic Components: The inorganic components of an ecosystem are oxygen, carbon dioxide, water, nitrogen, calcium, phosphate etc. (b) Organic Components: The organic components of an ecosystem are proteins, carbohydrates; lipids and amino acids. However, organic content is much lesser when compared to any other ecosystem. (c) Phyical factors: Climate, temperature, light, soil etc., are other abiotic components of the eco-system.

2. Biotic Substances (Living Components) a) Producers Plants seen in the desert include date palms, cacti, thorn acacia, bushes etc. Xerophytic plants like cacti store water in stems and have extended root system to get less water available. In many desert plants, leaves are reduced to spines to reduce loss of water by transpiration. They prepare food (starch) from water and CO2 in presence of sunlight and chlorophyll. Desert ecosystem has low productivity. b) Consumers A) Herbivores (plant eaters): They feed directly on producers and hence also known as primary consumers. They include small mammals like kangaroo rat, ground squirrels, squirrels , certain insects and Arabian camels. B) Carnivores (meat eaters): They feed on other herbivores. If they feed on herbivores they are known as secondary consumers. These are lizards, snakes like rattle snake, mongoose, tarantula and scorpions. Some animals eat both plants and animals. These are called omnivores. Some are called scavengers as they feed on dead animals. c) Decomposers Decomposers break down complex organic compounds present in the dead organisms to simple substances. which are easily absorbed by green plants. Decomposers include earthworms, bacteria, fungi etc. Very few decomposers are found due to poor vegetation. A typical desert food chain:

Date palm (producer)

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Kangaroo rats (herbivore)

Sandy cat (carnivore).

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1.6.4

Pond ecosystem

Ponds are shallow water bodies (depth~12-15 feet). Sunlight rays can penetrate to the bottom of the pond permitting the growth of plants there. Pond ecosystem is standing (lentic, not flowing) fresh water ecosystem where various organisms dependent on each other in water environment for their nutrients and survival. Ponds may be seasonal in nature i.e. receiving enough water during rainy season and devoid of water in summer. The functional components of a pond ecosystem

1. Abiotic components (Non-Living Components) Abiotic substances of pond ecosystem include basic inorganic and organic compounds of the environment or habitat of the organism. (a) Inorganic Components: Inorganic components of pond ecosystem are oxygen, carbon dioxide, water, nitrogen, salts etc. (b) Organic Components: Organic components of pond ecosystem ar e proteins, carbohydrates; lipids and amino acids. (c) Phyical factors: Climate, temperature, sunlight, soil etc., are other abiotic components of pond ecosystem.

2. Biotic components (Living Components) a) Producers Producers are of two types · ·

larger rooted and floating vegetations together termed macrophytes microscopic floating algae called phytoplanktons .

Phytoplanktons are available upto the depth of water where light penetrates. Example: filamentous alga like Ulothrix, Spirogyra, Oscillatoria and minute floating plants like Microcystis. Macrophytes include plants like lotus, hydrilla etc. b) Consumers Consumers of pond ecosystem are heterotrophs which depend for their nutrition on other organisms. Zooplanktons are the primary consumers which feed on phytoplankton. Insects, beetles, small fishes form secondary consumers as they feed on zooplanktons. Snakes, big fishes form tertiary consumers. c) Decomposers Most of the decomposers of pond ecosystem are saprophytes but some parasites are also found. Bacteria, fungi are decomposers. Generally the decomposers either live in the soil layer beneath water or in the mud. They act on dead and decayed organic matter of plants and animals and supply nutrients to the producers. A typical pond food chain:

Phytoplankton (producer)

1.6.5

Zooplankton (herbivore) Snake (carnivore).

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Small fish

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Big fish

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Lake Ecosystem

Lake is a much larger fresh water body when compared to pond. Depending upon the depth and distance from the shore, lake consists of four different zones. 1. Littoral zone: The littoral zone is the part of the lake closest to the shore. It is a shallow water zone where light penetrates to the bottom and supporting rooted plants and bottomdwelling animals.

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2. Limnetic zone: This is the zone next to littoral zone where moderate light penetration takes place. Photosynthesis mainly occur in this zone. 3. Profundal zone: This is the zone where sunlight doesn’t reach. It is dark and cold. Photosynthesis does not occur here. 4. Benthic zone: The bottom most part of the lake is benthic zone. This zone provides many nutrients to the plants because it has large volume of sediments and it contains many nutrients. Here light penetration is negligible.

The functional components of a lake ecosystem

1. Abiotic Substances (Non-Living Components) Abiotic substances of lake ecosystem include basic inorganic and organic compounds of the environment or habitat of the organism. (a) Inorganic Components: Inorganic components of an ecosystem are oxygen, carbon dioxide, water, nitrogen, salts etc. (b) Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids and amino acids. (c) Phyical factors: Climate, temperature, sunlight, soil etc., are other abiotic components of the ecosystem.

2. Biotic Substances (Living Components) Components) a) Producers Producers are of two types · ·

larger rooted and floating vegetations together termed macrophytes microscopic floating algae called phytoplanktons .

Phytoplanktons are available upto the depth of water where light penetrates. Eg: filamentous alga like Ulothrix, Spirogyra, Oscillatoria and minute floating plants like Microcystis. Macro phytes include plants like lotus, hydrilla etc. Floating plants are characterized by light hollow stem, wax coated leaves. b) Consumers Consumers of pond (lake) ecosystem are heterotrophs which depend for their nutrition on other organisms. Zooplanktons form primary consumers which feed on phytoplankton. Nectic animals like insects, beetles, small fishes form secondary consumers as they feed on zooplanktons. Benthic animals like snakes, big fishes live on nectic animals and are termed tertiary consumers. c) Decomposers Bacteria, fungi are major decomposers. Generally the decomposers either live in the soil layer beneath water or in the mud. They act on dead and decayed decayed organic matter of plants and animals and supply nutrients to the producers. A typical lake food chain:

Phytoplankton Phytoplankton (producer) ® Zooplankton (herbivore) ® Small fish ® Big fish ® Snake (carniv (car nivore). ore). 1.6.6

River or stream ecosystem

River or stream is an example of running water fresh water ecosystem. River is a much larger fresh water body when compared to stream. Due to continuous flow of water, dissolved oxygen content is more. The functional components of a river/stream ecosystem

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1. Abiotic componets (Non-Living Components) Abiotic components of river ecosystem include basic inorganic and organic compounds of the environment or habitat of the organism. (a) Inorganic Components: Inorganic components of an ecosystem are oxygen, carbon dioxide, water, nitrogen, salts etc. (b) Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids and amino acids. (c) Phyical factors: Climate, temperature, sunlight, soil, rock etc., are other abiotic components of the ecosystem.

2. Biotic Substances (Living Components) Components) a) Producers Producers are responsible for photosynthesis. These include phytoplanktons, algae, water grass, aquatic mosses etc. b) Consumers Consumers of river ecosystem are heterotrophs which depend for their nutrition on other organisms. Zooplanktons form primary consumers which feed on phytoplankton. Nectic animals like insects, beetles, small fishes form secondary consumers as they feed on zooplanktons. Benthic animals like snakes, big fishes live on nectic animals and are termed tertiary consumers. c) Decomposers Bacteria, fungi are major decomposers. Generally the decomposers either live in the soil layer beneath water or in the mud. They act on dead and decayed decayed organic matter of plants and animals and supply nutrients to the producers. A typical river food chain:

Phytoplankton Phytoplankton (producer) ® Zooplankton (herbivore) ® Small fish ® Big fish ® Snake (carniv (car nivore). ore). 1.6.7

Marine (ocean) ecosystem

Ocean covers nearly two third of the earth’s surface. Ocean environment is characterized by its high concentration of salts and minerals. Variety of plants and animals are seen in marine ecosystem. Based on the depth it can be classified into two 1. Pelagic (Open sea): This is upper part of the sea. They include most of the phytoplanktons. Zooplanktons, small fishes etc are also seen in this region. 2. Benthic Benthic (Deep sea): This refers to the lower most and bottom part of the sea.

The functional components of a marine ecosystem

1. Abiotic componets (Non-Living Components) Abiotic components of river ecosystem include basic inorganic and organic compounds of the environment or habitat of the organism. (a) Inorganic Components: Inorganic components of an ecosystem are oxygen, carbon dioxide, water, nitrogen, salts etc. (b) Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids and amino acids. (c) Phyical factors: Climate, temperature, sunlight, soil, rock etc., are other abiotic components of the ecosystem.

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2. Biotic Substances (Living Components) Components) a) Producers Producers are responsible for photosynthesis. These include phytoplanktons (diatoms), algae, water grass, sea weeds, aquatic mosses etc. b) Consumers Consumers of marine ecosystem are heterotrophs which depend for their nutrition on other organisms. Zooplanktons form primary consumers which feed on phytoplankton. Crabs, small fishes form secondary consumers as they feed on zooplanktons. Snakes, sharks feed on fishes and are termed tertiary consumers. c) Decomposers Decomposers decompose dead organic matter. Bacteria, fungi are major decomposers. Generally the decomposers either live in the soil layer beneath water or in the mud. They act on dead and decayed organic matter of plants and animals and supply nutrients to the producers. A typical marine food chain:

Phytoplankton (producer) 1.6.8

Zooplankton (herbivore)

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Small fish

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Shark (carnivore)

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Estuarine ecosystem

An estuary is formed where freshwater from rivers and streams flows into the ocean. In an estuary, seawater is appreciably diluted. Estuary may be considered as a transitional zone between fresh water and marine water. Estuary is rich in biodiversity. The functional components of an estuarine ecosystem

1. Abiotic componets (Non-Living Components) Abiotic components of an estuarine ecosystem include basic inorganic and organic compounds of the environment or habitat of the organism. (a) Inorganic Components: Inorganic components of an ecosystem are oxygen, carbon dioxide, water, nitrogen, salts etc. (b) Organic Components: Organic components of an ecosystem are proteins, carbohydrates; lipids and amino acids. (c) Phyical factors: Climate, temperature, sunlight, soil, rock etc., are other abiotic components of the ecosystem.

2. Biotic Substances (Living Components) Components) a) Producers Producers are responsible for photosynthesis. These include phytoplanktons (diatoms), algae, water grass, sea weeds, aquatic mosses etc. b) Consumers Consumers of marine ecosystem are heterotrophs which depend for their nutrition on other organisms. Zooplanktons form primary consumers which feed on phytoplankton. Crabs, small fishes form secondary consumers as they feed on zooplanktons. c) Decomposers Decomposers decompose dead organic matter. Bacteria, fungi are major decomposers. They act on dead and decayed organic matter of plants and animals and supply nutrients to the producers. A typical estuarine food chain:

Phytoplankton (producer)

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Zooplankton (herbivore)

Small fish

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crabs (carnivore)

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1.7

| BIODIVERSITY

Biodiversity is the diversity among various life forms. It is a measure of the variety in flora and fauna present in various ecosystems. Biodiversity can refer to genetic variation, ecosystem variation, or species variation. Thus, the variety and variability of life on earth is known as biodiversity.

1.8

| LEVELS (TYPES) OF BIODIVERSITY

Biodiversity is generally classified into three types. These three levels results in the complexity of life on earth.

1. Genetic diversity Genetic diversity refers to the variation of genes present within the species. Genes are responsible for both the similarities and differences between the organisms. Example: Dog: pug, bull dog, Dalmatian, Alsatian etc. Tiger: Royal Bengal tiger, Siberian tiger, White tiger etc. Elephant: Indian elephant and African elephant. Mango: Malgova, Alphonso, Banganapalle Rice: Basmathi, Jaya, IR8

2. Species diversity: Species is a group or class of animals or plants which have some common characteristics which distinguish it from other groups or species. Species diversity refers to the variation among species in a community. Example: Plant species: Apple, mango, orange, wheat, rice etc. Animal species: Lion, cow, deer, cat etc.

There are approximately 1.8 million different species classified on Earth. Of these nearly 1 million are insects. Every year, approximately 13,000 more species are being discovered.

3. Community or Ecosystem Diversity: Ecosystem diversity is the variation in the biological communities in an ecosystem. There is a variation in the structure and functions among different ecosystems. Example: Forest ecosystem and pond ecosystem are quite diverse.

1.9

| VALUES (IMPORTANCE) OF BIODIVERSITY

Biodiversity has great values in terms of its commercial utility, ecological services, social and aesthetic values. The values of biodiversity is classified into two categories, namely 1. Direct values 2. Indirect values

1. Direct values These are the uses that can be directly related to biodiversity. The two types of direct values are a) Consumptive use values b) Productive use values

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a) Consumptive use values The products due to biodiversity is consumed directly. Example: Food, fuel, drug etc. Food: A variety of plants are consumed by human beings as food. Example: Rice, wheat, fruits, pulses etc Drugs and medicine: Drug Penicillin is obtained from Penicillium fungi, Quinine, drug for malaria is obtained from plant cinchona, Anticancer drug Vinblastine is obtained from plant periwinkle. Ayurveda uses many medicinal plants as drugs. Fuel: Wood is widely used as fuel in many rural areas. High consumptive use values on resources may lead to deforestation, loss of biodiversity etc. b) Productive use values Productive value refers to products which are commercially harvested or used and sold in a market. These products may be derived from plants or animals. Animal products

Animal product

Animal/Insect

Wool

Sheep

Musk

Musk deer

Honey

Honey bee

Silk

Silk worm

Many industries directly dependent upon biodiversity products. Plant products

Plant product

Industry

Wood

Paper and pulp industry, plywood industry etc

Cotton

Textile industry

Frui ruits, ve vegetables

Food in industry stry

2. Indirect values Indirect values involve the functions performed by biodiversity which are not of any direct use. It has many types like a) Social values c) Aesthetic values e) Ecosystem service values

b) Ethical values d) Optional values f) Genetic value

a) Social values Social values of biodiversity refer to the manner in which the bio-resources are used by the society. Social value tends to vary from country to country as well as among cultures. These are values associated with the social, religion, spiritual aspects of life. Some plants and animals are considered holy. · · ·

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Holy plants: Tulsi, lotus, Peepal, Neem etc Holy animals: Cow, snake, peacock Holy river: Ganga, Cauveri, Pamba

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b) Ethical values Biodiversity lies in the understanding that humans are part of nature and one among the other species. It involves ethical issues like “All life must be preserved”. Other animals must be allowed to live on earth irrespective of whether a species may or may not be useful. The very existence of different species in nature gives pleasure. c) Aesthetic values The beauty of the nature has aesthetic values. Most important aesthetic value of biodiversity is eco-tourism. Eco-tourism facilitates the enjoyment of nature. It also generate many forms of income and employment in the tourism sector. d) Optional values It is quite possible that many of the values of biodiversity are still unexplored. Optional values include the potentials of biodiversity that are presently unknown and need to be explored. These could be useful in future. It is quite possible that we may have potential cure for many diseases like cancer, ebola, AIDS in the depths of sea or in a tropical rain forest. e) Ecosystem service value value Ecosystems serve all living things in variety of ways. These comes ecosystem service value. It include, ·

·

·

· · ·

Air Purification: Trees helps purifying air by absorbing greenhouse gases. During photosynthesis, trees absorb CO2, releasing O2, thus purifying the air. flow. It helps to replenish water table Protection of water: Trees regulates and stabilizes water flow. and helps to increase water yield and quality: Example: coastal wet lands and mangroves. Soil formatting and protection: Trees helps in the maintenance of soil quality. It also helps to prevent soil erosion. Nutrient cycling: Cycling of nutrients in the ecosystem Food production: Production of food for all life forms. Climate control: Forest plays an important role in checking global warming and hence regulating the climate

f) Genetic value Some ecosystems like rain forests are abundant in variety of flora and fauna. It can act as genetic reservoirs from which seed and other materials can be obtained. Biodiversity can be used as a “gene pool” for producing disease resistant, high yielding varieties. Greater the diversity among flora and fauna, greater is the diversity in “gene pool”.

1.10

| CLASSIFICATION OF SPECIES

Conservation status of a species indicates whether the species still exists and how likely the species is to disappear in the near future. Species are classified as follows. ·

·

·

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Extinct species: A species is said to be extinct when it is not seen in the wild for 50 years at a stretch. Example: Dodo, passenger pigeon, dinosaur, mammoth, saber-toothed tiger. Endangered species: A species is said to be endangered when the number has been reduced to a critical level or whose habitats have been drastically reduced. They can become extinct when not protected and conserved. Example: Giant panda, Indian elephant, Royal Bengal Tiger. Critically endangered species: These are species which face extremely high risk of extinction in immediate future. Example: Asiatic Cheetah

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Few endangered species of India

Species

Examples

Reptiles

Green sea turtle, Tortoise, Tortoise, Python

Birds

Peacock, Great Indian Hornbill, Pelican, Siberian White Crane

Carnivorous mammals

Indian wolf, red fox, royal Bengal tiger, lion, red panda, leopard, leopard, striped hyena, desert cat

Primates

Capped monkey, golden monkey, nilgiri langur, hoolock gibbon

Plants

Many species of orchids

Endemic species: Species which are restricted to a particular area is called as endemic species. Example: Nilgiri Tahr, Lion tailed macque. Endemic flora in India: Sapria himalayana, Uvaria lurida, Nepenthes Khasiana, Pedicularis perroter etc Endemic fauna: Lion-tailed macque, Nilgiri leaf monkey, Brown palm civet, Nilgiri Tahr Keystone Species: Species or set of species whose impact on its community or ecosystem is much larger and more influential are termed as keystone species. Extinction of keystone species may lead to the extinction of many other forms of life. Keystone species help to support the ecosystem (entire community of life) of which they are a part. In the African savanna (grassland), elephants are the key stone species as they shape their environment. They destroy trees, making room for the grass species. Without elephants, much of the savannah would turn into woodland or forest. Beaver, starfish are other examples. Indicator Species: Species that serve as early warnings of damage to a community or ecosystem. They are very sensitive and quickly respond to environmental change and are considered as biological indicators. They give early indications that a habitat is suffering. Indicator species are first to react to external influences such as water pollution, air pollution, or climate change. Example: Presence or absence of trout (a kind of fish) species in water indicates the quality of water. Stoneflies indicate high dissolved oxygen in water. Native species: Species that are normally seen in a particular ecosystem. Species, which are native to particular area. Exotic or alien Species: Species that migrate or accidentally introduced into an ecosystem by human beings.

1.11

| HOT SPOTS OF BIODIVERSITY

Hot spots are areas that are rich in endemic species and containing high diversity of species which are under threat. Key criteria for determining Hot Spots are: · Presence of large number of endemic species. The region should contain 0.5% of plant endemic species. · Degree of threat which is measured in terms of habitat loss (70% loss)

Around the world, at least 35 areas qualify under this definition. Two are present in India, namely the Eastern Himalayas and Western Ghats .

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1.11.1

Eastern Himalayas

Eastern Himalayas is the region comprising northeastern India, Nepal and Bhutan. This region have very high mountain ranges, which include Mount Everest and K2, two biggest mountain peaks in the world. Plants and animals are found even in high altitudes.

Biodiversity: Plants: Of the estimated 10,000 species of plants in the Himalaya hotspot, about 3,160 are endemic. Many rare plant species are found even in the highest reaches of the Himalayan mountains. Large number of rare orchids are found in this region. Birds: Nearly 1000 birds are found in this region, but only 15 are endemic. Mammals: Nearly a dozen mammals are found to be endemic. Endemic species include golden langur, the Himalayan tahr and Namadapha flying squirrel. Reptiles and amphibians: Of 175 reptiles recorded, only 50 are endemic. Among 105 amphibians known, more than 40 of which are endemic. 1.11.2

The Western Ghats

Western Ghats is a long mountain range running through the west coast of India. It covers the states of Kerala, Tamil Nadu, Karnataka, Goa, Maharastra and Gujarat extending upto 1600 kms length. Western Ghats is considered as one of the top ten global biodiversity hot-spots. Due to their proximity to the ocean they receive high rainfall. These regions have moist deciduous forest and rain forest. The region shows high species diversity as well as high levels of endemism. The vegetation in this hotspot originally extended over two lakh square kms. Currently, its been reduced to just 43,000 sq. km.

Biodiversity: Plants: Western Ghats covers about five percent of India’s land but nearly 30% of plant species (4,000 of 15,000 species) are found here. Nearly 1,800 of these are endemic to the region. Major part of the world’s world’s spices such as black pepper and cardamom are found in the Western Ghats. Birds: The Western Ghats has over 450 species of birds (35% endemic). Mammals: The Western Ghats has over 140 species of mammals (around 20% endemic). Reptiles: The Western Ghats has over 260 species of reptiles (over 60% endemic).

1.12

| RED LIST OF THREATENED SPECIES (RED DATA BOOK)

Red Data Book is a state document established for documenting rare and endangered and threatened species of animals and plants. International Union for Conservation of Nature and Natural Resources (IUCN) publishes list. The main objectives are · Identification and documentation of endangered species · Create awareness about the importance of threatened biodiversity · Defining conservation priorities and guiding conservation action

Species are classified by the IUCN Red List into nine groups according to rate of decline, population size, area of geographic distribution etc. · ·

·

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Extinct (EX): No known individuals remaining. Extinct in the wild (EW): Known only to survive in captivity like zoo etc. No animals found free in wild. Critically endangered (CR): Extremely high risk of extinction in the wild.

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Environment, Ecosystems and Biodiversity 27 · · · · · ·

Endangered (EN): High risk of extinction in the wild. Vulnerable (VU): High risk of endangerment in the wild. Near threatened (NT): Likely to become endangered in the near future. Least concern (LC): Lowest or no risk. Data deficient (DD): Not enough data to make an assessment of its risk of extinction. Not evaluated (NE): Has not yet been evaluated against the criteria.

1.13

| INDIA AS A MEGA DIVERSITY NATION

India is one of the 12 mega biodiversity countries in the world. India is divided into 10 biogeographic regions. Diverse physical features and climatic situations have resulted in formation of forests, grasslands, deserts, wetlands, coastal and marine ecosystems. It is estimated that India ranks 10th among the plant rich countries of the world, 11 th in terms of number of endemic species of higher vertebrates and 6 th among the centers of diversity and origin of agricultural crops. Species

Mammals

Number

Rank in the world

350

8

1,200

8

453

5

Plants

45,000

15

Ferns

1,022

Orchids

1,082

Insects

50,000

Butterflies and moths

13,000

Birds Reptiles

It is estimated that the number of unknown species could be several times higher. Out of a total of 35 biodiversity hot-spots in the world, India possesses two, one in the north-east Himalaya region and one in the western ghats.

Reasons for India as a mega-diversity nation 1. Endemism Species which are restricted only to a particular area are known as endemic. These species are not found anywhere else. Unique climate and geographic features of a certain region make many species endemic. India shows a good number of endemic species. About 4,900 species of flowering plants are endemic to the country. About 62% amphibians are endemic to India. Western ghats are the site of maximum endemism 2. Centre of origin Many species are known to have originated in India. Nearly 500 species of flowering plants have their origin in India. Nearly 166 species of crop plants and 320 species of wild relatives of cultivated crops originated in India. 3. Marine diversity 7500 km long coastline of our country exhibits a rich biodiversity. Mangroves, coral reefs back waters etc, are found along the coastline. Different types of fishes, amphibians, mollusks, crustaceans are also found.

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4. Hot spots of biodiversity Areas which exhibit high species richness as well as high species endemism are termed as hot spots of biodiversity. There are 35 such hot spots of biodiversity in the world out of which two are present in India, namely the Eastern Himalayas and Western Ghats

1.14

| BIOGEOGRAPHICAL CLASSIFICATION OF INDIA

India is seventh largest country in the world and Asia’s second largest country. Though India accounts to only 2 % of the total landmass of the world, it accounts for about 7% of the total species in the world. Biogeography refers to the study of distribution, evolution, dispersal and environmental relationship of plants and animals. Biogeographic classification of India is the division of India according to biogeographic characteristics. There are ten biogeographic zones in India. Each zone has its own characteristic climate, soil, topography and biodiversity. The ten biogeographic zones of India are 1. Trans–Himalayan rans–Hima layan region: The Himalayan ranges immediately north of the Great Himalayan range are called the Trans- Himalayas. The Trans-Himalayan region has sparse vegetation. A variety of wild sheep and goat community is found here. Plants: Pine, Deodar Animals: Snow leopard, black-necked crane. 2. The Himalayan region: The Himalayas consist of the youngest and high altitude, steep mountain chains in the world. Rich temperate flora is present. The forests are very dense with tall trees. Plants: Oak, chestnut, pine, deodar. Animals: Wild sheep, mountain goats, panda and snow leopard. 3. The Indian desert: This region consists of parts of Rajasthan, Kutch, and parts of Gujarat. The climate is very hot during summer and cold during winter. Annual rainfall is less than 70 cms. The plants are mostly xerophytes. Plants: Date palm, cactus, Babul, wild palm. Animals: Camels, wild asses, foxes, mice, desert cat and snakes. Indian Bustard, a highly endangered bird is also found here. 4. The semi arid region: region: Semi-arid regions are found near the desert. It is a transitional zone between the desert and the denser forests of the Western Ghats. The natural vegetation is thorn forest. Vegetation is generally discontinuous. Plants: Thorny scrubs, grasses, bamboos, xerophytic herbs etc. Animals: Birds, jackals, leopards, lion, eagles, snakes, fox, buffaloes etc. 5. The Western Ghats: Western Ghats is a 1600 km long mountain range running through the west coast of India. It covers the states of Kerala, Tamil Nadu, Karnataka, Goa, Maharastra and Gujarat. The mountains rise to average altitudes between 900 and 1500 m above sea level. Plants: Rubber, tea, coffee, pepper etc Animals: Monkey, elephant, deer etc 6. The Deccan peninsula: peninsul a: Beyond the Western Ghats is Deccan Plateau. It is a semi-arid region lying in the rain shadow of the Western Ghats. This is the largest unit of the Peninsular Plateau of India. Different types of forests are found here. Plants: Teak, Neem, Banyan etc Animals: Monkey, tiger, elephant, deer etc

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7. The Gangetic plain: In the north is the Gangetic plain extending up to the Himalayan foothills. This is the largest unit of the Great Plain of India named after the main river Ganga. Plants: Teak, sal, Banyan etc. Animals: Rhinoceros, Deer, Rabbit, Alligator 8. The coastal region: India has a coastline extending over 5,500 km. Larger parts of the coastal plains are covered covered by fertile soils on which different crops are grown. Plants: Coconut trees, Banana, Bamboo etc. Animals: Turtle, Dolphin, crabs etc 9. The north-east north-ea st region: It comprises the contiguous Seven Sister States (Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura), plus the Himalayan state of Sikkim. North-east India has one of the richest flora in the country. Plants: Bamboo, several species of orchids etc. Animals: Elephant, Rhinoceros etc. 10. The Indian islands: The two groups of islands, i.e., Lakshadweep in the Arabian Sea and Andaman-Nicobar islands in Bay of Bengal differ significantly in origin and physical characteristics. Plants: Coconut, Cashew nut Animals: Dolphin, Alligator

Biogeographical classification of India

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1.15

| THREATS TO BIODIVERSITY

Due to rapid increase in human population, the demand for food, shelter, energy, raw materials also increased. Deforestation resulted in the extinction of species. It is estimated that every year nearly 10000 species becomes extinct. Extinction of species results in the loss of biodiversity.

Factors leading to loss of biodiversity 1. Destruction of Habitats: Destruction and loss of natural habitat is the major reason for biodiversity loss. Due to deforestation animals are deprived of shelter and food. 2. Habitat Fragmentation: Sometimes the loss of habitat occurs slowly in instalments as it is is divided into small and scattered patches. This is known as habitat fragmentation. Some wild animals like bears and large cats need large territories to live and fluorish. Habitat fragmentation affects their population as they breed only in the interiors of the forests. 3. Disturbance and pollution: Man made activities such as air/water pollution, eutrophication etc affects biodiversity adversely. Increase in acidity of water bodies due to acid rain may result in the death of fishes and other aquatic organisms. Forest fire can result in habitat destruction and death of animals. Soil pollution due to the use of pesticides kills bacteria and insects. 4. Introduction of exotic species: species : Exotic species are new species entering a geographical region. They alter the habitat and natives cannot survive. Exotic species may kill or eat native species to the point of extinction. Disease causing microorganism if introduced may cause epidemic and eliminate the native species completely. Example: Water hyacinth is exotic species which was introduced from South America. Excessive growth of this resulted in clogging of rivers and lakes. It even threatens the survival of fishes and many aquatic species in India. 5. Hunting and over exploitation: exploitatio n: Man hunts wild animals for food, safety and pleasure which can result in extinction of species. Example: Disappearance of dodo. Over fishing is depleting marine and fresh water living resources. Many species of fishes, sea turtles, sea cows and whales are facing extinction. 6. Poaching: Killing of wild animals for illegal trading of wildlife products is called poaching. Despite international ban, products from endangered species, smuggling of wildlife items like furs, horns, tusks and herbal products are still going on. Animal products of commercial value include ivory, horn, teeth and bone. 7. Man wildlife Conflicts: Sometimes wild animals like elephant, lion and tiger may come out from their natural habitat and cause damage to life and property of humans. Conflicts between man and wild animals are called man- wildlife conflict. It is estimated that every year in our country around 300 people die due to animal attack. These attacks are common in places where human settlement is closer to forest areas.

Reasons for man-wild life conflict · · · ·

·

·

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Habitat loss: Loss of habitat forces the animal to move out of forests Human encroachment: Humans occupy animal habitat, leaving animals want of space. Disease: Ill, weak and sick animals attack humans for self protection. Shortage of food and water during summer: Severe summer may result in shortage of water and food. So animals enter human settlements in search of food and water. Electric fencing: Very often farmers put electric fencing around farm lands. Elephants and other animals may get injured, suffer in pain and turn violent. Protection: Females of many animals attack to secure their babies.

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Remedial measures to curb man-animal conflict · · ·

Ensure that adequate food and water is available for wild animals within the forest zones. Developmental and constructional work in and around forest region must be stopped. More space should be provided for protected area (National parks, bio reserves etc).

1.16

| CONSERVATION OF BIODIVERSITY

Biodiversity has so many uses (genetic, commercial, cultural, medical and esthetic) associated with it, hence it is worth protecting. Conservation of biodiversity refers to the protection, preservation, management, or restoration of plants and animals. Conservation of biodiversity can be achieved in two ways conservation situ conservation

·

In situ

·

Ex

1.16.1

In situ Conservation

conservation refers to the conservation of plants and animals in their own natural habitat where they survive. Example: Biosphere reserve, National parks, Wildlife Sanctuaries etc. The aim of in situ conservation situ conservation is to maintain biodiversity within the natural habitat where it is found. Plants are allowed to grow and develop as a part of their natural habitat.

In situ

National Parks A national park is an area dedicated for the conservation of wildlife along with its environment. It is also meant for enjoyment of tourism without harming environment. Activities such as cultivation, grazing, cutting etc are not allowed. Private ownership right and manipulation of habitat not allowed. Each national park aims to conserve one or more special species along with others. There are more than 150 national parks in India. India’s first national park was established in 1936, now known as Jim Corbett National Park, Uttarakhand. Some Important National Parks in India

National park

Animal preserved

Bandipur National Park, Karnataka

Tiger

Gir Forest National Park, Gujarat

Lion

Jim Corbett National Park, Uttarakhand

Bengal Tiger

Mudumalai National park Tamilnadu

Elephant, Bengal Tiger

Kaziranga National Park, Assam

One hor ned Rhino

Periyar National park

Elephant, Bengal Tiger

Wild life Sanctuaries Wildlife sanctuaries are also protected areas where killing, hunting, shooting or capturing of wildlife is prohibited. However, private ownership rights are permissible. Here, forestry operations are also permitted to a limited extent as long as it doesn’t affect the wildlife adversely. India has 515 Wildlife sanctuaries.

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32 Environmental Science and Engineering Some Important Wild life Sanctuaries in India

Wild life Sanctuaries Sanctuari es

Animal preserved

Vedanthangal Bird Sanctuary, TamilNadu

Water birds

Pulicat Lake Bird Sanctuary, Tamilnadu

Water birds

Indian wild ass Sanctuar y, Gujarat

Indian wild ass

Cauvery Wildlife Sanctuary, Sanctuary, Karnataka

Elephant, Spotted deer etc

Ranganthittu Bird Sanctuary, Sanctuary, Karnataka

Water birds

Sathyamangalam Sathyamangalam Wildlife Sanctuary and Tiger Reserve, Tamilnadu

Elephant, Tiger

Biosphere reserves A special category of protected areas where in people are an integrated part of the environment for long-term conservation. Area is much larger when compared to national park and wild life sanctuary. Protection is granted for flora, fauna and to the human communities who inhabit these regions and their ways of life. Within biosphere we can have one or more national parks. There are 18 biosphere reserves in India. Some Important biosphere reserves in India

Name

States

Nilgiri Biosphere Reserve

Tamil Nadu, Kerala, Karnataka

Gulf of Mannar Biosphere Reserve

Tamil Nadu

Sundarbans Biosphere Reserve

West Bengal

Nanda Devi Biosphere Reserve

Uttarakhand

Nicobar Islands

Andaman and Nicobar Islands

Roles of biosphere reserves Each biosphere reserve has three basic functions. · ·

·

Conservation of Biodiversity by conservation of ecosystems, species and genetic variation. Promoting Sustainable Development by assisting economic and human development which is socio-culturally and ecologically sustainable. Support for Logistics by supporting research, monitoring, education and information exchange.

Advantages of · ·

in situ conservation

It is cheap and convenient method. Species gets adjusted to the natural habitat and can lead a free “unmonitored” life.

Disadvantages of · ·


Large area is required. Maintenance of habitat is not proper due to shortage of staff and pollution.

1.16.2

Ex situ Conservation

Ex situ situ conservation include conservation of plant and animal species outside the habitat. The species are provided their habitat artificially. Threatened animals and plants are taken out from

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their natural habitat and kept in a place where they can be protected and given special care. Example: Gene banks, Botanical Gardens, Zoos, Genetic resource centers,

Methods of Ex-Situ Conservation Long Term Captive breeding Zoo’s and botanical Gardens are vital in preserving critically endangered species. Animals are bred in captivity. captivity. Special care and attention is given to their offsprings produced. Short Term propagation and release Rare species are bred in captivity and released into their natural habitat later. This will help to increase the number of animals in the wild. Example: Eggs of turtles are protected and helped to hatch. Young turtles are set into the sea. Cryo-preservation Seeds, pollen, gametes and embryos of endangered species are stored in liquid nitrogen at tem perature as low as –196°C. Tissue culture Tissue culture is the growth of tissues or cells outside the organism. Cells or tissues are collected from a donor and transferred into a semi-solid, or solid growth medium, such as broth or agar. Tissues multiply to give large number of tissues. Tissue culture can be employed for the culture of both plant and animal cells. By artificial insemination Breeding of the captive species can be done by artifical insemination. In this method healthy semen is collected from a male animal and is then injected to a female for breeding. Cloning Cloning is the process used to create an exact genetic replica of another cell, tissue or organism. The copied material, which has the same genetic characteristics as the original, is referred to as a clone. The most famous clone was a Scottish sheep named Dolly. There are three different types of cloning: · · ·

Gene cloning, which creates copies of genes or segments of DNA Reproductive cloning, which creates copies of whole animals Therapeutic cloning, which creates embryonic stem cells. Scientists use these cells to grow healthy tissue to replace injured or diseased tissues.

Seed banks and Gene banks Seeds and genetic resources of different strains of commercially important plants can be stored for long periods in seed banks Important Gene/Seed banks in India National Bureau of Plant Genetic Resources Res ources (NBPGR), New Delhi: Agricultural and horticultural crops are preserved by cryo- preservation National Bureau of Animal Genetic Resources (NBAGR), Haryana: Preserves the semen of domesticated bovine animals: National Facility for Plant Tissue Culture Repository (NFPTCR), New Delhi: Conservation of varieties of crop/plants/trees by tissue. Advantages of ·

·

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ex situ conservation

Survival of endangered species is increasing due to special care and attention. Some endangered species do not have any chance of survival if left free in nature. In captive breeding, animals are assured of food, water, shelter and security. Hence longer life span for animals.

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Disadvantages of · · · ·

ex situ conservation

It is an expensive method. Freedom of widelife is lost. Many captive animals struggle to survive when left free in natural environment. It can be adopted for only few species.

ANNA UNIVERSITY QUESTIONS 1. Define ecosystem. Give an account of structure and function of an ecosystem. (Anna Univ, Dec 2013) 2. With a neat sketch discuss nitrogen cycle

(Anna Univ, Dec 2014)

3. Explain the structure and functions of a grassland ecosystem. 4. Explain the structure and functions of a pond ecosystem. 5. Briefly explain the energy flow in the ecosystem. 6. Write a note on various hazards present in the environment. 7. With a neat sketch discuss oxygen cycle. 8. What is biodiversity? Discuss the values and significance of biodiversity. (Anna Univ, Dec 2014) 9. What do you mean by hotspots of biodiversity that extend in India? (Anna Univ, Dec 2014) 10. What do you mean by conservation of biodiversity? State and explain basic approaches to (Anna Univ, Dec 2014) wildlife conservation 11. What are the threats to biodiversity? 12. India is a mega biodiversity nation. Justify the statement. 13. Write a note on endangered and endemic species in India.

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Unit

2

POLLUTION

SYLLABUS Definition – causes, effects and control measures of: (a) Air pollution (Atmospheric chemistry- Chemical composition of the atmosphere; Chemical and photochemical reactions in the atmosphere - formation of smog, PAN, acid rain, oxygen and ozone chemistry;- Mitigation procedures- Control of particulate and gaseous emission, Control of SO2, NOX, CO and HC) (b) Water pollution: Physical and chemical properties of terrestrial and marine water and their environmental significance; Water quality parameters – physical, chemical and biological; absorption of heavy metals - Water treatment processes. (c) Soil pollution - soil waste management: causes, effects and control measures of municipal solid wastes – (d) Marine pollution (e) Noise pollution (f) Thermal pollution (g) Nuclear hazards–role of an individual in prevention prevention of pollution – pollution case studies – Field study of local polluted site – Urban / Rural / Industrial / Agricultural.

2.1

| INTRODUCTION

Environmental pollution can be defined as any undesirable change in the physical, chemical or biological characteristics of any component of the environment (air, water, soil), which can cause harmful effects on various forms of life or property. The material that causes pollution is called pollutant. One has to distinguish between pollutant and a contaminant in this context. Contaminant is a substance that is normally not present; but it need not cause harm to living beings. All pollutants are contaminants but all contaminants need not be pollutants. For example CO 2 is often classified as a contaminant rather pollutant as it does not cause any adverse health effects. On the other hand CO is termed as a pollutant as it can cause lot health complications. From an ecological perspective pollutants can be classified as follows: Biodegradable Biodegradable or non-persistent pollutants: These pollutants are biodegradable and can be easily broken down down by natural natural biological processes. Example: domestic sewage, discarded vegetables, etc Non-degradable Non-degradable pollutants: These are the pollutants, which decompose very slowly by the natural processes. Example: inorganic salts, metallic oxides, aluminium cans, DDT. On the basis of the form in which they persist in the environment, pollutants can be categorized under two types: Primary pollutants: These are substances which are emitted directly from some identifiable sources and remain in that form. Examples are

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Sulphur compounds: SO2 produced by the oxidation of fuel. Carbon compounds: Oxides of carbon (CO+CO2) and hydrocarbons. Nitrogen compounds: NO2 and NH3 Halogen compounds: Hydrogen fluoride (HF) and hydrochloric acid (HCl). Particulate matter: Soot Secondary pollutants: The secondary pollutants are produced from primary pollutants. Primary pollutants undergo chemical chemical reaction in the environment environment to become secondary secondary pollutant. Example: Smoke, a primary pollutant combines with fog to form hazardous smog. SO 3 is formed by the oxidation of SO 2.

2.2

| ATMOSPHERE

Atmosphere is a gaseous envelope surrounding the planet which is held together by Earth’s gravity. Earth’s atmosphere is over 100 kilometers thick, but major part of it is within 16 km from the surface. Pressure exerted by atmosphere is known as atmospheric pressure. At sea level, atmospheric pressure is about 1 kilogram per square centimeter.

Functions of atmosphere · · ·

· ·

Blocking harmful rays: Harmful ultra violet radiation from the sun is blocked by ozone layer, which is a part of our atmosphere. Source of Oxygen and Carbondioxide: Atmosphere acts a source for both oxygen and carbondioxide which is essential for respiration and photosynthesis. Maintenance of earth’s temperature: Atmosphere cause heat retention and keep earth surface warm. In the absence of atmosphere the temperature of earth would be sub zero in the night. Saving earth from meteors: Most meteoroids that enter the Earth’s atmosphere vaporize completely due to high temperature and friction and never reach the planet’s surface. Climate and weather: Earth gets heated non-uniformly by the sun resulting in different weather patterns. Air Air sets in motion resulting in winds causing cyclones, monsoon, rainfall etc.

Average composition of the atmosphere up to an altitude of 25 km.

Gas Name

Chemical Formula

Percent Volume

Nitrogen

N2

78.08%

Oxygen

O2

20.95%

Argon

Ar

0.93%

CO2

0.0360% (can vary)

Neon

Ne

0.0018%

Helium

He

0.0005%

Carbon Dioxide

2.2.1

Atmosphere layers

Atmosphere becomes thinner and thinner as we go higher. There is no distinct boundary between the atmosphere and space. An imaginary line called Karman line, represents the boundary between the Earth’s Earth’s atmosphere and outer space. It lies approximately 100 kilometers from earth’s surface. Earth’s Earth’s atmosphere is divided into five main layers according to their temperature characterisctics:

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Pollution 37 · · · · ·

Troposphere Stratosphere Mesosphere Thermosphere Exosphere

1. Troposphere Troposphere is the bottom layer of the atmosphere which is closest to Earth’s surface. It extends to an average height of 12 km (over the poles, 8 km; above the equator, 16 km). Temperature decreases with height in this layer. The rate of decrease of temperature with height is called, lapse rate. Average Average lapse rate in troposphere is –6.5° C / km. Troposphere ends at tropopause . On reaching tropopause, temperature stops decreasing with height. 2. Stratosphere Stratosphere is the second layer. It starts above the troposphere and extends to about 50 km above ground. Ozone layer is found in stratosphere and it absorbs harmful radiation from the sun. In this layer, temperature increases with height; just opposite to that in troposphere. The air is about a thousand times thinner here than it is at sea level. Thin air, absence of vertical winds and clouds helps smooth travel of jet planes. Stratospehere end at stratopause, where temperature neither decreases nor increases with height up to some level.

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3. Mesosphere Mesosphere starts at 50 km and extends to 85 km. In this layer, temperature decreases with height as in troposphere. This layer plays crucial role in radio communication. Sunlight passing through this layer causes molecules to ionize. These ionized particles reflects radio waves sent from earth. The top of the mesosphere, called the mesopause. At mesopause, the average tem perature is about minus 90°C. 4. Thermosphere Thermosphere extends from about 90 km to 1,000 km. Temperatures can get up to 1,500°C at this altitude. The density of air is very low. 5. Exosphere Exosphere is the outermost layer of the atmosphere. It is extremely thin and merges into outer space. It is composed of very widely dispersed particles of hydrogen and helium. Satellites orbits the earth in exosphere. 2.2.2

Chemical and photochemical reactions in the atmosphere

Atmosphere is a dynamic system with wide fluctuations of the parameters (composition, temperature, humidity and intensity of sunlight). So, different processes will be observed under different atmospheric conditions. Many chemical and physical processes take place in the atmosphere. Some of them occur naturally while others occur due to human interventions. The study of chemical reactions in the atmosphere is difficult due to a) very low concentrations involved b) low pressure c) high temperature d) high altitude. These reactions cannot be easily simulated in the laboratory and the detection and analysis of the reaction products extremely difficult. Chemical reactions in the atmosphere can occur · ·

as collisions between molecules in gas phase on the surfaces of solid particles (particulate matter) or in aqueous solution (in water droplets).

In gas phase reactions, the molecules are far apart. Therefore, some reactive species can exist for significantly longer time before reacting. The reactions that take place in water droplets are mostly acid-base reactions. Reactions on particle surfaces are of less importance because of the short residence time particles spend in the atmosphere.

2.3

| OXYGEN AND OZONE CHEMISTRY

Ozone layer is a layer in earth’s atmosphere containing relatively high concentration of ozone (O3). Ozone layer is found in the lower part of the stratosphere from approximately 20 to 30 kilometres above earth. The ozone layer is often referred to as the “umbrella of life” because it protects life on Earth from harmful UV rays. The Dobson Unit is the most common unit for measuring ozone concentration. One Dobson Unit is the number of molecules of ozone that would be required to create a layer of pure ozone 0.01 mm thick at a temperature of 0° C and a pressure of 1 atmosphere. Over the Earth’s surface, the ozone layer’s layer’s average thickness is about 300 Dobson Units or a layer that is 3 millimeters thick.

Ozone formation Ozone in the stratosphere is produced by photochemical reactions involving O 2. When molecular oxygen in the stratosphere absorbs ultraviolet radiation with wavelengths less than 240 nm, it breaks apart into two oxygen atoms. O2 + hn

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® 2

O (light of

l <240

nm)

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Pollution 39

These oxygen atoms formed combine with O 2 molecules to form ozone in the presence of a third body M. O + O2 + M (N2 or O2)

®

O3 + M

The third body M absorbs the excess energy liberated by the above reaction and there by stabilizes the O3 molecule.

Decomposition of ozone Ozone absorbs ultraviolet radiation with longer wavelengths (~290 nm and above). It causes the ozone to decompose into O2 molecules and oxygen atoms. O3 + hn

®

O2 + O (light of

l >290

nm)

There is a dynamic equilibrium between ozone formation and destruction. Ozone strongly absorbs uv light in the region of 220-290 nm and protects the life on earth from severe radiation damage. Only a strong fraction of uv light reaches the lower atmosphere and earth. Process of ozone production and destruction, destr uction, initiated by ultraviolet ultraviolet radiation, are often refer red to as Chapman Reactions. There is equilibrium between the formation and destruction of ozone. This equilibrium is disturbed by reactive atoms of chlorine, bromine etc. which destroy ozone molecules and result is thinning of ozone layer generally called ozone hole.

Causes for ozone hole formation Choloroflurocarbons: Major reason for the depletion of ozone layer is halogen atoms (F, Cl, Br) which are formed by the photochemical decomposition of CFC’s. CFC is an organic compound that contains only carbon, chlorine, hydrogen and fluorine. CFC’s are widely used as coolants in refrigeration systems and air conditioners, propellants for aerosols due to low boiling point. These slowly rise up and reach stratosphere and cause depletion of ozone. The chemical reaction can be represented as

CF2Cl2 + hn Cl + O3 ClO + O

®

CF2Cl +Cl

® ClO ® Cl

+ O2

+ O2

In the third step, Cl is generated again which can cause the reaction to continue like a chain reaction. One chlorine atom can thereby destroy thousands of ozone molecules. Similarly other atoms present in CFC like Fluorine and Bromine can also cause similar effect.

Effects of Ozone Depletion Ozone depletion in the stratosphere will result in more UV radiation reaching the earth especially UV-B (290-320 nm). In humans: · The UV-B radiations affect DNA. Any change in DNA can result in mutation. · Can cause skin cancer. · Absorption of UV rays by the lens and cornea of may result in cataract. · Melanin producing cells of the epidermis will be destroyed by UV-rays resulting in immuno-suppression. In plants and animals: · Phytoplanktons are sensitive to UV radiation. Decrease in phytoplankton population inturn affects the population of zooplankton, fish, marine animals, infact the whole aquatic food chain.

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40 Environmental Science and Engineering · ·

Yield of certain crops like rice, wheat, soybean, cotton, bean, pea etc will decrease. UV radiation result in increasing the rate of evaporation through leaf stomata and decreases the moisture content of the soil. This can result in decreased crop production.

Other implications: · UV radiation can cause degradation of paints, plastics and other polymer materials. · It contributes to the Global Warming. If ozone depletion continues, the temperature around the world may rise even up to 5 degrees. Control of ozone layer depletion · Reduce/replace the usage of CFC’s: One molecule of CFC destroys more than few thousands of ozone molecules via chain reaction. So usage of CFC’s has to be discouraged and kept minimum. Use of other alternative coolants which are less damaging has to be promoted. · Reduce the use of methyl bromide: Methyl bromide is an insecticide used for fumigation. It is a source for bromine atoms which can destroy ozone. Its use has to be controlled. · Control of deforestation: Check in deforestation will ensure slightly higher percentage of oxygen in the atmosphere. · Proper maintenance: Air conditioning and refrigerating units should regularly be checked for leaks and corrected if any.

2.4

| AIR POLLUTION

par ticulate matter, or biological materials that cause Air pollution is the introduction of chemicals, particulate harm or discomfort to humans or other living organisms, or cause damage to the environment. These substances include gases, particulate matter, radioactive substances etc. 2.4.1

Sources of air pollution

1. Natural sources: Forest fire and volcanic eruption can lead to air pollution. Hydrocarbons emitted by decomposition of organic matter can lead to air pollution. Pollen grains are also a pollutant. 2. Anthropogenic sources (human activity): Main reason for air pollution is human activities. a. Burning of fossil fossil fuels: Burning of fossil fuels such as petrol, diesel, coal etc leads to serious air pollution. Thermal power plants used for generating electricity emit fly ash and SO 2. b. Emissions from automobiles: Vehicles are mainly responsible for more than 80% of total air pollution. The major pollutants found in automobile exhaust are CO, NO x, SOx etc. c. Industrial emissions: Factories, petroleum refineries, fertilizer plants, and steel industries, thermal power plants are the main sources of air pollution. They add various harmful gases like CO, SO3, NO, Hydrocarbons etc., to the atmosphere. d. Agricultural Activities: Spraying of insecticides and pesticides also cause air pollution. 2.4.2

Common air pollutants

(i) Carbon dioxide: Low concentrations of CO2 are not harmful. A high concentration of CO2 can displace oxygen in the lungs. Less oxygen availability can result in rapid breathing, rapid heart rate, emotional upsets and fatigue. Lack of oxygen can result in permanent damage to organs including the brain and heart. CO 2 is the major gas that cause green house effect. (ii) Carbon monoxide: CO is a very poisonous gas and is produced by incomplete combustion of fuel. CO, being a very strong ligand, binds strongly with Fe present in the hemoglobin. CO has affinity for haemoglobin 210 times more than oxygen. Thus it interferes with the oxygen carrying capacity of blood

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HbO2 + CO Oxyhemoglobin Oxyhemoglobin

(iii)

(iv)

(v) (vi)

®

HbCO + O2

carboxyhemoglobin carboxyhemoglobin

In presence of CO, hemoglobin is unable to transport oxygen to various parts of the body. body. This causes the reduction in oxygen levels in the tissues. Prolonged exposure leads to dizziness, reduced vision and even death. People who survive severe CO poisoning may suffer long-term health problems. Oxides of Nitrogen: Nitrogen: These include NO and NO2 (usually denoted by NOx), which are released by automob automobiles iles and chemic chemical al industries industries as waste waste gases gases and also by burning burning of materials. materials. These are harmful and lower the oxygen carrying capacity of blood. Oxides of nitrogen especially NO2 can irritate the lungs and cause conditions like chronic bronchitis and emphysema. Oxides of nitrogen dissolve in water forming nitric acid resulting in acid rain. Oxides of Sulphur: High concentration of SO 2 causes chlorosis (yellowing of leaves), damage to mucous membrane etc. SO 2 and SO3 react with water to form Sulphuric and sulphurous acids resulting in acid rain. Hydrocarbons: These are unburnt discharges from incomplete combustion of fuel in automobiles. Particulate Particulate Matter: Industries and automobiles release fine solid and liquid particles into the air. These are injurious to respiratory tract.

2.4.3

Effects of Air Pollution

Effect on Plants: · · · · · · ·

SO2 causes chlorosis and also results in the death of cells and tissues. Fluorides and PAN damage leafy vegetables such as lettuce and spinach. Oxides of nitrogen and fluorides result in decrease in crop productivity. Smog bleaches and blaze foliage of important leafy plants. Hydrocarbons cause premature yellowing, fall of leave and flower buds, discoloration and curling of sepals and petals. Smoke and dust cover the leaf surface and reduce photosynthetic capacity of plants. Ozone damages cereals, fruits, and cotton crop.

Effect on Man: Effect of pollutants on animals and man are as follows ·

·

· · · ·

Ozone: Breathing ozone can result in a variety of health problems including chest pain, coughing, throat irritation etc. It can worsen bronchitis and asthma. Ground level ozone also can reduce lung function and can cause inflammation of the linings of the lungs. SO2: SO 2 causes drying of mouth, scratchy throat, irritates the nose and eyes and disorders of respiratory tract. It also cause coughing, wheezing, shortness of breath, or a tight feeling around the chest. NOx: Short or long term exposure to oxides of nitrogen can cause severe respiratory illness, aggravate asthma and cause lung malfunction. CO: CO diffuses into blood stream and reduces oxygen transport. CO damages cardiovascular cardiovascular system. Prolonged exposure leads to dizziness, reduced vision and even death. Hydrocarbons: Hydrocarbons can act as carcinogens and lead to different cancers. Suspended particles (Particulate matter): These can aggravate bronchitis and asthma. Prolonged exposure can lead to reduced lung function.

Effects on aquatic life: Air pollutants like oxides of nitrogen and sulphur, dissolve in rain water resulting in acid rain. High acidity (lower pH) in fresh water lakes affects aquatic organisms. Some of the freshwater lakes have experienced total fish death.

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Effects on materials: Air pollutants can cause damage to exposed surfaces. Presence of SO 2 and moisture can accelerate corrosion of metallic surfaces. SO2 can affect fabric, leather, paint, paper, marble and limestone. Ozone in the atmosphere can cause cracking of rubber tyres. Oxides of nitrogen can also cause fading of cotton and rayon fibres. 2.4.4

Control of Air Pollution

Air pollution can be minimized by the following methods: · · · · · · ·

2.5

Afforestation and controlling deforestation: Trees should be planted on the roadside, riverbanks, parks and’ open places as they can act as “pollution moderators”. Law enforcement: Pollution control laws should be enforced strictly. Constant monitoring of industrial/automobile exhaust must be carried out. Use of low sulfur coal: Using low sulphur coal in industries or removing sulphur from coal can considerably reduce air pollution. Using non-conventional sources of energy: Use of eco-friendly energy sources like solar energy, wind energy can reduce air pollution. Increasing the height of chimneys: The height of chimneys can be increased to the highest possible level so that pollutants are emitted to higher levels. Removal of particulate matter: Particles larger than 50 mm are separated in gravity settling tanks. Using cyclone collectors or electrostatic precipitators separates fine particles. Checking vehicular pollution: Pollution by vehicles can be minimized by regular tuneup of engines; replacement of more polluting old vehicles; installing catalytic converters.

| SMOG

Smog is a kind of air pollution. The word ‘ Smog ’ is derived from smoke and fog. When smoke is combined with the fog present in the atmosphere the smog is formed.

Smog = Smoke + Fog Types of Smog i) London smog: London smog usually occurs during early morning hours. Coal containing large amounts of sulfur, produce SO2 on burning which can result in smog. The main constituent of London-type smog is soot, fly ash, sulfur dioxide, sodium chloride and calcium sulfate particles. If concentrations are high enough, sulfur dioxide produces sulfuric acid. Due to the presence of reducing impurities it is known as reducing smog. Health problems: SO2 can severely affect respiratory system. Higher amounts of SO2 can even lead to death. Great smog of London in 1952 caused death of more than 4000 people. Smog -related deaths were primarily attributed to pneumonia, bronchitis, tuberculosis, and heart failure. ii) Los Angeles smog (Photochemical smog): Los Angeles smog usually happens in noon, as the reactions forming smog are triggered by sunlight. It was first reported in the city of Los Angeles and hence the name. It is mainly composed of ozone, volatile hydrocarbons (VOC), Peroxy acetyl nitrate (PAN), nitrogen dioxide etc. Since it contains oxidizing impurities it is also known as oxidizing fog.

NO2 + Sunlight

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® NO

+O.

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Pollution 43

O2 +O.

®

O3

O3 +NO ® O2 + NO2 Nitrogen dioxide (NO2) can also react with oxygen, hydrocarbons (unburnt petrol) or radicals produced from volatile organic compounds in the presence of sunlight to form toxic products such as peroxyacetyl nitrates (PAN) (CH3CO-OO-NO2):

It is also formed by the reaction of aldehydes and hydroxyl radicals.

PAN is relatively stable molecule and have long lifetimes in cooler air. Because of this, it may travel long distances. In warmer climates, it may break down and release toxic NO 2, which produces additional ozone and hydroxyl radicals. In this way way, PAN can be considered as a reservoir of NOx species. Problems associated with PAN: · · · ·

PAN is a highly potent oxidant that is both toxic and irritating. It causes eye irritations at very low concentrations (even in ppb levels). It also irritates the respiratory system. PAN can cause impaired breathing or lung lesions following inhalation exposure in animals. PAN inhibits efficiency of photosynthesis in plants. PAN is more toxic to plants than ozone. It causes discoloration of leaves. PAN also reduces the plant’s ability to store food, grow and reproduce. These plants are more vulnerable to attacks by pests and diseases.

Health problems caused by photochemical smog: Ozone has the ability to oxidize and destroy lung tissue. Short term exposures to elevated levels of ozone (above 75 ppm) can lead to coughing, wheezing, difficulty in breathing etc. Prolonged exposure to smog can cause a permanent reduction in lung function, elevate the risk of developing asthma. A comparison of London smog and photochemical smog

Name

Ch

t

London smog (New York smog, s mog, grey smog) s mog)

Photochemical smog (L.A. smog, Denver smog, brown smog)

Weather

It occurs early mornings.

It occurs during mid day (noon)

Content

Particulates, Sulfur oxides

NOx, ozone, PAN, hydrocarbons.

Sources

Burning coal.

Gasoline, combustion. (primarily from automobile exhaust)

Nature

Reducing in nature

Oxidizing in nature

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2.6

| ACID RAIN

Acid rain is rain or any other form of precipitation that is unusually acidic (pH below 5.6). Acid rain literally means ‘the presence of excessive acids in rain waters’. Acid rain can be wet or dry. Natural rain water has a pH of 5.6 at 20°C due to dissolution of CO2 in water(carbonic acid). Any precipitation less than pH 5.6 can be considered acidic. Typical acid rain has a pH value of 4 or lower. Acid precipitation is a mixture of strong mineral acids sulphuric acid (H 2SO4), nitric acid (HNO3) and in some locations, hydrochloric acid (HCl). Causes: i) Oxides of Nitrogen: Oxides of nitrogen, represented by NOx is mainly responsible for acid rain. Automobile exhaust, factory emission contains large amounts of NO2. It is also emitted by natural processes like lightning, volcanic eruptions, forest fires, and action of bacteria in the soil. Nitrogen dioxide (NO2) reacts with water to form nitrous acid (HNO2) and nitric acid (HNO3) 2NO2 + H2O ® HNO2 + HNO3 ii) Oxides of sulphur: Oxides of Sulphur (SO 2 and SO3 represented as SOx) are produced when fossil fuels containing sulphur are burnt. Small amounts are found in automobile exhaust. Large amounts of these gases are produced while processing of crude oil, in utility factories, and iron and steel factories. SO 2 is also produced naturally by volcanic activity.

Sulfur dioxide reacts with water to form sulfurous acid (H2SO3) SO2 + H2O

®

H2SO3

Sulfur dioxide (SO2) can be oxidised gradually to sulfur trioxide (SO 3) 2SO2 + O2

®

2SO3

Sulfur trioxide (SO3) reacts with water to form sulfuric acid (H 2SO4) SO3 + H2O 2.6.1

®

H2SO4

Effects of acid rain

On plant life: · Loss of waxy coating on leaves: Frequent acid rain dissolves the waxy protective coating of the leaves and plants become more susceptible to disease. When leaves are damaged, the efficiency of photosynthesis is reduced drastically. · Root damage: Roots of plants are damaged by acid rain, causing the growth of the plant to be stunted, or even in its death. · Death of micro organisms: Useful microorganisms which release nutrients from decaying organic matter, into the soil are destroyed. This can result in the availability of less nutrients for the plants. · Loss of beneficial nutrients from the soil: Acid rain washes away the beneficial minerals and nutrients in soil before the plants have a chance of using them for their growth. On animal life: ·

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Heavy metal leaching: Acid rain can cause leaching of harmful mercury and aluminium salts from the soil and rocks. It is then carried into the lakes causing damage to aquatic ecosystem.

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Pollution 45 ·

·

Death of aquatic organisms: When the pH reaches 5.5, plankton, certain insects and crustaceans begin to die. At a pH of around 5.0, the fish population begins to die. Below pH 5.0, entire fish population may die. Loss of fertility: It results in the fish’s ability to maintain their calcium levels. This impairs reproduction the ability of the fish, because the eggs become too weak or brittle. This can result in killing of fish.

In humans ·

Respiratory problems: Acid rain can cause nose and eye irritation, headache, asthma and dry coughs. Acid rain can aggravate asthma.

Buildings and monuments ·

·

Deterioration of buildings: It causes deterioration of buildings especially made of marble Acid rain caused tarnishing of Taj Mahal. Dry acid deposition containing SO 2 is primarily from the exhaust of Mathura refineries. Oil refineries in Mathura emit nearly 25 tonnes of SO2 per day despite using low sulphur content coal. Deterioration of objects: Acid rain corrodes ceramic, textiles, paints, and metals. Rubber and leather deteriorate if exposed to acid rain. It damages metals and car finishes.

2.6.2 · · · ·

· ·

2.7

Control of acid rain

Use of low sulphur content coal: Coal with lower sulphur content is desirable to use in thermal plants. Replacement of coal by natural gas: Replacement of coal by natural gas would also reduce the problem substantially. Reduction of NO x and SOx emission: Emission of SO2 and NO2 from industries and power power plants should be reduced by using pollution control equipments. Strict law enforcement: Strict laws must be brought for air pollution reduction (especially emission of CO2, NO2 and SO2). Heavy fine must be imposed if accepted emission levels are crossed. Use of renewable sources of energy: Use of alternate eco friendly sources of energy can minimize pollutants and hence acid rain. Use of eco-friendly vehicles: Pollutants can be minimized by using pollution control devices like catalytic converters in vehicles. Another method is the usage of natural gas as fuel in automobiles.

| PARTICULATE POLLUTION

Particulate refers to small, light weight solid particles which are suspended in air. They differ widely in terms of particle density and particle size. Its size varies from 0.1mm to 100 mm. Small particles have large total surface area and so it carries high pollutant load. Examples of particulate pollutants include aerosols, dust, smoke, fumes, mist, fly ash, soot etc. Causes: Main cause for particulate pollution are forest fires, volcanic eruptions, debris and fly ash formed by burning fuels, automobile exhaust etc. Consequences: Particulate matter may lead to severe health problems which include · · ·

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Premature death in people with heart or lung disease Nonfatal heart attacks Irregular heartbeat

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46 Environmental Science and Engineering · · ·

2.8

Aggravated asthma Decreased lung function and Increased respiratory symptoms such as ir ritation of the airways, coughing coughing or difficulty breathing.

| AIR POLLUTION CONTROL DEVICES

There are five main categories of particulate control devices which are widely used.

i)

Gravity settling chamber

As the name implies, gravity settling chambers are employed for the removal particles from the gas stream by simply settling under the influence of gravity. This method is used only for very large particles (approximately 75 micrometers and larger). Particles having heavier density obeys Stokes law and settle at the bottom of the chamber from where it is removed.

ii) Cyclone collector Cyclone collector is a mechanical separator where centrifugal force (instead of gravitational force) is used to remove the particulate matter. Centrifugal force which is several times greater than gravitational force can be generated by a spinning gas stream. This causes particulate containing gas to change direction often and particulate matter is thrown along the tangent and finally settles. It is used after the settling chamber to collect the smaller particulate matter that could not be collected in the settling chamber. Major disadvantage is that it is very expensive.

iii) Particulate wet scrubbers In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid. The scrubbing liquid is usually sprayed so as to remove the pollutants. It is very useful in removing SO2 and other small particulate matter.

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Advantages of wet scrubbers · · ·

Wet scrubbers have the ability to handle high temperatures and moisture. Wet scrubbers can remove both gases and particulate matter. Wet scrubbers can neutralize corrosive gases.

iv) Electrostatic precipitators An electrostatic precipitator (ESP) uses non-uniform, high-voltage fields to apply large electrical charges to polluted gas particles moving through the field. The charged particles move toward an oppositely charged collection surface, where they get collected.

v) Fabric filters Fabric filters consists of fabrics that allow the passage of gas but retain and collect particulate matter on the surfaces of filter bags. The bags can be made of cotton, synthetic, or glass-fiber material in either a tube or envelope shape. Gas containing dust enter the bag house and pass through fabric bags that act as filters. Periodically, the fabric composing the filter is shaken to remove the particulate matter. They are most efficient and cost effective types of dust collectors available. More than 99% for very fine particulates can be collected and removed from the gas stream.

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2.9

| EMISSION CONTROL OF NOx, CO, HC

Use of catalytic convertors: Catalytic convertors are used in automobiles to reduce emissions of certain harmful compounds like NOx, CO and hydrocarbons. Catalyst used in a catalytic converter is a combination of platinum (Pt), palladium (Pd), and rhodium (Rh). These metals coat a ceramic honeycomb (or ceramic beads) contained within a metal casing that is attached to the exhaust pipe. Honeycomb structure of the catalytic converter’s provides maximum surface area. Due to greater surface area only less amount of catalyst has to be used.

Three-Way Catalytic Converter A three-way catalytic converter has three simultaneous tasks: · · ·

Reduction of nitrogen oxides to nitrogen and oxygen Oxidation of carbon monoxide to carbon dioxide Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water.

In the first step, the catalytic converter uses a reduction catalyst composed of Rh to reduce the NOx. As the nitrogen oxides (NO and NO 2) pass through the device, the catalyst converts these to form oxygen gas (O2) and nitrogen gas (N2). 2NO

®

N2 + O2

2NO2

®

N2 + 2O2

In the second step, an oxidative catalyst of Pt and Pd decreases emissions of carbon monoxide (CO) and unburned hydrocarbons (HC) by converting into CO 2 and water. 2CO + O2

®

2CO2

C2H4 + 3O2

®

2CO2 + 2H2O

Reducing Pollution Catalytic convertors are widely used in modern gasoline engines. They are reliable and efficient in reducing pollution. Nearly 90% of the hydrocarbons, carbon monoxide, and nitrogen oxides produced are converted into less harmful compounds. Catalytic converters are not so efficient in diesel engines which runs at lower temperature than gasoline engines. Catalytic converters work best at higher temperatures.

2.10

| Indoor Air Pollution

The most important indoor air pollutant is radon gas. Radon gas can cause lung cancer. Radon is emitted from building materials like bricks, concrete, tiles etc. Radon is also present in groundwater and natural gas and is emitted indoors while using them.

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Many houses in the developing countries use fuels like coal, dung-cakes, wood and kerosene as domestic fuel. Incomplete combustion produces the toxic gas carbon monoxide. Coal contains varying amounts of sulphur which on burning produces sulphur dioxide

2.11

| AIR POLLUTION- CASE STUDY

Air pollution is a serious problem addressed by modern society. There have been many instances where pollution affected thousands of people. 2.11.1

Bhopal gas tragedy

Bhopal gas tragedy is considered to be the world’s worst industrial disaster. Place: Bhopal, Madhya Pradesh. Date: Night of 2nd and morning of 3rd December, 1984 Company: Union Carbide India Limited (UCIL) Gas responsible: Methyl isocyanate (MIC). MIC was an intermediate used for the production of pesticide, Sevin. Toxic effects of MIC: MIC is a volatile fluid with a boiling point of about 40˚C. MIC cause irritation of mucous membrane. At higher concentrations, it cause difficulties in breathing, with pressure over over the chest and pain when inhaling. MIC also has an irritating effect on moist skin and may cause injury to the cornea of the eye. Reason for the tragedy: It is widely believed that water entered the tank where about 40 ton MIC was stored. A combination of the human error and an improper plant safety system resulted in disaster. Tragedy: During the night of 2–3 December 1984, water entered tank containing 40 tons of MIC. This started the chemical reaction which was accelerated by contaminants, high temperatures and was catalyzed by iron (stainless steel pipelines). The resulting exothermic reaction increased the temperature inside the tank to over 200°C and raised the pressure forcing about 30 tons of MIC to escape. The gases were blown in southeastern direction over Bhopal. The huge cloud of deadly gas quickly spread out from the factory and enveloped an area of over 20 square kilometers. Early morning, people living around the Union Carbide chemical factory in Bhopal woke up coughing, their eyes burning. Thousands died immediately. People were in Panic and the police instructed people to run away from the gas. This only resulted in inhaling even more gas. By morning streets of Bhopal was covered by corpses of humans and animals. Death: Four months after the tragedy, the Indian government reported to its parliament that 1,430 people had died. However, it is estimated that the death toll could be much higher. Many lost vision permanently. After effects: Union Carbide Chairman, CEO Warren Anderson was arrested and released on bail by the Madhya Pradesh Police in Bhopal on 7 December 1984. Legal battle is still going on between Union Carbide (now Dow Chemicals) and Indian authorities. Most of the victims and their families are yet to receive the compensation.

2.12

| WATER POLLUTION

2.12.1

Introduction

Earth is the only planet containing water. Hence it is known as “blue planet”. About 71% of the earth’s surface is covered by water, out of which only 0.014% can be used for domestic, agriculture and industrial purposes and rest is locked in oceans, polar ice caps, giant glaciers and

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rock crevices. Water is so essential part of plant and animal life that without which life cannot survive. So it is important to save, preserve and reuse water. 2.12.2

Physical and Chemical Characteristics of terrestrial and marine Environment

Physical and chemical properties of water: 1. Colour Pure water is colourless. Sometimes underground water is coloured due to humus, iron, manganese salts. 2. Taste The taste of water is due to the presence of dissolved minerals and salts. The brackish taste of water is due to the presence of excess amounts of salts like NaCl and KCl. 3. Odor Pure water is odorless. Unpleasant odor may be due to the presence of organic matter, decaying vegetation, bacteria, gases like H2S and NH3. 4. Turbidity It is due to the presence of finely divided colloidal, insoluble impurities like inorganic matter, clay, silica, silt etc. 5. Specific heat Water has a high specific heat. So, it can absorb large amounts of heat energy before it begins to get hot. Environmental significance High specific heat means that water releases heat energy slowly when it cools. Water’s high specific heat allows for the stabilization of the Earth’s climate and helps organisms regulate their body temperature more effectively. 6. pH Water in pure state has a neutral pH. As a result, pure water is neither acidic nor basic. pH of water changes when salts or gases are dissolved in it. Rain has a naturally acidic pH of about 5.6 because it contains dissolved CO2 and SO2. 7. Surface tension Water has a high surface tension. This makes water drops spherical. It also causes water to stick to the sides of vessels. Environmental significance Water’s high surface tension allows for the formation of water droplets and waves, allows plants to move move water (and dissolved nutrients) from their roots to their leaves. Small insects walk on the surface of water due to this high surface tension. 8. Thermal properties Water has interesting thermal properties. Water contracts when heated from 0°C, its melting point, to 4°C. Water has maximum density at 4°C. It expands greatly as it freezes; as a result, ice is less dense than water and floats on it. Environmental significance In cold countries, only the top layer of the lake or river freezes. Underneath the frozen upper layer, the water remains in its liquid form and does not freeze. This thick layer of ice acts as an insulator and prevents freezing of the water below. Due to the presence of water beneath, fish and other aquatic animals are able to survive in the frozen lakes and ponds.

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2.12.3

Water quality parameters

Water quality refers to the chemical, physical, biological, and radiological characteristics of water. water. Physical tests: Colour, temperature, turbidity, suspended solids, odour and taste. Chemical tests: pH, BOD, COD Biological tests: Coliform count Parameters

Reason for analysis

Temperature

Many aquatic organisms are cold-blooded. Each species has its own optimum (best) water temperature. If the water temperature shifts too f ar from the optimum, the organism suffers. Temperature of water is influenced by: a) Color of the water. water. b) Depth of water c) Time of the year d) Volume of water e) Temperature of effluents dumped into water. water.

pH

pH is an indicator for healthy aquatic life. Any drastic change in pH can result in the death of the species. s pecies. Most fish can tolerate pH values of about 5.0 to 9.0. Cer tain organisms like mussels, clams, oysters are sensitive to acidic pH as it may cause the destruction of the CaCO 3 shell.

Turbidity

Turbidity refers to “how cloudy is water?”. Turbidity Turbidity results in scattering of light. Turbidity Turbidity may be due to organic and/or inorganic constituents. Water could be turbid due to the presence of algae. Turbidity Turbidity may cause the growth of microorganisms and hence may increase the possibility for waterborne disease.

Dissolved Oxygen (DO)

Dissolved oxygen (DO) is oxygen that is dissolved in water. water. DO level in good fishing waters is about 8 ppm. When DO levels drop below about 3.0 parts per million, most of the fishes die. A high DO level in drinking is good because it gives water a better taste. However, high DO levels speed up corrosion in water pipes.

Conductivity

The ability of water to conduct electricity is termed conductivity. conductivity. Presence of dissolved salts increases the conductivity conductivity of water. Rain water has very low conductivity conductivity (~50 µS/cm) while sea water has very high conductivity (~50,000 µS/cm). As conductivity measures the dissolved ions in water it is also commonly used as a measure of total dissolved solids.

Biochemical Oxygen Demand, BOD

BOD denotes the amount of oxygen needed by micro-organisms for oxidation of decomposable organic matter under aerobic conditions. High B.O.D. B.O.D. means that there is less of oxygen to support life and indicates organic pollution. High BOD is an indication of poor water quality. For details see section on BOD

Chemical Oxygen Demand, COD

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COD is a measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemicals such as ammonia and nitrite.

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For For details see section on COD Microbiological Total Coliform Count Faecal Coliform Count

2.12.4

Microbiological test is conducted to detect the Level of pollutions caused by living living things especially humans. These tests are based on coliform bacteria as the indicator organism. The presence of these bacteria confirms that the water has been polluted with faeces of humans or other warm-blooded animals.

Water pollution

Water pollution is the any alteration in physical, chemical or biological characteristics of water making it unsuitable for domestic and industrial purposes often causing health hazard. Sources of water pollution i) Point source: When a source of pollution can be readily identified, it is said to come from a point source. Example: Factory outlet, Power plant outlet. ii) Non point source: It is difficult to trace the origin of these water pollutants. Example: acid rain, percolation of fertilizer or pesticides into ground water. 2.12.5

Causes of water pollution

i) Domestic sewage: This includes household’s wastes like food wastes, synthetic detergents used for washing clothes and cleaning bathrooms and latrines. ii) Industrial effluents: Industrial wastes (often untreated) are discharged into the nearby rivers and other water sources. Textiles, sugar and fertilizers factories, oil refineries, drugs manufacture, rubber, and rayon fibers, the paper industries etc cause significant water pollution. iii) Agricultural sources: Extensive use of fertilizers, pesticides, herbicides result in severe water pollution. From soil these reach water causing eutrophication, biomagnification etc. iv) Thermal pollution: In power plants and nuclear power stations, water is used as coolant. Hot water produced when enters lakes or rivers raises temperature of water body, which kills fishes and other aquatic life. v) Pathogenic organisms: Sewage and domestic waste from houses contains pathogenic organisms viz., protozoa, worms-eggs and bacteria etc. This water if consumed causes jaundice, typhoid, typhoid, dysentery, dysentery, cholera, etc vi) Waste Waste heat: Discharge of waste heat from industries increases the temperature of water bodies and affects aquatic organisms. 2.12.6

Consequences of water pollution

Effects on ecosystem: Water pollution can kill many species, disrupting dis rupting the entire ecosystem. i) Ecosystem destruction: Water ii) Eutrophication: Excess of phosphates and nitrate may result in algal bloom called eutrophication . This may eventually lead to the death of the water body. iii) Loss of species: Many organisms find hard to survive in polluted environment which may lead to migration or extinction of species. Example: Acid rain severely affects mussels, oysters etc (shell made of CaCO3) vi) Biomagnification: Pesticide residues, heavy metals etc concentrate when passed through food chain or food web. web. While passing through the organisms, the concentration of pollutants gets increased, called biomagnification.

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Effects on Human Health i) Heavy metals: Compounds of mercury damages brain. Cadmium salts damages kidneys and liver. Lead compounds are known to affect the proper functioning of brain. ii) Water Water born diseases: disease s: Water pollution makes water unfit for drinking purposes. Polluted water can cause certain waterborne diseases like diarrhea, typhoid, cholera, and jaundice. iii) Other complications/diseases: Presence of excess nitrates and fluorides can cause blue baby syndrome and defects in teeth and bones called fluorosis respectively. Nitrates get reduced to nitrites in stomach which can result in stomach cancer.

Effects on animal health i) Shortage Shor tage of drinking water: Water pollution may lead to severe scarcity in drinking water for animals. This may lead to large scale death of aquatic and terrestrial animals ii) Imbalance in the ecosystem: Water pollution can lead to reduced reproduction rate, diseases, imbalances secondary food chains etc. 2.12.7

Control of water pollution

i) Water Water treatment: Domestic sewage and industrial wastes should be treated before discharging them into water bodies. ii) Minimal use of pesticides and fertilizers: Use of pesticides, insecticides and fertilizers should be done judiciously. Rapid biodegradable substitutes for pesticides should be employed. iii) Afforestation Afforestation and control control of deforestation: deforestation: Planting trees would reduce pollution by sediments, silt and mud in the river banks. iv) Cooling towers/ponds: These can be used to cool the hot water from industries before discharging into the rivers. This can control thermal pollution. v) Domestic methods: Separate ponds and tanks to be used for bathing cattle and animals. In villages, septic tanks should be made in every house. Rivers and lakes should not be used for bathing or washing as it contaminates water.

Some terminologies related with water pollution Biochemical oxygen demand (BOD) BOD is the measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria) in the oxidation of organic matter. The result is that the oxygen content of the water will be decreased. Generally, it takes 5 days to perform the BOD test. The BOD5 of natural water is calculated from the dissolved oxygen concentration, which is measured at zero time and after 5 days of incubation at 20 °C. The BOD5 can be calculated as BOD5 = D0 - D1, in which the BOD 5 is in mg/L and D0 and D1 are the dissolved oxygen concentration in mg/L at time 0 and 5 days, respectively. The difference is the dissolved oxygen used by the microorganisms in the biochemical oxidation of organic matter. Typical concentration of BOD5 for streams and rivers throughout the world are 2 to 15 mg/ L and the observed range is 2 to 65 mg/L. Chemical oxygen demand (COD) Chemical oxygen demand (COD) is a measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemicals such as Ammonia and nitrite. COD is typically determined by digesting the sample in a strong oxidizing agent under acidic conditions. This is a chemical method usually completed within few hours. KMnO4 is the oxidizing chemical and used as the oxygen source with concentrated sulfuric acid added to yield a strong acid medium. Silver sulfate is added as a catalyst and to minimize

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the interference of chloride. Mercuric sulfate is also added to inhibit interferences of metals on the oxidation of organic compounds. The COD observed in natural streams and rivers is 2 mg/L to 100 mg/L. The advantages of the COD test as compared to the BOD test are: · · ·

COD results are available much faster. The COD test oxidizes a wider range of chemical compounds. It can be standardized more easily.

COD and BOD do not necessarily measure the same types of oxygen consumption. BOD is only a measure of oxygen consumed by aquatic microorganisms to decompose or oxidize organic matter. COD refers the requirement of dissolved oxygen for the oxidation of both organic and inorganic constituents. Hence COD must be greater than BOD.

2.13

| Waste Water Treatment

Sewage is the liquid wastes from toilets, kitchens, baths etc that are disposed off through sewer. Sewage contains aerobic and anaerobic bacteria, pathogen, microorganism, chemicals etc. Domestic sewage and industrial wastes should be properly treated before these are drained in the mainstream water. The main functions of sewage treatment are the following. · · ·

Kill the pathogens Eliminate the harmful chemicals Remove the color and bad odor.

Three steps are involved in sewage treatment. · · ·

I.

Primary treatment Secondary treatment Tertiary treatment

Primary treatment:

It is used to remove suspended and floating wastes from waste water by physical and chemical methods. It involves the following steps. i. Screening: Using bar screens and mesh screens floating, suspended and coarse particles are removed by passing sewage water through it. ii. Silt Si lt and grit removal: Sand, powdered glass etc called grit are removed by slowly passing sewage water through grit chambers. Heavier sand and broken glass settles down by gravity. iii. Removal of oil and grease: Sewage water is kept in a skimming tank and compressed air is blown. Oil and grease form froath and float on the surface. It is skimmed off. iv. iv. Sedimentation Sedimentat ion process: In this process, the fine suspended particles which do not settle down by gravity are coagulated by the addition of coagulating agents like alum, FeSO 4 etc. Sedimented particles are filtered off.

Primary treatment can reduce the BOD of the incoming wastewater by 20–30% and the total suspended solids by some 50–60%.

II. Secondary treatment treatment (Biological (Biologi cal treatment): Secondary (biological) treatment removes the dissolved organic matter that escapes primary treatment. This is achieved by microbes consuming the organic matter as food, and converting

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it to carbon dioxide, water, and energy for their own growth and reproduction. Most commonly employed secondary treatment methods are activated sludge method and tricking filter method. a) Activated sludge method: Activated sludge is biologically active and has a large population of aerobic bacteria which rapidly oxidize the organic matter. Activated sludge is obtained by the aeration of the sewage in the earlier step of the treatment process. Wastewater after sedimentation is mixed with required quantity of activated sludge (containing micro organisms like algae and aerobic bacteria) in an aeration tank as shown in the figure.

The mixture is aerated by passing air through it for hours. Because of the aerobic conditions the organic matter in the sewage gets fully oxidized. After aeration, the sewage is finally passed through settling tanks to remove suspended impurities. Purified water plus sludge is sent to the tank where sludge settles down. A part of this sludge is used for the purification of fresh batch of sewage while the rest is pumped into sludge disposal tank. Purified water is pumped out and collected separately. b) Tricking filter method Trickling filter normally consists of a rock bed 1 to 3 meters in depth. The surfaces of these rocks are covered with microbial slime consisting of bacteria, protozoa, molds, algae, insect larvae etc. Sewage is sprinkled on it by means of slow rotating arms. As sewage trickles over, microorganisms present in the sewage grow on the surface of filtering media using the organic material of the sewage as food. On the completion of aerobic oxidation, the treated sewage is taken to the settling tank and sludge is removed. The advantages of this method is the ease of operation and low cost.

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III. Tertiary treatment: Both primary and secondary treatments remove most of the organic matter present in the sewage and it lowers the BOD. But this waste water still contain oxygen demanding wastes, nitrates, phosphates and toxic metal salts. These are removed removed by tertiary treatment. ·

Removal of phosphate: It is done by adding lime. Phosphates are precipitated as calcium phosphate.

3Ca(OH)2 + 2PO4 –3 ® Ca3(PO4)2 + 6OH – · · ·

Coagulation and sedimentation: Addition of alum or FeSO 4 neutralizes the charge on colloidal particles and precipitates them. Filtration: Water is then passed through bed filled with gravel, coarse sand and fine sand to remove suspended matter. Disinfection: Harmful bacteria are killed by passing Cl 2 gas, uv or ozone. Primary

Secondary Primary clarification

Aera Aerati tion on

Clar Clarif ific icat atio ion n

Sand and grit removal

Wastewater

Tertiary

Disinfection

Solids sludge

.. .. . .Cl ..Cl .. .. .. Liquid

Liquid

Effluent

Sludge 2

Activated sludge Coarse debris screen

Nutrient removal

Chlorine-{cl } or Ultraviolet light-{uv}

Sludge digesters Solids disposal

2.14

| WATER POLLUTION – CASE STUDIES

2.14.1

Minimatha diaster

Minamata disease was discovered for the first time at Minamata City, Japan, in 1956. Place: Minamatha Bay, Japan Date: In 1950’s Company: Chisso Corporation’s chemical factory Chemical responsible: Mercury compounds. Inorganic mercury salts are used as catalyst for the preparation of acetaldehyde. These compounds were drained into the bay without any treatment for many years. Gradually inorganic merucury were converted into highly toxic organic mercury species- methyl mercury, dimethyl mercury by microorganisms. This was consumed by weeds, small fishes and finally reached man. This was a classic example of biomagnification. Health issues: Symptoms of Minamata disease include numbness in the limbs, difficulty in moving the hands and legs, a narrow vision, difficulty in hearing, hand and leg tremors, and movement disorders of the eyeballs, etc. In severe cases, people could become mad or unconscious, leading to death. Animals were also severely affected. Cats became “mad” and “committed suicide”. Birds fell down from sky dead.

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2.14.2

Itai-itai disease

Itai-itai disease (ouch-ouch sickness”), was a case of mass cadmium poisoning in Toyama Prefecture, Japan, starting around 1912. Cadmium poisoning caused softening of the bones and kidney failure. This disease made bone fragile and weak, when touched caused severe pain causing the victim to say “Ouch-Ouch” and hence the name. The disease is named for the severe pains caused in the joints and spine. The mining companies were sued for the damage.

2.15

| SOIL POLLUTION

Soil is a thin covering over the land formed by weathering of rocks. It consists of a mixture of minerals, organic material, living organisms, air and water that together support the growth of plant life. Soil pollution is the presence of toxic chemicals (pollutants or contaminants) in soil which can cause health problems to living organisms or ecosystem.

Sources of Soil Pollution The major sources of soil pollution are etc produces i) Industrial Industri al Wastes: Many factories like sugar, cement, fertilizer, leather large amount of toxic solid wastes which causes severe soil pollution. Thermal power power plants generate a large quantity of “Fly ash”. Industrial sludge may contain various salts, toxic metals like mercury, lead, etc. ii) Urban Wastes: Wastes likes plastics, glasses, garbage and rubbish materials, rubber etc from houses can pollute soil. Many of these are non-biodegradable and quite toxic. iii) Agricultural practices: Fertilizers, Insecticides, fungicides, pesticides etc can accumulate in the soil. This can kill the useful microorganisms in the soil and finally enter the near by water bodies. iv) Radioactive pollutants: Radioactive fallout from nuclear dust, laboratories may contain highly radioactive radioactive materials. Isotopes of radium, uranium, thorium, strontium, iodine, caesium etc reach the soil and persist there for a long time and keep on emitting radiations. v) Biological Biological wastes: Human and animal wastes (excreta) can contaminate soil. The sewage sludge contains many pathogenic organisms, bacteria, viruses and intestinal worms which cause soil pollution.

Effects of soil pollution i) Decrease in agricultural productivity: productivity: Many waste materials like plastics, glass etc are non-biodegradable. Dumping them on land can change the pH of the soil, severely affect the fertility and hence productivity. Many of these substances are toxic for the useful micro organisms present in soil. ii) Ground water pollution: Percolation of toxic wastes causes ground water pollution. Chemicals, pesticides, pesticides, fertilizers from soil may percolate and contaminate contaminate ground-water ground-water resources. iii) Spread of diseases: Pathogens present in the wastes and excreta contaminate the soil. Housefly, mosquito etc can act as a carrier for these diseases. iv) Radiation sickness: Radioactive fallout on vegetation can cause radioisotopes toenter the food chain in the grazing animals. Some of these radioisotopes replace essential elements in the body and cause abnormalities. Example: Strontium-90 (instead of calcium) gets deposited in the bones and tissues. The bones become brittle and are prone to fracture. v) Salination of soil: Increase in the concentration of soluble salts in soil is called salination. This adversely affects the quality and productivity of soil. Excessive irrigation cause soil salinity and vegetation loss.

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Control of soil pollution i) Recycling of soild wastes: Materials like paper, glass and plastics can be recycled and reused. Metals should be recovered from scrap and disposed materials. ii) Use of eco-friendly eco-friendly agricultural agricultural methods: methods: Use of chemical fertilizers should be reduced. Biofertilizers and manures should be used. Use of pesticides can be reduced by adopting biological control of pests. ii) Proper disposal of solid wastes: Solid wastes should be properly collected and disposed off by appropriate method. iii) Production of bio-manure/bio-gas from soild wastes: Biodegradable organic waste should be used for generation of biogas. Cattle dung can be used for methane generation. Waste can be used for making compost manure.

2.16

| SOLID WASTE MANAGEMENT

Solid waste management refers to the collecting, treating, recycling and disposal of solid waste materials. Solid waste can be classified as municipal, industrial, agricultural, medical, mining waste and sewage sludge.

Sources of wastes: Waste from homes (Domestic waste): These contains discarded materials like polyethylene bags, metal cans, plastic bottles, waste paper, food waste etc. Waste from shops: This consists mainly of waste paper, packaging material, cans, bottles, plastic bags etc. Biomedical waste: This include anatomical wastes, pathological wastes, infectious wastes etc. Construction/demolition Construction/demolition waste: This include rubbles, wood, concrete etc. Industrial waste: This include packaging material, organic wastes, acids, alkalis and metals, radioactive wastes, fly ash, scrap metal, rubber, plastic, paper, glass, wood, oils, paints, tars, dyes, batteries etc.

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Classification: Biodegradable wastes: These are solid waste materials that can be degraded by micro-organisms. Example: vegetable wastes, stale food, tea leaves, egg shells etc. Non-biodegradable wastes: These are wastes that cannot be degraded by micro-organisms. Example: polyethylene bags, scrap metal, glass bottles etc.

Different steps in solid waste management are

a) Collection b) Transportation c) Storage d) Segregation e) Processing f) Disposal a) Collection: Waste from our homes is generally collected by our local authorities through regular waste collection for recycling. b) Transportation: Wastes are carried from homes to storage centre. Vehicles used for transportation of wastes shall be covered. Waste should not be left open and scattering should be prevented. c) Storage: Collected waste materials are stored properly. It should not create unhygienic and insanitary conditions around it. Wastes stored are not exposed to open atmosphere. Bins for storage of bio-degradable wastes shall be painted green, those for storage of recyclable wastes shall be printed white and those for storage of other wastes shall be printed black. d) Segregation: Collected solid wastes are separated. Some wastes are recycled. Recycling is the reprocessing of discarded materials into new useful products. Recycling occurs in three phases: a) sorting of wastes and collecting recyclables, b) creation of raw materials from recyclables, c) production of new products from raw materals. The process recycling saves money, energy and also reduces pollution. Recycling of paper will reduce cutting of trees for making fresh paper. e) Processing: Treatment methods are selected based on the composition, quantity, and form of the waste material. Treatment and disposal options are chosen according to the nature of waste.

Incineration: Incineration is the most common thermal treatment process. This method is often used when waste contain hazardous material and organic content. It is the combustion of waste in the presence of oxygen. After incineration, the wastes are converted to carbon dioxide, water vapour and ash. Incineration significantly reduces the volume of the waste, rendering it harmless and reducing transportation costs. During incineration high levels of toxic dioxins, furans, lead and cadmium may be emitted. Advantages: · · ·

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It requires minimum land It can be operated in any weather The volume of wastes are reduced to about 25%

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Disadvantages: · · ·

It is expensive to build and operate High energy requirement. Cause significant air pollution due to burning of wastes. Foul smell is also produced.

Pyrolysis and Gasification: Pyrolysis and gasification are similar processes which decompose organic waste by heating it to high temperatures. Gasification uses a low oxygen environment while pyrolysis allows no oxygen. Composting: Composting is the controlled aerobic decomposition of organic matter by the action of micro organisms and small invertebrates. Separated compostable wastes are dumped into earthen trenches and then covered with earth. Organic matter such as dead and dry leaves and twigs are decomposed by worms and insects, and is finally broken down by bacteria and fungi, to form a dark rich soil-like material called compost. This soil can be used as a manure for farms and gardens. Most widely used composting is vermicomposting-using earthworms. Sanitary landfill: Sanitary Landfills are designed to greatly gr eatly reduce or eliminate the risks that waste disposal may pose to the public health and environmental quality. In a sanitary landfill, garbage is spread out in thin layers. It is then covered with mud or clayor plastic and then compacted. Next layer of wastes is spread on top of this, followed by another layer of soil. Suitable precautions are taken so that underground water is not contaminated. When landfill is full it is covered with clay, sand, gravel and top soil to prevent seepage of water. Landfill Advantages · · ·

Segregation not required. Simple and economical. When a landfill is complete, it can be reclaimed, built on or used as parks or farming land.

Landfill Disadvantages · · · · · ·

Landfill can pollute the water, the air, and also the soil. Landfill can result in decrease in soil fertility. Improperly constructed landfill can pollute underground water. Landfill can attract animals and insects like rats, mosquitoes, cockroaches etc. Landfill can also cause sicknesses in communities. Anaerobic decomposition produces methane, a dangerous greenhouse gas.

2.17

| MARINE POLLUTION

Marine pollution is defined as the discharge of hazardous waste substances (solid or liquid) into sea water causing harm to marine organisms.

Causes of marine pollution i) Oil spillage: Most important marine pollutant is oil. Tankers transporting oil cause oil pollution. On the successful delivery of oil through sea-route, empty tankers are filled with water called ballast-water to maintain balance. The ballast-water containing residual oil is released into the sea on completion of return journey. Leakage in oil tankers, oil pipe lines also causes oil spillage. Oil spillage is also caused by refinery operations. ii) Heavy metals: Heavy metals like lead, cadmium, mercury etc can reach sea through various rivers, sediments etc. iii) Pesticides and Insecticides: Indiscriminate use of fertilizers and pesticides can lead to marine pollution. Finally these chemicals make their way into the ocean.

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iv) Other man made pollutants: Plastics and other synthetic materials are light weight and non biodegradable. Hence cause a serious threat to marine life.

Effects of marine pollution i) Oil: Oil, being lighter than water, forms a layer and floats on the surface of water. This affects the exchange of O2 and CO2 between atmosphere and sea water. The equilibrium is affected. This in turn affects phytoplankton, zooplankton, algal species, various species of invertebrates, coral reefs, fish, birds, mammals etc. Fishes die because the fish gills get laden with oil. Oil also affects water birds. Oil disrupts the insulating capacity of feathers. Death occurs due to loss of buoyancy and birds drown. ii) Heavy Heavy metals: Heavy metals like mercury, cadmium, lead etc cause severe health hazards for aquatic flora and fauna. These metals can magnify over food chain (biomagnification) iii) Pesticides Pesticides and other chemicals: Many of the chemicals are non-bio degradable and stay in water for long time. Many pesticides like DDT can cause biomagnifications. v) Plastics: Many animals like fishes, turtles consume plastic causing gastro-intestinal health problems.

Control measures of marine pollution · · · · · ·

Industrial wastes should not be discharged in coastal waters. Dumping of toxic, hazardous wastes and sewage sludge should be banned. Developmental activities on coastal areas should be minimized. Oil and grease from service stations should be processed for reuse. Oil ballast should not be dumped into sea. Ecologically sensitive coastal areas should be protected by not allowing drilling.

2.18

| NOISE POLLUTION

Noise pollution is excessive, displeasing, unwanted and undesirable sound that disrupts the activity or balance of human or animal life. Noise is undesirable and unwanted sound. Not all sound is noise. What may be considered as music to one person may be noise to another. Unlike other pollutants noise does not accumulate in the environment. Sound is measured in a unit called the ‘Decibel’. Ordinary conversation has a noise value of 60 decibels. If loudness exceeds 80 decibels, it can cause noise pollution. Noise becomes troublesome above 140 decibels.

Sources of Noise Pollution i) Transport/Traffic: ranspor t/Traffic: One of the main sources of noise is various modes of transportation (like air, road, rail-transportation). For example, noise caused by taking off and landing of airplanes exceed 110 db. ii) Industrial activity: Use of sirens, heavy machines, engines, turbines, cutting, grinding etc causes significant noise pollution. iii) Domestic activity: Use of grinders, food blenders, television, music system can produce unpleasant loud sound disturbing the neighborhood. iv) Celebrations: People celebrate festivals by exploding crackers. Diwali, New year, marriages etc involve extensive use of firecrackers.

Effects of Noise pollution Noise pollution can cause the following effects. ·

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Hearing damage: Noise can cause temporary or permanent hearing loss. It depends on intensity and duration of sound level.

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62 Environmental Science and Engineering ·

· · ·

Physical and mental balance: Constant noise affects a man physically and mentally. Physical effects include blood vessels to contract, skin to become pale, muscles to constrict and rise in blood pressure leading to tension, insomnia (sleeplessness) and nervousness. Lack of concentration anxiety, stress and mental fatigue are significant health effects of noise. Interferes with man’s communication: In a noisy area communication is severely affected. This may increase the rate of accidents especially in industries. Affects efficiency and productivity: Noise pollution result in decreased work efficiency and productivity. Sometimes, accidents can also happen. Health effects: Loud and sudden noise affects the brain. Loud noise can affect health of pregnant mothers and small infants.

Control of Noise Pollution Following methods can be used to control noise pollution: · · ·

· ·

·

Reduce noise at the source: Sources of noise pollution like heavy vehicles and old vehicles may not be allowed to ply in the populated areas. Proper maintenance: Proper oiling will reduce the noise from the machinery and other moving parts. Use of sound absorbing substances/silencers: Use of substances that absorb sound or silencer in motor vehicles can reduce the intensity of noise pollution. Proper acoustics of buildings will reduce noise pollution. Planting trees: Trees should be planted all around the hospitals, libraries and schools and colleges. These trees can absorb noise. Personal precaution: Industrial workers should be provided with ear plugs or cotton plugs. Rooms in hospitals can be made sound proof. People should not cause nuisance to public by playing music, television very loud Law enforcement: Strict legislation can minimize noise pollution during various festivals and social functions. Use of loud horns should banned.

2.19

| THERMAL POLLUTION

Thermal pollution is a form of water pollution that refers to degradation of water quality by any process that changes ambient water temperature. It can be defined as presence of waste heat in the water which can cause undesirable changes in the natural environment. Industries take water from rivers and lakes, use it for cooling purposes and then returns the heated water back to its source. Thermal power plants, nuclear power plants uses water as a coolant. Here, water is heated to produce steam, which is used to drive the turbines that generate electricity. Steam is condensed into water after it leaves the turbines. For this condensation, water is taken from a water body. This heated water, which is at least 15°C higher than the normal is discharged back into the water body.

Causes i) Industries: Heat producing industries like thermal power plants, nuclear power plants, oil refineries, steel mills etc uses water for various purposes. Waste water, often above ambient temperature is discharged to nearby water body causing thermal pollution. ii) Nuclear power plants: Nuclear power plants use water as coolant. After heat exchange water having higher temperature is discharged to water body. iii) Domestic homes: Hot water discharged from homes (geyser) and kitchen can also cause thermal pollution.

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Effects of Thermal pollution i) Reduction in amount of dissolved oxygen: Thermal pollution can lead to decrease in dissolved oxygen content of water. Solubility of oxygen in water is decreased at high temperature. This can severely affect aquatic plants and animals as they depend on dissolved oxygen for photosynthesis. ii) Death of aquatic organism: Most of the marine animals are unable to withstand a temperature increase of 4 to 5°C. Sponges, mollusks and crustaceans are killed when temperature reaches above 37°C. This can result in significant changes in the aquatic ecosystem. iii) Increased toxicity toxicity of chemicals at higher temperature: temperature: Toxicity of pesticides, detergents and chemicals in the effluents increases with increase in temperature. iv) Migration of fishes: Some of the less tolerant fishes migrate to cooler areas due to thermal pollution. v) Change in the ecosystem: The composition of flora and fauna of the ecosystem will change. The species sensitive to increased temperature are destroyed and are replaced by temperature tolerant species. vi) Reduced fertility rate in fishes: The eggs of fish may hatch early or fail to hatch at all causing decrease in population. vii) Change in metabolic metabolic activities: activities: At higher temperatures, aquatic organisms require more oxygen for metabolic activities.

Control of Thermal pollution The following methods can be employed for control of thermal pollution:

(i) Cooling ponds, (ii) Spray Ponds and (iii) Cooling towers i) Cooling Ponds: Cooling ponds constitute simplest method of controlling thermal pollution. The cooling pond receives hot water from the thermal plant’s condensers and it is stored in ponds. Energy is dissipated mainly through evaporation (natural evaporation cools the water). Once the water has cooled in the pond, it is reused by the plant or discharged in nearby water body. New water is added to the system to replace the water lost through evaporation.

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ii) Spray Ponds: Hot water from condensers is received in spray ponds. Received water is sprayed through nozzles where fine droplets are formed. Excess heat from these fine droplets is dissipated to the atmosphere. Water gets cooled as it comes down. Cooled water is collected and returned to the water body.

iii) Cooling Towers: (a) Wet cooling tower: Hot water is sprayed over baffles. Cool air is made to enter from the sides. This takes away the heat and cools the water. Cooled water can be discharged to the water body. One major disadvantage of this method is that large amount of water is lost through evaporation.

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(b) Dry cooling tower: tower: In dry cooling tower, hot water is made to flow through a series of coiled pipes. Cool air is passed over these hot pipes mechanically with the help of fans. Unlike the previous method, there is no significant water loss. However, installation and operation cost makes dry cooling tower much expensive than wet cooling tower.

2.20

| NUCLEAR HAZARDS

Nuclear energy can be both beneficial and harmful depending on the way way in which it is used. For example, X-rays are used to examine bones for fractures, cancer is treated with the help of radioactive isotopes. Nuclear power plants are used for production of electricity. However, nuclear energy can be used for the manufacture of nuclear weapons. The radioactive wastes generated from nuclear power plants can cause serious environmental damage. Nuclear hazards is defined as the physical pollution of air, water or land by radioactive substances emitting harmful radiations which can cause health hazards to living beings.

Causes i) Natural causes: Natural sources of radiation include cosmic rays coming from space, Radioactive Radon-222 present in rocks, Uranium, Thorium and other species present in rocks and minerals. ii) Anthropogenic Anthropogenic causes: These are some man made radiation sources. a) Nuclear power plants: plants : Every nuclear power plant produces few kilogram of highly radioactive wastes. Many of these wastes have long half life period and will continue to emit radiations for many years if not disposed properly. b) Nuclear accidents: Accidents happening in a nuclear reactor may lead to the leakage of radioactive materials which can cause serious health concerns. Example: Chernobyl reactor meltdown in 1986, Fukushima Daiichi leakage in 2011. c) Weapons of mass destruction: destruc tion: Many developed countries have the technology to prepare nuclear weapons. Use of these weapons can pollute environment and can have devastating effects. Eg: Atomic Bomb dropped on Hiroshima and Nagasaki.

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d) Laboratories: X-rays are widely used in hospitals. Radioactive materials are used in cancer therapy and treatment. Leakage of these can cause various problems.

Biological Effects of Radiations · ·

·

·

Death: Very high radiation doses are found to be harmful and may kill the organisms which are exposed within minutes. Mutation: Radiations can result in genetic damage, which induce mutations in the DNA. Mutations alter the genetic makeup of the organism and may be transmitted to several generations. Cancer: Radioactive iodine (I 131) accumulates in thyroid gland and causes thyroid cancer. Radioactive Strontium-90 can replace calcium in the bones and causes leukemia or cancer of bone marrow. Ionizing radiations can also induce various types of cancer. Somatic domages: Somatic damage includes burns, miscarriages, eye cataract etc can happen if a person is exposed to radiation beyond permissible limit. Low level exposure can result in temporary decrease in Red blood cell count, Mild radiation sickness etc.

Control of Radiation pollution i) Nuclear power plants: · · · · · ·

Nuclear power plants should be located in a place where density of population is very ver y less. Proper disposal of wastes, from both laboratories and nuclear power plants, should be done. Better operator training and better instrumentation is required to avoid nuclear accidents. Leakage of radioactive elements or radiations from nuclear reactors, laboratories should be checked regularly. regularly. Regular inspection of areas of nuclear activities for radiation level must be done. Workers in nuclear plants should be given training about nuclear safety. They should be provided with safety measures to safe guard them against accidents.

ii) General awareness: awareness: Public should be made aware about various hazards of nuclear radiation and should be educated about the precautionary measures to be taken, in case of a radioactive fall out.

Methods used for disposal of nuclear wastes ·

· ·

Deep ocean disposal: In this method, nuclear wastes are filled in containers made of borosilicate boros ilicate glass. Borosilicate Borosi licate glass prevents leakage of any nuclear radiation. radiat ion. This container is enclosed in another water-tight metal container and dumped into the ocean. These containers will rest in the ocean floor. Deep geological burial: In this method, radioactive wastes are buried in containers deep underground. These materials will decay naturally over thousands of years. Nuclear waste recycling: In this method, radioactive wastes are recycled or reused. Wastes containing uranium, plutonium and other fission products are separated using various chemical processes. However, this method is very expensive and can be used only for some nuclear wastes.

2.21

| NUCLEAR HAZARDS-CASE STUDIES

As of January 2015, thirty countries worldwide are operating 437 nuclear reactors for electricity generation and 71 new nuclear plants are under construction in 15 countries. Nuclear power plants provided 12.3 percent of the world’s world’s electricity production in 2012. Most of the nuclear hazards known are related to nuclear reactors. Due to human or machine error, nuclear chain reaction

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goes uncontrolled resulting in core melt down. Radioactive debris is spread all over resulting in massive destruction to life and property. 2.21.1

Hiroshima and Nagasaki incident

Place: Hiroshima and Nagasaki Date: August 6,1945 at 8:15 a.m and August 9,1945 at 11:02 am Name of the bomb: Little boy and Fat man . Little Boy was simple uranium 235-based bomb and was untested till Hiroshima. Fat Man, the Nagasaki bomb, was a more complex plutonium bomb. Reason: Attack of Japan on Pearl harbour. Hiroshima Bombing: Atomic bomb was dropped on Hiroshima on August 6,1945 at 8:15 am. The energy released was equivalent of 20,000 tons of TNT. Within few seconds half of the city vaporized. According to estimates, 80,000 people were instantly vaporized. Over 1.5 lakhs were injured by radiation. Most of buildings collapsed making people homeless. The city was unbelievably unbelievably devastated. devastated. After the explosion, it rained heavily in northwest of the city. This “black rain” contained dirt, dust, soot and highly radioactive particles. It caused more contamination even in areas that were remote from the explosion. Nagasaki Bombing: At 11:02 a.m., the atomic bomb, “Fat Man,” was dropped over Nagasaki. It was a plutonium based atomic bomb. Half of the population were killed and many sustained severe injuries. City was completely devastated by the bombing. People were clueless about the situation, they ran for help. The tragedy was not limited to present population. Future generations also suffered from various diseases. Even the babies in the mother’s womb were affected. Blindness, deafness, skin diseases and cancers, distortion of bones and other parts became common for many years. For many years high amounts of cancer, birth defects, and tumors made life of the victims miserable. 2.21.2

Chernobyl disaster

Place: Chernobyl nuclear power plant, Ukraine Date: 26 April, 1986 Reason: Faulty operations of shutting down the plant Incident: On 26 April, 1986 the accident occurred at the reactor of the Chernobyl power plant which was designed to produce 1000 MW electrical energy. The reactor working continuously for 2 years was to be shut down for intermediate repairs. Top executives were busy in the preparations for national holiday, holiday, The May Day. Day. Due to improper shutting down operations, an explosion occurred in the reactor at 01.23 hrs on April 26, 1986. It was soon followed by another explosion three seconds later. Graphite rods caught fire. The reactor temperature rose to more than 2000°C. Fuel and radioactive debris shot as a cloud. The debris and gases drifted over most of the Europe. Belarus, Poland, Denmark, Sweden and Norway were affected. Hundreds of people died and many were hospitalized. Radioactive Radioactive cloud was rich in Iodine-131, Cesium-134 and Cesium-137. It was estimated that nearly 6 lakh were exposed to the radiations. People were warned not to consume milk, water and other products. There was huge increase in cancer cases especially, thyroid cancer and leukaemia. Number of cases reported for thyroid cancer in children shot up as they consumed contaminated milk and milk products. Fields could not be cultivated for many years. Trees were destroyed. Now, Chernobyl is free from radiation and is a popular tourist destination.

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2.21.3

Fukushima – Daiichi nuclear disaster

Place: Fukushima, Japan Date: Started on 11 March, 2011 Reason: Tsunami on 11 March 2011 Incident: Fukushima Daiichi nuclear disaster was a result of series of equipment failures and nuclear meltdowns. Large amount of radioactive materials were released from the Fukushima Nuclear Power Power Plant, following an earthquake and tsunami on 11 March 2011. It is the largest nuclear disaster since the Chernobyl disaster of 1986. The plant had six separate boiling water reactors. Tsunami caused flooding of the rooms containing the emergency generators. These generators stopped working. This resulted in stoppage of water (coolant) circulation in the reactor. Reactors were overheated and reactors 1, 2 and 3 experienced full meltdown in few days. Several chemical explosions occurred. People were evacuated within few mile radii. Large amounts of radioactive materials might have been released into ocean waters. People were advised not to use tap water and certain food materials. On 16 December 2011, Japanese authorities declared the plant to be stable.

2.22

| ROLE OF AN INDIVIDUAL IN PREVENTION OF POLLUTION

The role of an individual in maintaining a pollution free, pure and congenial environment and in preserving its resources is actually the need of the hour. Every human being has the responsibility to protect the mother earth. A small effort made by each individual at his own place can have pronounced effect at the global level. It is aptly said, “Think globally act locally” . Individuals can play an important role in abatement of air, water, soil or noise pollution. Some roles are given below.

Air pollution reduction · · · · · · ·

Maintenance of vehicles should be proper as to avoid introduction of harmful gases and other pollutants in to the atmosphere. Cut down the use of chlorofluorocarbons (CFCs) as they destroy the ozone layer. Use CFC free refrigerators. Use of less polluting fuels like hydrogen, natural gas instead of coal, petrol etc. Use mass transport system. For short-visits use bicycle or go on foot. Decrease the use of automobiles. Plant more trees. Trees can act as scvangers for many toxic gases. Concentrate more in pollution prevention than pollution control.

Water pollution reduction · · · · ·

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Use pesticides only when absolutely necessary. Overdose of pesticides should be avoided. Use alternate pest control methods (biological control). Use phosphate-free detergents. This can minimize eutrophication of water bodies. Commercial inorganic fertilizers can be replaced by organic manure. Hazardous wastes from industries must be treated before dumping to water bodies. Don’t wash laundry, vehicles or clean vessels in open water bodies.

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Soil pollution reduction · · · ·

Biodegradable materials can be converted into compost or maure or for the production of bio-gas. Plastics bags, glass bottles etc can be reused. Use of rechargeable batteries will reduce soil metal pollution. Promote reuse and recycling wherever possible and reduce the production of solid wastes.

Noise pollution reduction · · · · · ·

Music lovers can use head phones to listen to music systems. Minimize the use of loud speakers and other devices which produce noise. Proper maintenance of vehicles to prevent making loud noise. Planting trees can help in reduction of noise pollution. Limit the use of crackers during festival season. See to it that crackers don’t produce unbearable noise. The use of horn while driving should be minimized.

ANNA UNIVERSITY QUESTIONS 1. Describe the various chemical and photochemical reactions in the atmosphere. (Anna Univ, Dec 2014) 2. Write a detailed account of ozone layer depletion. 3. What is acid rain? How is it formed? Explain the impact of acid rain on the environment. 4. How is smog fog formed? What are health impacts of smog? 5. Describe in detail the methods for the control of particulate pollution and gaseous emission. 6. Describe the significance of any six parameters of drinking water quality standards. (Anna Univ, Dec 2014) 7. Write informative notes on water treatment process.


8. Write a detailed note on solid waste management. 9. Explain the various sources, effects and control measures of marine pollution. 10. Explain the various sources, effects and control measures of noise pollution. (Anna Univ, Dec 2014) 11. What is thermal pollution? How can it be minimized? 12. Describe the role of an individual in the prevention of pollution.

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Unit

3

NATURAL RESOURCES

SYLLABUS Forest resources: Use and over-exploitation, deforestation, case studies- timber extraction, mining, mining , dams and their effects on forests and tribal people – Water resources: Use and overutilization of surface and ground water, dams-benefits and problems – Mineral resources: Use and exploitation, environmental effects of extracting and using mineral resources, case studies – Food resources: World food problems, changes caused by agriculture and overgrazing, overgrazing, effects of modern agriculture, fertilizer-pesticide problems, water logging, salinity, case studies – Energy resources: Growing energy needs, renewable and non renewable energy sources, use of alternate energy sources. Energy Conversion processes – Biogas – production and uses, anaerobic digestion; case studies – Land resources: Land as a resource, land degradation, man induced landslides, soil erosion and desertification – role of an individual in conservation of natural resources – Equitable use of resources for sustainable lifestyles. Introduction to Environmental Biochemistry: Proteins –Biochemical degradation of pollutants, Bioconversion of pollutants. Field study of local area to document environmental assets – river / forest / grassland / hill / mountain.

3.1

| INTRODUCTION

A natural resource may be defined as any material obtained from nature which can be used as such or transformed to something more valuable and useful. They include the air to breathe, water to drink, land to live on, walk on and grow the food on etc. The natural resources are of two kinds. Renewable resources are resources that are naturally regenerated within a given span of time. Most of them are continuous. However, some renewable resources may become non renewable if over-exploited or not given enough time for regeneration. Example: Solar energy, forests, wildlife, wind energy, biomass energy, tidal energy, hydro power etc. Non-renewable resources are resources that have limited supply. They exhaust after certain time period. Once we exhaust these reserves, the same cannot be replenished. Example: Fossil fuels like coal, petroleum, minerals etc. The important natural resources are

1. Forest resources 2. Water resources

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3. 4. 5. 6.

3.2

Mineral resources Food Food resources Energy resources Land resources

| FOREST RESOURCES

Forests are one of the most important natural resources on this earth. A forest is a natural ecosystem having diversified species of herbs, shrubs, small trees, large trees in different stages of lifespan. A variety of microorganisms, insects, reptiles, mammals, are seen in forests. 3.2.1

Uses or Functions of forests

Ecological functions 1. Production of oxygen: During photosynthesis trees release oxygen which is so vital for all life forms. They are called earth’s lungs. 2. Reducing global warming: CO2 (a major greenhouse gas) is absorbed by the forests during photosynthesis. Thus forests helps to keep earth cooler by absorbing green houses.. 3. Regulation Regu lation of hydrological cycle: Forests help to regulate water cycle by condensing water vapor in clouds resulting rains. 4. Prevention of soil erosion: Roots of the trees hold together the top soil and prevent from directly washing soil away. It also prevents land slides and flash floods. 5. Improving Improving soil s oil fertility: fer tility: Leave litter helps in maintaining soil fertility. It helps to maintain soil nutrients and structure. 6. Pollution moderators: moderators : Forests can absorb many toxic gases, purifying air. They also absorb noise, thus reducing noise pollution. 7. Regulation of heat: Forests play a crucial role in controlling heat by the absorption of solar heat during evapotranspiration. 8. Wild life habitat: Millions of wild animals live in forests. Forests are home to millions of plant species too. It is estimated that about 7 million species are found in the tropical forests alone. 9. Reducing Red ucing the rate of surface run-off of water: Trees retain the water with the help of roots and reduces surface run off.

Productive functions 1. Supply of Raw Material: Materia l: Forest is a source of raw material for various industries. Wood is a major raw material which is widely used as fuel, raw material for pulp, paper, furniture etc. firewood, 2. Commercial uses: Forests yields a large number of commercial goods like timber, firewood, food items, gum, resins, fibers, lac, fodder, medicine, drugs etc.

Recreational, Developmental and Educational Functions 1. Eco tourism: Forests and dams can promote eco tourism. 2. Employment functions: functions : Forest directly and indirectly act as a source for employment to a number of people. 3. Revenue: Forest contributes to the economic development of the country because they provide goods and services to the people and industry. industry.

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3.2.2

Deforestation:

Removal of earth’s forest is known as deforestation. It is the cutting of trees, transforming a forest into cleared land. This can result in serious environmental problems. The world’s rain forests could completely vanish in a hundred years at the current rate of deforestation.

Causes 1. Agriculture: Agricultu re: Conversion of forests to agricultural land to feed growing numbers of people. Forests are cut down to plant cash crops like pepper, rubber etc. 2. Fuel requirements: Growing population result in increased fuel demands. In rural areas, wood is still the major fuel. Tress are cut down for the demand of firewood. 3. Developmental projects: Constructing roads, railway tracks etc require clearing of forests on a large scale. 4. Dams and reservoirs: Dams and Hydroelectric projects in forest area cause massive deforestation. Over 60,000 hectares of forest area was cleared for the construction of Narmada Dam. Several hectares of forest were submerged under water. water. 5. Raw materials for industrial use: Wood is an important raw material for many purposes. For making furniture, boxes, plywood, pulp for paper trees are cut down. 6. Mining: Surface and sub-surface mining for the extraction of mineral resources cause extensive deforestation. Digging a coal, diamond or gold mine requires the removal of all forest cover. Forests are further cleared for the transport of trucks and other equipment. 7. Forest Forest fires and volcanic eruption: Forest fires and volcanic eruption can cause deforestation. Forest fire is common in tropical regions during summer. 8. Overgrazing: Overgrazing by cattle’s cause deforestation. They not only destroy the vegetation but also pull out the roots of plants.

Consequences 1. Global warming: Increasing CO2 levels lead to rise in temperature of earth. Forests are known as earth’s lungs as they play a great role in regulating the amount of greenhouse gases like CO2. 2. Soil erosion: Roots of trees helps to hold soil together preventing soil erosion. Removal of trees will lead to easy removal of top soil by water, wind etc. 3. Loss of habitat: Due to deforestation, forest animals and plants will lose their natural habitat. This may cause migration of animals or man-animal conflicts. 4. Loss of soil fertility: Leaf litter is rich in organic matter which is converted into nutrients by micro organisms present in the soil. Absence of leaf litter can reduce soil fertility. fertility. 5. Change in rainfall pattern: Forests play an important role in regulation of hydrological cycle. Deforestation can cause decrease in rainfall or erratic rainfall pattern. 6. Lowering of water table: Deforestation results in less rainfall which may result in lowering of water table. 7. Shifting of tribal people: Large scale deforestation may result in shifting of tribal population to urban areas. 8. Loss of biodiversity, Genetic and species diversity: Deforestation will lead to the loss of biodiversity. biodiversity. Deforestation will lead to loss of many varieties of flora and fauna. Endangered plants and animals may become extinct. 9. Loss Los s of forest products: Many forest products like honey, medicinal plants etc will become costly. 10. Desertification: Large scale deforestation may lead to forest becoming arid, semi-arid or desert.

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Steps to prevent deforestation or the role of individual in preserving forest resources

1. Starting afforestation (tree planting) programs. 2. Educating people about the ill effects of deforestation deforestation through movies, documentaries, play, play, newsletters etc. 3. Strict implementation of Forest Conservation Act 4. Implementing people’s people’s participatory programmes. Example: Joint Forestry Management (JFM). 5. Avoids diversion of forest lands for other activities activities through acts like like Forest Forest Conservation Act and Wild life (protection) Act 6. Control forest diseases and forest fire 7. Recycling or replacing replacing forest products may may result in in less dependence of forest.

3.2

| WATER RESOURCES

Earth is the only known planet to contain water, hence known as “ blue planet”. All life of earth depends on water. About 97% of the earth’s surface is covered by water and most of the animals and plants have 60-65% water in their body. About 97% of the earth’s water supply is found in oceans. This is unfit for domestic purposes. 2% is locked in the polar ice-caps which again is unusable. Thus only 1% is available as fresh water in rivers, lakes, streams, reservoirs and ground water which is suitable for human consumption. 3.2.1

Hydrological cycle

The movement of water on the earth’s surface and through the atmosphere is known as the hydrologic cycle or water cycle. Water vapor reaches the atmosphere from earth’s surface form through evaporation, condenses and form clouds. Water then returns to the surface of the earth in liquid (rain) or solid (snow, sleet, etc.) form.

Step 1: Evaporation and transpiration Water bodies like oceans, lakes and the river bodies absorbs heat energy from the sun and turns into water vapor. Through evaporation, water moves from hydrosphere to atmosphere. Transpiration is a process similar to evaporation where liquid water is turned into water vapor by the plants. It is the evaporation evaporation of water from f rom leaves through stomata (very tiny openings on leaves) as water vapor.

Step 2: Condensation Water vapour formed by evaporation, rises up in the atmosphere. At high altitudes, where the temperature is low, the water vapor changes into very tiny particles of ice /water droplets. This process is called condensation. These water particles come close together and form clouds and fogs in the sky.

Step 3: Precipitation Due to wind or change in temperature, the water droplets in clouds combine to make bigger droplets and precipitates as rain. If the temperature is less than zero, the water droplets fall as snow.

Step 4: Runoff and infiltration Water that pours down as rain leads to runoff. Runoff is the process where water runs over the surface of earth. During run off water carries top soil and minerals along with the stream. This runoff combines to form small channels and then rivers and ends up into lakes, seas and oceans.

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A part of rainwater does not runoff into the rivers, but moves deep into the soil through different layers. This is called infiltration. This water which seeps down increases the level of ground water table.

Types of freshwater resources Freshwater may be present either as surface water or as underground water Surface water: Surface water refer to water present on the surface of earth, either stagnant type or flowing type. Stagnant water bodies are called lentic and flowing water bodies are called lotic water. Examples: Lentic water: Lakes, ponds etc Lotic water: Rivers, streams etc. Underground water: Underground refers to the water present under the earth’s surface. A layer of sediment or rock that is highly permeable and contains water is called an aquifer. Aquifers are of two types: Unconfined aquifers receive water seeping down from above. It is constantly recharged. Upper boundary of an unconfined aquifier is water table. Confined aquifers are sandwitched between two impermeable layers of rock or sediments. It is recharged only in those areas where the aquifer intersects the land surface. 3.2.2

Over exploitation of ground water

Due to rapid population growth and industrial growth, the demand for water has increased rapidly. Indiscriminate and unscientific use of water resources has resulted in water scarcity and water pollution.

Causes 1. Agriculture: Agricultu re: The main reason for the over exploitation of ground water is agriculture. Extensive irrigation including for livestock requires lot of water. 2. Increase in population: Domestic and industrial needs of the growing population requires water. 3. Inadequate rainfall rainfall / Drought: To meet severe weather conditions ground water is over exploited.

Consequences 1. Lowering of water table: Large number of tube wells built can result in lowering of water table. 2. Ground subsidence: subside nce: When groundwater withdrawal is more than its recharge rate, the clay layers in the aquifer get compacted and settle. This result in the sinking of land called ground subsidence. This can result in damage of buildings, fracture in pipelines etc.

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3. Water logging and salinity: Rapid removal of ground water can cause the intrusion of sea water which results in increase in salinity. When excessive irrigation is done with brackish water it raises the water table gradually leading to water-logging and salinity problems. 4. Water pollution/Chemical contamination: Removal of large volumes of ground water can result in water pollution. Chemicals contamination can occur. Due to pollution, water will become unfit or drinking and domestic uses. 5. Decline in agricultural production: production: Lowering of water table can bring about water scarcity which can cause decrease in agricultural crop production. This can lead to drought or famine. Salt water intrusion can also lead to destruction of crops. 6. Drying up of lakes, rivers and water bodies: Indiscriminate use of ground water at a rapid rate can cause drying up of many surface water bodies. 7. Desertification: Loss of underground water may convert semi-arid places into desert. 8. Waste of energy: Lowering of water table result in wastage of energy due to pumping. It increases the cost of pumping ground water. 3.2.3

Dams

Dam is a solid barrier constructed at a suitable location across a river valley to store water. Dams have been referred to as ”Temples of modern India” by the country’s first Prime Minister, Jawaharlal Nehru.

Benefits 1. Generation of electricity: Water Water stored in dams can be used for the generation of electricity in hydro-electric power stations. 2. Floods and famine control: Dams help to control or mitigate floods. It can act as a reservoir of water during famine. 3. Water Water for irrigation: irrigatio n: Dams provide water for irrigation. This is particularly useful during summer. 4. Source of drinking water: Dams can also act as reservoir of fresh water for domestic uses. 5. Promoting navigation and fishery: Big dams also promote navigation and fishery. 6. Promote tourism: Dams also promote tourism. Constructing a dam presents a beautiful view of a lake. Recreational activities like boating, swimming, fishing etc can promote eco tourism. 7. Economic growth: Dams directly or indirectly provide employment to many and raising the standard and quality of life.

Problems Impacts at the upstream level 1. Displacement of tribal people: Constructing large dams causes large scale displacement of tribal people. Settlement and rehabilitation of these people is a major concern. 2. Loss of forest, forest, flora and fauna: Construction of dams include massive deforestation and submergence of land under water. This can result in the loss of flora and fauna. Sometimes, plants and animals may become endangered or even extinct. 3. Changes in aquatic habitat: Construction of dams result in the variation of natural flow of the river which may result in changes in aquatic ecosystem. 4. Siltation Sil tation and sedimentation sediment ation of reservoirs: Dams block the sediment load normally found in a river flow. This result in siltation and sedimentation. 5. Loss of non-forest non-forest land: Non forest land may be submerged under water during the construction of large dams.

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6. Stagnation Stag nation and water logging: Stagnation and water logging can happen near the reservoir. 7. Breeding Breedi ng of vectors and spread of vector-borne diseases: diseas es: Dams, reservoirs in tropical areas are breeding grounds for mosquitoes, snails, and flies, the vectors that carry malaria and other diseases. 8. Reservoir induced seismicity (RIS): Large dams carry enormous volume of water and it can cause significant impact on the strength of soil and rock strata beneath the surface. It can result in generating seismic waves which result in earthquake. 9. Growth of aquatic weeds: Dams may result in the rapid growth of aquatic weeds. 10. Microclimatic Microcl imatic change: Large dams may result in the climatic change around the reservoir. Impacts at the downstream 1. Water Water logging and salinity: salinit y: Over irrigation in the downstream region may result in water logging and increased soil salinity. 2. Micro-climatic Micro-climati c changes: Large dams may result in the climatic change around the reservoir. 3. Silt deposition: Soil erosion may lead to silt deposition on river mouths. 4. Flash floods: Opening of reservoir shutter may result in flash floods. 5. Salt water intrusion: intrusio n: Salt water intrusion can happen at the river mouths. 6. Breeding of vectors and spread of vector-borne diseases: diseas es: Dam reservoirs in tropical areas are breeding grounds for mosquitoes, snails, and flies, the vectors that carry malaria and other diseases. 3.2.4

Case study: Sardar Sarovar Dam

Sardar Sarovar dam is situated on river Narmada and is spread over three states of Gujarat, Maharashtra and Madhya Pradesh. Although the project is aimed at providing irrigation water, drinking water and electricity to the three states, the environmental impacts have been quite severe. A total of 1.5 million hectares of land will be submerged by the dam, out of which 60,000 hectares is forest land. A total of 573 villages were submerged by the Narmada Dam. Over 75,000 people had to be evicted and resettled. 3.2.5

Effects of dams on tribal people

Large dams have a great impact on the lifestyle and identity of tribal people. Tribals are socially, economically and politically the weakest community in India. Most of them are illiterate. In India, these tribals live in rural areas as communities in close proximity to forests, rivers and mountains. They depend heavily on natural resources for their livelihood. Due to developmental work (dams, road, railway tracks) they are evicted from their ancestral homes. Tribals are either forced to migrate to urban slums in search of employment or become landless laborers in rural areas. However, these tribal people do not share the benefits of developmental projects which resulted in their displacement. Most of them are deprived of the basic amenities like roads, electricity, transport, communication, healthcare, drinking water or sanitation. Most of the natives are illiterate and are exploited. They are forced to work at low wages. Tribal people also find it increasingly difficult to adjust with urban life. After displacement, often conflicts happen with other communities. They not only lost their habitat and it is quite possible that they may lose their cultural and traditional values which they inherited over generations. 3.2.6

Floods

A flood is an overflow of water that submerges land which is usually dry. This happens when river carries water much beyond its normal capacity.

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Floods have been regular features of some parts of India, China and Bangladesh causing huge economic loss as well as loss of life. Bhrahmaputra and its tributaries cause heavy floods every year.

Causes 1. Excessive Excess ive rainfall: High rainfall/heavy monsoon may result in floods. During north west monsoon many of the Indian rivers are flooded which results in large scale destruction of life and property. 2. Global warming: Increase in temperature may result in melting of snow which may result in floods. Many rivers which originate from the Himalayas are flooded during summer. 3. Dams: When carrying capacity of dams exceeds, water is released by opening shutters of the dam. This can result in flash floods. 4. Change in direction of river: Any change (natural or man made) in the direction of river can lead to floods. 5. Deforestation: Removal of trees result in rapid stream flow which result in floods.

Consequences 1. Destruction of life and property: Floods can cause severe damage to life and property. 2. Decline in agricultural production: production: Floods can lead to submergence of fields under water. This can result in decreased harvest. 3. Water logging: Flooding can result in stagnation of water or water logging over a long period. This can result in the spread of water borne diseases. 4. Scarcity of drinking water: Flood results in water pollution and may lead to scarcity of drinking water. 5. Outbreak of epidemic: Contaminated water and low quality food can result in the outbreak of various epidemics. 6. Rehabilitation: Rehabilita tion: People affected by floods have to be given temporary accommodation, food etc. 7. Increased soil fertility (Good): Downstream soil quality will be better due deposition of top soil. 8. Increased fish output (Good): Can result in increased fish production

Control measures for the prevention of flood 1. Building dams: Building dams across the river can help to regulate the water flow. 2. Networking of rivers: Interconnecting various rivers can result in the steady water flow. This can help to control flood and drought across the country. 3. Watershed management: Proper and scientific watershed management practices can control floods. 4. Control of deforestation: Effective check on deforestation can cause steady river flow. 5. Floodwalls: Floodwalls built on the banks of “flood prone” rivers can reduce the impact of heavy floods. 3.2.7

Droughts

Scarcity of water which occurs due to inadequate rains, late arrivals of rains and excessive withdrawal of ground water is called drought. Any lack of water for normal needs of agriculture, livestock, industry or human population may termed as drought. Droughts occur in all of the world’s continents. It can produce serious hydrological imbalance.

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Causes 1. Less rainfall/ Failure of monsoon: Less rainfall/ monsoon failure may result in severe water scarcity cause drought. 2. Deforestation: Unscientific cutting down of trees can result in change in hydrological cycle which can lead to drought. 3. Overgrazing: Cattles may eat away the vegetation converting the land into dry, arid or semi-desert lands which may cause drought. 4. Unscientific agricultural practices: Erroneous, intensive agricultural methods, unscientific practices may lead to water scarcity leading to drought. 5. Mining: Mining practices can cause severe irrecoverable damage (pollution, acid drainage) to many ecosystem. This may result in desertification and drought.

Consequences 1. Malnutrition: Malnutrition : Lack or shortage of food can result in malnutrition. 2. Decline in agricultural production: Droughts results in heavy decline in agricultural production. 3. Famine/ Stravation / Death: Severe drought can result in famine and death. 4. Increased food prices: Food commodities can become expensive due to high demand and severe shortage in supply. 5. Outbreak of epidemic: Contaminated water and low quality food can result in the outbreak of various epidemics. 6. Migration: People and animals may migrate to another place for want of better resources. 7. Severe damage to ecosystem: Prolonged drought can result in changes in biotic components of the eco-system.

Control measures for the prevention of drought 1. Building dams: Dams can store water which can be released at the time of drought. 2. Networking of rivers: Networking of various rivers can result in the steady water flow even during water shortage. 3. Rainwater harvesting: Rainwater harvesting methods can enable to store water during rains, to be used later. 4. Watershed management: Proper and scientific watershed management practices reduce the intensity of droughts. 5. Control of deforestation: Effective check on deforestation can cause steady river flow. 6. Scientific agricultural practices: Dry farming techniques, drip irrigation, mixed cropping etc can reduce the wastage of water and thus frequency of drought. Sustainable water management: This refers to the use of water resources in a judicious and sustainable manner. The following measures can be adopted · · · ·

Building several small reservoirs instead of few mega projects. Preventing leakages from dams and canals. Effective rain water harvesting in urban environments. Water conservation measures in agriculture such as using drip irrigation.

3.2.8

Water conflicts

Water conflict is a term describing a conflict between countries, states, or groups over an access to water resources.

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National conflict Cauvery Water dispute River: Cauvery Origin: Talakaveri, Karnataka Length: 765 KM States Involved: Karnataka, Tamilnadu (Major) Kerala, Pondicherry (Minor) Upstream: Karnataka Downstream: Tamilnadu Dam: Mettur dam, Krishna Raja Sagara Dam History: The history of this conflict is due to signing of two controversial agreements (1892 and 1924) between the erstwhile Madras Presidency and Princely State of Mysore.

ag reements were written heavily heavily in favor of the Madras Karnataka’s claim: Karnataka claims that agreements Presidency, and demanded new agreement based on equal sharing of water. Tamilnadu’s cliam: Tamilnadu claims that it has already developed almost three million acres of land for cultivation. According to Tamilnadu, any change (decrease) in amount of water will adversely affect the livelihood of millions of farmers in the state. The crisis of 1995–1996 In 1995, the monsoons failed badly and Karnataka had to give water to Tamilnadu. Farmers of Karnataka protested against this and formed human barricade infront of the dam to stop release of water. Tamilnadu protested against this and the condition was taken up by various political parties and became a burning issue. Result and verdict A tribunal was set up by The Government of India in 1990 to solve the crisis. After hearing arguments of all the parties involved, the tribunal delivered its final verdict on 5 February 2007. In its verdict, the tribunal allocated 419 billion ft³ (12 km³) of water annually to Tamil Nadu and 270 billion ft³ (7.6 km³) to Karnataka; 30 billion ft³ (0.8 km³) of Cauvery river water to Kerala and 7 billion ft³ (0.2 km³) to Pondicherry.

Mullaperiyar dam issue River: Periyar Period of construction: 1887-1895 States involved: Kerala and Tamilnadu Details of the dam: Mullaperiyar Dam is a gravity dam made with concrete prepared from limestone and “surkhi” (burnt brick powder), and faced with r ubble. The main dam has a maximum height of 53.6 m and length of 365 m. Lease: Although Mullaperiyar dam is located in Kerala, it is operated by the government of Tamil Nadu. A 999-year lease agreement was signed between Madras Presidency and British government. This dam was built to irrigate farmland on Tamilnadu side. Nature of conflict: For Tamilnadu, Mullaperiyar dam and the diverted Periyar water act as a lifeline for Theni, Madurai, Sivaganga and Ramnad Districts. This water is used water for irrigation, drinking and power generation. Kerala is concerned about the safety posed by the 116 year old dam. Tamil Nadu insists insists that dam is safe and that water levels levels can be raised to 142 feet. In May 2014, Supreme Supreme Court of India ruled that Water level in the dam can be increased from 136 feet to 142 feet.

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International conflicts River: Nile (World’s longest river) Origin: White Nile Length: 6,650 Km Countries involved: Nine countries

Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt. Control and conflict: Of the four major tributaries to the Nile, three originate from Ethiopia - the Blue Nile, Sobat and Atbara (85% of water in Nile). Ethiopia is planning to control more water. Sudan is also planning to divert more water. This could badly affect Egypt. The population of Egypt is expected to double in next 20 years and will require more water. Almost all countries want more water from nile. Nile Basin Initiative (NBI) The Nile Basin Initiative (NBI) was formed by Nile conflict countries to develop the river in a cooperative manner, share socioeconomic benefits, and promote regional peace and security. It was formally launched in February 1999 by the water ministers of 9 countries that share the river. 3.2.9 · · · · · · ·

3.3

Role of an individual in conserving water resources

Do not waste water. Don’t keep water tap open while brushing, shaving, washing etc. Check and repair leaking taps and pipes. Collect rain water. Build rain water harvesting system in your house. Recycled water can be used for watering garden plants. Install water-saving toilets that use not more than 6 liters per flush. Water the plants early morning or evening when evaporation losses are minimum. Use drip irrigation and sprinkling irrigation to improve irrigation efficiency and reduce evaporation.

| MINERAL RESOURCES

Minerals are naturally occurring, inorganic, crystalline solids having a definite chemical composition and characteristic physical properties. The economic development of a country depends, to a great extent on the availability of minerals. Minerals like mica, copper, lead and zinc are of vast economic importance. Thorium and uranium are atomic energy minerals. Based on their properties, minerals are basically of two types: Non metallic minerals: Graphite, diamond, quartz, feldspar. Metallic minerals: Bauxite, laterite, haematite etc.

Uses of minerals The main uses of minerals are as follows: · · · · ·

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Development of industrial plants and machinery. Generation of energy: coal, lignite, uranium. Construction, housing, settlements. Defence equipments: weapons, armaments. Communication: telephone wires, cables, electronic devices.

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82 Environmental Science and Engineering · · ·

Preparation of alloys for various purposes Agriculture: as fertilizers, seed dressings and fungicides. Jewellery: Gold, silver, platinum, diamond.

Mineral wealth of India India is rich in minerals like coal, bauxite, mica etc. Deccan plateau is rich in many minerals. Some of the minerals present in our country are ·

·

·

·

· ·

Bauxite: Important deposits occur in Andhra Pradesh, Bihar, Goa, Gujrat, Jammu and Kashmir, Karnataka, Kerala, Madhya Pradesh. Coal and Lignite: Coal is India’ I ndia’ss largest mineral resource and presently India is fifth largest of coal producer in the world. Large deposits are found in West Bengal, Orissa, Bihar, Madhya Pradesh, Andhra Pradesh and Maharashtra. Bulk of the lignite reserves occur in and around Neyyeli in Tamil Nadu. Mica: India is world’s leading producer of sheet mica and accounts for about 60 per cent of global mica trade. Iron Ore: Haematite mainly occurs in Bihar, Orissa, Madhya Pradesh, Maharashtra, Goa, and Karnataka. Large reserves of magnetite ore occur along West Coast, primarily in Karnataka. Diamond: Main diamond bearing area in India is Panna belt in Madhaya Pradesh. Gold: There are two important gold fields in the country, namely, Kolar Gold Field in Kolar District and Hutti Gold Field in Raichur District (both in Karnataka). Mining in Kolar Gold Fields have been stopped in 2001 due to low gold production.

3.3.1

Mining

Minerals and their ores have to be extracted from the earth’s interior. This process of extraction is known as mining . Mining operations follow four phases. · · ·

·

Prospecting: Searching for minerals. Exploration: Assessing the size, shape, location, and economic value of the deposit. Development: Work of preparing access to the deposit so that the minerals can be extracted from it. Exploitation: Extracting the minerals from the mines.

Two types of procedures are used for mining- Open pit mining and Deep mining. Depending on the location, safety, environmental impact, maximum yield at low cost an appropriate mining method is chosen.

Impacts of mining Impacts of mining can be due to the mine itself, disposal of mine wastes, transport of the material and processing of the ore. 1. Deforestation: Large area of forest is usually cleared for various mining (surface and subsurface) activities. This can result in · Loss of biodiversity · Loss of genetic and species diversity · Loss of habitat for plants and animals · Species may become extinct 2. Land subsidence: Underground mining may cause land subsidence. This may cause cracking of roads, bending of railway tracks etc. 3. Groundwater and surface water contamination: contamina tion: Mining activities can result in acid mine drainage, heavy metal contamination etc.

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4. Air pollution: Mining process and processing (smelting, roasting etc) can introduce lot of pollutants and particulate matter into air. Suspended particulate matter (SPM), SOx, soot, arsenic particles, cadmium, lead etc. released into the atmosphere can cause several health problems. 5. Soil erosion: Mining leads to erosion of the fertile top soil. This may be carried as sediment into streams, rivers and lakes. 6. Occupational health hazards: Many miners suffer from various respiratory and skin diseases due to constant exposure to chemicals and toxic substances. Diseases like asbestosis, silicosis, black lung disease etc are quite common among miners.

3.4

| FOOD RESOURCES

Food is defined as anything that is able to satisfy the appetite or hunger. It should be able to meet the physiological needs of growth, to supply essential energy required for activity. Food is an essential requirement for human survival. Man eat variety of food as no single food provide us with all the nutrients that we need. Main components of food are carbohydrates, protein, fat, vitamins and minerals. Though there are more than a million plant species we eat only less than hundred. 90% of our food is provided by just 15 plants and 10 animals. The Food and Agriculture Organization (FAO) (FAO) of United Nations recommends minimum caloric intake of 2,500 calories/day. People receiving less than 90% of recommended calorie intake are called undernourished and if it is less than 80% they are said to be seriously undernourished. 3.4.1

World food problems

Shortage of food is a serious problem faced by many countries. In developing countries, food production is unable to meet the demands of the growing population. It is estimated that more than 25% grown food are destroyed by pests and nearly 25% of food is wasted. Another serious problem faced by the world is malnutrition. A rough estimate shows that every year 40 million people (half of which are infants below 5 years) die of undernourishment and malnutrition. WHO aims for food security for all in near future. Food security is achieved only when everyone have access to sufficient, safe, nutritious food all the time. 3.4.2

Environmental impacts related to food resources

1. Overgrazing 2. Impacts of traditional agriculture a) Deforestation b) Soil Soil erosion c) Depletion Depletion of nutrients 3. Impacts of modern agriculture a) Fertilizer related problems b) Pesticide related problems 4. Water logging 5. Salinity problems

1.

Overgrazing

The rapid consumption of grass and other small plants by cattle stock (cows, goat, buffalo, sheep) without giving enough time to regenerate is known as overgrazing. Impacts of overgrazing removal of vegetation · Land degradation and desertification: Overgrazing may result in the removal which leads to land degradation and desertification. In many cases even the roots are eaten away by the cattle.

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·

Soil erosion: Removal of vegetation by cattle stock exposes the topsoil which can removed by water, water, air etc. The grass roots strongly bind top soil. On the removal removal of grass, the soil becomes loose and can be easily removed removed by wind and water. water. Loss of useful species: Overgrazing can result in change in the composition of plant population and its regeneration capacity. capacity. Useful plants may be slowly slowly replaced by thorny bushes, weeds etc.

2. Impacts of traditional traditiona l agriculture agricul ture Traditional agriculture is the most practised form of agriculture around the world. It involves the use of animals for ploughing fields, organic manures etc. Use of chemical fertilizers and pesticides are quite limited. Production is moderate ·

·

·

Deforestation: Forests are cleared for creating more land for cultivation. This can lead to land degradation, loss of fertility of soil and desertification. Soil erosion: Conventional tilling methods make top soil loose which can be easily removed removed by water, water, wind etc. Depletion of nutrients: Repeated monoculture can lead to depletion of soil nutrients and loss in fertility.

3. Impacts of modern agriculture agricul ture Fertilizer related problems A fertilizer is any material which is applied to soil to supply one or more plant nutrients which are essential for plant growth. Fertilizer is essential for increasing soil fertility and hence crop productivity. It has been estimated that about 70 per cent of growth in agriculture can be attributed to increased fertilizers application. However, indiscriminate use of fertilizers can cause the following problems. a) Micronutrient imbalance Plants require nitrogen, phosphorus and potassium (NPK) in large quantities called macronutrients . Other elements like zinc, iron, selenium etc are required in small quantities called micronutrients . Farmers use macronutrients in large quantities for boosting plant growth. This can result in the deficiency of micronutrients affecting soil productivity and fertility. b) Nitrate pollution Nitrogen based fertilizers, especially ammonium nitrate is widely used for increasing crop productivity. It finally reaches water bodies. It also leaches into groundwater. Presence of nitrates in water can cause harmful biological effects. High concentrations can cause a condition called methaemoglobinemia. In presence of nitrate, haemoglobin is oxidized into Methemoglobin. Latter has a decreased affinity for oxygen and can cause reduced oxygen intake to muscles and tissues. Infants may develop a condition called “Blue baby Syndrome or Infantile methaemoglobinemia” where the skin of the infant turns blue due to lack of oxygen. This usually happens when concentration of nitrates exceed 25 mg/L. A high concentration of Nitrate (50 mg/L or more) may cause gastric cancer in adults. It can also adversely affect the proper functioning of central nervous system (CNS). c) Eutrophication Eutrophication is the process by which a water body becomes enriched in dissolved nutrients (as phosphates). Presence of these excess nutrients result in excessive aquatic plant growth which result in the depletion of dissolved oxygen. Eu means “more” and trophic means “nutrition”. Due to eutrophication algae can grow faster using up nutrients.

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Consquences of eutrophication · Increased biomass of phytoplankton · Increased water turbidity · Decrease in Dissolved oxygen content · Loss of fish and other aquatic organisms · Decreases in aesthetic value of the water body · Difficulty in transport

d) Alteration of soil properties Addition of fertilizers changes the pH of the soil. This can kill useful micro organisms present in the soil.

Pesticide related problems Pesticide is a chemical used to kill or retard the growth of pests that damage crops. The ideal pesticide should a) kill only target pest, b) should not cause genetic resistance in the target organism c) biodegradable d) be cost-effective. Indiscriminate use of pesticides has lead to following problems. a) Creation of super pests: Continuous use of pesticides may give rise to pests which are immune to pesticides known as super pests. Species which survive after pesticide spray give rise to highly resistant generations. About 20 species of pests are now known to be super pests. Example: In 1950’s housefly resistant to DDT evolved. Now many fruit flies have become resistant to pesticide Malathion. b) Death of non target organism: Many pesticides applied not only kill the target pests but also several non-target species that are useful to us. Example: Many pesticides are toxic to earthworms, honey bee etc. c) Biological magnification: Many pesticides like DDT are non-biodegradable and water insoluble. However, they are fat soluble and accumulate in the fatty tissues of organisms. This process is called bioaccumulation. The tendency of these chemicals to concentrate in the body of higher organisms of the food chain is called biomagnification.

d) Can induce cancer: Many of the pesticides are known to be carcinogens. Pesticides like endosulfan cause severe genetic and health disorders. Pest control methods · Use of biological predators · Provide homes for the pest enemies · Integrated crop management · Bring in natural enemies · Use pheromones to lure pests into traps · Use hormones to disrupt life cycles

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4. Water logging Waterlogging is saturation of the soil by groundwater sufficient to prevent or hinder agriculture. Flooding and over-irrigation brings under groundwater to the surface. Causes · Over irrigation: Over irrigation of croplands by farmers can result in water logging. · Excessive rainfall and floods: Excessive rainfall and floods may result in water logging if there is no proper drainage system. · Lack of proper drainage: Lack of proper drainage facility can result in water logging. In poorly drained soils, water can’t penetrate deeply, so it is left stagnant on the surface. · Raised water table: Raised water table results in the soils becoming waterlogged. · Incorrect method of cultivation: If the agricultural land is not levelled properly before cultivation, it can result in waterlogging. · Nature of the soil: Some soil like black cotton soil have low permeability and does not allow water to percolate through it. Over irrigation or flooding in such soil may result in water logging. Consequences · Increase in soil salinity: Water logging increases the soil salinity. When water evaporates, the salts are deposited there. This can result in the reduction of crop yield. · Destruction of crops: When soils are water logged, air spaces in the soil are filled with water and cause decay of roots and plant destruction. · Damage of soil structure: Water logging may result in damage of soil structure. · Destruction of micro organisms in soil: Water logging may result in death of useful micro organisms in soil. Waterlogging reduces nitrogen fixation by the nodules of legume · Reduce nitrogen fixation: Waterlogging plants. Nitrogen is lost from waterlogged waterlogged soils by denitrification. · Fall of soil temperature: Due to water logging the soil temperature is lowered. At lower temperature, the activity of soil bacteria becomes slow. · Growth of weeds and aquatic plants: Continuous water logging may convert agricultural land to marshy land. Weeds and aquatic plants may grow plenty. Control measures · Preventing excessive irrigation: Adequate irrigation and not over irrigation can check water logging. · Improving drainage facilities: Water logging can be reduced considerably by improving drainage facilities. · Choice of crops: Some species of crop are more tolerant to water logging than others. Crops having high rate of evapotranspiration should be recommended for the areas susceptible to water logging. · Biodrainage trees: Planting biodrainage trees like eucalyptus can reduce water logging.

5.

Salinity

Soil salinity is the salt content present in the soil. The process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salt content of soil increases mainly by weathering of rocks. Very salty soils may have a white layer of dry salt on the soil surface. Most crops do not grow well on highly saline soils. Where the concentration of sodium salts is high relative to other types of salt, the soil is called sodic soil. Causes · Over irrigation: Over irrigation of croplands by farmers can result in salinity. During day time water evaporates leaving behind salts in the top soil.

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Natural Resources 87 ·

Saltwater intrusion: Intrusion of sea water to farmlands can also result in the increase in salt content of the soil.

Consequences · Low productivity: Most crops do not grow well on salty soil. Highly saline soil is harmful for the plants as the water uptake is reduced. · Varying pH of soil: Salts present in soil will vary the pH of the soil. Soil is made acidic or alkaline depending on the major salts present. Sodic soils are basic in nature. · Death of useful micro organisms: Increase in soil salt content varies the pH of the soil. Variation in pH may result in the death of useful bacteria present in the soil. Control measures · Flushing with fresh water: Excess salt can be washed away by flushing with water. · Plants tolerant to salinity: Certain plants are more tolerant to a high salt concentration than others. Example: Barley, Sugar beet, cotton etc. Cultivating such plants can reduce salinity. Integrated crop management Integrated crop management is a system of crop production which uses sustainable methods conserving the natural resources and with very low environmental impact. 3.4.3 · · · · · · ·

3.5

Role of an individual in conserving food resources

Do not waste food. Take as much as you can eat. Don’t cook food more than required. Reduce the use of chemical pesticides. Use organic fertilizers for your crops. Use drip irrigation to water the crops. Have a vegetable garden at your own home so that you can get fresh vegetables. Eat local and seasonal vegetables.

| LAND RESOURCES

Land refers to the part of earth’s surface which is not covered by water. Land forms one fifth’s of earth’s surface. Surface layer of land is soil. Soil is a dynamic natural body, one the surface of earth in which plants grows and is composed of organic, inorganic materials and organisms. It is formed by the weathering of rocks. Soil has four major components- a) mineral matter b) organic matter c) soil water and d) soil air. Top layer of the soil (top soil) is very fertile containing all the essential nutrients required by plants. It takes approximately approximately 500 to 1000 years for an inch of the top soil to form. 3.5.1

Soil erosion

Removal of top soil from one place to another by various agents like water, wind etc is known as soil erosion. Soil erosion results in the loss of fertility of the soil because of the loss of top soil layer which is fertile. Various agents that bring about soil erosion are water, wind, land slides etc. Every year in India alone water erosion causes loss of 6,000 tonnes of top soil. Causes · Deforestation: Removal of trees make top soil loose and hence can be easily removed by agents of erosion. · Floods and heavy winds: Floods and heavy winds may wash(carry) the top soil causing soil erosion. · Agricultural practices: Traditional agricultural practices like tilling and ploughing expose top soil, which is prone to erosion.

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Control measures 1. Adopt farming farming practices that that conserve conserve soil fertility a. No till farming: No-tillage or zero tillage causes minimum disturbance to the top soil. Here, the seeds are directly inserted into untilled soil. Special tillers are used to break up and loosen the subsurface soil without turning over the topsoil. Small slits are made by tilling machines in the unploughed soil. Seeds, fertilizers, herbicides and water are placed in the slit, so that the seed germinates. b. Contour farming: In contour farming slope is tilled along the lines of consistent elevation. Each row planted horizontally along the slope of the land acts as a small dam to help hold soil and thus preventing soil erosion. This technique also permits increased infiltration of water into the soil.

c. Terracing: This method is used to farm on a hilly or mountainous terrain. Small step like terraces are built on the hilly terrain. This decreases erosion and surface water run off. Rice is cultivated by terracing in many asian countries.

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d. Strip Cropping: In strip cropping, different crops are grown on alternates strips close by. For example, wheat, or other small grains are grown along with strips of crops, such as corn, soybeans, cotton etc. Strip cropping is very efficient in checking erosion.

e. Alley Cropping: In alley cropping, crops are cultivated between the rows of trees or shrubs. This is also called Agro forestry. Even when the crop is harvested, no soil erosion happens as trees and shrubs still hold on to the top soil. Trees like walnut, oak etc are used.

f. Shelter Belt/ Wind breakers: Wind breakers are used in the areas where wind is the major agent of erosion. One or more rows of trees or shrubs planted in such a way that it blocks the wind. The wind speed is thus substantially reduced which helps in preventing wind erosion of soil.

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2. Other methods to prevent soil erosion · Control deforestation. · Afforestation · Construction of series of check dams · In deserts build wind breakers perpendicular to wind movement · Along coasts, growing mangrove forests are effective 3.5.2

Land degradation and desertification

Land degradation refers to the temporary or permanent reduction of the productive capacity of land. Land degradation is a serious environmental issue and it is estimated that up to 40% of the world’s agricultural land is seriously degraded.

Causes: Overgrazing, deforestation, soil erosion, water-logging, water-logging, salinization improper agricultural practices and contamination of the soil with heavy metals, fly-ash etc causes degradation of land.

Consequences: · · · ·

Decline in agricultural output Land may convert into semi-desert or desert. Loss of biodiversity Migration of animals to another place

Desertification is a type of land degradation in which a relatively dry land region is converted into a desert. Over a period land becomes drier, losing water bodies, vegetation and wildlife. Due to drought and desertification each year 12 million hectares are lost (23 hectares/minute!).

Causes: Both natural and anthropogenic (man-made) may lead to desertification. Deforestation: Cutting down of trees result in soil erosion, loss of fertility and loss of water. These all may lead to desertification gradually.

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Overgrazing: Overgrazing of cattle lead to the loss of herbs, shrubs in grasslands. Land may become barren and prone to erosion. Over utilization of ground water: Over utilization of ground water may result in lowering of water table which can lead to desertification. Mining and quarrying: Mining and quarrying lead to the loss of vegetation. Denudation of extensive land areas leads to desertification.

Consequences: · · ·

Loss of productive capacity of land Loss of biodiversity Lowering of water table.

Control measures to prevent desertification · · · · ·

Preventing deforestation and promoting afforestation. Planting of grasses can check soil erosion, floods and water logging. Crop rotation and mixed cropping improve the fertility of the soil. Scientific methods in farming like adopting drip irrigation, no-till farming etc. Employing rain water harvesting methods to preserve and store water

3.5.3

Man induced land slides

Landslides refers to the sudden movement of large amounts of earth, rock, sand or mud or any combination of these. During construction of roads and mining activities near hilly terrain, trees are cut down. This may destabilize soil structure and fragile mountain slopes eventually leading to land slides.

Causes of landslide: Deforestation: Removal of vegetation, trees can destabilize soil structure. It can lead to soil erosion and land slides. Underground mining: Underground mining causes land subsidence. Heavy Rainfall: When sloped areas become completely saturated by heavy rainfall many times landslides can occur. Ground water level: Over exploitation of ground water can lead to landslides. Earthquakes: Seismic waves (small or big) can trigger landslides.

Consequences of landslide: Loss of life and property: Landslides cause large scale destruction of life and property. Severe economic loss may result from landslides. Loss of transportation and communication: Destruction of roads and railway tracks cuts may leave people stranded. Destruction of telephone lines can affect communication. Increase in turbidity in lakes: Due to falling of land masses in the near by lakes, turbidity can increase. Avalanche: Landslides in snow clad mountain ranges can lead to avalanche. 3.5.4 · ·

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Role of an individual in conserving land/soil resources

Plant more trees. Trees help to hold top soil firmly. Adopt no-till farming, terracing, countour farming etc to minimize soil erosion.

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· ·

3.6

Do not irrigate the plants using a strong flow of water, as it would wash off the soil. Use sprinkling irrigation. Grow grass in the open areas which will bind the soil and prevent its erosion. Do not over irrigate agricultural fields. It may result in soil erosion, water logging and salinisation.

| ENERGY RESOURCES

Energy is the capacity to do work. Developmental activities of a nation depend upon the consumption of energy. Lighting, industry, heating and cooling in buildings, household, transportation, all need energy. Energy may in the form of mechanical, chemical, nuclear, thermal, solar etc. Energy in one form can be transformed to another. 3.6.1

Energy conservation process

Energy conversion is the process of converting one form of energy to another. An energy conversion device converts one form of energy into another. Schematic representation of an energy conversion device is given below.

Tasks performed by common energy conversion devices

Energy Conversion Device

Energy Input

Useful Energy Output

Battery

Chemical energy

Electricity

Electric motor

Electricity

Mechanical energy

Fluorescent lamp

Electricity

Light

Silicon solar cell

Solar energy

Electricity

Electric heater

Electricity

Thermal energy

Fuel cell

Chemical energy

Electricity

Conversion efficiency of engines are governed by laws of thermodynamics. 3.6.2

Non-renewable energy resources

These are resources which cannot be renewed. It might become exhausted if not used judiciously. Most of the fuels come under this category. Fuel is any combustible substance which when burnt in oxygen or air, produces significant amount of heat which can be economically used for domestic and industrial purposes for generating power. power. In the process of combustion, the chemical energy of fuel is converted converted into heat energy. energy. Fuel + Air

Products + Energy

®

Solids: Coal, Coke etc Liquid: Petroleum and its derivatives

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Gas: Natural gas Coal: Coal is a fossil fuel which was formed due to the decomposition of plant matter due to heat and pressure over millions of years. There are mainly three types of coal, namely anthracite, bituminous coal and lignite. Anthracite coal has maximum carbon (90%) and hence greater calorific value. When coal is heated strongly in the absence of air, it loses volatile matter and gets converted into lustrous, strong, dense, porous and coherent mass known as coke. Petroleum: Petroleum (also known as crude oil) is found in nature at varying depths below the earth’s surface. The term petroleum comes from latin terms petra means “rock” and oleum means “oil”. Petroleum was formed by the anaeorbic decay of marine animals over millions of years. Under the action of high pressure and temperature, biological matter decomposed to give viscous dark greenish brown liquid known as crude oil. Crude oil obtained from earth cannot be used directly as a fuel but various fractions obtained from its distillation are used as a fuel. The process of removing impurities and seperating the crude oil into various fractions having different boiling points is called refining of petroleum. Refining of petroleum yields different fragments (according to boiling points) such as gas, petroleum ether, petrol, diesel, paraffin wax, asphalt etc. These fragments are used for variety of uses. Nuclear energy: During a nuclear reaction, the nuclei of the atoms changes, i.e. it involves the change in number of protons and neutrons producing atoms of the new element. The energy released during nuclear reaction is very much greater than ordinary chemical reactions. The splitting up of a heavier nucleus using projectile, into two or more lighter nuclei with the liberation of large amounts of energy is known as nuclear fission. The process of fission is always accompanied by the ejection of two or more neutrons. 235 92U

+ 0n1

®

94 36Kr

+

139 56Ba

+ 30n1 + Energy

A nuclear reactor is a device in which nuclear fission reaction is carried out in a controlled rate so that the liberated energy can be utilized for constructive purposes like generation of electricity, heat and mechanical power etc. There are many nuclear reactors in India located at Tarapur (Maharashtra), Rana Pratap Sagar near Kota (Rajasthan), Kalpakkam, Koodankulam (Tamil Nadu) and Narora (U.P.). Advantages of nuclear power generation: power generation does emit relatively relatively low amounts of CO2 and other greenhouse · Nuclear power gases. · It is possible to generate a high amount of electrical energy in one single plant. Disadvantages of nuclear power generation: · The wastes from nuclear reactors are extremely dangerous (highly radicactive) and their disposal is a huge concern. · Despite very high security, accidents can still happen. The consequences of an accident would be absolutely devastating. · Nuclear power power plants could be preferred targets for terrorist attacks. · The energy source for nuclear energy is Uranium. Uranium is a scarce resource, its supply is estimated to last only for the next 30 to 60 years.

Due to rapidly growing population, the demand for energy is also increasing. Conventional energy sources like firewood, coal, petroleum are unable to meet the growing energy requirements. Hence, in the past few decades there is a constant search for new non-conventional energy resources. Nuclear energy, solar energy, wind energy etc are some examples of non-conventional energy resources.

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3.6.3

Renewable energy resources

Renewable energy is defined as energy that comes from resources which are continually replenished (renewed). Example: solar energy, wind energy, geothermal energy, tidal energy etc. 3.6.4

Solar energy

Sun is the ultimate source of energy. All other organisms depend on sun directly or indirectly. The nuclear fusion happens in sun, converting hydrogen to helium. Enormous quantities of energy is released in the form of heat and light. Solar energy is harvested by i) thermal conversion ii) photovoltaic photovoltaic conversion. conversion.

(i) Thermal conversion If heat (thermal) energy associated with the sunlight is used directly for energy conversion, it is called thermal conversion. Some examples are solar water heater, solar cooker etc. Solar water heater Solar water heating system is a device which supplies hot water at 60°C to 80°C using only solar thermal energy. It is usually installed at the terrace or roof top where sunlight is readily available. Water is heated during day time which is stored in an insulated storage tank for use when required. It has three main components, namely,

1. Solar Collector (sensor) 2. Insulated hot water storage tank and 3. Cold water tank with required insulated hot water pipelines and accessories. Working: · Solar collectors collect solar energy. · A dark insulated pipe warms up under the sunlight. · Within the pipe is a heat transfer liquid called the “primary liquid.” · The pipe flows into a cold water tank, the water is warmed up by this pipe and heated water is stored in the tank. · Hot water having lower density moves upwards and cold water with higher density moves down from the tank due to gravity head.

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Solar cooker In solar cooker, solar energy is used to cook, boil water etc. Construction and working A box type solar cooker consisted of an insulated box with a glass cover and a top lid, which has a mirror on its inner side. Mirror reflects sunlight into the box when the lid is kept open. The inner part of the box is painted black. Cooking vessels are placed inside the box. The glass top allows infrared radiations emitted by the sun into the box but reflected radiations of longer wavelength are trapped inside the cooker. Thus temperature inside the box slowly increases. The cooking time is about 1 to 3 hrs depending upon the items being cooked and the intensity of solar radiation.

Advantages of solar cooker Solar cooker has a number of advantages over the traditional cooking devices. These are: · · · ·

It preserves the nutrition value of the food (because the cooking is done at low temperature). It does not require constant attention. It is safe, simple and pollution free. It saves money and fuel.

Disadvantages of solar cooker · Cooking is difficult on winter, rainy or overcast days as availability of sunlight is limited. · Cooking time is longer than conventional cooking. · Factors like wind, rain, mist, snow etc can seriously affect the proper functioning of cooker.

Solar energy can be converted as

(ii) Photovoltaic conversion Photovoltaic cells are semiconductor devices that convert sunlight into electricity. Photovoltaic cells or solar cells are semi conductors made of silicon, cadmium sulphide, gallium arsenide etc which absorbs photons from sunlight and creates electron hole pairs (+ve and –ve charges). A typical photovoltaic cell is composed of a thin wafer consisting of an ultra thin layer of phosphorus doped (n type) silicon on top of a thicker layer layer of boron doped (p- type) silicon. Hence a p-n junction is formed between the two.

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When sunlight strikes the surface of a photovoltaic cell, electron-hole pair is produced. Electrons are drifted and collected at the n-type end and the holes are drifted to and collected at the p-type end. When these two ends are electrically connected through a conductor, there is a flow of current between the two ends through the external circuit. A typical silicon PV cell produces about 0.5-0.6 V dc under open circuit, no load conditions. The current (and power) output of a photovoltaic cell depends on its efficiency and size (surface area), and is proportional to the intensity of sunlight striking the surface of the cell. The electron flow provides the current. Applications · Solar cells are used to provide power supply for space satellites. · Solar cells are used in calculators, watches etc. · Solar cells can provide electricity for street lighting in remote areas, and to run water pumps, radio, TV etc. · Solar cell provide electric power to light houses Advantages of solar energy harvesting devices · Renewable and continuous: Doesn’t exhaust in another million years. · No green house gases: solar energy devices create no pollution. · Long life time for photovoltaic cells: Photovoltaic cells last for more than 10 years · Quick installation: Solar powered panels and products are easy to install. · Low environmental impact: The environmental impact made is positive · Can be moved easily: Solar energy based devices are very convenient to handle. · Low maintenance: The maintenance expenditure is very less. · Government incentive: Tax incentives, various credits and rebates encourage people to go green. · Can be used for many purposes: Solar devices include solar panel, solar water heater, solar cooker, solar powered vehicles. Disadvantages · Expensive: The Solar Cells/ Solar Panels tend to be very expensive when you first purchase them. · Cannot be used all the time: Solar power cannot be harnessed during a storm, on a cloudy day or at night. · Large area: A solar energy installation requires a large area for the system to be efficient in providing a source of electricity. · Affected by pollution: Pollution can degrade the efficiency of photovoltaic cells · Low efficiency: Solar cells have less efficiency (~ 25%).

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3.6.5

Wind energy

Wind is air in motion. Moderate to high speed wind has lot of energy in them. Wind energy can be harnessed by making use of wind mill. In a wind mill, kinetic energy present in the wind is converted into more useful form of mechanical energy or electrical energy. The wind power potential of our country is estimated to be about 45,000 MW. Largest wind farm established near Kanyakumari in Tamil Nadu generates 380 MW of electricity. India ranks fifth in harnessing wind energy for the production of electricity. electricity. The minimum wind speed required for satisfactory working of a wind generator is 15 km/hr.

Wind turbines are used to produce electricity. The blades of wind turbines will keep on rotating continuously due to the force of the striking wind. The rotation of the blade spins a shaft which is connected to a generator that produces electricity. Merits · Wind energy is renewable and readily available. · It does not create any kind of pollution. · Relatively easy installation. · Area beneath the farm can be used for cultivation, grazing etc. Limitations · Minimum speed of the wind should be 15 km/hr. · Direction of wind is not predictable. · Seasonal variation occurs in the velocity of wind. · Wind farms can disturb radio and TV signals. · Wind farms cause noise pollution. 3.6.6

Biogas energy

Biogas is produced by the decomposition of biological matter by bacterial action(anaerobic action) in the absence of oxygen. The common biological matters used for decomposition are wood, crop residues, cattle dung, manure, sewage, agricultural wastes etc. Cheapest and easily obtainable biogas is gobar gas produced by the anaerobic fermentation of cattle dung.

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The essentials of a gobar gas plant are · · ·

a digester, a well constructed masonry work, dug and built usually below the ground level. a steel gas holder which cover digestor. a pipeline for transport.

The raw material for the biogas is mainly cow dung, which subjected to anaerobic fer mentation. Anaerobic fermentation refers to fermentation in the absence of free air, caused by anaerobic bacteria. The process is car ried out in a closed steel or concrete tank. A slurry slur ry is made by mixing equal parts of fresh cattle dung and water, is poured into the tank. Anaerobic bacteria which are present in the dung, digest this slurry forming mainly methane and CO2. The gas produced is transported by the pipeline. The optimum temperature for this fermentation is 34 - 38 °C. The gas generated is collected in a steel gas holder, placed on the top of digestion tank. The average composition of gobar gas is CH4 = 55%; H2 = 7%; CO2= 35% N2 = 3% Advantages · Biogas is a renewable source of energy. · Biogas produces much lesser pollution. · Biogas energy is relatively cheaper and reliable. · Biogas can be generated from everyday human and animal wastes. · Heat energy that one gets from biogas is about three times the heat from burning wood. Disadvantages · Initial investment for construction of the plant is high. · Continuous supply of biomass is required to generate biomass energy. A continuous supply is not easy. · Crops which are used to produce biomass energy are seasonal and are not available over whole year. · Continuous generation of biomass is not easy unless one have cattle farm. · Some people don’t like to cook food on biogas produced from sewage waste. · Biogas plant requires space and produces dirty smell. · It is difficult to store biogas in cylinders. · Transportation of biogas through pipe over long distances is difficult; hence the gas stove or burner must be quit close to the plant. 3.6.7

Geothermal energy

Geothermal energy is the energy obtained from the inside of the earth. High temperature exists below the earth’s earth’s surface in many places. Temperature Temperature increases by 3 degree Celsius, for every 100 meter depth. Cold water is injected into the wells drilled into this rock. Some of this water will absorb intense heat and become steam. This steam is used to spin turbines and produce electricity.

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Advantages · Geothermal energy generally involves low running costs. · Geothermal energy reduce the reliance on fossil fuels. · Geothermal energy does not create any pollution and help in creating clean environment. · Since ancient times, people having been using geothermal energy for taking bath, heating homes, preparing food etc. Today this is also used for direct heating of homes and offices.

Disadvantages ·

Geothermal energy can harnessed only at some selected location.

3.6.8

Ocean thermal energy

In oceans, there is a temperature difference between cooler deep and warmer shallow or surface ocean waters. Ocean thermal energy conversion makes use of this temperature difference to run a heat engine and produce useful work, usually in the form of electricity. A difference of 20°C or more is required between surface water and deeper water to harvest Ocean Thermal Energy effectively. With this heat difference, low boiling liquid like ammonia is boiled, the vapors formed are used to turn the turbine of a generator and produce electricity. OTE conversion can also supply quantities of cold water as a by-product. Advantages · Renewable process · No pollution, no greenhouse gas emission. · Works day and night. · Once installed, it is cheap. Less maintenance costs. Disadvantages · Needs a large difference in temperatures (surface and deep) for best results. · Extremely low efficiency. · Seawater is corrosive, storms can do great damage 3.6.9 · · · · ·

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Role of an individual in conserving energy resources

Turn off lights, fans and other appliances when not in use. Use pressure cooker for cooking. This makes cooking faster and saves fuel. Use fluorescent lamps and LED’s instead of incandescent lamps. This save a lot of power. Always cook in closed containers so that energy wastage is minimum. Check your vehicle for oil leakages and maintain it in a good condition.

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· ·

· ·

·

3.7

Swtich off electrical equipment completely when not in use. For example switching off the television just with the remote still consume power. Dry the clothes in sun instead of drier. Use solar cooker for cooking your food and solar water heater will cut down on your energy expenses. Use solar lanterns. Grow trees near the houses and get a cool breeze and shade. This will cut off your electricity charges on A/C and coolers. Drive less and use mass public transportations whenever possible. Use bicycles to commute. Join a car-pool to office and return. Use metro rail service for easy hassle free travel.

lifestyles | Equitable use of resources for sustainable lifestyles

Natural resources are limited. Scarcity of resources is a big problem addressed by human community. Many parts of the world are using natural resources at a rate faster than the nature can replenish it. If unchecked, natural resources will be over exploited. It is essential to use natural resources wisely. We should conserve natural resources so that it may yield benefit to the present generation while maintaining its potential to meet the needs of the future generation. Sustainable development is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The following methods may be suggested for the equitable use of resources

·

Proper management of water resources. Proper watershed management and adopting rain water harvesting techniques. Checking deforestation and promoting afforestation. Practicing scientific and eco friendly agricultural practices.

·

Use of renewable energy resources.

· · ·

3.8

| Environmental biochemistry

Environmental biochemistry refers to the treatment of polluted air, waste water and solid waste using metabolic activities of micro-organisms. A xenobiotic is a foreign chemical substance found within an organism that is not normally naturally produced by or expected to be present within that organism (Greek, xenos “foreign”; bios “life”). Environmental xenobiotic are xenobiotic substances with a biological activity that are found as pollutants in the natural environment. 3.8.1

Degradation of proteins

Proteins are macromolecules, consisting of one or more long chains of amino acid residues. Proteins catalyze metabolic reactions, replicating DNA, responding to stimuli, and transporting molecules from one location to another. Proteins contain numerous peptide bonds, hence known as a polypeptide. Peptide bonds are formed by the reaction between a carboxylic acid and amine.

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Protein can be easily hydrolyzed by acids and bases. Proteins on hydrolysis give individual amino acids from which it is formed. Aminoacids are futher decomposed to ammonia. Some bacteria like Nitrosomonas species convert convert ammonia (NH3) to nitrite (NO 2 – ). While species like nitrobacter converts nitrites (NO2 – ) to nitrates(NO3-) which are readily absorbed by plants. Amino acid 3.8.2

Ammonia

®

Nitrites

®

Nitrates

®

Biochemical degradation and Bioconversion of pollutants

Microbes have the ability to transform and/or degrade man made chemicals. Biotransformation of organic contaminants in the natural environment has been widely studied. According to the definition by the IUPAC, the term biodegradation is “Breakdown of a substance catalyzed by enzymes in vitro or in vivo”. Biodegradation can be alteration of chemical structure resulting in the loss of harmful property or it can be converted to non hazardous compound. In some cases, complete breakdown of the pollutant happens. It is either fully oxidized or reduced to simple molecules (such as CO2/CH4, NO3 – /NH4+ and H2O). The most common biodegradation is that of organic compounds in the presence of air called aerobic process. In the absence of air, anaerobic biodegradation also happens. Detoxification refers to the biological conversion of a toxic substance to a less toxic species. An example for detoxification is the enzymatic conversion conversion of paraoxon (a highly toxic organophosphate insecticide) to p-nitrophenol, which has only about 1/200 th toxicity of the parent compound.

The complete bioconversion of a substance into inorganic species such as CO 2, H2O, NH3, phosphate etc is called mineralization. Certain bacteria convert phenol, toluene into CO 2 and water.

Biodegradable Biodegradable plastics are plastics that are capable of being decomposed by bacteria or other living organisms.

Examples of biodegradable plastics ·

· ·

While aromatic polyesters are almost totally resistant to microbial attack, most aliphatic polyesters are biodegradable due to their potentially hydrolysable hydrolysable ester bonds. Polyanhydrides, Polyvinyl alcohol Most of the cellulose and starch derivatives

Biodegradation of pesticides Many pesticide residues (organochlorines, organophosphates and carbamates) are degraded by micorganisms like fungi, bacteria, viruses, protozoa etc. Extend of pesticide degradation depends on the physico-chemical properties of the pesticide, characteristics of the soil, environmental conditions and management practices.

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Pesticide Structure Pesticides having polar groups such as OH, COOH and NH 2 are relatively easily attacked by micro organisms. Halogen or alkyl substituents are more resistant to biodegradation.

Pesticide concentration Generally, the rate of degradation decreases with increase in the residual pesticide concentration.

Pesticide Solubility Pesticides with low water solubility tend to be more resistant to microbial degradation than compounds of higher water solubility.

Biodegradation of DDT Many soil bacteria which belong to genera Bacillus, Pseudomonas, Arthrobacter and Micrococcus are involved in organochlorine degradation.

ANNA UNIVERSITY QUESTIONS 1. Describe the causes and effects of deforestation


2. Discuss the effects of over utilization of surface and groundwater. 3. Explain any two conflicts pertaining to our nation. 4. What are the benefits and problems associated with dams? 5. Discuss the effect of dams on tribal people. 6. Explain the environmental impact of mining. 7. Explain in detail about the problems of chemical fertilizers and pesticides on modern agriculture. (Anna Univ, Dec2014) 8. What is land degradation? Discuss the factors responsible for land degradation? (Anna Univ, Dec2014) 9. What are the changes caused by agriculture and overgrazing?

(Anna Univ, Dec2014)

10. What is soil erosion? How can it be prevented? 11. Write a short note on renewable energy resources. 12. Write a note on biochemical degradation of pollutants. 13. Discuss the production of biogas. Mention its uses.

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Unit

4

SOCIAL ISSUES AND THE ENVIRONMENT

SYLLABUS From unsustainable to sustainable development – urban problems related to energy – water conservation, rain water harvesting, watershed management – resettlement and rehabilitation of people; its problems and concerns, case studies – role of non-governmental organization- environmental ethics: Issues and possible solutions – 12 Principles of green chemistry- nuclear accidents and holocaust, case studies. – wasteland reclamation – consumerism and waste products – environment production production act – Air act – Water act – Wildlife protection act – Forest conservation act –The Biomedical Waste Waste (Management and Handling) Rules; 1998 and amendments- scheme of labeling of environmentally friendly products (Ecomark). enforcement machinery involved involved in environmental legislation- central and state pollution control boards- disaster management: floods, earthquake, cyclone and landslides. Public awareness.

4.1

| SUSTAINABLE DEVELOPMENT

Rapid increase in human population and urbanization has led man to overexploit overexploit natural resources. Now, Now, our natural resources are depleting on an alarming rate. If this over over exploitation goes unchecked, it can cause various environmental problems. Sustainable development can be defined as meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. Sustainable development means improving the life of the people. It suggest that well being of humans and other living beings should be extended over over many generations than just few years.

Achieving sustainable growth and development ·

·

·

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Adopting green technology: Using green technology (environment and eco-friendly, pollution free) can help in making the development development sustainable. Refuse, Reduce, Reuse, and Recycle approach: The 4-R approach (Refuse, Reduce, Reuse, and Recycle) suggests refusal of non-renewable resource unless it is absolutely essential, minimization of resource use, using and reusing rather than passing it on to the waste stream and recycling the materials can help in achieving the goals of sustainability. These steps help to reduce pressure on our resources and minimize waste generation and pollution. Environmental education and awareness: Teaching people about environment, the need for preserving environment help to create an environmental awareness. Environmental education right from childhood can help to develop an aptitude for environmental protection and preservation.

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·

·

·

4.2

Prudent use of renewable resources: Natural resources must be used such that the consumption should not exceed regeneration capacity. This means that enough time should be given for the resource to replenish naturally. naturally. That is, over exploitation should be avoided. avoided. Conservation of non renewable resources: Non renewable resources should be conserved by recycling and reusing. Population control: Population explosion is the root cause of many the environmental problems. By controlling controlling or slowing slowing down down population growth, growth, sustainability can be achieved. achieved. Government Policies: Strict policies and laws must be enforced regarding the use of natural resources. Coordinated efforts are required across all government government and non-government non-government sectors.

| URBAN PROBLEMS RELATED TO ENERGY

Energy is essential for humans irrespective of where he lives (rural or urban). Though over 75% of Indian population lives in rural areas, only less than 25% of energy is consumed by them. This essentially means that major chunk of energy are being consumed by urban society. This is because urban people have a higher standard of life and their life style demands more energy. Energy is used primarily for (i) residential and commercial purposes, (ii) industry and (iii) transportation. Some of the major urban problems related to energy are as under: ·

·

Electricity: Electricity is an absolute necessity for urban society. Housing gadgets like television, computer, fan, refrigerator, music systems, geysers, lights, air conditioners, microwaves, etc. all work using electricity. A major part of electricity is lost in transmission and some part is stolen. Remaining part is simply not enough to meet the urban energy requirements. So, many cities face power regulation for 1-3 hours daily. Fossil fuels (petroleum, natural gas and coal): Man depends greatly on fossil fuels for transportation and energy.

i) Petrol and Diesel: Petrol and diesel are obtained from crude oil. Internal combustion engines use petrol and diesel as fuels. Every day thousands of new vehicles hit the road which causes demand for fuel and lead to price hike. Fuel prices are also increased. Any increase in fuel price will lead to inflation and rise in commodity prices. ii) Liquified Petroleum Gas (LPG): Liquified Petroleum Gas (LPG) is widely used as domestic fuel. With the expanding population, there is a greater demand for LPG cylinders. Earlier, LPG was used only for cooking. Now many vehicles are powered by LPG. iii) Coal: Coal is a non-renewable resource. Entire coal reserves may last for another 150 years. Many thermal power plants are powered by coal. Railway also uses coal widely. iv) Fuel wood: Many rural people still depend on firewood as their primary fuel. Use of wood as fuel is mainly responsible for deforestation.

4.3

| WATER CONSERVATION

Clean water is becoming increasingly scarce globally. Since less people have access to fresh water, it has to be conserved. One of the most widely used method for conservation of water is rainwater harvesting. 4.3.1

Rainwater harvesting

Rainwater harvesting is a technique of collecting and storing rainwater and increasing the recharge of ground water by collected water.

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Social Issues and the Environment 105

Objectives: Rainwater harvesting has the following objectives: · · · · ·

to to to to to

meet the growing water requirements raise the water table by recharging ground water reduce run off loss avoid flooding of roads reduce groundwater contamination

There are two main techniques of rain water harvestings a) Storage of rainwater on surface for future use b)Recharge to ground water. a) Storage of rainwater on surface for future use In this method rain water collected from the roof of the building and then sent to a storage tank. Storage tank is designed according to the water requirements and amount of rainfall. Drainpipe have a mesh filter at mouth and is filtered before connecting to the storage tank. Water from storage tank can be used for secondary purposes such as washing and gardening etc. This is the most cost effective way of rainwater harvesting. It also saves transportation and distribution expenses.

b) To recharge ground water Rainwater harvesting can be used to recharge ground water aquifers to ensure percolation of rainwater preventing surface run-off. Commonly used recharging methods are include recharging of bore wells, dug wells, recharge pits etc. Structures like recharge pits and trenches allows water percolation through soil at lower depth while other structures like borewell allows water percolation to greater depth. In roof top rainwater harvesting, rain-water from the top of the roofs can be used to recharge water table by sending the stored water through dug-well or hand pump.

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Advantages of Rainwater harvesting Rainwater harvesting helps in · · · ·

4.4

recharging the aquifers improving groundwater quality improving soil moisture content reducing soil erosion by minimizing run-off water.

| WATERSHED MANAGEMENT

A watershed is a geographic area through which water flows across the land and drains into a common body of water, whether a stream, river, lake, or ocean. Size of watershed can vary from a few square kilometres to few thousand square kilometers. Watershed consists of complex interactions between various biotic and abiotic factors. Watershed is directly involved in agricultural production, water supply for irrigation, power generation, transportation etc.

Objectives of watershed management · · ·

To use watershed for domestic water supply, irrigation, hydropower generation etc. To use watershed for minimizing soil erosion and moisture retention. Effective watershed management can be used to minimize the risks of floods, droughts and landslides.

Various measures taken up for management include the following: Soil conservation: A series of long trenches are built to hold the rainwater and allow it to percolate into the ground and fully recharge water table. Trees, grass, herbs are planted to hold

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the soil together and prevents it from being washed away during rain. Modern agricultural practices such as no-till farming, terracing, contour cropping, strip cropping are also practiced to reduce erosion. Rain water harvesting: Rainwater harvesting is done to replenish the water table. It also helps in moderation of floods. Afforestation and Agroforestry: Afforestation and agroforestry help to prevent soil erosion and retention of moisture. Woody trees are grown in high rainfall areas in between crops to reduce the surface runoff and loss of top soil. Scientific mining and quarrying: Unscientific mining may result in lose of stability of hilly terrain. This can result in landslides, rapid erosion etc. Public participation: Public participation only makes a watershed management program success. Government and NGO have a big role to play. Awareness and environment education or paying certain incentives to them can help in effective public participation.

4.5

| RESETTLEMENT AND REHABILITATION ISSUES

Major projects like dams, mine, railway, express highways etc may result in displacing large number of people. Native people who occupy the project site are directly affected. These native people are generally very poor, uneducated and directly depend on natural resources for their livelihood. Displacement problems due to dams: In India, in the past 50 years more than 20 million people have been directly or indirectly affected by the construction of big dams. Hirakud Dam has displaced more than 20,000 people residing in about 250 villages. Displacement due to Mining: Mining also cause displacement of the native people in large numbers. Several thousands of hectares of land are required for mining operation. Forests are destroyed and the native people are displaced. Displacement due to Creation of National Parks: To protect some endangered species, some forest area is often declared as a National Park. This restricts and prohibits any kind of human activity within the forest area. Natives and tribals are forced to shift from their habitat.

Rehabilitation problem Some problems associated with rehabilitation are Poverty: Tribals are usually the most affected amongst the displaced as they are already poor. Displacement and rehabilitation only increases their poverty due to loss of land, home, jobs, food insecurity etc. They often find it difficult to adjust with the new living conditions. Loss of cultural values: Most of the cultural activities are very closely associated to their habitat. Marriages, social and cultural functions, their folk-songs, dances and activities suffer with their displacement. Loss of heritage: Culture and indigenous knowledge inherited from forefathers are lost. Tribals have great knowledge about local medicinal plants and know how to cure many diseases. Ignorant of market trends: Tribals are not familiar with the current market policies and trends. They are illiterate and are exploited and fooled easily. Conflicts: Resettlement also affects the people who have been living in that area which was selected for resettlement. Cultural diversity, religious practices, food habits etc can result in conflicts. Both communities can fight over natural resources.

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4.6

| ROLE OF NGO

NGO’s NGO’s are nongovernmental nongovernmental organizations. The main function of NGO’s NGO’s is to advise the government about some local environmental issues. They can act both as an ‘action group’ or a ‘pressure group’. NGO’s can be very effective in organizing public movements for the protection of environment through creation of awareness. NGOs have been constantly working day-in and day-out to solve various problems concerning global and local environment issues. The activities of NGO are not limited to environmental, social and human rights work. It plays a major role in improving society, promoting citizen participation etc.

Objectives of NGOs · · · · · ·

·

Conducting awareness programs about environmental protection. By undertaking research and publication on environment and development related issues. NGOs can inform or suggest policy makers about the local needs and priorities. Helping the public in case of disaster, hazards etc. Filing public interest litigations Remaining neutral and un-biased while passing relevant information to the public and governmental bodies Solidarity and support to eco-warriors, environmental supporters.

Some of the activities taken up by NGO’s include – solid waste management, zero waste management, afforestation, vegetable roof gardening, rainwater harvesting, AIDS awareness, pollution control etc. Greenpeace is a non-governmental environmental organization with offices in over fifty countries with head office in Amsterdam, the Netherlands. Activities of Greenpeace have made huge impacts all over the globe. In India NGO has played crucial role for environmental protection. Chipko Movement for conservation of trees by Dasholi Gram Swarajya Mandal or the “Narmada Bachao Andolan” against Narmada dam are some examples. The Bombay Natural History Society (BNHS), the World Wide Fund for Nature - India (WWF, India) Kerala Sastra Sahitya Parishad, Centre for Science and Environment (CSE) and many others are playing a significant role in creating environmental awareness. The total number of NGOs in our country is about 70,000. They have a great role in creating environmental awareness, awareness, disseminating information and promoting sustainable growth and development.

4.7

| ENVIRONMENTAL ETHICS—ISSUES AND POSSIBLE SOLUTIONS

Environmental ethics deals with issues related to the rights of individuals that are fundamental to life and well being. It includes a search for moral values and principles. Ethics also deals with the rights of other living creatures to exist. Needs of future generations are also addressed. The attitude of people in ancient time towards environment was mainly governed by religious beliefs, practices and cultural traditions. For example, ancient people used to worship sun, moon, earth. Plants like tulsi, neem, banyan etc were considered holy. Animals like cow, elephant, snake etc were worshipped. Rivers like Ganga, Yamuna, Pamba were considered holy. We believed everything is made up of panchabhootha (five elements- prithvi (earth), jal (water), agni (fire), vayu (air) and akash (sky)). But now man exploits nature for his own prosperity. Some important ethical guidelines known as Earth ethics or Environmental Ethics are as follows: ·

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Whole earth is a part of our body and we must learn to respect it as we respect ourselves. Honor the earth since it has blessed you with life and governs your survival.

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Social Issues and the Environment 109 · ·

· ·

·

4.8

Nature doesn’t exist primarily for human use but for all living species. Humans are not above other living things and have no right to drive other living things to extinction. Man should be grateful to the plants and animals as they nourish you by giving food. Natural resources should not be over over exploited as it is for the use of future generations as well. Future generations have their right to live in a clean and safe planet. Mahatma Gandhi has aptly summarized ethics as “There is enough for everybody’s need, but not for anybody’s anybody’s greed”.

| 12 PRINCIPLES OF GREEN CHEMISTRY

Green chemistry is a philosophy of chemical research and engineering that encourages the design and synthesis of chemicals and processes in an environmental friendly way. Paul Anastas and John C. Warner developed 12 principles of green chemistry, which help to explain what the definition means in practice. 1. Prevention: It is better to prevent waste than to treat or clean up waste after creation. 2. Atom Economy: Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. 3. Less Hazardous Chemical Syntheses: Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment. 4. Designing Safer Chemicals: Chemical products should be designed to affect their desired function while minimizing their toxicity. 5. Safer Solvents and Auxiliaries: The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used. 6. Design for Energy Efficiency: Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure. 7. Use of Renewable Feedstocks: A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable. 8. Reduce Derivatives: Unnecessary derivatization (use of blocking groups, protection/ deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste. 9. Catalysis: Catalytic reagents (as selective as possible) are superior to stoichiometric reagents. 10. Design for Degradation: Degradati on: Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment. 11. Real-time analysis for Pollution Prevention: Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances. 12. Inherently Safer Chemistry for for Accident Prevention: Prevention: Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions, and fires.

4.9

| CLIMATE CHANGE

Climate change refers to change in average weather conditions over a period of time. Earth’s temperature has changed considerably during past few decades. The surface of the Earth has

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warmed, on average, 0.3 to 0.6 °C over last century. Change in rainfall pattern, hot or cold spells of temperature, or cyclones and floods was observed in many countries. 4.9.1

Green house effect and global warming

Sun is the primary source of energy for earth. Nearly 30% of the solar radiation falling on earth’s surface is reflected back to the space. Rest of the radiation is trapped by earth’s atmosphere. The amount of heat trapped in the atmosphere depends mostly on the concentrations cer tain gases called green house gases. The major green house gases are carbon dioxide, ozone, methane, nitrous oxide, chlorofluorocarbons (CFCs) and water vapor . The resultant warming of earth’s surface due to increase in concentration of these these gases gases is called called the greenhouse effect. Heating effect is similar in nature to a botanical greenhouse. In greenhouse, glass panes allows the sunlight to enter inside but it cannot escape outside as it is trapped. This causes inside of green houses to remain warm in winter. The average global temperature is 15°C. In the absence of green house gases this temperature would have been –18°C. Therefore, Green House Effect contributes a temperature rise of about 33°C. Heat trapped by green house gases in the atmosphere keeps the planet warm.

The concentration of CO2 in the Earth’s atmosphere was about 280 parts per million by volume (ppmv) in 1750, before the Industrial revolution began. In 2014, it is 397 ppmv and rising by about 1.5 ppmv per year. If emissions continue at current rate, the concentration will be around 500 ppmv by the end of this century. century. Deforestation, use of fossil fuels, use of CFC’s CFC’s are responsible for increase in green house gases. In the past few decades, earth’s temperature has increased by 2-3 degrees. This effect is known as global warming. Greenhouse effect leads to global warming.

Causes of green house effect ·

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Deforestation: Due to deforestation, photosynthesis takes place to lesser extend. This increases CO2 content in the atmosphere resulting in global warming. Burning of fossil fuels: Large amount of greenhouse gases (CO2, NOx, SOx etc) are released into the atmosphere due to the burning of fossil fuels, oil, coal and gas. Electrical Appliances: Chlorofluorocarbons (CFCs) are widely used in refrigerators as coolants, in aerosol cans, foaming agents, fire extinguisher chemicals etc. These gases slowly make way into earth’s atmosphere resulting in global warming. Population explosion: Population growth increases CO 2 level (by respiration). With the increase in population, the needs and wants of people increase leading to urbanization and industrialization resulting in higher green house emission.

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Consequences of Greenhouse Effect ·

·

·

·

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·

Global temperature increase: It is predicted that the earth’s average temperature will rise between 2 to 5°C by 2050 if greenhouse gas emission continues to rise at the present rate. Rise in Sea Level: With the increase in global temperature there will be rise in sea water levels mainly due to melting of polar ice caps and glaciers. An increase in the average temperature of 3°C would raise the average global sea level by 0.2-1.5 meters. Many coastal cities like Cairo, Bangkok, Sydney and Venice may submerge. Agricultural fields in Bangladesh, India, China will be submerged in water. This will also cause damage to lagoons, estuaries and coral reefs. Effects on Human Health: Global warming will lead to changes in the rainfall pattern in many areas. Places where experience more rainfall may result in the spreading of vector borne diseases like malaria, filariasis etc. Warmer temperature and water stagnation may assist breeding of mosquitoes and other vectors. Effects on Agriculture: Global warming can lead to water scarcity and may result in drought. As a result of global warming, soil moisture will decrease and evapo-transpiration will increase. This can result in damage of many crops like wheat, maize etc. Rise in temperature and humidity will increase growth of pests. Natural disasters: Source of origin for many Indian rivers like Brahmaputra, Ganges, Indus are The Himalayas. Melting of ice can lead to frequent flooding. Rise in temperature of oceans may result in more frequent and stronger hurricanes. Ocean acidification: Increased levels of CO2 in atmosphere cause more dissolution of CO2 in ocean water. CO2 dissolved in the ocean forms carbonic acid, resulting in acidification. This can adversely affect marine organisms.

Control of Global Warming To slow down global warming the following steps will be important: · · · · · · · ·

Control deforestation and plant more trees. Shift to renewable energy resources. Cut down the current rate of use of CFCs and fossil fuels. Use energy more efficiently. Nuclear Pow Power er Plants can be used for generating electricity as it emits emits less green house gases. Shift from coal to natural gas. Adopt sustainable agriculture. Stabilize population growth.

4.10

| WASTE LAND RECLAMATION

Wasteland is an empty area of land which is devoid of cultivation or built on or used in anyway. These are economically unproductive unproductive lands suffering fr om environmental deterioration. The wastelands include salt-affected lands, sandy areas, gullied areas, snow covered areas, glacial areas, barren hill-ridge etc. Wasteland has nearly or completely lost its topsoil. It is unfit for cultivation. Waste land formation can happen due to · · ·

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Water and wind erosion. Physical degradation like water logging, desertification etc Chemical degradation like salinisation, acidification, nutrient removal, decrease of organic matter.

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Wasteland can be classified into three forms: a) Easily reclaimable b) reclaimable with some difficulty and c) reclaimable with extreme difficulty. Easily reclaimable wastelands can be modified and used for agricultural purposes. Those which can be reclaimed with some difficulty can be utilized for agroforestry. Wastelands that are reclaimed with extreme difficulty can be used for forestry or to recreate natural ecosystems. National Wasteland Development Board (NWDB) aims at the reclamation and use of waste lands.

Methods for reclaiming land Land development and leaching: For reclamation of highly saline soil, salts from the root-zone is removed by applying excess amount of water to push down the salts. This is known as leaching. Continuous leaching and flushing for few hours can remove 90% of soluble salts. Reclamation of waterlogged land: Drainage is required r equired for water-logged land. In many fields water stands on the fields after heavy rains. In such places, ditches are built to runoff the excess water. Irrigation Practices: Scientific irrigation practices can help in waste land recovery. recovery. Over-irrigation may lead to water-logging while under-irrigation may lead to desertification. Selection of tolerant crops and crop rotations: Some crops like barley, sugar beet and date-palm are highly tolerant which do not suffer from any reduction in crop yield even in highly saline soil. Wheat, pearl millet, soyabean, mustard and coconut are also salt-tolerant crops. Such crop combinations can be grown on saline soils and wasteland can be reclaimed. Adding Gypsum: Adding gypsum to high sodium soils reduces soil sodicity as calcium from gypsum replaces sodium. Green-manures, fertilizers and biofertilizers: Salinity of soil was improved by the addition green manure or nitrogen fertilizers. Biofertilizers based on blue green algae were found to improve salt-affected soils. Afforestation Programmes: Afforestation can prevent the problem of spreading wasteland.

4.11

| CONSUMERISM AND WASTE PRODUCTS

Consumerism refers to the consumption of resources by the people. It refers to the increased use of consumer products by the people to satisfy their needs and lead a more easy life. People in developed countries make up 20% of the world population but consume 80% of the world’s resources and produce 80% of wastes. Two types of conditions of population and consumerism exist. (i) People over-populati over-population: on: This occurs when population is huge and supplies of food, water etc are limited. This leads to poverty, under nourished people and even deaths. This occurs in less developed countries (LDCs). Here, per capita consumption is less although overall consumption is high. (ii) Consumption Cons umption over-populati over-population: on: This occurs when population size is smaller. Resources are abundant and due to luxurious life-style, per capita consumption of resources is very high. This is found in more developed countries (MDCs). More consumption leads to more waste generation and greater is the degradation of the environment.

In LDC.s - No. of people is very high, but per capita use of resources and waste generated are less.

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In MDC.s - No. of people is low, but per capita use of resources and wastes generated are very high.

4.12

| ENVIRONMENTAL LEGISLATION

The need for environmental protection was discussed in the U.N. Conference on Human Environment in Stockholm, on 5th June, 1972. From then on, 5 th June is celebrated all over the world as World Environment Day. Many countries including India took substantive legislative steps by enforcing laws for environmental protection. Some acts developed by our country include The Wildlife (Protection) Act was passed in 1972, followed by the Water (Prevention and Control of Pollution) Act 1974, the Forest (Conservation) Act, 1980, Air (Prevention and Control of Pollution) Act, 1981and subsequently the Environment (Protection) Act, 1986. 4.12.1

The Environment Protection Act, 1986

This act came into force on November19, 1986, the birth anniversary of our late Prime Minister, Indira Gandhi. This act is aimed to protect and improve the quality of environment by Central Government with the coordination with State Government. The Act clearly states and explain each and every term very precisely like environment, environmental pollutants, environmental pollution, handling, hazardous substance, prescribed.

General Powers and functions of the Central Government 1. Subject to the provisions provisions of this Act, the Central Government Government shall have the power power to to take all measures, as it deems necessary for the purpose of protecting and improving the quality of the environment. 2. Planning and execution execution of a nationwide program for the prevention, control and abatement abatement of environmental pollution; 3. Laying down standards for the quality of environment environment in its various various aspects; 4. Laying down standards for emission or discharge discharge of environmental environmental pollutants from various various sources. 5. Restriction of areas in which any industries, operations or processes processes or class of of industries, industries, operations or processes shall not be be carried out or shall be carried out subject to certain certain safeguards; 6. Laying down procedures and safeguards for the the handling of hazardous hazardous substances; 7. Examination of such manufacturing processes, materials and substances substances which which are likely likely to cause environmental pollution; 8. Carrying out and sponsoring investigations investigations and research relating to problems of environmental environmental pollution; 9. Inspection of any premises, plant, equipment, machinery, machinery, manufacturing or other processes, and to take steps for the prevention, control and abatement of environmental pollution; 10. Preparation of manuals, codes codes or guides relating to to the prevention, prevention, control and abatement of environmental pollution.

Functions of the state government The important functions of the state government are 1. Advice the industries in the state to treat their wastes before their their release into the environment. environment. 2. Encouraging industries to recycle and reuse their wastes.

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3. Promoting the implementation of clean technologies by the industries in in order to increase fuel efficiency and reduce environmental pollution. 4. Granting permission for the discharge of effluents effluents and emissions into the environment only after assessing the assimilative capacity of the receiving atmosphere/water body. The Environmental protection of 1986 was amended in 1994 to include Environmental Impact Assesment (EIA) of various developmental projects. These projects have to take clearance from the Central government prior to establishment. 4.12.2

The water (Prevention and control of pollution) Act, 1974

Indian Government has formulated this Act in 1974 to prevent pollution of water by industrial, agricultural and household wastewater. Pollution is defined as contamination of water, or alteration of the physical, chemical or biological properties of water, water, or discharge which is likely to render the water harmful or injurious to public public health, health, or to aquatic aquatic plants or animals. The salient features and provisions of the Act are the following: ·

· ·

·

·

It provides for maintenance maintenance and restoration of quality of all types of surface and ground water. It provides for the establishment of Central and State Boards for pollution control. It confers them with powers and functions to control pollution. The Central and State Pollution Control Boards are widely represented and are given comprehensive powers to advise, coordinate and provide technical assistance for prevention and control of pollution of water. The Act has provisions for funds, budgets, accounts and audit of the Central and State Pollution Control Boards. The Act makes provisions provisions for various penalties for the defaulters and procedure for the same.

The main regulatory bodies are the Pollution Control Boards, which have been, conferred the following duties and powers:

Central Pollution Control Board (CPCB): ·

·

·

· ·

· · · · ·

It has the power to advice the central government in matters related to prevention and control of water pollution. Coordinates the activities of State Pollution Control Boards and provides them technical assistance and guidance. The main function of the Central Board is to promote the cleanliness of rivers, lakes, streams, and wells in the country. Organizes training programs for prevention and control of pollution. The Board organizes a comprehensive awareness program on water pollution through mass media. Collects, compiles and publishes technical and statistical data related to pollution. Prepares manuals for treatment and disposal of sewage and trade effluents. Lays down standards for water quality parameters. Plans nation-wide programs for prevention, control or abatement of pollution. Establishes and recognizes laboratories for analysis of water, sewage or trade effluent sample.

State Pollution Control Board: ·

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The Board has the power to advice state government on any matters concerning water pollution. It lays down standards for effluents and is empowered to take samples from any stream,

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·

· ·

well or trade effluent or sewage passing through an industry. The Board inspects sewage or trade effluents, treatment plants, purification plants and the systems of disposal and also evolves economical and reliable methods of treatment of sewage and other effluents. The Board suggests efficient methods for utilization, treatment and disposal of trade effluents. Penalties are charged for actions that have caused pollution. This includes failing to furnish information required by the Board, or failing to inform the occurrence of any accident or other unforeseen act. An individual or organization that doesn’t follow the law can be convicted or punished with imprisonment for a term of three months or with a fine of R10,000 or both and in case failure continues an additional fine of R5,000 everyday.

4.12.3

The air (Prevention and control of pollution) Act, 1981

Indian Government has formulated this Act in 1981 to prevent air pollution. According to this act, air pollution has been defined as the presence of any solid, liquid or gaseous substance (including noise) in the atmosphere in such concentration which may be harmful to human beings or any other living creatures or plants or property or environment. The main objectives of the Act are as follows: · · ·

To provide for the Prevention, Control and abatement of air pollution. To establish Central and State Boards with a view to implement the Act. To confer on the Boards the powers to implement the provisions of the Act and assign to the Boards functions relating to pollution.

The main regulatory bodies are the Pollution Control Boards, which have been conferred the following duties and powers:

Central Pollution Control Board (CPCB): ·

· ·

· · · ·

The main function of the Central Board is to implement legislation created to improve the quality of air and to prevent and control air pollution in the country. It advises the central government government in matters related r elated to prevention and control of air pollution. It coordinates the activities of State Pollution Control Boards and provides them technical assistance and guidance. Organizes training programs for prevention and control of air pollution. Organizes comprehensive programs on pollution related issues through mass media. Collects, compiles and publishes technical and statistical data related to pollution. Plans nation-wide programs for prevention, control or abatement of pollution.

State Pollution Control Boards (SPCB) ·

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The State Boards have the power to advice the State Government on any matter concerning the prevention and control of air pollution. They are expected to inspect air pollution control areas at intervals or whenever necessary. Penalties are charged for actions that have caused pollution. An individual or organization that doesn’t follow the law can be convicted or punished with imprisonment for a term of three months or with a fine of R10,000 or both and in case failure continues an additional fine of R5,000 everyday. In consultation with the State Pollution Control Board, the state government may declare an area within the state as “air pollution control area” and can prohibit the use of any fuel other than approved fuel in the area causing air pollution. No person shall, without prior consent of State Board operate or establish any any industrial unit in the air pollution control area.

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4.12.4

The wildlife protection act, 1972

This Act passed in 1972 safeguards wild animals, birds and plants. The act is adopted by all states in India except Jammu and Kashmir. The Amendment to the Wildlife Protection Act in 2002 is more stringent and prevents the commercial use of resources by local people. · ·

· ·

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The Act provides for setting up of National Parks, Wildlife Sanctuaries etc. It provides for the appointment of wildlife advisory Board, Wildlife warden, their powers, duties etc. The Act imposes a ban on the trade or commerce in scheduled animals. Under the Act, comprehensive comprehensive listing of of endangered wild life species was done for the first time and prohibition of hunting of endangered species as mentioned. There is provision for trade and commerce in some wildlife species with license for sale, possession, transfer etc. It provides for legal powers to officers and punishment to offenders. It provides for captive breeding program for endangered species.

Penalties A person who breaks any of the conditions of any license or permit granted under this Act shall be treated guilty. guilty. The offence is punishable with imprisonment for a term which may extend to three years or with a fine of R25,000 or with both. An offence committed in relation to any animal specified in Schedule I, or Part II of Schedule II, like the use of meat of any such animal, or animal articles like a trophy, shall be punishable with imprisonment for a term not less than one year and may extend to six years and a fine of R25,000.

Some drawbacks of Wild life protection act Offenders are not given harsh punishments. They can get away by paying paltry amount as fine. Jammu and Kashmir follows its own wild life protection act. Hunting, trading of many endangered species which are prohibited in other states are allowed there. 4.12.5

Forest (conservation) act, 1980

Forest conservation act was enacted to safeguard forests and their conservation. Except Jammu and Kashmir, the act is adopted all over India. The Act covers under it all types of forests including reserved forests, protected forests or any forested land irrespective of its ownership. The salient features of the Act are as follows: · ·

· · ·

To check deforestation, the root cause for environmental deterioration. Puts restrictions on the use of forest land for non forest purpose. If at all state wants to use it in any other way, it has to take prior approval of central Government. Exercises control over shifting cultivation and encroachment on forest lands. It expresses states that the network of Protected Areas should be strengthened and extended. It gives States the ability to provide power to the local panchayats to manage local forest resources.

Penalties for offences in Protected and Reserved Forests: No person is allowed to make clearings or set fire to a Reserved Forest. Cattle are not permitted to trespass into the Reserved Forest. Felling, collecting of timber, bark or leaves, quarries or collecting any forest product is punishable with imprisonment for a term of six months, or with a fine which may extend to R500, or both.

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4.12.6

Biomedical Waste and Handling

Biomedical waste is generated from biological and medical sources and activities, such as the diagnosis, prevention, or treatment of diseases. Biomedical waste is waste that is potentially infectious. Biomedical waste may be solid or liquid. Examples of infectious waste include discarded blood, blood, unwanted microbiological cultures and stocks, identifiable body parts, other human or animal tissue, used bandages and dressings, discarded gloves etc.

Treatment and disposal Bio-medical waste shall be treated and disposed of as below.

Treatment and disposal Bio-medical wastes shall be treated and disposed of as below.

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Treatment & Disposal

Category No. 1

Human Anatomical Anatomica l Waste Waste (human tissues, organs, body parts)

Incineration /deep burial

Category No. 2

Animal Waste (animal tissues, organs, body parts etc)

Incineration / deep burial

Category No 3

Microbiology & Biotechnology Waste (wastes from laboratory cultures, stocks or specimens of micro-organisms, human and animal cell culture used in research and industrial laboratories)

Local autoclaving / microwaving waving / incineration

Category No 4

Waste sharps (needles, syringes, blades, glass, etc. that may cause puncture and cuts)

Disinfection /chemical treatment /auto claving / microwaving waving and mutilation/ shredding

Category No 5

Discarded Medicines and Cytotoxic drugs Incineration /destruct ion and (wastes comprising of outdated, outdated, drugs disposal in secured contaminated and discarded medicines) landfills

Category No 6

Solid Waste (Items contaminated with blood, blood, and body fluids including cotton dressings, other material contaminated with blood)

Incineration autoclaving / microwaving

Category No. 7

Liquid Waste (waste generated from laboratory and washing, cleaning, house-keeping and disinfecting activities)

Disinfection by chemical treatment and discharge into drains.

Category No. 8

Incineration Ash (ash from incineration of any bio-medical waste)

Disposal in municipal landfill

Category No. 9

Chemical Waste (chemicals used in production of biologicals, chemicals used in disinfection, disinfection, as insecticides, etc.)

Chemical treatment and discharge into drains for liquids and secured landfill for solids

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Segregation, packing, transportation and storage · ·

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·

· ·

Bio-medical waste shall not be mixed with other wastes. Bio-medical waste shall be segregated into containers/bags at the point of generation prior to its storage, transportation, treatment and disposal. The containers shall be labeled. If a container is transported from the premises where bio-medical waste is generated to any waste treatment facility outside the premises, the container shall that information. Untreated biomedical waste shall be transported only in such vehicle as may be authorised for the purpose by the competent authority as specified by the government. No untreated bio-medical waste shall be kept stored beyond a period of 48 hours The Municipal body of the area shall continue to pick up and transport segregated non bio-medical solid waste generated in hospitals and nursing homes, as well as duly treated bio-medical wastes for disposal at municipal dump site.

4.13

| ENFORCEMENT MACHINERY INVOLVED IN ENVIRONMENTAL LEGISLATION

Environmental legislation is aimed to protect our environment as a whole, our health, and the earth’s resources. Several government bodies along with NGO’s are devoted for the protection of environment. All countries have framed Environmental laws to protect natural resources and minimizing pollution. In India, Pollution control boards are the main agency which ensures that these laws are strictly implemented. Central and state pollution control boards are involved controlling pollution. Both have well defined goals and objectives. 4.13.1

Central Pollution Control Board

Central Pollution Control Board (CPCB) of India is a statutory organization under the Ministry of Environment and Forests (MoEF) established in 1974. It is the national apex body for assessment, monitoring and control of water and air pollution. It co-ordinate the activities of the State Boards by providing technical assistance and guidance and resolve disputes among them. The board is led by its chairman, who is nominated by the Central Government.

Functions of the Central Board at the National Level ·

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Advise the Central Government on any matter concerning prevention and control of water and air pollution and improvement of the quality of air. Suggest any modification or amendments or introduction of new clause in existing environmental laws. Planning and executing nation-wide program (organize training of persons) for the prevention, control or abatement of water and air pollution;

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Social Issues and the Environment 119 ·

· ·

·

·

Provide technical assistance and guidance to the State Boards, carry out and sponsor investigation and research relating to problems of water and air pollution, and for their prevention, control or abatement. Co-ordinate the activities of the State Board and resolve disputes among them; Organise through mass media, a comprehensive compr ehensive mass awareness awareness programme progr amme on the prevention, control or abatement of water and air pollution; Collect, compile and publish technical and statistical data relating to water and air pollution and the measures devised for their effective prevention, control or abatement; Prepare manuals, codes and guidelines relating to treatment and disposal of sewage and trade effluents.

4.13.2

State Pollution Control Board

State Pollution control board has similar functions to national pollution control board but power limited inside the state. It enacts and enforce the implementation of environmental laws within the state. Tamil Nadu Pollution Control Board (TNPCB) is the governing body to monitor and control air, noise, and water pollution in the state of Tamil Nadu. TNPCB was established in 1982 and has Head Office at Chennai.

Functions of the State Board ·

· ·

·

Advise the state Government on any matter concerning prevention and control of water and air pollution and improvement of the quality of air. Co-ordinate the activities of the district Boards. Periodic inspections, collections of air and water samples for analysis for different areas within the state. Carry out investigation on problems related to water and air pollution, and for their prevention, control or abatement.

4.14

| ENVIRONMENTAL IMPACT ANALYSIS/ASSESSMENT

Environmental Impact Assessment (EIA) is a process of evaluating the likely environmental impacts of a proposed project or development. EIA takes into account socio-economic, cultural and human-health impacts of the proposed project. Both good and adverse effects of the project are taken into account. EIA would necessarily involve the following stages: 1. Screening: In the first step, it is determined whether a proposed project falls within existing rules and regulations and whether proposed project is likely to have a significant effect on the environment and therefore requires an assessment. 2. Scoping: In scoping, one identifies which potential impacts of the projects are relevant to assess. The applicant can ask the local planning authority for their opinion on what information needs to be included (‘scoping opinion’). This is usually expert knowledge, existing laws, international conventions, expert knowledge and public involvement etc. Alternative solutions are also identified to mitigate or compensate environmental problems. 3. Preparing the Environmental Impact Statement (EIS) or EIA report: When an assessment is required, the applicant must compile the information which is required to assess the likely significant environmental effects of the project. Public bodies can help the applicant by passing on any relevant environmental environmental information. The information finally compiled by the applicant is known as an Environmental Impact Statement (EIS) .

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4. Review of the Environmental Impact Statement (EIS) , based on the terms of reference and public participation. 5. Decision-making Decision -making on whether to approve the project or not, and under what conditions; and 6. Monitoring, compliance, complianc e, enforcement and environmental auditing . If the proposal is sanctioned, one has to monitor whether the predicted impacts and proposed mitigation measures occur. It has to be ensured that unpredicted impacts or failed mitigation measures are identified and addressed in a timely fashion.

4.15

| ECOMARK

In order to increase the consumer awareness about environmental issues, the Government of India have intiated a eco-labelling scheme called “ Ecomark ” in 1991 for the identification of eco friendly products. It is a certification mark issued by the Bureau of Indian Standards (BIS) to products that are manufactured with least impact on the eco system.

Objectives of the scheme: ·

· · · ·

To provide an incentive for manufacturers for reducing adverse environmental environmental effects during manufacture of products. To provide an incentive for manufacturers to produce eco friendly products. To make consumers care for the environment. To encourage citizens to purchase products which have less harmful environmental impacts Ultimately to improve the quality of the environment and to encourage the sustainable management of resources.

Scope of Eco-Mark: The Eco-Mark scheme covers about 17 product categories which include a wide range of products. Criteria for evaluating the products under these categories are initially identified and analyzed. Every step starting from the procurement of raw raw materials materials to manufacturing, usage and disposal are are analyzed analyzed and evaluated (cradle to grave approach, ie, from raw material extraction to manufacture and disposal). An earthern pot (matka) has been chosen as the logo for the Ecomark scheme in India. Renewable resource earth is used in the making of pot. It does not produce hazardous waste and consumes little energy in making. Earthen pot has been used by our forefathers for carrying and storing water. It is able to put across a strong environmental message to the public.

4.16

Ecomark logo

| DIASTER MANAGEMENT

Disaster is a sudden event which causes sudden disruption to the normal life of a society, and causes damage to property and lives. Disasters are mainly of two types, 1. Natural disasters: Disaster caused by natural reasons. Example: Earthquakes, floods, cyclones, landslides etc. 2. Manmade disasters: Disaster caused by anthropogenic (man made) reasons Example: War, bomb blasts, chemical leaks, etc. Diaster management: Disaster management involves preparing for a disaster before it happens, response to the disaster (eg: emergency evacuation, quarantine etc.), and also supporting, and rebuilding society after the occurance of the disaster.

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Disaster management = Management before, during and after the disaster Disaster management is a multidisciplinary area where different issues varying from forecasting, warning, evacuation, search and rescue, relief, reconstruction and rehabilitation are included. It involves active participation of administrators, scientists, politicians, planners, volunteers and communities. The main aim of disaster management is to reduce the impact of disaster though we cannot prevent the disaster itself. The process of disaster management involves involves four phases: mitigation, preparedness, response, and recovery. i) Mitigation: Mitigation refers to the attempt to prevent hazards from becoming disaster or to reduce/minimize the effects of disasters when they occur. Mitigation is different from other phases as it focuses on the preparedness to meet a disaster before the event actually happens. Mitigation is aimed to reduce or eliminate risk. Mitigation is the most cost effective method for reducing the impact of hazards. Public can be trained. Structural and Non-structural measures can be taken to limit the impact of disasters. Structural Mitigation: This refers to the construction of buildings that are resistant to disasters. For example, earthquakes happen frequently in Japan. To reduce the impact of the earthquake, houses are made of wood rather than concrete. Non Structural Mitigation: This refers to measures taken other than improving the structure of building. ii) Preparedness: Disaster does not coming with any warning. Everyone should be prepared to face a natural disaster at any point of time. Some disaster like cyclones, hurricanes etc can be forecasted even 72 hours before. In such cases, people can stock food materials, water and stay in the basement till the disaster gets over. Police, army and medical team can coordinate effectively to deal the situation. iii) Response: This include rapid rescue actions taken to save lives in the event of disasters. Response refers to the implementation of action plans like emergency evacuation, quarantine, mass decontamination, etc. It also includes provisions for temporary food and shelter, clearance of debris, reestablishment of damaged roads, bridges and communication network. network. iv) Recovery: Recovery refers to restoring of affected area to its normal state. After immediate needs are addressed recovery efforts starts. It include rebuilding destroyed property, rehabilitation and resettlement, re-employment re-employment and the repair of other essential infr astructure.

4.17

| FLOODS

Floods happen when rivers and streams carry more water than its carrying capacity. Excess water overflows leading to the inundation of low land areas surrounding the riverbed. Floods arise from abnormally heavy rains, dam failures, snow melts, river blockages.

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Types of Floods Floods can be classified into three categories as under: River floods: Rivers carry water above its carrying capacity due to heavy rains or by melting of snow or sometimes both especially in the mountainous tracts. Coastal floods: Coastal flooding happens due to tropical cyclones arising at the ocean surface. Prolonged and indefinite rains in the rainy or monsoon season result in floods in coastal river basins. Flash floods: Flash floods happen within few hours of beginning of rainfall due to runoff from heavy rain. They are also caused by sudden release of water from dams, dam breakage etc.

Effects of Floods ·

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Floods results in extensive damage to life and property. It destroys everything which is lying on its path. Humans and animals die by drowning. Fresh water sources are destroyed or contaminated. Water borne diseases like dysentery, cholera etc can spread. Farmlands and crops are destroyed which can result in acute food shortage. Floods result in soil erosion. Top soil is carried away by running water which make soil infertile.

Flood Control ·

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Increasing the storage capacity of dams and reservoirs to store more water during rainy season. Networking of rivers within the country. country. Excess water can be diverted to some other river within the same country. Water carrying capacity of the river can be increased by increasing the depth and width of the riverbed. This will help the river to carry larger loads and thus reduce the damage caused by floods. Prevention of over-bank spilling by the construction of embankments and floodwalls.

Post Disaster Requirements Primary response: Search and Rescue operations, drinking water provision, Medical assistance, food and and temporary shelter. Secondary response: Reconstruction of houses, equipment and tools supply, Creation of employment, distribution of farm animals, financial assistance etc. Two great river systems cause serious flood problems in India: Brahmputra River and River Ganges. North eastern regions in India are flooded year after year by the Brahmaputra river and its tributaries. The river floods in monsoon season or in summer season due to the melting of ice in Himalayas. It causes a great damage to both life and property. Tributaries of the Ganga, namely the Rapti, the Sharada, the Ghaghra and the Gandak cause extensive flooding along their banks. Damodar cause extensive flooding. In Delhi and Haryana it is the Yamuna, the biggest tributary of the Ganga, which causes a marginal amount of flooding.

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Flood Mitigation

Before the Disaster ·

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During the Disaster

Listen for warning signs and community alert systems Stock emergency building materials Store enough food and drinking water. Plan immediate an evacuation evacuation route Have disaster supplies and first-aid kit on hand Develop an emergency communication plan in case of separation Teach family members how and when to turn off the gas, electricity, electricity, and water and teach children how and when to call emergency numbers Ask your insurance agent about flood insurance

4.18

After the Disaster

During a flood watch: If indoors: · Turn on battery operated radio to get latest emergency information · Get pre-assembled emergency supplies · If told to leave, do so immediately. If outdoors: · Climb to high ground or trees and stay there · Avoid walking through any floodwaters. · If in a car, turn around and go another way; if your car stalls, abandon it immediately and climb to higher ground. During an evacuation: · If advised to evacuate, evacuate, do so immediately, follow recommended evacuation routes and listen to radio for evacuation evacuation instructions

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Don’t return home until authorities express it is safe to do so Use extreme caution when entering buildings Inspect foundations for cracks or other damage and examine walls, floors, doors, and windows to make sure that the building is not in danger of collapsing Watch out for animals, especially poisonous snakes, that may have come into your home with flood waters Take pictures of damage for insurance claims Look for fire hazards Throw away all food came in contact with flood waters Service damaged septic tanks as it can cause water contamination.

| EARTH QUAKE

An earthquake is a sudden downward motion of the ground surface. It can range from a faint tremor to a violent shake which can cause massive destruction of buildings. The point of origin of an earthquake is called the epicenter. Richter scale was created by Charles Richter in 1935 to measure the magnitude of energy released by an earthquake. The severity of an earthquake is generally measured by its magnitude on Richter Scale, as shown below below Richter scale

Severity of earthquake

Less than 4

Insignificant

4.0 – 4.9

Minor

5.0 – 5.9

Damaging

6.0 – 6.9

Destructive

7.0 – 7.9

Major

More than 8.0

Great

The science that studies the behavior and patterns of seismic waves is called seismology.

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Plate Tectonic Theory suggests that the earth is composed of solid and moving plates having continental crust or oceanic crust. The earth’s crust consists of 6 major plates (Eurasian plate, American plate, African plate, Indian plate, Pacific plate and Antarctic plate) and 20 minor plates. These plates are constantly moving in relation to each other. Collision of plates can cause earthquakes.

Causes of Earthquakes Major reasons for earthquakes are Volcanic activity Volcanic activity can result in earthquakes. Volcanic activity and earthquakes are so related that, earthquakes may follow each volcanic eruption and many of the severe earthquakes cause volcanic eruptions. Example: The famous eruption of Cracatoa on August 26, 1883 is one of the most disastrous volcanic eruptions. It sent up debris 26 kilometers high and 6,000 kilometers wide, and the explosion could be heard thousands of miles away. The huge tidal waves created by the explosion destroyed destroyed 165 villages in Sumatra and Java, killing more than 36,000 people. ·

Anthropogenic Causes Certain human activities like over exploitation of ground water and oil, deep underground mining, blasting of rocks by dynamites for constructional pur poses etc. also cause earthquakes. Constr uction of large dams and enormous volume of water in big reservoirs can result in loss of rock stability below. Under ground nuclear testing can result in earthquakes. ·

Effects of Earthquake Damage to Life and property Structures such as buildings, roads, rails, factories, dams, bridges can be completely or partially destroyed by earthquakes

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Landslides and avalanche Earthquakes can cause landslides. It can also trigger avalanche.

Damages to Government Infrastructure Earth quakes can result in cutting of water supply, telecommunication cables etc. Thus, there is total disruption of power and communication. Contamined water can cause spread of epidemics.

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Fire Hazard Strong oscillations of earthquakes can cause severe fires in houses and factories because of bursting of cooking gas cylinders, contact of live electric wires etc. ·

Flash Floods Strong seismic events result in the damages of dams and cause severe flash floods. Dams may crack or break. This can result in flow of huge volumes of water.

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Tsunamis Earth quakes which originate beneath the ocean floor can result in the formation of gigantic sea waves which approach the sea shore and cause great loss of life and property. These are called tsunami.

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Earthquake Mitigation


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Make sure all family family members know how to respond after an earthquake

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During the Disaster ·

If indoors: Take Take cover cover under a piece of heavy furniture or against an inside wall and stay inside

After the Disaster · ·

Be prepared for after shocks Help injured injured or trapped persons and give first aid where appropriate

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Teach children when and how to call emergency numbers Have disaster supplies supplies (food, water and first aid) Develop an emergency communications plan in case of separation during the earthquake Built earth quake resistant structures. A big earth quake quake is often followed followed by small secondary tremors. Watch Watch out for them.

4.19

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If outdoors: Move Move into the open, away from buildings, street lights, and utility wires and remain there until shaking stops If in a moving moving vehicle: vehicle: Stop quickly, stay in vehicle, move to a clear area away from buildings, trees, overpasses, overpasses, or utility wires

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Listen to a battery operated radio for emergency information Stay out of damaged buildings and return home only when authorities say it is safe

| CYCLONES

Cyclones are the centers of low pressure characterized by inward spiraling winds that rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. They range in shape from circular, elliptical to V shape. Temperate cyclones occur in mid latitudes i.e. 400 to 600 N & S. These are formed due to convergence of the warm (tropical) and Cold (Polar) air masses. Tropical cyclones are those which occur in lower latitudes, normally 10 0 to 300 N & S latitudes and are caused due to the convergence of warm dry and warm moist air masses. Tropical cyclones are called hurricanes in the Atlantic, Caribbean and north eastern Pacific, typhoons in the western Pacific and ‘ cyclones in the Indian Ocean and willy willies in the sea around Australia.

Environmental impact of Cyclones The destruction from a tropical cyclone depends mainly on its intensity, its size, and its location. Change in weather: The main effects of tropical cyclones include heavy rain, strong wind, large storm surges at landfall, and tornadoes. Destruction to life and property: Cyclones can cause severe damage to human lives and property. property. It can result in destruction of buildings, transport systems, water and power power supply systems, disruption of communication system, destruction of agricultural crops, domestic and wild animals, natural vegetation etc. Nearly two million people die globally due to tropical cyclones. Change in landscape: Tropical cyclones remove forest canopy as well as change the landscape near coastal areas. It can cause extensive erosion along the coast by moving and reshaping sand dunes. Spread of diseases: Scarcity of drinking water can result in the spread of water borne diseases. Standing water can cause mosquitoes to breed. Hurricane Mitigation

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Before the Disaster

During the Disaster

Plan an evacuation evacuation route. Have disaster supplies on hand

Hurricane Watch (conditions within 24-36 hours): · Listen to battery-operated radio for progress reports; check emergency supplies

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After the Disaster ·

Stay tuned to radio for information, return home only when authorities advise it is safe to do so

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Develop an emergency Fuel car fully fully communication plan in case Secure buildings buildings by by closing of separation and boarding up windows Teach family members Remove Remove outside antennas when and how to turn off Store drinking water in gas and electricity clean bathtubs, jugs, and Trim back dead or weak weak bottles branches from trees Review evacuation plan Hurricane Hurrican e Warning: Warning: Teach children when and how to call emergency Listen to radio for numbers instructions Make arrangements for Store valuables valuables in family pets because some waterproof container emergency shelters may not Avoid elevators. allow pets If at home: Leave the neighbourhood neighbourhood on Stay inside, away away from hearing hurricane warning. anything glass Stay in another city and Keep a supply of batteries come back after hurricane. and flashlights Charge your your mobile mobile phones If evacuation evacuation is necessary: and emergency lamps. leave immediately, avoiding avoiding flooded roads and washed-out bridges Secure home by unplugging appliances and turning off electricity and the main water valve Take blankets blankets and sleeping sleepi ng bags to a shelter and leave immediately ·

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Help injured or trapped persons and give first aid where appropriate Avoid loose or dangling power power lines and report them to the power company or fire department Beware of snakes, insects, and animals driven to higher ground by flood water Open windows windows and doors to ventilate and dry your home Check refrigerated foods for spoilage Take pictures of the damage damage for insurance claims Drive only if necessary and avoid avoid flooded roads and washed-out bridges Use telephones telephones only only for emergency calls.

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4.20

| TSUNAMI

A tsunami is a giant wave (or series of waves) created by an undersea earthquake, volcanic eruption or landslide. “Tsunami” in Japanese means “harbor wave”. Tsunamis are not “tidal waves”

Causes of Tsunami ·

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Earthquakes: These are the most destructive and common cause for tsunamis. When earthquake is massive, at least 7.5 in magnitude, it displaces enough water vertically to case a huge wave. Volcanic eruption: A massive volcanic eruption can disturb the ocean floor which can lead to the formation of tsunami. The explosive eruption of Krakatau in 1883 created a tsunami that claimed more than 36,000 lives. Landslides: Enormous submarine landslides can occur on the flanks of ocean islands which can lead to tsunami. Landslides can be triggered by earthquake or volcanic activity. Meterorites: Asteriods falling into the ocean can lead to tsunami.

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Theory of tsunami propagation Tsunamis are generated by under seaquakes which suddenly displaces large volumes of water vertically. Speed of tsunami is proportional to depth of water, so tsunami slows down on reaching the shore. Tsunami’s energy flux (which remains constant) depends on both its wave speed and wave height. For the energy flux to remain constant, the tsunami’s speed decreases as it travels into shallower water but its height increases. It travels as fast as 200 m/s in open ocean. As a tsunami reaches the shore, it begins to lose energy. Towering waves of tsunamis reach the coast with tremendous amounts of energy to cause massive destruction.

Effects of Tsunami · ·

Large scale destruction to life and property. Tsunami cause fire, disrupt communication and transportation.

Tsunami Mitigation


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Find out if your house house is in danger and know the height of your street above above sea level Be familiar with warning warning signs (earthquakes, ground rumbling, or rapid rise and fall of coastal waters) Ensure all family members know how to respond Make evacuation evacuation plans with more than one route and pick an elevated elevated inland location Teach children how and when to call emergency numbers. Have disaster supplies supplies on hand (flashlight, extra batteries, portable batteryoperated radio, first aid kit, emergency food and water, cash and credit cards) Develop an emergency communications plan in case of separation during the earthquake Ask an out-of-state relative or friend to serve as the family contact.

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During the Disaster ·

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Listen to radio for emergency and evacuation evacuation information Climb to higher higher ground as soon as warning of a tsunami is released Stay away away from the beach. Do not assume that one wave wave means the danger is over - the next wave may be larger than the first Stay out of the area and do not return until authorities say it is safe to do so Waves move move much faster faste r than you think. Don’t go to beach to watch tsunamis.


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Stay tuned to radio for emergency information Help injured injured or trapped persons and give first aid. Stay out of damaged buildings Enter home with caution, caution, checking for electrical shorts and live wires Do not use appliances appliances or lights until properly checked by an electrician Open windows windows and doors to help dry the building Check food supplies, throwing out all fresh food that may be contaminated and have tap water tested by local health department.

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4.21

| LANDSLIDES

The sliding down of a mass of earth or rock from a mountain or cliff is called landslide.

Causes of landslides: Geological causes: Earthquakes, Weathered materials, Sheared materials, Ground water changes, Rainfall and snow fall etc Morphological causes: Erosion, Vegetation change etc Human causes: Over exploitation of ground water, mining, quarrying, deforestation Landslides Mitigation


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During the Disaster

Get a ground assessment of If indoors: Stay inside and get cover your property under a sturdy piece of Minimize home hazards furniture. If outdoors: (plant ground cover on Try to get out of path of slopes, build retaining mudflow walls, and in mudflow areas, Run to nearest high ground build channels or deflection in a direction away from walls to direct flow around path buildings) If rocks and other other debris are Make evacuation evacuation plans, approaching, run for nearest planning at least two routes routes shelter such as a group of allowing for blocked and trees or a building closed roads If escape is not possible, Develop an emergency curl into a tight ball and communication plan and protect your head. ask an out-of-state relative or friend to serve as the family contact Purchase home insurance.


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4.22

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Stay away away from slide area Check for injured and trapped persons and give first aid where needed Listen to battery-operated radios for emergency information Remember flooding flooding may occur after a mudflow or landslide Check for damaged utility utility lines and report damage to the utility company Check the building foundation, chimney, and surrounding land for damage Replant damaged ground as soon as possible since erosion caused by loss of ground cover can lead to flash flooding.

| PUBLIC AWARENESS

We are facing various environmental challenges. The only way to protect and preserve our degrading environment is by public awareness. Everyone needs to understand it because. environment belongs to all. The electronic media, the press, school and college education, adult education, are all essential part of public awareness. awareness. Eco-friendly acts can be promoted for sustainable development. development.

Methods to Propagate Environmental Awareness ·

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Among students through education: Environmental education must be imparted to the students’ right from the childhood. He should be taught to take care of “mother earth”. Environmental studies now form a part of curriculum in all schools and colleges following directions from the Supreme Court.

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Social Issues and the Environment 129 ·

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Among the Masses through mass-media: Mass-Media plays an important role to educate the people on environmental issues through articles, rallies, campaigns, street plays etc. Serials, documentaries etc can help promoting environmental awareness. By leaders, most influential people: Influential people, film stars, sports person can promote environmental environmental activities by their partymen, fan club etc.

ANNA UNIVERSITY QUESTIONS 1. What is sustainable development? How can it be achieved? 2. What are the major urban problems related to energy?


3. What are the objectives of water conservation? How is it carried out? (Anna Univ, Dec 2014) 4. What is rain water harvesting? Explain their types with suitable sketches. (Anna Univ, Dec 2014) 5. What is a watershed? Critically discuss the objectives objectives and practices of watershed management. (Anna Univ, Dec 2013) 6. Discuss the rehabilitation and resettlement of people, its problems and its concerns. (Anna Univ, Dec 2014) 7. Write notes on NGO’s in environmental environmental protection and management. a) role of NGO’s b) environmental environmental ethics 8. Write notes on a) Principles of green chemistry b) Wasteland reclaimation 9. Briefly discuss the salient features of wildlife protection act. 10. Write short notes on the following acts a) Water prevention and control of pollution act of 1974 b) Forest conservation act 1980



11. Write an elaborate note on the salient features of Environmental protection act. (Anna Univ, Dec 2013) 12. Briefly describe the role of central and state pollution control boards in controlling pollution. 12. What is an earthquake? Enumerate its effects. What efforts should we take to mitigate this (Anna Univ, Dec 2014) disaster? 13. Write short notes on nuclear accidents and ozone layer depletion. (Anna Univ, Dec 2013)

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Unit

5

HUMAN POPULATION AND THE ENVIRONMENT

SYLLABUS Population growth, variation among nations – population explosion – family welfare programme – environment and human health – human rights – value education – HIV / AIDS – women and child welfare – Environmental impact analysis (EIA) – GIS-remote sensing-role of information technology in environment and human health – Case studies.

5.1 | POPULATION Population is defined as the number of individuals of same species in a given area at a given time. Population dynamics refers to change of population with time. Demography is the statistical study of human population. It deals with (i) Changes in population size (growth or decline) (ii) Composition of the population (age groups, sex ratio) (iii) Distribution of population. Current World population is 7.4 billion (May 2015). World population exceeded 7 billion in March 2012. World population was around 1 billion in 1810. It became 7 times in past 200 years. DEMOGRAPHICS OF INDIA

Current Indian population:

1.21 billion (2011 census)

Indian population growth rate:

1.41% (ranked 102nd in the world in 2010)

Birth rate:

22.22 births/1,000 population

Death rate:

6.4 deaths/1,000 population

Life expectancy:

69.89 years

–male:

67.46 years

–female:

72.61 years

Fertility rate:

2.5 children born/woman

Infant mortality rate:

30.15 deaths/1,000 live births

Most populated city:

Mumbai (12.5 million)

Population of Chennai:

4.6 million (2011 census)

One out of every seven person in the world is an Indian. 75% of the population of India lives in the villages.

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5.2 | POPULATION CHARACTERISTICS 1. Nature of Population growth Population growth refers to the variation in population (increase or decrease) with time. Negative growth leads to decrease in population. Three types of population growth has been observed. a) Exponential growth b) Logistic Logistic growth c) Zero growth a) Exponential growth: If a population has a constant birth rate and no other factors like food or disease influence the population, then exponential growth is observed. In this case, birth rate alone controls the population. Eg: growth in bacteria, some insects etc. It can be represented mathematically as, P = P0ert, where P is future population after t years, Po is the present population, r is the annual growth rate. The curved obtained is ‘J’ shaped curve. b) Logistic Growth: The logistic curve shows three phases · · ·

Lag phase: slow growth Exponential phase: rapid growth Stationary phase: stable growth

The curve is ‘S’ Shaped. In most real populations both food and disease become important factors to check population growth. Environment cannot support indefinite number of individuals. The maximum number it can support is determined by the “carrying capacity” of the environment. Carrying capacity of environment is defined as the number of species (humans, plants, animals) that it can support without environmental degradation.

c) Zero (population) growth More developed countries (MDC) show zero population growth. This happens when birth rate becomes equal to death rate.

2. Population Dispersion It describes how individuals are distributed themselves in their habitats. Three types of dispersion are seen a) Uniform Dispersion: Species are evenly distributed about their habitat. · ·

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Species has the ability to survive anywhere in the habitat. This kind of distribution is more seen in plants so that there is less competition for water and nutrients as they are widely spaced. Animals like penguins show territorial behaviour. Eg. Arrangement of shrubs in deserts.

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Human Population and the Environment 133

b) Random Distribution: Population found randomly about their habitat. · ·

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Individual have been distributed by chance Natural resources are distributed randomly, randomly, so animal populations which depend on them are also randomly distributed. Eg: Dandelions grow randomly.

c) Clumped Dispersion: Population are clustered together (high density patches). This is the most common population distribution in nature. ·

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Caused by a number of factors: species are together for protection, species are grouped around natural resources necessary to their survival. Eg. Herd of lions, flock of birds.

3. Population Doubling Time Population doubling time is the time needed for a population to double its size at a constant annual growth rate. Td = 70/r, where Td -doubling time in years (r- annual growth rate). For example if a country has annual growth rate of 2%, its population doubling time will be 70/2 = 35 years.

4. Total Fertility ertili ty rate (TFR) Total fertility rate is the average number of children that would be born to a woman in her lifetime. TFR is almost 2 in most developed nations and around 5 in developing nations or less developed nation. In our country TFR was 6.1 in 1950 and currently it is 2.6 (2011 census).

5. Crude birth rate Crude birth rate is the number of live births occurring during the year, per 1,000 people. Crude birth rate =

Number of live births

×

Estimated midyear population of that year r

1000

6. Mortality rate Mortality rate is the number of deaths per thousand of individuals in a year. Decrease in mortality rate will increase population. Due to technological advancements, better medical facilities and better literacy rate, the mortality rate has gone down in many countries.

7. Infant mortality rate It is the number of infants dying before reaching one year of age, per 1,000 live births. The rate has declined in the last 50 years in our country.

8. Crude death rate It is the number of deaths in a particular year per thousand people in a particular region. Crude death rate =

Number of deaths Estimated midyear population of that year

×

1000 1000

9. Replacement Replacemen t level Replacement level is number of offsprings replacing two parents. For a developing nation this is always greater than 2, while for a developed country it is mostly under 2.

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10. Migration Migration is the movement of individuals into (immigration) or out of place (emigration) or country. People migrate from one place to another for better economic and social life.

11. Female –Male sex Ratio Sex-ratio is the number of females per thousand males. Due to female f emale infanticide and gender-based abortions, ratio has declined in many developing countries including India (933 : 1000).

12. Life expectancy Life expectancy is the average age that a newborn infant is expected to attain in a given country.

13. Demographic transition Demographic transition is the correlation between population growth and industrialization or economic development. Demographic transition occurs in four phases: (a) Pre industrial phase: This is characterized by high growth and death rates and overall increase in population is low. (b) Transitional phase: Industrialization begins. Better hygiene, medical facility and food results in decreased death rate. Birth rate remains high. Most of the developing countries are currently in this phase. (c) Industrial phase: Birth rate drops. Many developed countries are currently in this stage. A few developing countries have entered this phase. (d) Post industrial industria l phase: Birth rate drops further and zero population growth is achieved. Many European countries are in this stage now. In some cases, population even declines.

14. Carrying capacity: Carrying capacity is the number of individuals of a species that can be indefinitely sustained in a given area without harming the habitat. It depends and varies with the habitat. If growth exceeds carrying capacity, environmental resistance lower population size and population enter the death phase. Species will become threatened, endangered or extinct. For example, example, in an aquarium if we introduce more fishes, the carrying capacity will be exceeded which result in the collapse of entire ecosystem.

15. Environmental Resistance: Environmental resistance is any factor in the environment limiting carrying capacity.

5.3

AMONG NATIONS | VARIATION OF POPULATION AMONG

World population has crossed 7 billion. The existing population is not uniformly distributed. Less developed countries have 75% of world’s population while developed countries have only 25%.

Population pyramid Variation in population can be easily represented with the help of a population pyramid. A population pyramid represents the age and sex structure of a population. The shape of the pyramid reflects the characteristics of a population. ·

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Graphs are on their sides with the axis in the middle. Population plotted on the X-axis and age on the Y-axis. The number of males is shown on the left, females on the right in five-year age groups.

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Human Population and the Environment 135 ·

Different age classes are pre-productive (0-14 yrs) reproductive (15–44 yrs) and post productive (45yr and above) above)

Information derived from Population Pyramids The following information can be obtained from population pyramids · · · · · ·

Birth and death Rate Life expectancy Sex ratio Fertility Rate Infant Mortality Rate Can relate to social and economic problems of the nation.

Based on the shape of the population pyramid there are three types of population pyramids 1. Pyramid Shaped 2. Bell shaped 3. Urn shaped

1. Pyramid Shaped: (Growing population)-Least populati on)-Least Developing Countries Characteristics · Pyramid has a broad base and narrowing as it goes higher. · Very young population is more and old people are less. · Young individuals will soon enter into reproductive age resulting an increase in population. · As the number of older people are less, death rate is less. · This type of behaviour is characteristic of developing countries indicated by i. High Birth rate ii. Percentage of young population is higher. higher. iii. Slow/moderate Slow/moderate but steady growth rate. · Developing countries like Congo, Philippines, Ethiopia, Nigeria etc

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2. Bell Shaped (Stable or zero population populati on growth): Characteristics · It is bell shaped pyramid. · It is characterized by almost equal birth and death rates. · Birth rate is low, so the number of people in between 0-35yrs remains almost the same. Number of individuals entering into reproductive age group remains almost the same. These pyramids indicate stable population results in zero population growth. · Many developed countries follow this type of population behaviour. It is characterized by i. Declining Fertility ii. Declining Mortality iii. Moderate Growth Rate · Countries like Finland, France have this kind of population growth.

3. Urn Shaped (Negative growth) Characteristics · · · ·

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This pyramid has a narrow base and narrow top. Declining birth and death rates. People in post-reproductive phase is higher hence there is a decline in the population. These are future developed countries characterised by i. Low fertility ii. Low Mortality iii. Ceasing Growth Rate iv. iv. Very old Population Germany, Italy, Hungary, Sweden, Japan have this type of population pyramid.

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5.4 | POPULATION EXPLOSION Population explosion is the rapid and significant increase in the size of a population caused by such factors fac tors as a sudden sudde n decline decl ine in infant inf ant mortali mor tality, ty, death deat h rate or an increase incr ease in life expectancy.

Causes of population explosion i) Better health care facilities: In the past few decades there has been a remarkable improvement in the health facilities which resulted in the decrease of mortality rates. ii) Increased food productivity and distribution: distributio n: Green revolution, use of scientific methods in agriculture resulted in increased food production which could feed millions. In other words, famine and drought incidents reduced considerably. iii) Illiteracy and lack of awareness awareness about about family planning concepts: Due to illiteracy, many people in the under-developed countries still remain ignorant of family planning techniques. iv) Believes and cultural cultural reasons: In many middle east countries, polygamy is common. Number of male children is of family prestige and pride. So parents prefer to have as many off springs (preferably male) as possible. Many parents believe that more children are needed to take care of them at their old age. v) Eradication/control of diseases: Many diseases like small pox have been eradicated completely. Other diseases like plague, polio, malaria is under check in many countries. Earlier, these diseases used to wipe out entire city. vi) Government and other agencies funding: Many agencies like WHO, World bank, UNO and other agencies monitor the progress of many under developed countries by releasing funds for improved health facility, better living conditions. Many schools in India have adopted free mid day meal program which reduce poverty and starvation.

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Consequences of population explosion i) Inadequate fresh water: Population explosion can lead to severe shortage of drinking water, especially in semi-dry or dry areas. ii) Depletion of natural resources: It can lead to over exploitation of many natural resources (water, forest, mineral, food, energy, soil etc). iii) Pollution: More number of people will result in severe environmental pollution (air, water, soil, marine, noise etc). iv) Deforestation: Forests will be cleared for human settlement, agriculture etc. Deforestation cause extinction of rare and endangered species. v) Poverty, malnutrition and starvation: Shortage of food and drinking water among people can result in poverty and malnutrition. vi) Emergence of new new epidemics epidemics and diseases: Malnutrition along with unhygienic living conditions and lack of good healthcare facility can result in the emergence of epidemics unemployment vii) Unemployment issues, issues , Lower wages: Population explosion can result in serious unemployment issues as the number of people having minimum education will be more. Severe competition may result in the underpayment. viii) Climate change: Growing population can result in the increase of greenhouse gases which can result in global warming. ix) Migration: Population explosion may result in the migration of people from one place to another in search of food, water and facilities.

Control of population explosion · · · · · · · ·

5.5

Adoption of any family planning methods Late marriage reduce the fertility rate Health and sanitation Recreation facilities Emigration to other countries in search of better opportunities. Educating the youth about the problems associated with population explosion. High standard of living Creating awareness

| ENVIRONMENT AND HUMAN HEALTH

World health organisation (WHO) defines health as a state of complete physical, mental and social well-being and not merely the absence of diseases or infirmity. Environment and human health are very much related. Degradation of environment and poor living conditions may result in being sick. Some health issues related to environment are i) ii) iii) iv) v) vi) vii) viii)

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Infectious Diseases Disposal of Chemicals Pesticide and heavy metal contamination Occupational hazards Noise Radiation Food Settlement

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i) Infectious diseases Unhygienic conditions of environment forms the breeding grounds for various deadly diseases causing organism like virus, bacteria, vectors etc. This scenario is more common in the developing countries. Infectious organisms cause food poisoning, respiratory diseases and gastrointestinal diseases. · · · · ·

Water-borne(Polluted water): Cholera, Dysentery, Amoebiosis, Hepatitis Air-borne(Polluted air): Asthma, Bronchitis, Pneumonia, Tuberculosis Food-borne(Food-poisoning): Cholera, Dysentery Vector-borne: Malaria, Typhoid, Filaria Animal-borne: Plague

ii) Disposed Disposed Chemicals A large number of chemicals are introduced in the environment by human activities. Chemicals can be hazardous (Eg: explosives and inflammable chemicals), Carcinogenic (Eg: aromatic hydrocarbons like benzene, various amines etc), Mutagenic (Eg: Polycyclic aromatic hydrocarbon, benzene) etc.

iii) Pesticide and heavy metal contamination Many pesticides can cause severe physiological problems. They can cause cancer, tumors, deformation of body parts, inhibit hormones in humans and other species and affect reproduction etc. Chemicals like DDT and other chlorinated pesticides accumulate in food chain and concentrate in body tissues as it goes to top of the food chain. Heavy metals, arsenic, chromium, lead, mercury can cause severe health issues.

iv) Occupational Hazards Workers in various factories, mines, construction of dams, buildings, commercial forms, forestry and agriculture are exposed to risks, especially health hazards Dust (lung diseases), dust contaminating free silica (silicosis), finest fibres of asbestos (asbestosis).

v) Noise Sound levels beyond the permissible level of human ear may damage ears. Prolonged exposure to noise can cause hearing impairment, hypertension, heart diseases etc. It can affect pregnant mothers and their foetus.

vi) Radiation Cosmic and ultraviolet rays cause harmful har mful effects on human health which may include cancer.

vii) Diet Contamination of food can cause indigestion, food poisoning and other various ill effects. Undernutrition or malnutrition makes humans prone to other diseases.

viii) Settlement Improper settlement and poor hygiene around settlement can cause various psychological problems.

5.6 | FAMILY PLANNING Family planning is the planning of when to have children, how many children to have and the use of birth control and other techniques to implement such plans. Family planning allows couples to decide their family size and also the age interval between two offsprings. In short, family planning means a deliberate attempt to limit the size of family.

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Following are some of the important family planning measures: ·

Use of contraceptives (Mechanical, Chemical methods):

Contraception means the prevention of pregnancy. There are many contraceptive techniques available for use.

Mechanical method ·

·

·

Condom (For male’s use): The condom is a thin sheath of rubber, which is put over the erect penis. Condom prevents sperms reaching the vagina during ejaculation. It is a cheap and effective method for family planning. It also protects from many sexually transmitted diseases by avoiding direct skin to skin contact. Diaphragm (For female’s use): The diaphragm is a rubber cup stretched over collapsible metal spring coil. It is designed to fit over the cervix (the mouth of uterus). Intrauterine Contraceptive Device (IUD): It is a small metal or plastic device, which is designed to fit inside the uterus mouth. A doctor must fit and remove IUD. Eg: Copper T

Chemical Method ·

·

·

Jellies, creams and foam: Jellies, creams, and foams are used as contraceptive agents. These jellies, creams or foams have germicidal power and kill sperms. They are applied on to vagina five to fifteen minutes before copulation to take place. Oral contraceptive: These are popularly known as birth control pills or simply pills. It contains hormones (estrogens and progesterone) which suppress the production of ovum. E.g. mala D. Sterilization: It is surgical technique by which the passage of sperms or ovum is disconnected. Both men and women can be sterilized without loosing their ability to function sexually.

Vasectomy: In man, the sterilization procedure is called a vasectomy. In this procedure the vasa deferentia, the tubes that lead from the testes to the ejaculatory ducts, are cut so that the sperm produced in the testis cannot reach the ejaculatory ducts to ejaculate. Tubectomy: In females, tubectomy is done. In this procedure, the fallopian tubes, which transport the egg from the ovaries to the uterus are cut and tied off.

5.7

| WOMEN AND CHILD WELFARE

Women and child development is of great importance in the socio-economic growth of any country because of following reasons. i) They form high priority group as they they form 70% of population population in developing developing countries (65% in India) ii) They constitute constitute vulnerable vulnerable or special risk as soft, weak, weak, prone to diseases easily and and most of them are economically depended on their spouse or parents. In recent years, the empowerment of women has gained considerable interest. National Commission for Women was set up by an Act of Parliament in 1990 to protect the rights of women. Reservation of seats in the local bodies of Panchayats and Municipalities for women were made mandatory to involve women in decision making at the local levels.

Rights and Privileges of women · · ·

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Men and women have equal rights and opportunities in the political, economic and social spheres. Equal protection of law, Prohibit discrimination against any citizen on grounds of religion, r eligion, race, caste, sex or place of birth,

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Human Population and the Environment 141 · · ·

Securing all citizens, men and women, equally, the right to means of livelihood Equal pay for equal work Humane conditions of work and maternity relief.

Important Social Legislation relating to Women · · · · ·

The Child Marriage Restraint (Amendment) Act, 1976 The Equal Remuneration Act, 1976 The Medical Termination of Pregnancy Act, 1971 The Dowry Prohibition Act, 1961 Family Courts

Policies Concerning Women’s development · ·

·

The National Plan of Action for Women (NPA) was adopted in 1976. The National Perspective Plan for Women (NPP) aims at holistic approach for the development of women. National Policy for the Empowerment of Women (2001)

National Policy for the Empowerment of Women (2001) The policy aims at: The advancement, development and empowerment of women in all spheres of life. Ensuring women’s equality in power sharing and active participation in decision-making. Comprehensive economic and social empowerment of women. Partnership with community-based organizations. Implementation of international commitments and cooperation at the international, regional and sub-regional levels. · · · · ·

Various other schemes for women welfare ·

Balika samridhi yojana (1997) – to encourage enrolment & retention of girl child in schools by providing free education for girl child along with a financial grant to the family below poverty poverty line Current Prime minister of India, Sri Narendra Modi has introduced and initiated many new schemes for women. Some are the following. · Beti Bachao Beti Padhao (save girls, teach girls) in Haryana · Sukanya Samriddhi Accounts: This account can be opened on a girl child’s name by her natural (biological) parents or legal guardian.

Child welfare in India The welfare of children is of utmost importance in the country’s developmental agenda. Children are our supreme assets and also the future human resources of the country

Legislative measures and policies ·

· · · ·

Child Labour (Prohibition & Regulation Act) (1986): An Act to prohibit child labour in certain employments and to improve the conditions of work of children in certain other employments. The Child Marriage Restrain Act, 1929 -to abolish and eliminate child marriage. The Juvenile Justice (Care and Protection of Children) Act, 2000. The Commissions for Protection of Child Rights Act, 2005 The National Policy for Children (1974)

This Policy aims at providing adequate services towards children, both before and after birth and during the growing stages for their full physical, mental and social development.

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Constitutional Provisions for children · · ·

Free and compulsory education to all children of the age of six to fourteen years Prohibits trafficking of human beings and forced labour. Prohibits employment of children below the age of fourteen years in factories, mines or any other hazardous occupation

Other Schemes for Children welfare ·

· · · · ·

·

·

Schemes/Projects Programmes being implemented by the Ministry of Women and Child Development are as under: Integrated Child Development Services (ICDS) Scheme Rajiv Gandhi National Creche Scheme for the children of working mothers Gramodya Yojana and Nutrition Programme for Adolescent Girls Integrated Programme for Juvenile Justice Balwadi Nutrition programmaes (1970-71) -to provide nutrition, informal schooling for providing early education to children of 3-5yrs Child labour eradication scheme (1984) -to shift child labour from hazardous jobs into schools Mid day Meal scheme for school children (1995) -To provide free mid day meal to primary school children in the country

Integrated Child Development Scheme (ICDS) -Launched in 1975 Objectives of ICDS: · Proper psychological and overall development of the child · Improve nutritional and health status of children 0-6 years · Reduce incidence of mortality, morbidity, malnutrition and school drop-outs · Enhance the capability of the mother and family to look after the health, nutritional and development needs of the child · Achieve effective coordination of policy and implementation among various departments to promote child development

A few of the organisations who work with children’s rights in India are Plan India, CRY (Child Rights and You), Save the Children, Bal Vikas Dhara-New Delhi, Bachpan Bachao Andolan.

5.8

| HIV / AIDS

HIV: HIV (Human Immunodeficiency Virus) is a virus that causes AIDS (Acquired Immunodeficiency Syndrome). AIDS is a health condition in which a person is easily vulnerable and affected by a series of diseases due to poor immunity. ·

HIV by itself is not an illness and does not instantly lead to AIDS.

AIDS: Acquired Immunodeficiency Syndrome is a health condition that results from the deficiency in the body’s immunity following HIV infection. It is a break down the body’s immune system leaving the patient to a number of life threatening infections

Origin of HIV/AIDS AIDS was discovered in 1983. Though definite source of this virus is not known, some theories have been suggested. It is generally believed that HIV has been transferred to humans from African monkeys.

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Transmission of HIV ·

· · ·

·

Contaminated Fluids: Contamination of blood stream with HIV infected body fluids, particularly blood, blood, semen, breast milk and vaginal fluid. Sharing of needles: Sharing of HIV contaminated needles in blood transfusion. Unprotected sex: By sexual contact with affected person Maternal-fetal transmission: Infected mother give birth to infected baby. Breast milk can also act as a transmission-medium. Improperly sterilized hospital tools: If surgical devices like syringes and scalpels, or even certain instruments, used on an infected person, are used on another person without proper sterilization. Contaminated needles or syringes used drugs. can cause infection.

HIV is not spread by · · ·

Physical touch of infected persons Air borne- by means of sneezing or coughing Water borne -by means of saliva, tears etc

Mechanism of HIV infection ·

HIV is a retro virus which damages immune system by destroying lymphocytes (white blood cell), helper T cell

Development of HIV: · ·

Incubation period is longer- an average of eight years During the incubation period, the virus will be multiplying, infecting, and killing cells of the immune system

Four Stages of infection · · · ·

Initial Infection:destruction of helper T cells or lympocytes Asympotic or incubation period AIDS related complex (ARC) Final stage- Fully infected AIDS patients receiving different kinds of infection

What are the early and later symptoms of HIV/AIDS? · ·

Many people do not develop any symptoms when they first fir st become infected infe cted with HIV. HIV. More persistent or severe symptoms may not surface for several years, even a decade or more.

Symptoms at later stage · · · · · · ·

Lack of energy Rapid weight loss. Frequent fevers and sweats Fatigue combined with headaches and dizziness Long-lasting bouts of diarrhoea Swelling or hardening of glands located in the throat, armpit, or groin Increasing shortness of breath

How is HIV diagnosed? Two types of tests are available to diagnose HIV infection 1. Study the presence of antibodies antibodie s produced by by body in response to HIV · ELISA (Enzyme Linked Immuno sorbent Assay), · Western Blot (WB) · Immunoflouroscent Assay (IFA). · Saliva and Urine test

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2. Study the presence of virus itself. Polymerase Chain Reaction (PCR) looks for HIV itself in the blood. This test can recognize the presence of the virus in the blood. It can detect the virus within a few days of infection.

Treatment against HIV and AIDS HAART (Highly Active Antiretroviral Therapy) The commonly available treatment for AIDS is the treatment against opportunistic infections.

Prevention of AIDS · · · · ·

· ·

Global education about disease Use of screened blood samples, disposable infections. Protected Sex (use of condoms) Monogamy or abstinence from sex The risk of HIV transmission from a pregnant woman to her baby is significantly reduced if she takes treatment during pregnancy It is necessary to treat STD as soon as you suspect infection (NARI) was established in 1992 with the mission The National AIDS Research Institute (NARI) to promote biomedical research on HIV/AIDS in India with an aim to compliment and strengthen the National AIDS Control Programmes.

5.9 | HUMAN RIGHTS Human Rights and the salient features of the Universal Declaration of Human Rights was adopted by UN on December 10th 1948. Human rights are the rights a person has, because he or she is a human being. Human rights are held by all persons equally, universally, and forever. Human rights cannot be taken away from a person under any circumstances. These rights cannot be lost. Human rights are considered as the basic standards without which people cannot live in dignity. dignity. To violate a person’s human rights is to treat that person as though he or she was not a human being. Human rights demands that the human dignity of all people be respected. Some of the most important characteristics of human rights are the following: · · · ·

Human Human Human Human

Rights are guaranteed by international standards and legally protected. Rights focus on the dignity of the human beings. Rights are indivisible and hence one cannot be denied, waived or taken away. rights are interrelated and universal.

Human Rights in India Our Constitution guarantees every citizen of India seven fundamental rights. 1. Right to equality: This advocates equality before law. All are treated equal irrespective of religion, race, caste, gender or place of birth. All have equality of opportunity in matters of employment. 2. Right to freedom: This right includes freedom for speech and expression. It also includes right to practice any profession or occupation, right to life and liberty, right to education. 3. Right against exploitation: exploitatio n: This prohibits all forms of forced labour, child labour and traffic of human beings. 4. Right to freedom of religion: This right ensure a person freedom to practice any religion and also freedom to manage religious affairs.

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5. Cultural and Educational rights: It preserves the right of citizens to conserve their culture, language or script. The right of minorities to establish and administer educational institutions of their choice are also preserved. 6. Right Rig ht to constitutional constitu tional remedies: This right advocates for the enforcement of Fundamental Rights. 7. Right to life: This gives the right to live with human dignity. This includes rights such as right to education, health, shelter and basic amnesties that the state shall provide.

5.10 | VALUE EDUCATION Education assists in bringing about socio-economic and cultural progress of a country. It does not simply mean acquiring knowledge and information, it also mean the use of knowledge for the betterment of society. ‘Values’ – Ones own principles and standards that enable one to judge between the right and wrong behavior behavior or actions or practices. practices.

Need for value based Environmental education Environment is a common property and our actions affect environment. Any degradation in environment affects our health and well being. Value education in relation to environment provides an understanding and appreciation of nature and the importance of its conservation. It helps to promote the concept “citizen of the earth”. It advocates duty of each individual to care for the earth and use its resources in a sustainable way.

Value-based Education Value based education teaches about · · · · · ·

Distinction between good and bad How to live life How to be happy and make others happy How to be compassionate, helpful, loving, generous and tolerant. How to move towards sustainable future Responsibility towards society and nation.

Following attitudes and behavior to be incorporated through value based education 1) Human values To develop positive attitudes towards environment and to recognize that ‘man in nature’ rather than ‘nature for man’. 2) Social Values To develop values such love, compassion, tolerance and justice towards nature so that all forms of life (biodiversity) can be protected. 3) Cultural Cu ltural and Religious Religiou s Values To nurture, respect and protect every aspect of nature by considering them sacred (plants, rivers, mountains etc are sacred) 4) Ethical Ethical values To promote earth – citizenship thinking rather than human centric thoughts/ views 5) Global Values To recognize that nature and all the natural phenomenon occurring in the earth are interconnected and exist in harmony. Disturbing the harmony will lead to ecological collapse.

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6) Spiritual Spiritual values To develop principles of self control, contentment, reduction of desires and freedom from greed. These values will help to attain sustainable development and environmental conservation.

5.11

| ENVIRONMENTAL IMPACT ANALYSIS/ASSESSMENT

Environmental Impact Assessment (EIA) is a process of evaluating evaluating the likely environmental impacts of a proposed project or development. It takes into account various inter-related socio-economic, cultural and human-health impacts of the proposed project, both beneficial and adverse. EIA would necessarily involve the following stages: 1. Screening: This is the first step in EIA. Screening determines whether a proposed project falls within the remit of the Regulations, whether it is likely to have a significant effect on the environment and therefore requires an assessment. 2. Scoping: Scoping is done to identify which potential impacts that are relevant to assess. This is done based on legislative requirements, expert knowledge and public involvement. Alternative solutions are suggested so that adverse impacts on environment is minimized. 3. Preparing the Environmental Impact Statement (EIS) or EIA report: When it is decided that an assessment is required, the applicant must compile the information required to assess the likely significant environmental effects of the development. This can be done with the help of public authorities who provides him any relevant environmental information in their possession. The information finally finally compiled by the applicant is known known as an Environmental Impact Statement (EIS) . 4. Review of the Environmental Environmental Impact Statement (EIS): Review is based on the terms of reference and public participation. 5. Decision-making: A final decision is made on whether to approve the project or not, and under what conditions. 6. Monitoring, Monitorin g, compliance, complianc e, enforcement and environmental auditing: Finally, after sanctioning the project, it is closely monitored to see whether the predicted impacts and proposed mitigation measures occur. It also ensures that unpredicted impacts or failed mitigation measures are identified and addressed in a timely fashion.

5.12

OF INFORMATION INFORMATION TECHNOLOGY IN | ROLE OF ENVIRONMENT AND HUMAN HEALTH

Information Technology (IT) is defined as the collection, processing, storage and dissemination of information. IT is of immense help in the field of environmental education and health. It helps the development of internet facilities, Geographical information system, Remote sensing technologies etc. IT also assist to generate up-to-date information on various aspects of Environment and health. Obtained data is in computerized form and can be retrieved whenever required.

5.12.1 Role of IT in Environment i) ENVIS – Environmental Information System · Government of India established Environmental Information System (ENVIS) , in 1982. It was created to collect, handle and store Environmental Information. · Collects information from 25 centers all over the country. · Generates network of database on areas like pollution control, remote sensing, biodiversity, Environmental Management, renewable r enewable energy, energy, Desertification, Deser tification, Mangroves, Mang roves, Wildlife, Wildlife, Mining etc. e tc.

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Few objectives of ENVIS a) To build build up a repository and dissemination centre in Environmental Environmental Science and Engineering b) To support support and promote research and development development in the area of environmental environmental information technology. c) To promote exchange of information amongst developing developing countries. ii) NIMS – National Management Management Information System System The National Science and Technology Management Information System (NSTMIS), a division of Department of Science and Technology (DST) was created to build the information database on a continuous basis on natural resources in the country. It is devoted to scientific and technological activities. iii) RIS – Remote Sensing Information System · Remote Sensing is the collection of data by sensors not in direct contact with the phenomena of interest. · A typical RIS system has four elements: a source, the sensor, interactions with the atmosphere, and interactions with the earth’s surface. · Satellite imageries provide the actual information about various resources and their degradation in a digital form through remote sensing. · Satellite data provides correct, reliable and verifiable information about forest coverage, desertification, afforestation etc. · Provides information of ozone layer depletion, smog, approach of monsoon etc. · To discover many new reserves of oil, minerals etc. · To find out land cover, forest cover, bio diversity etc. by mapping · Plays a key role in Environmental Management, Environmental Impact Assessment etc.

iv) GIS – Geographical Information System ·

·

· · ·

·

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GIS is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. Different thematic maps containing digital information on a number of environmental aspects like water resources, soil type, forest land, grass land etc. are superimposed in a layered form in computer using software. For interpretation of polluted zones, degraded lands, emission sources etc. Zoning Atlas is prepared by GIS to locate suitable areas for industrial growth GIS plays a key role in resource mapping, environmental conservation, management, planning, Coral reef mapping etc. Helps in disaster Management and relief operations

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v) WWW – World World Wide Web Web · Internet and web resource materials, online learning centre, provides the most current and relevant information on environmental applications, problems & solutions etc. · Student and teacher friendly features: To get detailed information, case studies, current articles, career information, encyclopedia (Wikipedia), videos (youtube) etc. vi) Computer based instruments for environment studies Environmental monitoring, data collection and analyses involve the extensive use of computers. Many techniques involve automated sampling and analysis. Almost all analytical techniques involved like Atomic absorption spectrometry, flame photometry etc are attached to computer where data can easily read, analysed, compared and stored.

5.12.2 Role of IT in Human Health Information technology (IT) has the potential to improve the quality, safety, and efficiency of health care. Combination of IT and health is bioinformatics . Some applications of computer based technology in the field of health are listed below. below. i) Electronic health records (EHR) · EHR is a collection of electronic health information about individual patients. · It is a digital record which can be easily shared. · EHRs may include a range of data, including medical history, medication and allergies, immunization status, laboratory test results etc. · EHR saves considerable amount of time for doctors, as it contains entire medical history of the patient. · It also helps in easy access and sharing of information. ii) Automated Automated dispensing machines (ADMs) (ADMs) · This is an advanced automated technology which distributes required medication doses to the prescribed patients on time. iii) Picture archiving and communications system (PACS) · This captures and integrates diagnostic and radiological images from various devices (e.g., X-ray, MRI scan), stores them, and disseminates them to a medical record, a clinical data repository etc. iv) Medical Transcription · Medical transcription is the transcribing (typing) of doctor’s reports from dictated audio files. These files are used for diagnosis, information sharing and health care delivery. v) Teleconferencing eleconfe rencing · Using latest computer aided technology, it is possible for a physician to have a teleconference with other medical experts in the middle of surgery. vi) Endoscopy and Laproscopy · Endoscopy involves examining the inside of a person’s body using an endoscope. An endoscope is a medical device consisting of a long tube with light or cameras attached that is used to look inside a body cavity or organ. The image of the organ can be seen on computer monitor and can be studied for the growth of tumor, cancer etc. · Lapscropic (key hole) surgery uses computer based applications. vii) Instruments in health care · Magnetic resonance imaging unit (MRI scan), Computed Axial Tomography (CT scan), Intensive Care units (ICU) etc widely use computers for functioning.

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viii) Mobile blood banks · Mobile blood banks have data of different blood groups and those who are in need of blood to meet critical medical situations can get it from these banks. Software application can help people to find a nearest donor from his/her own locality. List of blood donors with their blood group and phone numbers will be available through the application.

ANNA UNIVERSITY QUESTIONS 1. With a neat diagram explain the variation in population growth among various nations. (Anna Univ, Dec 2013) 2. Write a brief note on family welfare programmes initiated by Government of India. (Anna Univ, Dec 2013) 3. Discuss the role of Information Technology in environmental protection and human health. (Anna Univ, Dec 2013) 4. Explain the effects and control of AIDS


5. Explain the environmental problems posed by population explosion (Anna Univ, June 2013) 6. Write the methods and strategies on imparting value education


7. Briefly describe the various activities launched for women and child welfare in India (Anna Univ, Dec 2014) 8. Write a short note on human rights.

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APPENDIX

ANNA UNIVERSITY TWO MARKS QUESTIONS AND ANSWERS UNIT I

Environment, Ecosystems and Biodiversity 1. Define environment. Environment is the sum total of air, water and land, inter relationships among themselves and also with human beings, other living organisms and property. The word Environment is derived from the French word “Environ” which means “surrounding”.

2. State the significance significa nce and scope of environmental education. education . Environment studies have become significant for the following reasons: ·

Environment issues being of international importance Environment issues like global warming and ozone depletion, loss of biodiversity etc are not merely national issues but are global issues. These issues must be addressed with international efforts and cooperation.

·

Problems associated with industrialization and development Rapid growth of science and technology resulted in industrialization. This rapid industrialization has caused severe environmental damage due to its activities.

·

Population explosion Total world population has crossed 7 billion. This population explosion will cause depletion of all natural resources.

·

Natural resources: Conservation and management Due to over exploitation, many natural resources are being depleted at an alarming rate. Proper steps have to be taken for their preservation.

·

Environmental pollution and control Human activities have resulted in wide spread pollution of land, water and air. Irrecoverable damage to environment can happen if pollution is not checked.

3. What is hazard? A Hazard is a potential source of harm or adverse health effect on a person or persons. Or it is the way in which an object or a situation may cause harm. A hazard exists where an object (or substance) or situation has a built-in ability to cause an adverse effect. Such hazards include uneven pavements, unguarded machinery, an icy road, a fire, an explosion and a sudden escape of toxic gas.

4. What is a risk? A risk is chance or probability that a person may be harmed or suffers adverse health effects if exposed to a hazard. Risk can be high or negligible.

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Factors that influence the degree of risk include: · · ·

how much a person is exposed to a hazardous thing or condition, how the person is exposed (e.g., breathing in a vapour, skin contact), and how severe are the effects under the conditions of exposure. Risk = hazard + exposure

5. What is an ecosystem? ecosyste m? What are its components? An ecosystem is a group of biotic communities of species interacting with one another and with their non-living environment exchanging energy and matter. Ecology is the study of ecosystems. Two major structural components of ecosystem are Abiotic components: Non-living components (physical and chemical) of an ecosystem collectively are called abiotic components. Biotic components: Living organisms or living members in an ecosystem form biotic components. It includes plants, animals and microorganisms present in an ecosystem.

6. What is food chain? The transfer of energy within the ecosystem (among various levels) by a sequence of eating and being eaten in an ecosystem is known as food chain. An example of a simple food chain is: Grass

® grasshopper ® Frog ® Snake ® Hawk

(Grassland ecosystem)

7. What are the main functions of the ecosystem? The major functions of ecosystems are (i) (ii) (iii) (iv) (v)

Food Food chain, chain, food webs and trophic structure (Ecological (Ecological pyramids) Energy flow Cycling of nutrients nutrients (Biogeochemical (Biogeochemical cycles) Primary and Secondary production production Ecosystem development development and regulation

8. What is biodiversity? Biodiversity is the degree of variation of life. It is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation (number of species) within an area, biome, or planet. The variety and variability of life on earth is known as biodiversity.

9. What are extinct species? Give Give examples. A species is said to be extinct when it is not seen in the wild for 50 years at a stretch. Example: Dodo, passenger pigeon, dinosaur, mammoth, saber-toothed tiger.

10. What are endangered species? Give examples. A species is said to be endangered when the number has been reduced to a critical level or whose habitats have been drastically reduced. They can become extinct when not protected and conserved. Example: Giant panda, Indian elephant, Royal Bengal Tiger.

11. What are endemic species? Give examples. Species which are restricted to a particular area is called as endemic species. Example: Nilgiri Tahr, Lion tailed macque.

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Appendix 153

12. What is a keystone species? Species or set of species whose impact on its community or ecosystem is much larger and more influential are termed as keystone species. Extinction of these species would consequently lead to the extinction of many other forms of life. In the African savanna (grassland), elephants are the key stone species as they shape their environment. They destroy trees, making room for the grass species. Without elephants, much of the savannah would turn into woodland or forest.

13. What is red data book? Red Data Book is a state document established for documenting rare and endangered and threatened species of animals and plants.

14. What do you mean by


of biodiversity?

conservation refers to the conservation of plants and animals in their own natural habitat where they survive. Example: Biosphere reserve, National parks, Wildlife Sanctuaries etc.

In situ

15. What do you mean by

exsitu conservation

of biodiversity?

Ex situ situ conservation include conservation of plant and animal species outside the habitat. The species are provided their habitat artificially. Threatened animals and plants are taken out from their natural habitat and placed in a place where they can be protected and given special care. Example: Gene banks, Botanical Gardens, Zoos, Genetic resource centers.

UNIT II

Pollution 1. Define pollution. pollutio n. Environmental pollution can be defined as any undesirable change in the physical, chemical or biological characteristics of any component of the environment (air, water, soil), which can cause harmful effects on various forms of life or property. The material that causes pollution is called pollutant.

2. What are the functions of atmosphere? Functions of atmosphere are · · · · ·

Blocking harmful rays: Harmful ultra violet radiation from the sun is blocked by ozone layer, which is a part of our atmosphere. Source of Oxygen and Carbondioxide: Atmosphere acts a source for both oxygen and carbondioxide which is essential for respiration and photosynthesis. Maintenance of earth’s temperature: Atmosphere cause heat retention and keep earth surface surfac e warm. In the absence of atmosphere the temperature of earth would be sub zero in the night. Saving earth from meteors: Most meteoroids that enter the Earth’s atmosphere vaporize completely due to high temperature and friction and never reach the planet’s surface. Climate and weather: Earth gets heated non-uniformly by the sun resulting in different weather patterns. Air Air sets in motion resulting in winds causing cyclones, monsoon, rainfall etc.

3. How is ozone layer formed? Ozone in the stratosphere is produced by photochemical reactions involving O 2. When diatomic oxygen in the stratosphere absorbs ultraviolet radiation with wavelengths less than 240 nm, it breaks apart into two oxygen atoms.

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O2 + hn

® 2

l <

O (light of

240 nm)

The resulting oxygen atoms combine with O 2 molecules to form ozone in the presence of a third body M. O + O2 + M (N2 or O2)

®

O3 + M

The third body M absorbs the excess energy liberated by the above reaction and there by stabilizes the O3 molecule.

4. Describe the chemistry behind ozone hole hole formation. formation. Major reason for the depletion of ozone layer is halogen atoms (F, Cl, Br) which are formed by the photochemical decomposition of CFC’s. CFC’s. CFC is an organic compound that contains only carbon, chlorine, hydrogen and fluorine. CFC’s CFC’s are widely used as coolants in refrigeration ref rigeration systems and air conditioners, propellants for aerosols due to low boiling point. These slowly rise up and reach stratosphere and cause depletion of ozone. The chemical reaction can be represented as CF2Cl2 +hn Cl + O3 ClO + O

®

CF2Cl +Cl

® ClO ® Cl

+ O2

+ O2

In the second step, Cl is generated again which can cause the reaction to continue like a chain reaction. One chlorine atom can thereby destroy thousands of ozone molecules. Similarly other atoms present in CFC like Fluorine and Bromine can also cause similar effect.

5. Explain the effect of ozone layer layer depletion depletio n ·

· · · ·

Ozone depletion in the stratosphere will result in more UV radiation reaching the earth especially UV-B (290-320 nm). The UV-B radiations affect DNA. Any change in DNA can result in mutation. Can cause skin cancer (basal and squamous cell carcinoma) which donot cause death but cause disfigurement. Easy absorption of UV rays by the lens and cornea of may cause cataract. Ozone depletion will result in decrease in phytoplankton population thereby affecting the population of zooplankton, fish, marine animals, infact the whole aquatic food chain. Yield of vital crops like corn, rice, soybean, cotton, bean, pea and wheat will decrease.

6. Why is carbon monoxide considered as a very harmful pollutant? CO is a very poisonous gas and is produced by incomplete combustion of fuel. CO, being a very strong ligand, binds strongly with Fe present in the hemoglobin. CO has affinity for haemoglobin 210 times more than oxygen. Thus it interferes with the oxygen carrying capacity of blood. HbO2 + CO Oxyhemoglobin

®

HbCO + O2 carboxyhemoglobin

Haemoglobin is, therefore, unable to transport oxygen to various parts of the body. This causes the reduction in oxygen levels in the tissues. Prolonged exposure leads to dizziness, reduced vision and even death. People who survive severe CO poisoning may suffer long-term health problems.

7. What is smog? Smog is a kind of air pollution, originally named for the mixture of smoke and fog in the air

Smog = Smoke + Fog

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Appendix 155

8. What is acid rain? Acid rain is a rain or any other form of precipitation that is unusually acidic (pH below 5.6). Acid rain literally means ‘the presence of excessive acids in rain waters’. Acid rain can be wet or dry. Natural rain water has a pH of 5.6 at 20°C because of formation of carbonic acid due to dissolution of CO2 in water. Any precipitation less than pH 5.6 can be considered acidic. Typical acid rain has a pH value of 4 or lower. Acid precipitation is a mixture of strong mineral acids sulphuric acid (H2SO4), nitric acid (HNO3) and in some locations, hydrochloric acid (HCl).

9. Define BOD and COD Biochemical oxygen demand (BOD) is the measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria) in the oxidation of organic matter. The result is that the oxygen content of the water will be decreased. Chemical oxygen demand (COD) is a measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemicals such as Ammonia and nitrite.

10. What is soil pollution? How is it caused? Soil pollution is the presence of toxic chemicals (pollutants or contaminants) in soil in high enough concentrations to be of serious risk to health of living organisms or ecosystem. The major sources of soil pollution are

i) ii) iii) iv) v)

Industrial Wastes Urban Wastes Agricultural practices Radioactive pollutants Biological Biological wastes

11. What is noise pollution? How is it caused? Noise pollution is excessive, displeasing human, animal, or machine-created environmental noise that disrupts the activity or balance of human or animal life. Sources of Noise Pollution · · · ·

Transport/Traffic: One of the main sources of noise is various modes of transportation (like air, road, rail-transportation). Industrial activity: Use of sirens, heavy machines, engines, turbines, cutting, grinding etc causes significant noise pollution. Domestic activity: Use of grinders, food blenders, television, music system can produce unpleasant loud sound disturbing the neighborhood. Celebrations: People celebrate festivals by exploding crackers. During Diwali, New year, marriages etc involve extensive use of

12. Suggest some methods to reduce noise pollution Following methods can be used to control noise pollution: · · · ·

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Reduce noise at the source: Sources of noise pollution like heavy vehicles and old vehicles may not be allowed to ply in the populated areas. Proper maintenance: Proper oiling will reduce the noise from the machinery and other moving parts. Use of sound absorbing substances/silencers: Use of substances that absorb sound or silencer in motor vehicles can reduce the intensity of noise pollution. Planting trees: Plants and trees should be planted all around the hospitals, libraries and schools and colleges. These trees can absorb noise.

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156 Environmental Science and Engineering · ·

Personal precaution: Industrial workers should be provided with ear plugs or cotton plugs. People should not cause nuisance to public by playing music, television very loud Law enforcement: Strict legislation can ensure that sound production is minimized at various festivals and social functions. Fire crackers shall not be used at any time in silence zones, as defined by the Ministry of Environment and Forests.

13. Explain the role of an individual to reduce soil pollution. · · · · ·

Use rechargeable batteries. Rechargeable batteries will reduce metal pollution. The solid waste generated during one manufacturing process can be used as a raw material for some other processes. Promote reuse and recycling wherever possible and reduce the production of solid wastes. Biodegradable materials can be converted into compost or mature or for the production of bio-gas. Timely disposal of waste to prevent decomposition of household refuge as to check foul odors and spread of disease by insects, flies and other pathogenic bacteria.

UNIT III

Natural Resources 1. Distinguish Distinguis h between renewable renewable and non renewable renewable resources. Renewable resources are inexhaustive and can be regenerated within a given span of time. Example: Forests, wildlife, wind energy, biomass energy, tidal energy, hydro power etc. Non-renewable resources are resources which cannot be regenerated. Example: Fossil fuels like coal, petroleum, minerals etc. Once we exhaust these reserves, the same cannot be replenished.

2. What is deforestation? What are its consequences? consequence s? Removal of earth’s forest is known as deforestation. It is the clearing of trees, transforming a forest into cleared land. Consequences of deforestation are · Global warming · Soil erosion · Loss of habitat for plants and animals · Loss of soil fertility · Lowering of water table · Shifting of tribal people · Loss of biodiversity, Genetic and species diversity · Desertification

3. What is an aquifer? What are are its types? A layer of sediment or rock that is highly permeable and contains water is called an aquifer. Aquifers may be of two types: Unconfined aquifers which are overlaid by permeable earth materials and they are recharged by water seeping down from above in the form of rainfall and snow melt. Confined aquifers which are sandwitched between two impermeable layers of rock or sediments and are recharged only in those areas where the aquifer intersects the land surface.

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Appendix 157

4. What are are consequences consequenc es of over over exploitation exploitati on of ground ground water? water? Consequences of over exploitation of ground water are · Lowering of water table · Ground subsidence · Water logging and salinity · Water pollution/Chemical contamination · Decline in agricultural production · Drying up of lakes, rivers and water bodies · Desertification

5. What are floods? How can it be pr prevented? evented? A flood is an overflow of water that submerges land which is usually dry. This happens when river carries water much beyond its normal capacity. Control measures for the prevention of flood · Building dams · Networking of rivers · Watershed management · Control of deforestation · Floodwalls

6. What is drought? How is it caused? Scarcity of water which occurs due to inadequate rains, late arrivals of rains and excessive withdrawal of ground water is called drought. Causes 1. Less rainfall / Failure of monsoon: Less rainfall/ monsoon failure may result in severe water scarcity result in drought. 2. Deforestation: Unscientific cutting down of trees can result in change in hydrological cycle which can lead to drought. 3. Overgrazing: Cattles may eat away the vegetation converting the land into dry, arid or semi-desert lands which may cause drought. 4. Unscientific agricultural practices: Erroneous, intensive agricultural methods, unscientific practices may lead to water scarcity leading to drought.

7. What is eutrophication? eutrophication ? What are its consequences? consequence s? Eutrophication is the process by which a body of water becomes enriched in dissolved nutrients (as phosphates) that stimulate the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen. Eu means “more” and trophic means “nutrition”. Consquences of eutrophication · Increased biomass of phytoplankton · Decreases in water transparency (increased turbidity) · Colour, smell, and water treatment problems · Dissolved oxygen depletion · Loss of desirable fish species · Decreases in aesthetic value of the water body · Difficulty in transport

8. What is the role role of an individual in conserving conservin g food food resources? resources? · ·

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Do not waste food. Take as much as you can eat. Don’t cook food more than required.

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158 Environmental Science and Engineering · · · · ·

Reduce the use of chemical pesticides. Use organic fertilizers for your crops. Use drip irrigation to water the crops. Have a vegetable garden at your own home so that you can get fresh vegetables. Eat local and seasonal vegetables. This saves saves lot of energy on transport, storage and preservation.

9. What is soil erosion? erosion? How How is it caused? Removal of top soil from one place to another by various agents like water, wind etc is known as soil erosion. Soil erosion results in the loss of fertility of the soil because of the loss of top soil layer which is fertile. Causes · Deforestation: Removal of trees make top soil loose and hence can be easily removed by agents of erosion. · Floods and heavy winds: Floods and heavy winds may wash(carry) the top soil causing soil erosion. · Agricultural practices: Traditional agricultural practices like tilling and ploughing expose top soil, which is prone to erosion.

10. What is desertification? Desertification is a type of land degradation in which a relatively dry land region becomes increasingly arid, losing its bodies of water as well as vegetation and wildlife. In short conversion of a dry land into a desert is called desertification.

11. What is the role of an individual in conserving energy resources? · · · · · · · ·

Turn off lights, fans and other appliances when not in use. Use pressure cooker for cooking. This makes cooking faster and saves fuel. Use fluorescent lamps and LED’s instead of incandescent lamps. This save a lot of power. Always cook in closed containers so that energy wastage is minimum. Switch off electrical equipment completely when not in use. Dry the clothes in sun instead of drier if it is a sunny day. Use solar lanterns. Drive less, make fewer trips and use public transportations whenever possible. Use bicycles to commute.

UNIT IV

Social Issues and the Environment 1. What is sustainable development? Sustainable development is a development that meets the needs of the present without com promising the ability of future generations to meet their own needs. Sustainable development development means improving the life of the people. It refers that the progress in well being of humans and other living beings should be extended or prolonged over many generations than just few years.

2. What is rainwater harvesting? harvesting? What are are its advantages? advantages? Rainwater harvesting is a technique of collecting and storing rainwater and increasing the recharge of ground water by collected water.

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Rainwater harvesting helps in · recharging the aquifers · improving groundwater quality · improving soil moisture content · reducing soil erosion by minimizing run-off water.

3. What is green house effect? Nearly 30% of the solar radiation falling on earth’s earth’s surface is reflected back to the space. Rest of the radiation is trapped by earth’s atmosphere. The amount of heat trapped in the atmosphere depends mostly on the concentrations certain gases called green house gases. The major green house gases are carbon dioxide, ozone, methane, nitrous oxide, chlorofluorocarbons (CFCs) and water vapor . As the effect is similar in nature to what happens in a botanical greenhouse (the glass panes allows the light energy to enter inside but diminishes the loss of heat), these gases are called greenhouse gases and the resultant warming from their increase is called the greenhouse effect.

4. What are the consequences consequence s of greenhouse effect? Consequences of Greenhouse Effect are the following · Global temperature increase · Melting of polar icecaps and rise in Sea Level · Decline in agricultural production. · Natural disasters disasters like floods can happen · Ocean acidification

5. What is ecomark? In order to increase the consumer awareness about environmental issues, the Government of India have intiated a eco-labelling scheme called “ Ecomark ” in 1991 for the identification of eco friendly products. It is a certification mark issued by the Bureau of Indian Standards (BIS) to products that are manufactured with least impact on the eco system.

6. What are the consequences consequence s of earthquake? earthqua ke? Earthquake can result in · Damage to Life and property: Structures such as buildings, roads, rails, factories, dams, bridges can be completely or partially destroyed destroyed by earthquakes · Landslides and avalanche: Earthquakes can cause landslides. It can also trigger avalanche. supply, · Damages to Government Infrastructure: Earth quakes can result in cutting of water supply, telecommunication cables etc. Thus, there is total disruption of power and communication. Contamined water can cause spread of epidemics. · Fire Hazard: Strong oscillations of earthquakes can cause severe fires in houses and factories because of bursting of cooking gas cylinders, contact of live electric wires etc. · Flash Floods: Strong seismic events result in the damages of dams and cause severe flash floods. Dams may crack or break. This can result in flow of huge volumes of water. · Tsunamis: Earth quakes which originate beneath the ocean floor can result in the formation of gigantic sea waves which approach the sea shore and cause g reat loss of life and property. These are called tsunami.

7. What is Tsunami? How How is it caused? A tsunami is a giant wave (or series of waves) created by an undersea earthquake, volcanic eruption or landslide. “Tsunami” in Japanese means “harbor wave”. Tsunamis are not “tidal waves”

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Causes of Tsunami · Earthquakes: These are the most destructive and common cause for tsunamis. When earthquake is massive, at least 7.5 in magnitude, it displaces enough water vertically to case a huge wave. · Volcanic eruption: A massive volcanic eruption can disturb the ocean floor which can lead to the formation of tsunami. The explosive eruption of Krakatau in 1883 created a tsunami that claimed more than 36,000 lives. · Landslides: Enormous submarine landslides can occur on the flanks of ocean islands which can lead to tsunami. Landslides can be triggered by earthquake or volcanic activity. · Meterorites: Asteriods falling into the ocean can lead to tsunami.

8. What is disaster management? Disaster management involves preparing for a disaster before it happens, response to the disaster (eg: emergency evacuation, quarantine etc.), and also supporting, and rebuilding society after the occurance of the disaster. Disaster management = Management before, during and after the disaster

UNIT V

Human Population and the Environment 1. Define population populatio n and population populati on dynamics. Population is defined as the number of individuals of same species in a given area at a given time. Population dynamics refers to change of population with time.

2. What is population populatio n explosion? Population explosion is the rapid and significant increase in the size of a population caused by such factors as a sudden decline in infant mortality, death rate or an increase in life expectancy.

3. What is population populatio n doubling time? Population doubling time is the time needed for a population to double its size at a constant annual growth rate. Td = 70/r, where Td -doubling time in years (r- annual growth rate). For example if a country has annual growth rate of 2%, its population doubling time will be 70/2= 35 years.

4. What are the consequences consequence s of population populati on explosion? Inadequate fresh water: Population explosion can lead to severe shortage of drinking water, especially in semi-dry or dry areas. Depletion of natural resources: It can lead to over exploitation of many natural resources (water, forest, mineral, food, energy, soil etc). Pollution: More number of people will result in severe environmental pollution (air, water, soil, marine, noise etc). Deforestation: Forests will be cleared for human settlement, agriculture etc. Deforestation cause extinction of rare and endangered species. Poverty, malnutrition and starvation: Shortage of food and drinking water among people can result in poverty and malnutrition.

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Emergence of new epidemics and diseases: Malnutrition along with unhygienic living conditions and lack of good healthcare facility can result in the emergence of epidemics Climate change: Growing population can result in the increase of greenhouse gases which can result in global warming.

5. What is population populatio n pyramid? A population pyramid represents the age and sex structure of a population. The shape of the pyramid reflects the characteristics of a population. ·

·

Graphs are on their sides with the axis in the middle. Population plotted on the X-axis and age on the Y-axis. The number of males is shown on the left, females on the right in five-year age groups. Different age classes are pre-productive (0-14 yrs) reproductive (15-44yrs) and post productive (45yr and above) above)

6. Name some schemes initiated initiate d by by Government Government of India for the uplift of women · · · ·

National Policy Policy for the Empowerment Empowerment of Women (2001) Balika samridhi yojana (1997) Beti Bachao Beti Padhao Sukanya Samriddhi Accounts

7. Name some Legislative Legisla tive measures and policies polici es initiated initiate d by Government of India for child welfare · · · · ·

Child Labour (Prohibition & Regulation Act) (1986) The Child Marriage Restrain Act, 1929 The Juvenile Justice (Care and Protection of Children) Act, 2000 The Commissions for Protection of Child Rights Act, 2005 The National Policy for Childre n (1974)

8. What are the applications applicat ions of Geographical Geographica l Information System? GIS is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. GIS plays a key role in resource mapping, environmental conservation, management, planning, Coral reef mapping etc. GIS helps in disaster Management and relief operations.

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SOLVED ANNA UNIVERSITY QUESTION PAPERS B.E / B.Tech Degree Examination Nov/Dec 2014 GE6351- Environmental Science and Engineering Third Semester Regulation 2013 Time: Three hours

Maximum: 100 Marks

Answer ALL questions PART A – (10 X 2 = 20 marks) 1. What is an abiotic environment? Non-living components components (physical and chemical) chemical) of an ecosystem collectively collectively are called abiotic components of the environment. Example: Sunlight, soil, water, air etc. 2. What are are called endangered species? species ? A species is said to be endangered when the number has been reduced to a critical level or whose habitats have been drastically reduced. They can become extinct when not protected and conserved. Example: Giant panda, Indian elephant, Royal Bengal Tiger. 3. Mention the effect of ozone on plants . Ozone damages vegetation and ecosystems by reducing the ability of plants to open the microscopic pores on their leaves to breathe. It reduces photosynthesis process. High levels of ozone leads to reduced agricultural crop productivity. Plants become more susceptible to diseases, pests etc. 4. List the sources of marine pollution pollution . Sources for marine pollution are oil spillage, industrial wastes, domestic wastes, wastes from nuclear power plants etc. 5. What are renewable resources? Renewable resources are inexhaustive and can be regenerated within a given span of time. Example: Forests, wildlife, wind energy, biomass energy, tidal energy, hydro power etc. 6. Define the the term landslide. Landslides refers to the sudden movement of large amounts of earth, rock, sand or mud or any combination of these. Causes of landslide: Deforestation, underground mining, heavy rainfall, earthquakes. Consequences of landslide: Loss of life and property, Loss of transportation and communication, Increase in turbidity in lakes, Avalanche.

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Solved Anna University Question Papers 163

7. What is rainwater harvesting? Rainwater harvesting is a technique of increasing the recharge of groundwater by capturing and storing rainwater. This is done by constructing special water harvesting structures like dug wells, percolation pits, lagoons, check dams etc. 8. What are the objectives of water act? Water act aims at maintaining and restoring the wholesomeness of water by preventing and controlling its pollution. It provides for the establishment of Centre and state pollution control board which lays down standards for water quality parameters. Act makes provisions for various penalties for defaulters. 9. Define the term nuclear nuclear energy. The splitting up of a heavier nucleus using projectile, into two or more lighter nuclei with the liberation of large amounts of energy is known as nuclear fission. The process of fission is always accompanied by the ejection of two or more neutrons and a large amount of energy.

U235 + 0n1

92

→

Kr 94 +

36

Ba139 + 30n1 + Energy

56

10. What are the sources of HIV infection? Contaminated Fluids: Contamination of blood stream with HIV infected body fluids, particularly blood, blood, semen, breast milk and vaginal fluid. Sharing of needles: Sharing of HIV contaminated needles in blood transfusion. Unprotected sex: By sexual contact with affected person Maternal-fetal Maternal-fetal transmission: Infected mother give birth to infected baby. Breast milk can also act as a transmission-medium. Improperly Improperly sterilized hospital tools: If surgical devices like syringes and scalpels, or even certain instruments, used on an infected person, are used on another person without proper sterilization. Contaminated needles or syringes used drugs.

PART B – (5 X 16 = 80 marks) Give an account of structure and features of grassland 11. (a) (i) Define ecosystem. Give ecosystem. Refer 1.6.2, Page 16 (ii) What is biodiversity? Discuss the values and significance of biodiversity biodiversity.. Refer 1.7, 1.9, Page 22

(8) (8)

Or (b) (i) With a neat sketch discuss Nitrogen cycle. Refer 1.5.3, Page 13

(8)

(ii) What do you mean by conservation of biodiversity? biodiversity? State and explain the basic approaches to wildlife conservation. (8) Refer 1.16, Page 31

12. (a) (i) Describe the various chemical and and photochemical photochemical reactions reactions in the atmosphere. atmosphere. (8) Refer page 38

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(ii) Explain the sources, measures and control measures of noise pollution. Refer 2.18, Page 61

(8)

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Or (b) (i) Write informative notes on water treatment process. Refer 2.13, Page 54 (ii) Describe the role of an individual in the prevention of pollution. Refer 2.22, Page 68

13. (a) (i) Describe the causes and effects of deforestation. Refer 3.2.2; Page 73

(8) (8) (8)

(ii) What is land degradation? degradation? Discuss the factors responsible for land degradation. (8) Refer 3.5.2; Page 90

Or (b) (i) What are the changes caused by agriculture and overgrazing? overgrazing? Refer 3.4.2; Page 83 (ii) Discuss the production of biogas. Mention its uses Refer 3.6.6; Page 97

14. (a) (i) What are the objectives objectives of water conservation? How is it carried out? Refer 4.3, Page 104

(8) (8) (8)

(ii) What is an earthquake? Ennumerate its effects. What are the measures to be taken to mitigate this disaster. (8) Refer 4.18, Page 123

Or (b) (i) Discuss the resettlement and rehabilitation of of people, its problem and concerns. (8) Refer 4.5, Page 107 (ii) Briefly discuss the salient features of wildlife protection act. Refer 4.12.4, Page 116

15. (a) (i) Discuss the variation of population among nations Refer 5.3, Page 134 (ii) Write the methods and strategies of imparting value education. Refer 5.10, Page 145

(8) (8) (8)

Or (b) (i) Write explanatory notes on women and child welfare. Refer 5.7, Page 140

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(ii) Explain the role of information technology technology in environment and human health. Refer 5.12, Page 146

(8) (8)

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B. E / B.Tech Degree Examination April /May 2015 Ge2211- Environmental Science And Engineering Third Semester Regulation 2013 Time: Three hours

Maximum: 100 Marks

Answer ALL questions PART A – (10 X 2 = 20 marks) 1. 1 . What is the difference between renewable and non-renewable resources? Renewable resources are inexhaustive and can be regenerated within a given span of time. Example: Forests, wildlife, wind energy, biomass energy, tidal energy, hydro power etc.

Non-renewable resources are resources which cannot be regenerated. Example: Fossil fuels like coal, petroleum, minerals etc. Once we exhaust these reserves, the same cannot be replenished.

2. What is overgrazing?

The rapid consumption of grass and other small plants by cattle stock (cows, goat, buffalo, sheep) without giving enough time to regenerate is known as overgrazing. Overgrazing leads to deforestation, soil erosion, land degradation, desertification etc. 3. Define ecological succession. Ecological succession is defined as the orderly changes that happens in a community structure and function over a period of time. Quite often it is observed that one type of community is totally replaced by another over a period of time. In other words, a community evolves slowly from a simple community to a much complex community. 4. How is estuary formed formed in coastal zones?

Estuary is formed when river meets the sea. Estuarine ecosystem is a rich ecosystem, water is brackish. 5. What is the difference difference between sound sound and noise?

Noise is undesirable and unwanted sound. Not all sound is noise. What may be considered as music to one person may be noise to another. Sound is measured in a unit called the ‘Decibel’. Ordinary conversation has a noise value of 60 decibels. If loudness exceeds 80 decibels, it can cause noise pollution. 6. List out the sources and causes of thermal thermal pollution Sources i) Industries: Heat producing industries like thermal power plants, nuclear power plants, oil refineries, steel mills etc uses water for various purposes. ii) Nuclear power plants: Nuclear power plants use water as coolant. After heat exchange water having higher temperature is discharged to water body. iii) Domestic homes: Hot water discharged from homes (geyser) and kitchen can also cause thermal pollution.

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Effects of Thermal pollution i) ii) iii) iv) v)

Reduction in amount of dissolved oxygen Death of aquatic organism Increased toxicity of chemicals at higher temperature Migration of fishes Reduced fertility rate in fishes

7. Differentiate between inter and intra generation equity in sustainable sustain able development development .

Intragenerational equity equity is concerned with equity between people of the same generation. Interagenerational equity is equity is concerned with equity between people of the different generation. 8. What are the prime objectives of rain water harvesting?

Rainwater harvesting has the following objectives: to meet the growing water requirements to raise the water table by recharging ground water to reduce run off loss to avoid flooding of roads to reduce groundwater contamination 9. What is doubling time? How How is it calculated?

Population doubling time is the time needed for a population to double its size at a constant annual growth rate. Td = 70/r, where Td-doubling time in years (r- annual growth rate). For example if a country has annual growth rate of 2%, its population doubling time will be 70/2 = 35 years. 10. Write the social values values of environmental environmental education .

To develop values such love, compassion, tolerance and justice towards nature so that all forms of life (biodiversity) can be protected. Value based education teaches about Distinction between good and bad How to live life How to be happy and make others happy How to be compassionate, helpful, loving, generous and tolerant. How to move towards sustainable future Responsibility towards society and nation.

PART B – (5 X 16 = 80 marks) 11. (a) (i) Discuss the major mineral resources in India Refer 3.3, Page 81 (ii) Explain nuclear reactions with respect to nuclear fission and fusion reactions.

(8) (8)

Refer 3.6.2, Page 93 Or (b) (i) Describe how geological erosion differ from accelerated erosion?

(8)

Refer 3.5.1, Page 87

(ii) Explain the role of individual in conservation of natural resources

(8)

Refer 3.2.9, 3.4.3, 3.5.4, 3.6.9, Page 74

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12. (a) (i) Compare the ecological pyramids of grassland and forest ecosystem. Refer 1.5.1, Page 10

(16)

Or (b) (i) Discuss the hot-spots of biodiversity in India Refer 1.11, Page 25

(8)

(ii) Explain the energy flow in the ecosystem with suitable diagram. Refer 1.5.2, Page 11

(8)

13. (a) (i) Write short note on minamatha disease and blue baby syndrome Refer 2.14.1; Page 56, 84

(8)

different types of disaster managements managements (ii) Explain the different Refer 4.16, Page 121

Or (b) (i) Discuss the effects and control measures of soil pollution Refer 2.15; Page 57 (ii) As an individual, how will you you prevent prevent the pollution pollution load load in the environment environment Refer 2.22; Page 68

14. (a) (i) Explain the urban problems associated to watershed management. Refer 4.4, Page 106 (ii) List out the salient features of forest conservation act in detail. Refer 4.12.5, Page 116

(8) (8) (8) (8)

Or (b) (i) Discuss the environment environment ethics to be practiced towards towards issues and possible solution. Refer 4.7, Page 108

(8)

(ii) Explain the climatic changes due to global warming and acid rain. Refer 4.9.1, Page 110

(8)

Government of India. 15. (a) (i) Explain the family welfare programmes practiced by Government Refer 5.7, Page 140

(8)

(ii) Explain the role of information technology technology in environment and human health. Refer 5.12, Page 146

(8)

Or (b) (i) Discuss the highlights of human rights and value based education Refer 5.9, 5.10, Page 144, 145

A

di i dd 167

(ii) Give a detailed account on the women and child welfare Refer 5.7, Page 140

(8) (8)

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A

di i dd 168

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