1

DISCLAIMER
The Current study material is meant to supplement, not replace
the text books prescribed by the J &K Board of School Education
(JKBOSE). The information in the form of facts, figures, graphs
and tables presented herein has been collected from the reputed
publications and authentic online resources. Although, every effort
has been made to avoid errors or omissions in this study material,
errors might creep in. Any mistake, technical inaccuracies,
typographical errors or discrepancy noted by the readers or
learners may be brought to the notice of the authors along with
evidence of it being incorrect. All such errors shall be corrected at
the earliest.

COPYRIGHT
All rights reserved. No part of the study material may be
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electronic or mechanical, including photocopying) without the
explicit written permission of the authors. Breach of the condition
is liable for legal action. Authorization to reproduce such material
must be obtained from the copyright holders

AUTHORS
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Preface
The present plight of the world as a victim to a plethora of environmental setbacks ranging
from global warming, ozone layer depletion to an alarming increase in world pollution
levels and present pandemics (COVID-19) is threatening the existence of the most
intelligent species on earth. This has been enough for both environmentalists and laymen
to wake up to the indisputable importance of environmental education. Almost every
sphere that man has forged into has undergone a major demarcation from what it was
before to suit the needs and greed of man better.
In this regard this study material will help students to understand the basic concepts of
Environmental science in a simple and narrative language. We hope this material shall
provide a solid foundation for students to understand environmental problems and their
possible solutions. It integrates information from a wide range of disciplines such as Biology,
Chemistry, Agriculture, Forestry, Ecology and Soil science. This is a concise and affordable
study material that will fill the need of both science and non-science students.
The study material is prepared in compliance with the revised syllabus as prescribed by
the J&K Board of school education. The material is divided into seven chapters in a logical
sequence which strikes a reasonable balance between environmental science and human
social systems. The more concise presentation of the content focuses on key topics on
scientific methods and ideas and lifelong learning skills of students. The study material is a
modest attempt by the contributing team to meet the challenges and requirements of
students studying environmental science at 10+2 level.
All the chapters of this study material offer an insight into the fundamentals of
environmental science. The first chapter of this publication describes the sources, possible
hazards and control measures of Air and Noise Pollution, second chapter deals with
understanding the problems of Water Pollution and Sewage treatment Processes and the
third one embodies the description of Soil Degradation. Fourth one describes Solid and
Hazardous Waste Management and the fifth one describes the Biodiversity Management.
Sixth chapter evaluates Global Environmental Issues while as the Environmental
Management and Legislation is summarized in the last chapter of the publication.
Any suggestions for the improvement of this study material is highly appreciated and
thankfully acknowledged.

Environmental science team

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List of contributors
Name of the Official Qualification Present Place of Posting
Dr. Javid Andrabi Ph.D,PDF (GATE,NET) GHSS PULWAMA

Dr. Mukhtar Sheikh M.Sc, Ph.D, B.ED BHSS,Khrew

Dr. Arif Yaqoob Malik M.Sc,B.Ed, NET, Ph.D, HSS,Litter

Mr. Kaiser Rafiq M.Sc M.Phil , (NET,SET) DIET,Pampore

Mr. Altaf Hussain M.Sc (JRF/NET,SET) GHSS,Magam

Ms. Irm Fatima M.Sc , M.Phil BHSS,Magam

Mr. Javid Ahmad M.Sc, M.Ed HSS,Safapora

Distribution of Work

Name of official Units Assigned

Dr. Javid Andrabi Global Environmental Issues

Dr. Mukhtar Sheikh Air and Noise Pollution

Mr.Kaiser Rafiq Solid and Hazardous Waste Management

Dr. Arif Yaqoob. Biodiversity Management

Mr. Altaf Hussain Environmental Management and Legislation

Ms. Irm Fatima Water Pollution

Mr. Javid Ahmad Mir Soil Degradation

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Table of Contents

Preface

List of Contributors

S. No. Name of the Unit/Content Page Number

01 Air and Noise Pollution 08-29

02 Water Pollution 30-60

03 Soil Degradation 61-78

04 Solid and Hazardous Waste Management 79-108

05 Biodiversity Management 109-120

06 Global Environmental Issues 121-185

07 Environmental Management and Legislation 186-204

08 Glossary 205-209

09 Appendix-I 210-217

10 Appendix-II 218-222
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UNITIZATION
(10 marks for each Unit)
UNIT 1: Air and Noise Pollution
1.1. Air pollution: Sources and Types
1.2. Impact of Air Pollution on Environment

1.3. Control of Air Pollution (Gaseous and Particulate)

1.4. Noise Pollution: Sources and Effects on health

1.5. Control of Noise pollution

UNIT 2: Water Pollution

2.1. Water pollution: Sources and impacts

2.2. Concept of Eutrophication and Biomagnification
2.3. Marine Pollution
2.4. Water Pollution Control
2.5. Sewage treatment (Primary and Secondary)

UNIT 3: Soil Degradation

3.1. Soil Composition and Profile

3.2. Soil types (Indian Classification of Soils)
3.3. Soil Erosion: Causes, Impacts and Control
3.4. Soil Pollution: Causes and Impacts
3.5. Control of Soil Pollution
52-61
UNIT 4: Solid and Hazardous Waste Management
4.1. Solid Waste, Sources, Generation and impacts
4.2. Disposal of Solid Waste (Composting, Incineration, Sanitary
landfill)
4.3. Management of Solid Waste
4.4. Hazardous Waste: Disposal and Characteristics
4.5. Management of Hazardous Waste (Deep well injection, Plasma Torch,
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Incineration)

UNIT 5: Biodiversity Management

5.1. Biodiversity and its levels
5.2. Importance of Biodiversity
5.3. Threats to Biodiversity: Causes and Impacts
5.4. Concept of threatened species (As per IUCN: Extinct, Endangered,
Vulnerable, Rare)
5.5. Biodiversity Conservation: In-Situ and Ex-Situ

UNIT 6: Global Environmental Issues

6.1. Climate change and Global Warming: Causes, Impacts and international efforts
for combating global warming (Kyoto Protocol)
6.2. Ozone Layer depletion: Causes, Impacts and global efforts for its protection
(Montreal Protocol)
6.3. Acid Rain: Causes, Impacts and Control
6.4. Smog and Its types
6.5. Desertification and its Control

UNIT 7: Environmental management and Legislation

7.1. Concept of Sustainable Development

7.2. Environmental Impact Assessment: Scope and Key Elements
7.3. Salient Features of Environmental (Protection) Act, 1986
7.4. Salient Features of Water (Prevention and Control of Pollution) Act, 1974
7.5. Salient Features of Air (Prevention and Control of Pollution) Act, 1981
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Unit 1- Air and Noise Pollution

❖ Learning outcomes

 Develop the understanding in students about air and noise pollution.

 Develop the understanding in students the concept of indoor and outdoor pollution.

 Develop the understanding in students about sources and effects of air and noise
pollution.

 Develop the understanding in students how we can control air and noise pollution.

After learning this chapter the student are able to prepare for all types of examinations

1.1Air Pollution:Sources and Types

Clean air is an essential component of a healthy environment and for life, therefore, air pollution
threatens us all. Air pollution may be defined as contamination of the atmosphere by gaseous,
liquid or solid substance present in the atmosphere in such concentrations that may be injurious
to human health and other living organisms or their property or enjoyment. In simple words, any
undesirable change in the physical, chemical and biological state of air is known as Air
Pollution.

Air pollution may be defined as contamination of the atmosphere by gaseous, liquid or solid
substance present in the atmosphere in such concentrations that may be injurious to human health
and other living organisms or their property or enjoyment. In simple words, any undesirable
change in the physical, chemical and biological state of air is known as Air Pollution.

Air pollution is of serious concern these days. These days air pollution is considered a global
problem. Air pollution from power plants, transportation, industry and agricultural activities
contribute to heavy environment degradation that is affecting human health ecosystems and
materials throughout the planet.
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1.1.1 Sources of Air Pollution

Air pollution mainly takes place by the following two main causes, natural and anthropogenic.
However, thenatural sources of atmospheric pollution are limited and their effect can be
reversed.

1.Natural:

i. Volcanic eruptions,
ii. forest fires, marsh gases,
iii. storms, pollen grains, fungal spores
2. Human or Anthropogenic activities:

i. Transportation -ships, aero planes, trains, and automobiles.

ii. Fuel combustion from stationary sources -power plants.
iii. Industrial processes-Steel mills, Textile mills & paper mills.
iv. Solid waste disposal-open burning, incineration, sanitary landfills.
v. Miscellaneous processes- domestic and agricultural activities like pesticide spray.

i.Transportation: There has been a tremendous increase in the number of motorized vehicles in
the past few decades including cars, buses, trucks and three wheelers. All these vehicles run on
petrol or diesel which are fossil fuels. The burning of fossil and their incomplete combustion
releases harmful gases into the atmosphere. Some of these like Co, Co2 , No2 , So2 have ill
effects on human health.

ii. Fuel combustion from stationary sources i.e., power plants

The use of Coal in thermal power plants has led to the increase in air pollutants such as oxides of
carbon, Sulphur, nitrogen etc. Apart from these thermal power plants produce large quantities of
fly ash products leading to sulphur & nitrogen from thermal power plants combines with rain to
form acid rain.

iii.Industrial processes: Increased industrial activity since the industrial revolution is the main
causes of Air pollution. The steel and chemical plants, paper mills, refineries petrochemical
plants released various harmful gases.
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iv. Solid waste disposal: Solid waste disposal by open burning, incineration and sanitary
landfills are sources of air pollution. Open burning and dumping are very old practices of waste
disposal .Open burning also generates methane besides other gaseous pollutants.

v. Miscellaneous sources: Pollutants are also generated from the houses and offices in both rural
and urban areas. The major domestic pollutants are smoking, burning of coal, fire wood, cow
dung cakes, kerosene oil etc.

The burning of fossil fuels and destruction of forests are the main causes of atmospheric
degradation and its sources are divisible into two categories:

(i) Stationary Source:- These sources have relatively a fixed location and include:

• -Point sources that emit pollutants from one or more identifiable points such as smoke
stacks.
• Fugitive sources generate pollutants form open areas exposed to wind that do not go
through a stack such as soil erosion, strip mining, construction etc.
• Area sources are more diffused over the land and include urban runoff, forest fires, and
agricultural sprays.
(ii) Mobile Sources:- Include automobiles, trains, aircrafts, rockets and anything else that emits
pollutants as it moves from place to place.

Fig. 1.1. Sources of air pollution

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1.1.2.Types of Air Pollution

Air pollution is broadly divided into two types.

1. Outdoor air pollution

Outdoor air is often referred to as ambient air. The common sources of outdoor air pollution are
emissions caused by combustion processes from motor vehicles, solid fuel burning and industry.
Other pollution sources include smoke from bushfires, windblown dust, and biogenic emissions
from vegetation (pollen and mould spores).

The most common air pollutants of ambient air include:

• Particulate matter (PM10 and PM2.5)

• Volatile organic compounds (VOC)
• Nitrogen dioxide (NO2)
• Carbon monoxide (CO)
• Sulphur dioxide (SO2)

• Corbon dioxide (CO2)

2. Indoor air pollution

Indoor air pollution refers to the alteration in

the physical, chemical and biological
characteristics of air in the indoor
environment with in a home, building, or an
institution or commercial factory.Indoor air
pollution is caused by burning solid fuel
sources – such as firewood, crop waste, and
dung – for cooking and heating. The burning
of such fuels, particularly in poor
households, results in air pollution that leads Fig.1.2. indoor air pollution
to respiratory diseases which can result in premature death.
When we think of polluted air, the first images that come to our minds are often big factories
pumping out smelly clouds or old cars puffing out grey exhaust. However, indoor air pollutants
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can be even more dangerous than outdoor air pollution.The common indoor air pollutants in
homes are:
• Carbon monoxide (CO)
• Radon
• Nitrogen dioxide (NO2)
• Smoke
• Lead particles
• Asbestos
• Mold

1.1.3. Types of Air Pollutants:-

The atmospheric pollutants could be conventionally divided into two groups i.e. primary
pollutants that are directly emitted into the atmospheric e.g. CO and SO2 by urning of coal, oil
and natural gas – and secondary pollutants which are formed due to reaction of primary air
pollutants with other air components e.g. H2SO4. Besides conventional or Criteria pollutants are
a group of seven major pollutants (SO2, CO, particulates, volatile organic compounds, oxides of
Nitrogen, Ozone and lead) for which there are legal standards or criteria for human

Fig.1.3. Types of air pollutants

health for taking suitable measures for their control.

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1.Carbondioxide (CO2 ). Carbon dioxide is a natural component of the atmosphere, essential for
plant life and given off by the human respiratory system. Because of its role as a greenhouse
gas it has been described as "the leading pollutant" and "the worst climate pollutant"
CO2 currently forms about 410 parts per million (ppm) of earth's atmosphere, compared to about
280 ppm in pre-industrial times, and billions of metric tons of CO2 are emitted annually by
burning of fossil fuels. CO2increase in earth's atmosphere has been accelerating.

2. Sulfur oxides (SOx). Particularly sulfur dioxide, a chemical compound with the formula SO2.
SO2 is produced by volcanoes and in various industrial processes. Coal and petroleum often
contain sulfur compounds, and their combustion generates sulfur dioxide. Further oxidation of
SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain is
formed. This is one of the causes for concern over the environmental impact of the use of these
fuels as power sources.
3.Nitrogen oxides (NOx). Nitrogen oxides, particularly nitrogen dioxide, are expelled from high
temperature combustion, and are also produced during thunderstorms by electric discharge. They
can be seen as a brown hazedome above or a plume downwind of cities. Nitrogen dioxide is a
chemical compound with the formula NO2. It is one of several nitrogen oxides. One of the most
prominent air pollutants, this reddish-brown toxic gas has a characteristic sharp, biting odor.

4. Carbon monoxide (CO). CO is a colorless, odorless, toxic gas. It is a product

of combustion of fuel such as natural gas, coal or wood. Vehicular exhaust contributes to the
majority of carbon monoxide let into our atmosphere. It creates a smog type formation in the air
that has been linked to many lung diseases and disruptions to the natural environment and
animals.

5.Volatile organic compounds (VOC).VOCs are a well-known outdoor air pollutant. They are
categorized as either methane (CH4) or non-methane (NMVOCs). Methane is an extremely
efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon
VOCs are also significant greenhouse gases because of their role in creating ozone and
prolonging the life of methane in the atmosphere. This effect varies depending on local air
quality. The aromatic NMVOCs benzene, toluene and xylene are suspected carcinogens and may
lead to leukemia with prolonged exposure. 1,3-butadiene is another dangerous compound often
associated with industrial use.
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6. Particulate matter. Particulate matter / particles, alternatively referred to as particulate matter

(PM), atmospheric particulate matter, or fine particles, are tiny particles of solid or liquid
suspended in a gas. In contrast, aerosol refers to combined particles and gas. Some particulates
occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living
vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power
plants and various industrial processes also generate significant amounts of aerosols. Averaged
worldwide, anthropogenic aerosols—those made by human activities—currently account for
approximately 10 percent of our atmosphere. Increased levels of fine particles in the air are
linked to health hazards such as heart disease, altered lung function and lung cancer. Particulates
are related to respiratory infections and can be particularly harmful to those already suffering
from conditions like asthma.

1.2 Impact of Air Pollution on Environment

Air pollution has both acute and chronic effects on human heath ranging from minor irritation
of eyes and upper respiratory system to chronic respiratory disorder, heart diseases lung cancer
and even death. Therefore it is important to devise ways to reduce and prevent atmospheric
pollution.

• Damage to leaves
i. Necrosis is the killing or collapse of tissue.
ii. Chlorosis: - chlorosis is the loss or reduction of green pigment chlorophyll.
iii. Abscission :-Leaf Abscission is dropping of leaves .
iv. Epinasty: - Is the down word curvature of leaf surface.
• Health Effects
i.Eye irritation.
ii. Nose & throat irritation.
iii. Irritation of the respiratory tract.
iv. Increase in mortality and morbidity rate.
v. Chronic pulmonary disease like bronchitis and asthma by So2, No2 , particulate matter.
vi) Cocombines with hemoglobin of blood & increases cardiovascular & pulmonary
diseases.
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However a brief summary of most important established effects of air pollution is as follows:

(a) Effects on Atmosphere:- Atmosphere properties are affected by means of reduced visibility,
fog formation, solar radiation reduction, alteration in precipitation, temperature and wind
distribution.

(b) Effects on Vegetation:- Pollutants which affect vegetation are known as phytotoxicants.
Plants respond to air pollutants like SO2, O3 and HNO3 by development of necrotic spots on
leaves, increase in leaf senescence and leaf drop, change in root to shoot ratio, reduced activity
of stomata and reduced growth. Once, lodged in leaf of the plant, they destroy chlorophyll,
disrupt photosynthesis, cause flower dropping, leaf abnormalities, bleaching, chlorosis, growth
suppression and reduction in yield. Plant exposure to pollutants results in the formation of free
radicals like H2O2, O3 which oxidise fatty acids in the cell membranes and cause cell death. NO2
enters the leaf through stomata and is converted to inorganic nitrates and PAN that causes
oxidation of proteins of the chlorophyll and hence affecting photosynthesis. NO2also reacts with
water to form nitric acid that acts as a strong oxidizing agent damaging lipids in plant tissues.

(c) Effect on Humans:-The main route of pollutants to human body being respiratory tract. Both
upper as well as lower respiratory system affected besides other life processes in human body.
The prominent effects being bronchitis, RTI, breathlessness, nasal discharges, respiratory
oedema, air way swelling, reduced O2 carrying capacity, eye and throat irritation etc. SO2 on
reaching to upper respiratory tract reacts with cellular constituent chemicals like enzymes, forms
sulphuric acids and lowers pH and impairs enzyme activity. It also causes irritation reaction
causing blood capillaries to dilate and exudes fluids leading to swelling, tissue fluid
accumulation, bronchial spasms, pulmonary fibrosis and shortness of breath. CO impairs the
ability of haemoglobin to carry oxygen and hence cause dizziness, headache and vision
impairment, nausea and abdominal pain. H2S causes asphyxiation and paralysis of breathing
control centre. Lead affects bone marrow cells and brain leading to mental retardation, lowered
IQ and abnormal behaviour and reduces haem synthesis. Particulate matter causes
pneumoconiosis, silicosis and black lung diseases causing structural change in lungs.

(d) Effects on Monuments:- Air pollutants like oxides of sulphur and nitrogen form acid rain
that accelerates weathering of precious statues and buildings especially made of limestone and
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marble is known as stone leprosy. It also causes corrosion of metallic surfaces and tarnishing of
copper surfaces. It develops cracks in rubber and destroys painted surfaces. Moreover, air
pollutants damage leather, paper, aluminium and silver waste surfaces by chemical reactions.

1.3. Control of Air Pollution (gaseous and particulate)

Atmospheric Pollution is of major concern these days. It has become a global problem these
days. The atmosphere pollution control involves a number of focuses and techniques. It is not
possible to control atmospheric pollution absolutely but it is possible to minimize it to some
extent. The aim is reduction of total load of pollution or dilution (in the context of air pollution
this may involve high chimneys which disperse pollution)
Generally air pollution can controlled by fallowing methods:-
1. Control of vehicular pollution:-In order to deal with the vehicular pollution, both fuel as
well as the engine need to be improved. e.g using unleaded petrol in combination with catalytic
converters and use of diesel with 30ppm sulphur in combination with a particulate trap. Exhaust
filter is used to trap and burn the particulate matter from diesel engines. The catalytic converter
is an effective pollution control device used in vehicles to remove pollutants. The catalytic
converter consists of a ceramic support, a wash coat made of aluminium oxide to provide a larger
surface area and a layer of precious metal such as rhodium, palladium or platinum to perform the
function of a catalyst. Usually two types of catalytic converters are used viz. Oxidation catalysts
which control hydrocarbons and Co emissions and oxidation reduction catalysts which control

Fig.1.4: Catalytic Converter

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CO, oxides of nitrogen and hydrocarbons. These catalytic converters are installed to the exhaust
of the vehicle and as the emissions pass over the catalyst, carbon monoxide is oxidised to carbon
dioxide, oxides of nitrogen are reduced to simple nitrogen and hydrocarbons are oxidised to
water and CO2 making the emissions free from pollutants.

2. Dilution :- Dilution of emission can be accomplished by using tall stacks. The height of
chimneys should be increased to the highest as for as possible level to reduce the effect of
pollutants, they disperse easily into the atmosphere and pollution is avoided at the ground level.

3. Control at source:- The most effective method of controlling the air pollution is to prevent
emission from the source itself. This can be done by switching to the process which generates the
least amount of pollutants as by products .This can be done through raw material substitution,
operational changes, modification or replacement of process equipment or replacement of
process equipment or effective use of equipment.
4. Afforestation:- Air pollution control by planting trees and growing vegetation, by the
development of green belts around the industries or growing vegetation can reduce the spread of
air pollutants emitted from industrial sources because tress are very helpful in reducing air
pollution caused due to fly ash , particulate matter.

5. Zoning:- Location of industries should be far away from thickly populated area.The zoning of
the industries is done based on the type of industries, their function etc., it prevents the invasion
of undesirable industries in and around residential areas and thus toxic pollutants area prevented
from entering the human settlements.

6. Desulphurization:- SO2 pollution can be controlled by extracting sulphur from the fuel before
use.
7. Legislation:-Pollution controlling laws should be enforced strictly.
8. Fuel selection:-By the use of better fuel the production of air pollutants can be reduced. This
can be done by replacing the fossil fuel like coal or petroleum by renewable sources like solar
energy, hydropower, wind energy etc.
1.3.1.Control of gaseous pollutants
1.Adsorption:- The pollutants gas molecules bind to a solid phase through chemical or physical
bonding when effluent gas is passed through adsorbent . The commonly used absorbers include
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activated carbon, Silica gel etc. It is a surface phenomena which is used to remove odour at
chemical manufacturing and food processing units besides removing VOCs from air streams at
industrial facilities. Activated carbon is the primary and most common adsorbent material used
for this process as it being very porous with high ratio of surface area to volume where
intermolecular attractive forces in the bulk of the solid are available at its surface to hold other
materials. A well designed carbon adsorption unit may work with an efficiency of 95%.
Generally, these are of two types viz; stationary bed units in which the polluted gas stream enters
from the top and passes through a layer or bed of activated carbon and leaves at the bottom and
moving bed units where activated carbon moves slowly down wards opposite to the air to be
cleaned in a countercurrent flow in small channels.
Important aspects for effective removal of gaseous pollutants by adsorption process are:

• Contact of the pollutant with the solid adsorbent.

• Separation of the adsorbed gas from the solid adsorbent.
• Recovery of gases for final disposal.

2. Absorption:- in this process effluent gasses are passed through absorbers which contain liquid
absorbents, which remove the pollutant from the gas stream .The efficiency of the process
depends upon the amount of surface contract between the gas and the liquid. The absorbing
solutions used in these devices include Ammonium sulphate, Sodium sulphate, ethanolamine,
water, Sodium hydroxide etc. Absorption process is used to remove, SO2, H2S, SO3, F and
oxides of Nitrogen from the polluted gas stream. It involves the transfer of gaseous pollutant
molecules from the air stream into a contacting liquid which must be able to serve as a solvent
for the pollutant or should capture it by means of chemical reactions. e.g. water, NaOH
thermoplastics. The efficiency of this process depends upon:

• Amount of surface contact between pollutant gas and the liquid absorbent.
• Concentration of the absorbing liquid.
• Contact time.
• Speed of the reaction between the gases and the liquid absorbent.

3. Condensation:-It is a process where a gas or a vapour is converted into a liquid by either

lowering the temperature or increasing the pressure. When the pollutants are emitted in the form
 19

of a gas or a vapour, these are allowed to pass through a device containing condensers (surface or
contact condensers) which inturn remove the heat content from the waste gas and convert it into
a liquid which can later be recovered and hence a pure gas stream free of pollutants is obtained.
In surface condensers, the pollutant gas or vapour comes in contact with a cooled surface to
become a liquid while as in case of contact condensers, the gas comes in contact with a cooled
liquid. In case of contact condensers, the condensate can not be re-used because of
contamination by the pollutant which may cause waste disposal problem. Thus, to overcome this
problem, surface condensers are widely used where the contaminated gas is separated by a
physical barrier without mixing with the cooling medium. Condensation is used to recover VOCs
from polluted gas stream and gasoline and fuel vapours at gasoline loading terminals.

4.Combustion:-it is mostly used to control emissions of organic compounds from released from
the industrial processes where rapid oxidation of a substance through the combination of oxygen
with the combustible material in presence of heat takes place. Combustion may be considered for
control of (carbon monoxide and hydro carbons). In this process organic compounds released
from different manufacturing operations and converted to C02 & H20. In thermal incineration
process, the waste gas is passed through a flame into a residence chamber where complete
oxidation of the waste gas takes place with an efficiency of 99%. Combustion process is used
with success for the control of effluent gases, fumes and odors from refineries, baking ovens and
chemical plants.

1.3.2. Control of particulate matter.

The particulate emitted in gaseous stream consists of discrete and minute suspended particles,
their size ranges from 100 milli microns to 0.1 milli microns. The devices or equipments which
can be used for removing particulate matter from gas steam are:
1. Electrostatic Precipitator:

It is commonly used method for removing fine particulates from air streams.it is a physical
process in which particles suspended in air stream are electrically charged and get separated from
the gas stream under electric field. A high D.C voltage of 100,000 volts is applied to the
electrodes to charge the particles which then are attached to oppositely charged plates on which
they get trapped, the plates are cleaned by knocking to shake off the layer of dust that
 20

accumulated. E.P can remove particles as small as 1 micron with an efficiency exceeding 99%,
it is used in power plate, cement and paper mill.

Fig.1.5:Electrostatic Precipitator(source britanica)

2. Wet Scrubbers
A wet scrubber employ the principal of trap suspended particles by direct contact with a spray of
water or other liquid. A scrubber washes the particles out of the dirty air stream as they collide
with and are entrained by the countless tiny droplets in the spray.These use high-energy liquid
spray to remove aerosol and gaseous pollutants from air stream. They commonly control the
sulphur emission. Pre filters are installed upstream of scrubber to catch larger particles.

Fig.1.6: Wet Scrubber

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3.Venturi Scrubber:-

Energy from a polluted gas stream is used to atomize the liquid being used to scrub the gas
stream passing through a scrubber with a converging section, a throat or neck and a diverging
section. Both the gas stream as well as the liquid are moving at very high velocity creating
turbulence and mixing and exhibiting a good collection efficiency. The gas enters the converging
section and as the area decreases, the gas velocity increases in the throat area and the high
velocity gas stream shears the liquid from its walls producing enormous amount of tiny droplets.
The fog of the tiny droplets thus produced mixes with the gas stream, comes in contact with the
particulate and causes the removal of the particles in the diverging section. Venture scrubbers
have 99% efficiency for particles as small as 0.5 µm.

Fig.1.7: Venturi Scrubber

4 .Cyclone collector:
It works on the principle of centrifugal force remove
particles by causing the dirty air stream to flow in a spiral
path in a cylindrical chamber. They are used as pre-
cleaners followed by ESP’s and bag houses. For particles
larger than 20 micron they achieve efficiency is helpful in
combating the global warming world energy consumption is
rising by 2% per year choosing energy efficient appliances
will save a considerable amount of energy ,which results in
Fig.1.8:Cyclone collector
 22

the less use of fuels, there by reduces the emission. These utilize centrifugal force to remove p.m
from gas stream. They are effective in the removal of small particles. The particle laden gas upon
entering in cyclone cylinder recives rotating motion, centrifugal force is developed which
thwows particles towards wall, the partcles then
slode down the wall and fall on the bottom of the
cylinder where from they are removed.

5. Gravitational settling chamber: They are

used to remove particles more than 50 micron. In
this chamber gravitational force dominates vertical
passing motion. The gas stream with its particles is
allowed to flow at a low speed to allow time for
particles to settle at the bottom by gravity.

Fig.1.9: Gravitational settling chamber

6.Fabric Filter or Bag Filter:-
It refers to an assembly of fabric –filter bags (FFBs)
which on combination form a filter bag house.it is
comprising of a long array of tall and narrow bags of a
25 cm (10 inches) length. This bag assembly kept
suspended upside downs in a large enclosure. This large
enclosure is facilitated with electrical fans .when an
industry starts to work the resultant gaseous -
pollutant stream is blown through these filter bags.
During the course of this process, the particulate
matter (PM) gets entrapped into the assembly of filter
bags and the clean air passes out. .This control device
canremove 100% particulate matter. However, this
pollution control technology is highly expensive , Fig. 1.10 :Fabric Filter
requires the implantation of cooling units.
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1.4 Noise Pollution: Sources and Effects on Health

The word Noise (Latin nausea) is an unwanted or unpleasant sound that causes discomfort. Noise
is wrong sound in the wrong place at the wrong time. Noise Pollution is the unwanted sound
dumped into the atmosphere leading to health hazards. Noise Pollution may be defined as the
state of discomfort and restlessness that is caused to man by unwanted high intensity sound
known as noise. Noise is a form of sound without agreeable musical quality i.e. it is undesirable
or unwanted disturbing and harmful sound in the ambient atmosphere that interferes with
hearing, causes physiological stress and hampers the work efficiency. Thus it is the human
beings the recipients who are the ultimate judges of what noisy sound is and what is not. It may
be also defined as wrong sound at wrong place at wrong time. So it is sound that is disagreeable
and disturbs the normal way of living of the listener. The intensity of sound (loudness) is
measured in decibels (db) and this scale is a logarithmic one. One decibel is the faintest sound a
human ear can hear and the loudest sound a person can stand without damage is 65 db.

Table 1.11 : Zone wise noise levels according to CPCB of India

Zone Day time db (6 am to 9 pm) Night time db (9pm to 6 am)

Industry 75 70
Commercial 65 55
Residential 55 45
Silent Zone 50 40

1.4.1: Sources of Noise Pollution

The sources of noise are numerous but may be broadly classified as:

a)Industrial sources:- Most of the noise that travels through the atmosphere is of human origin
from various industries operating in cities like transportation, factories, aircrafts, rockets, defence
equipments, explosions etc.

b) Non-Industrial Sources:- Among the non-industrial sources the important ones are
loudspeakers, amplifiers, electric appliances, microphones, radio, TV, Construction work etc.
 24

These sources of noise may be also classified as:

a)Mobile sources: -Mobile sources are various modes of transportation (like air, road, rail
transportation).

a)Stationary sources:- Stationary sources include industrial operation, construction activities

and celebrations (social, religious functions, elections.) electric home appliances like TV, mixer
grinder, pressure cooker, washing machine etc.

Fig.1.12:Sources of Noise Pollution

1.4.2 :Effectsof Noise pollution on Health

Noise can affect a listener by a number of ways. But its main effects are precisely categorised as:
• Auditory Effects: - These are those that affect the hearing system of an individual.
Human hearing impairment can occur at a noise level above 65db. These include auditory
fatigue associated with whistling and buzzing sound in ears. Very loud noise (more than
140 db) causes pain, damage to the eardrum and permanent hearing loss.
• Non-auditory Effects: -These include interference with speech and communication,
annoyance, reduced work efficiency, and physiological disorders which occur due to
prolonged exposure to excessive noise that seriously affects heartbeat, peripheral
circulation, hypertension, headache, muscle tension, sleeplessness, lack of concentration,
release of stress hormones and other physiological effects.
 25

Fig.1.13: Effects of Noise Pollution

1.5.Control of Noise Pollution

The solution to the alarming noise pollution problem might require modifications of certain basic
elements. Putting up some types of shields between the noise source and the receiver can help in
controlling noise pollution coupled with modifying the source to reduce the noise output. Forests
and dense growth of hedges and bushes can effectively act as noise barriers. Persons exposed to
high levels of noise can use earplugs and ear muffs to protect themselves from noise damage. In
heavy industries sound proof jackets and filters can be used by the workers to reduce noise from
machines. Noise pollution can be controlled by various ways some of them are listed below:

i) Tree plantation: The effective solution for noise pollution control is to plant bushes and
trees around the sound generated sources. Sound passage is blocked by the dense shrubs and
tress. Tress can be planted in the surrounding are to live peacefully.
ii) Sound proof Homes: To block unwanted noise from outside sound proof doors and
windows can be installed. If you stay in crowded city area these sound proof options are
important for complete relaxation.
iii) Factory Location: From the residential areas, factories and industries should be located in
far off places. Installation of sound detectors will help in analysing the sound frequencies on a
regular basis.
iv) Loud speaker Prohibition: The major cause of noise pollution in public areas is
loudspeaker, for the welfare of the people, it should be banned at any cost. Those who violate
 26

and play loudspeakers in crowded areas and public places, strict laws should be imposed
against them.
v) White Noise Machine: For overcoming the effects of noise pollution, the latest technology
is using White Noise Machine. This device converts the unbearable noise into pleasant sound.
A White Noise Machine is placed between the source of noise and the receptor. It produces
soft sound like that of a waterfall, fan and soft music.
vi) Machine Quality: The quality of machines should be optimised to reduce sound
production. Lubrication of the machinery and servicing should be done to minimise noise
generation.
 27

SELF ASSESMENT

A) Long Answer Type Question

Q.1: Define air pollution. What are different sources of air pollution?
Q.2: Explain impacts of air pollution on different components of environment.
Q.3: Explain some control devices used to control particulate matter.
Q.4: Discuss absorption and adsorption as control measures for gaseous pollutants.
Q.5: Define noise. Explain its sources and effects.
B) Short Answer Type Questions
Q.1: Explain how noise pollution can be controlled?
Q.2: What do you mean by auditory effects of noise?
Q.3: What are different impacts of air pollution on plants?
Q.4: Write down the control measures of noise pollution.
Q.5: Describe various sources of air pollution.
Q.6: Write down the working of cyclone scrubbers.
C) Very Short Answer Type Questions
Q.1: Define incineration.
Q.2: How air pollution destroys monuments?
Q.3: what are non-auditory effects?
Q.4: Define a pollutant.
Q.5: write down the principle of electrostatic precipitator.
Q.6: what are wet scrubbers?
D) Objective Type Questions
1. Ozone depletion is caused by
a) CO2 b) CFCs C) H2 d) CO
2. Causative agents of acid rain are
a) CO2 b) CH4 c) Sox and NOx d) Ozone
3. Noise level is measured in
a) ml b) ppm c) Hertz d) Decibel
 28

4. Which one is most efficient

a) Wet scrubber b) Bag filter c)Electrostatic precipitator d) Venturi scrubber
5. Catalytic converters are used to control which pollutant
a) Oxide of sulphur b) Nitrogen oxide c) CO d) Hydrocarbons
6. pH value of acid rain is
a) 5.6 b) 7 c) 8 d) 1
7. The safe noise level described by WHO is
a) 60db b) 30db c) 45db d) 85 db
8. Electrostatic precipitator works on the principle of
a) Electrostatic attraction b) Suspension c) Gravitational Pull d) Magnetic field
9. Which among the following is used to remove gaseous pollutants
a) Adsorption b) Gravitation c) Rotation d) Combustion
10. De-oxygenation in humans results by inhaling
a) CO2 b) NO c) CH4 d) CO
11. Which is the potential green house gas
a) CH4 b) CFC c) CO d) NO2
12. vehicular pollution is controlled by
a) Scrubber b)Spray tower c) Bag filter d)Catalytic converter

.REFRENCES

1. A Text Book of Environmental Chemistry and Pollution Control- S S Dara. S.Chand&

Company Ltd., New Delhi.

2. A Text Book of Environmental- S SPurohit, Q J Shammi and A K Agarwal. Student

Edition, Jodhpur.

3. Air Pollution- V P Kudesia. PragatiPrakashan, Meerut.

4. Ecology and Environment- P D Sharma. Rastogi Publications, Meerut.

5. Environment, Problems & Solutions- D K Asthana and MeeraAsthana. S.Chand&

Company Ltd., New Delhi.

6. Environmental Chemistry- B.K. Sharma. GOEL Publishing House, Meerut.

 29

7. Environmental Pollution, Causes, Effects and Controls- K C Agrawal. Nidhi publishers,

Bikaner.

8. Environmental Science- Daniel B. Botkinand Edward A. Keller.Wiley India Pvt.Ltd., New

Delhi.

9. Environmental Science- G.Tyler Miller, JR. Cengage Learning India Pvt.Ltd.

10. Environmental Science- S C Santra. New Central Book Agency (P) Ltd, India.

11. Introduction to Environmental Engineering and Science. Gilbert M. Masters and

Wendell P. Ela. PHI Learning Private Limited, Delhi.

12. Principles ofEnvironmental Science&Technology-K. Saravanan, S. Ramachandran and R.

Baskar.New Age International Publishers, India.
 30

UNIT 2: WATER POLLUTION

❖ Learning outcomes: -

The student after completing this unit will be able to:

• define water pollution, its different causes,sources and impacts.

• have an understanding of eutrophication and its control.
• know what is marine pollution and its impacts.
• Develop the understanding of how water pollution is controlled.
• learn how sewage treatment controls water pollution.
• Develop the understanding of different processes undergoing during primary and
secondary sewage treatment

2.1. INTRODUCTION:
Water is one of the most vital natural resources on earth. It is one of the abundantly available
substance in nature. It is essential constituent of all animal and vegetable matter and forms about
75% of the matter of earth’s crust. It is also an essential ingredient of animal and plant life.
Water is distributed in nature in different forms, such as rain water, river water, spring water and
mineral water.

The Earth has more than two-thirds of its surface covered with water. This translates to just over
1 octillion liters (1,260,000,000,000,000,000,000 liters). Of water distributed in the oceans,
rivers, lakes and streams. That is a lot of water, however, less than 0.3% is accessible to human
consumption. As commercialization and industrialization have progressed, that number
continues to dwindle down. Furthermore, the inefficient and outdated practices, lack of
awareness and a plethora of other circumstances have led to water pollution.
 31

Fig. 2.1. Distribution of water on earth (different sources)

2.2. WATER POLLUTION

Water pollution is the contamination of water bodies (like oceans, seas, lakes, rivers, aquifers,
and groundwater) usually caused due to human activities. Water pollution is any change in the
physical, chemical or biological properties of water that will have a detrimental consequence of
any living organism.

Water pollution may be defined as addition of excess of

undesirable substances to water that make it harmful to man,
animal and aquatic life. It is an any adverse change in conditions According to UNICEF,
more than 3000
or composition of the water so that it becomes less suitable for children die every day
the purpose for which it would be suitable in its natural state. It is globally due to
consumption of
the contamination of water with substances whose character and contaminated drinking
quantity impair the usefulness of natural water and renders it bad water.

to the sense of sight, taste or smell.

Thus, water pollution disturbs the normal uses of water for irrigation, agriculture, industries,
public water supply and aquatic life. It is now considered not only in terms of public health, but
also in terms of conservation, aesthetics and preservation of natural beauty and resources.
Actually, it represents the state of deviation from the pure condition, whereby its normal function
and properties are affected. Water pollution is mainly caused by:
 32

• Natural process in which the decomposed vegetable, animal and weathered products are
brought into main water resources. All these processes are interdependent on each other
and lead to deterioration of natural environment.

• Anthropogenic processes such as industrial, agricultural, urban, domestic, radioactive,

mining sources, use of pesticides and fertilizers by man etc. these pollutants are
constantly poured in water deteriorating it to such an extent that it becomes unfit for
living communities.

Fig.2.2. Different types of water pollutants generated from different sources

2.3. SOURCES OF WATER POLLUTION

The two chief sources of water pollution can be seen as Point and Non-Point.

• Point refers to the pollutants that belong to a single source. An example of this would be
emissions from factories into the water.

• Non-Point, on the other hand, means pollutants emitted from multiple sources.
Contaminated water after rains that has traveled through several regions may also be
considered as a Non-point source of pollution.
 33

Fig. 2.3 point and non-point sources.

a) INDUSTRIAL EFFLUENTS

Industrial effluents discharged into water bodies contain toxic

chemicals, hazardous compounds, phenols, aldehydes,
metallic wastes, oils, greases, dyes, biocides, suspended Around 70% of the industrial
solids, non-biodegradable matter etc. The effluents, i.e. waste is dumped into the
water bodies where they
discharges from the industries such as that of pollute the usable water
pharmaceuticals, breweries, tanneries, dyeing, textiles, paper, supply.

plastic, chemical, metallurgical, fertilizer, pesticides etc. are

some of the most important agents of water pollution. The
toxicity of various pollutants to aquatic environment is variable but all of them contaminate on
the bottom of water systems where they poison or smother the aquatic organisms. Most of the
industrial effluents are insusceptible to degradation. Toxic metals are extremely lethal for living
beings.

b) SEWAGE AND DOMESTIC WASTE

About 75% of water pollution is caused by sewage, domestic wastes and food processing plants.
It also includes human excreta, soap, detergent, metals, glass, rubbish garden waste and sewage
sludge from cess pool etc. Domestic sewage and other wastes are thrown untreated or partially
treated into the water bodies such as ponds, lakes, streams and rivers. Since the dumping is
uncontrolled especially near big cities, the water bodies are not able to recycle them and their
self-regulating capability is lost. This may lead to a number of serious problems. If domestic
 34

waste or sewage is not properly handled after it is produced, there is chance of water being
polluted.

c) AGRICULTURAL DISCHARGES
Plant nutrients, pesticides, insecticides, herbicides, fertilizers, farm wastes, manure slurry, soil
erosion containing mostly the inorganic materials are reported to cause heavy pollution to water
sources. In modern agricultural practices NPK fertilizers containing nitrate and phosphate are
added to the soil. Some of these are washed off through rain fall, irrigation and drainage into
water bodies, where they severely disturb the aquatic ecosystem. The excessive use of plant
nutrients led to the disruption of nitrogen and phosphorus balance in water affecting plant
growth. Organic wastes increase the BOD of receiving water.
d) TOXIC METALS

Among the industries with the highest emissions of heavy metals are the mining industry,
metallurgical industry, chemical industry, distilleries, battery industry, thermal power plants etc.
Toxic metals are added in aquatic system from industrial processes, domestic sewage discharge,
land run off etc.

In aquatic environment, sometimes heavy metals in their pure form are not toxic, but when
combined with something, they may be toxic. For example, combination of heavy metals with
salts or with organic compounds in particular is very toxic.

e) LEAKAGE FROM SEWER LINES

A small leakage from the sewer lines can contaminate the underground water and make it unfit
for the people to drink. Also, when not repaired on time, the leaking water can come on to the
surface and become a breeding ground for insects and mosquitoes.

f) LEAKAGE FROM LANDFILLS

Landfills are nothing but a huge pile of garbage that produces the awful smell and can be seen
across the city. When it rains, the landfills may leak and the leaking landfills can pollute the
underground water with a large variety of contaminants.

g) THERMAL POLLUTANTS
 35

These pollutants include the waste heat chiefly from atomic, nuclear and thermal power plants.
The discharge of unutilized heat is highest in the thermal power plants which adversely affect the
aquatic environment. Apart from electric power plants, various industries with cooling
requirement contribute to thermal loading.

Fig.2.4. Chief causes of thermal pollution

h) OIL SPILLS
Oil spill poses a huge concern as a large amount of oil enters into the sea and does not dissolve
with water; thereby opens problem for local marine wildlife such as fish, birds and sea otters. For
e.g.: a ship carrying a large quantity of oil may spill oil if met with an accident and can cause
varying damage to species in the ocean depending on the quantity of oil spill, size of the ocean,
the toxicity of pollutant.
2.4. IMPACTS OF WATER POLLUTION

Pollution of water affects both humans and aquatic life. Most water sources close to cities and
urban centres are polluted by garbage and dumping of chemicals, legally or illegally. Below are
some of the common as well as adverse effects of polluting water bodies.

a) EFFECTS ON HUMAN BEINGS

Life is a cycle, and humanity’s irresponsible behaviour often comes back to haunt it. Adding
contaminants to water bodies has affected the human family in several ways. According to a
 36

2017 WHO report, 2.1 billion people do not have access to safe water. In 2019, it stated that 785
million people lack access to essential drinking water.
One of the main effects of this is diseases. World Health Organisation notes that there are about
120,000 cholera-related deaths annually. Also, the Fukushima tragedy, for example, increased
the prevalence of thyroid cancer in exposed infants by 70%.

b) DEATH OF AQUATIC LIFE

Animals and plants that depend on water for life are the most affected by polluted water.
Deformities of fish, birds etc. sometimes leading to fish consumption advisories and even to
complete loss of fish.
c) FOOD CHAIN DISRUPTION

Pollution disrupts the food chain by moving the toxins from one level in the chain to higher
levels. In some cases, pollution can wipe out an entire part of the food chain. Such affect the
other organisms by either causing excessive growth, in case the predator dies or death (if it wipes
out the prey).

d) DESTRUCTION OF ECOSYSTEMS

The introduction or elimination of certain microorganisms distorts the ecosystem. Nutrient

pollution, for example, leads to an increase in algae, which depletes the water of oxygen, thereby
leading to the death of fish and other aquatic life.

e) ECONOMIC EFFECTS

Managing and restoring polluted water bodies is expensive. For example, Japan declared in 2019
that it is running out of space to contain the contaminated water after the Fukushima disaster. It
currently has over a million tons of contaminated water stored in tanks. Research shows that it
will cost at least $660 billion to clean up the effects of the disaster.

In normal conditions, it costs more to purify drinking water, not to mention the health cost of
treating diseases resulting from contaminated water.

2.5 EUTROPHICATION
 37

Eutrophication (from Greek eutrophos, "well-nourished"), or hypertrophication, is when a body

of water becomes overly enriched with minerals and nutrients which induce excessive growth of
algae. This process may result in oxygen depletion of the water body. One example is an "algal
bloom" or great increase of phytoplankton in a sandy body as a response to decreased levels of
nutrients. Eutrophication is often induced by the discharge of nitrate or phosphate-containing
detergents, fertilizers, or sewage into an aquatic system.

Eutrophication most commonly arises from the oversupply of nutrients, most commonly as
nitrogen or phosphorus, which leads to overgrowth of plants and algae in aquatic ecosystems.
After such organisms die, bacterial degradation of their biomass results in oxygen consumption,
thereby creating the state of hypoxia.

Fig.2.5.Process of eutrophication

All water bodies are subject to a natural and slow eutrophication process, which in recent
decades has undergone a very rapid progression due to the presence of man and his activities (so
called cultural eutrophication). The cultural eutrophication process consists of a continuous
increase in the contribution of nutrients, mainly nitrogen and phosphorus (organic load) until it
 38

exceeds the capacity of the water body (i.e. the

capacity of a lake, river or sea to purify itself) ,
triggering structural changes in the waters. These
structural changes mainly depend on 3 factors:

• Use of fertilisers:

Agricultural practices and the use of fertilisers in

the soil contribute to the accumulation of nutrients.
When these nutrients reach high concentration
levels and the ground is no longer able to assimilate
them, they are carried by rain into rivers and
groundwater that flow into lakes or seas. Example
of fertiliser spreading on agricultural land

• Discharge of waste water into water bodies:

In various parts of the world, and particularly in developing countries, waste water is discharged
directly into water bodies such as rivers, lakes and seas. The result of this is the release of a high
quantity of nutrients which stimulates the disproportionate growth of algae. In industrialised
countries, on the other hand, waste water can be illegally discharged directly into water bodies.
When instead water is treated by means of water treatment plants before discharge into the
environment, the treatments applied are not always such as to reduce the organic load, with the
consequent accumulation of nutrients in the ecosystem. Example of discharge of waste water into
a reservoir

• Reduction of self purification capacity:

Over the years, lakes accumulate large quantities of solid material transported by the water
(sediments). These sediments are such as to able to absorb large amounts of nutrients and
pollutants. Consequently, the accumulation of sediments starts to fill the basin and, increasing
the interactions between water and sediment, the resuspension of nutrients present at the bottom
of the basin is facilitated. This phenomenon could in fact lead to a further deterioration of water
quality, accentuating the processes connected with eutrophication
 39

2.5.1. Formation mechanism

Eutrophication is characterised by a significant increase of algae (microscopic organisms similar

to plants) due to the greater availability of one or more growth factors necessary for
photosynthesis, such as sunlight, carbon dioxide and nutrients (nitrogen and phosphorus). When
algae start to grow in an uncontrolled manner, an increasingly large biomass is formed which is
destined to degrade. In deep water, a large amount of organic substance accumulates, represented
by the algae having reached the end of their life cycle. To destroy all the dead algae, an excessive
consumption of oxygen is required, in some cases almost total, by microorganisms. An anoxic
(oxygen-free) environment is thus created on the lake bottom, with the growth of organisms
capable of living in the absence of oxygen (anaerobic), responsible for the degradation of the
biomass. The microorganisms, decomposing the organic substance in the absence of oxygen, free
compounds that are toxic, such as ammonia and hydrogen sulphide (H2S). The absence of
oxygen reduces biodiversity causing, in certain cases, even the death of

Fig.2.6. Formation of Eutrophication

 40

animal and plant species. All this happens when the rate of degradation of the algae by
microorganisms is greater than that of oxygen regeneration, which in summer is already present
in low concentrations. Eutrophication process representation (Feem re-elaboration from Arpa
Umbria, 2009)

2.5.2. Effects

The disturbance of aquatic equilibria may be more or less evident according to the enrichment of
water by nutrients (phosphorus and nitrogen). An aquatic environment with a limited availability
of phosphorus and nitrogen is described as "oligotrophic" while one with high availability of
these elements is called "eutrophic"; a lake with intermediate availability is called "mesotrophic".
When the eutrophication phenomenon becomes particularly intense, undesirable effects and
environmental imbalances are generated. The two most acute phenomena of eutrophication are
hypoxia in the deep part of the lake (or lack of oxygen) and algal blooms that produce harmful
toxins, processes that can destroy aquatic life in the affected areas (www.unep.or.jp ). The main
effects caused by eutrophication can be summarised as follows (N. Sechi, 1986): • abundance of
particulate substances (phytoplankton, zooplankton, bacteria, fungi and debris) that determine
the turbidity and colouration of the water; • abundance of inorganic chemicals such ammonia,
nitrites, hydrogen sulphide etc. that in the drinking water treatment plants induce the formation
of harmful substances such as nitrosamines suspected of mutagenicity;

• abundance of organic substances that give the water disagreeable odours or tastes,
barely masked by chlorination in the case of drinking water. These substances, moreover,
form complex chemical compounds that prevent normal purification processes and are
deposited on the walls of the water purifier inlet tubes, accelerating corrosion and
limiting the flow rate;

• the water acquires disagreeable odours or tastes (of earth, of rotten fish, of cloves, of
watermelon, etc.) due to the presence of particular algae;
• disappearance or significant reduction of quality fish with very negative effects on
fishing (instead of quality species such as trout undesirable ones such as carp become
established);
 41

• possible affirmation of toxic algae with potential damage to the population and animals
drinking the affected water;

Fig.2.7. effects of Eutrophication

• prohibition of touristic use of the lake and bathing, due to both the foul odour on the
shores caused by the presence of certain algae, as well as the turbidity and anything but
clean and attractive appearance of the water; bathing is dangerous because certain algae
cause skin irritation;

• reduction of oxygen concentration, especially in the deeper layers of the lake at the end
of summer and in autumn.

In the light of these significant repercussions and serious consequent economic and naturalistic
damage, there is a clear need to curb the progress of eutrophication, avoiding the collapse of the
affected ecosystems.

2.5.3.Control

In the past, the traditional eutrophication reduction strategies, including the alteration of excess
nutrients, physical mixing of the water, application of powerful herbicides and algaecides, have
proven ineffective, expensive and impractical for large ecosystems. Today, the main control
mechanism of the eutrophic process is based on prevention techniques, namely removal of the
nutrients that are introduced into water bodies from the water. It would be sufficient to reduce
the concentrations of one of the two main nutrients (nitrogen and phosphorus), in particular
phosphorus which is considered to be the limiting factor for the growth of algae, acting on
localised loads (loads associated with waste water) and widespread loads (phosphorus loads
 42

determined by diffuse sources such as land and rain). The load is the quantity (milligrams,
kilograms, tons, etc.) of nutrients introduced into the environment due to human activity.

The possible activities to be undertaken to prevent the introduction of nutrients and to limit
phosphorus loads can be summarised as follows

• improvement of the purifying performance of waste water treatment plants, installing

tertiary treatment systems to reduce nutrient concentrations;

• Implementation of effective filter ecosystems to remove nitrogen and phosphorus present

in the run-off water (such as phyto-purification plants);

• reduction of phosphorous in detergents;

• rationalization of agricultural techniques through proper planning of fertilisation and use

of slow release fertilisers;

• oxygenation of water for restore the ecological conditions, reducing the negative effects
of the eutrophic process, such as scarcity of oxygen and formation of toxic compounds
deriving from the anaerobic metabolism;

• chemical precipitation of phosphorous by the addition of iron or aluminium salts or

calcium carbonate to the water, which give rise to the precipitation of the respective iron,
aluminium or calcium orthophosphates, thereby reducing the negative effects related to the
excessive presence of phosphorus in the sediments.

2.6. BIOMAGNIFICATION

Bio-magnification is defined as the accumulation of a particular substance in the body of the

organisms at different trophic levels of a food chain. Bio-magnification, also known as bio-
amplification or biological magnification, is any concentration of a toxin, such as pesticides, in
the tissues of tolerant organisms at successively higher levels in a food chain. This increase can
occur as a result of:

• Persistence – where the substance cannot be broken down by environmental processes

 43

• Food chain energetics – where the substance's concentration increases progressively as it

moves up a food chain
• Low or non-existent rate of internal degradation or excretion of the substance – mainly
due to water-insolubility

Biological magnification is often refers to the process whereby certain substances such as
pesticides or heavy metals work their way into lakes, rivers and the ocean, and then move up the
food chain in progressively greater concentrations as they are incorporated into the diet of
aquatic organisms such as zooplankton, which in turn are eaten perhaps by fish, which then may
be eaten by bigger fish, large birds, animals, or humans. The substances become increasingly
concentrated in tissues or internal organs as they move up the chain. Bioaccumulants are
substances that increase in concentration in living organisms as they take in contaminated air,
water, or food because the substances are very slowly metabolized or excreted.

Fig.2.8. showing Biomagnification

 44

2.6.1. Causes of Biomagnification

a) Agricultural products
The chemicals used in agricultural sector contain highly toxic substances that mainly result in
biomagnification. These chemicals include herbicides, pesticides, fungicides, and inorganic
fertilizers. These chemical penetrate into the soil where they accumulate to toxic levels and also
find their way into the rivers and lakes through surface runoff during storms.The industrial
effluents and wastes from agriculture industries also contribute to Biomagnification. These
chemicals used in the farms or released in industries contain traces of heavy metals namely, lead,
copper, arsenic, mercury, and cadmium. In water and soil, the toxic chemicals and heavy metals
are absorbed by the zooplankton and plants respectively and once ingested by other consumers
the toxic chemicals and heavy metals are released into the primary consumers’ body tissues.
In the tissues, they accumulate to toxic levels that may cause adverse health effects and
transferred to the next trophic level upon consumption, gradually move up the food chain in
much higher concentrations.
b) Organic contaminants
The biosolids that are used in agriculture farms are treated using toxic chemicals that may
contain heavy metals. When these organic substances are released into the farms they release
harmful substances that are absorbed by the primary consumers and later accumulate in other
organisms.
c) Plastic pollution
Disposal of plastic waste near or in water bodies may not only be directly harmful to aquatic
organisms but also other animals up the trophic level in general. Research shows that plastic
contains a harmful chemical called Bisphenol A which is one of the major contaminant released
into the water bodies. Once in the body of the fish as well as the minute disintegrated plastic
particles, they are taken up by other consumers that ingest the fish.
d) Mining
When mining substances such as zinc, copper, cobalt, lead and other chemicals, these mineral
deposits may be released into the aquatic and adjacent farm environment where their toxicity
levels rise tremendously upon absorption by aquatic and farm animals or crops.They are then
consumed by the organisms that are in the lower trophic levels. These organisms are then
 45

consumed by other organisms in higher trophic levels leading to accumulation of these metals in
different trophic levels.
2.6.2. Effects of Biomagnification
a) Human Health
In recent years, consumption of seafood has been linked to certain types of cancer. This is as a
result of the accumulation of mercury and the Polycyclic Aromatic Hydrocarbons in the tissues
of marine organisms. Mercury is known to have an adverse effect on humans such as
deterioration in the nervous system, impaired vision, hearing, gait and speech, lead to
involuntary muscle movements, and corrosion of skin and mucosa.
In addition, consumption of plants or aquatic animals that have assimilated heavy metals and
toxic substances may lead to long-term effects such as different types of cancers, Kidney failure,
respiratory disorders, brain damage, birth defects and heart diseases. Fishes that live in areas
where pollution is rampant have shown traces of mercury, and lead which are highly toxic in the
human body if ingested.
b) Effect on Aquatic animals
The ingestion and subsequent accumulation of metals in the tissues of marine organisms have an
adverse effect in their development and reproduction. Consumption of heavy toxic metals in
seabirds has an effect on egg production. The seabirds produce eggs with soft and thin shells
which easily crashes as they try to incubate them.Other cases that result from contamination of
water bodies with toxic chemicals such as Selenium and mercury include damage to the
reproduction systems of fish. Few fishes would mean less food to other creatures that depend on
them for survival. Polychlorinated biphenyls (PCBs) are highly concentrated in water bodies and
have the same effect in aquatic animals.
c) . Food Chain
Accumulation of substances that cause biomagnifications can disrupt the natural food chain that
is essential for the survival of all animals in a given biosphere.
The primary consumers such as plants are then consumed by secondary consumers which in turn
are consumed by other organisms. The chain continues up to the highest trophic level leading to
Biomagnification. However, if a group of organisms were to die due to the toxic substances the
natural flow of the food chains become disrupted. This may have a long-term effect which might
not be noticed in short term.
 46

Fig.2.9. Mercury biomagnifications in the food web

2.6.3. Solutions of Biomagnification
a) Elimination of use of some heavy metals
Heavy metals can be found in almost every industrially manufactured product such as petroleum.
Therefore, toxic substances such as lead arsenic and mercury ought to be prohibited and
completely eliminated and their usage in petroleum products and other industries banned.
Also, industries such as coal plants that produce and rely on various heavy metals should have
preservation and wellsprings that will help in the reduction of this toxic substance. Meanwhile,
the coal industry needs to come up with innovative strategies to eliminate mercury emissions.
b) Cleaning of contaminated locale
Areas that have been exposed with toxic metals should be cleaned completely and expeditiously.
The government should identify areas that are contaminated with solid wastes and also medicinal
wastes incinerators and close those areas down.
They should then supplant them with waste decrease programs and carry out other programs that
are aimed at treating and rehabilitating the soil for future use.
c) Role of institutions using toxic substances
Health sectors especially the dental departments should eliminate the use of mercury-containing
items and use more secure alternatives. The government should also evacuate and securely store
indoor regulators and thermometers that contain mercury.They also have a part to play in unison
with the schools to avoid providing leaded water to the children in schools and instead strategize
on a better alternative of clean and treated water.
 47

d) Be cautious on using treated wood

Woodwork industries should avoid the use of CCA and ACZA additives. These chemicals have
arsenic which is highly poisonous. In homes built with such treated woods, it is impossible to
remove the arsenic from the wood, however, a better solution would be to paint them with
unleaded paints that are environmentally friendly.
e) Watch out for the lead paints
Homes that were built before the 1980s are most probably painted with the toxic lead paints. In
case the paints are peeling off a decrease labourer can be contracted to either redesign, repaint or
remove the aged paint from the walls. The drinking water should be covered to prevent the lead
dust from getting in and also the other sources of water supply should be covered as well.
f) Avoid usage of the PVC
When buying plumbing materials it is important to avoid the PVC. It contains lead that
may contaminate the drinking water and the environment. If they are already installed an
alternative would be to avoid drinking or using the hot water that rushes out of the tap after
initially opening it because it contains lead traces. The best water is the icy cold one that pours
after several minutes.
g) Other solutions
The cooking oil, grease, household chemicals, and medications should be disposed of properly.
Also, when doing the laundry, phosphates bleaches and soaps are recommended because they
lack metal traces.

2.7. MARINE POLLUTION

Marine Pollution (UN definition) – “The introduction by man, directly, or indirectly, of

substances or energy to the marine environment resulting in deleterious effects such as: hazards
to human health, hindrance to marine activities, impairment of the quality of seawater for various
uses and reduction of amenities.”

Marine environment is submitted to contamination that comes in many different forms, such as
toxic chemicals (e.g., organic compounds, DDT, PCB, metals, pharmaceuticals, gas), solid waste
(e.g., plastics), increased nutrient (e.g., nitrates and phosphates) and sediment inputs due to
human activities (e.g., industry, agriculture, deforestation, sewage discharge, aquaculture),
radioactivity, oil spills, and discarded fishing nets. Marine contamination changes the physical,
 48

chemical, and biological characteristics of the oceans and coastal zones, and potentially threatens
marine organism, ecosystems, and biodiversity and affects thus the quality and productivity of
marine ecosystems. In this context, the contamination causing damage or negative impact on
marine ecosystem is called pollution. The ultimate effect of pollution on marine resources
depends on the form, intensity (acute or chronic), and location of the contamination, with some
marine environments, ecosystems, and species being more sensitive than others to pollution.

2.7.1. Major sources of marine pollution

The major known marine pollutants are summarized in Table 1. These pollutants depending on
their concentrations or magnitude cause negative impacts on marine life. In order to understand
the impacts of the coastal pollutants, individual consideration of sources and types of pollutants
are needed and therefore are briefly

a) Oil pollution
Oil pollution is a significant problem along major shipping routes and an increasing number of
accidents have occurred in recent years. The total global production of crude oil is about 3 billion
tonnes per year and approximately half of this is transported by sea. This means that on any
given day there are approximately 8.25 million tonnes afloat
around the oceans. According to one estimate, between 0.05 and
Major Marine Pollutants
0.1 percent of the sea's surface is covered with an oil film at any
Worldwide
one time. Recent,studies show that in many coastlines of the
• 10 billion tonnes of ballast
world, the tar ball concentrations have reached levels of water with invasives
kilograms per meter area of beach. Nearly 750 – 1,000 tonnes of • Est. 10,000 million gallons
the tar-balls get deposited along the west coast of India every of sewage annually

year. • 3.25 million metric tonnes

of oil annually • Millions of
b) Fertilizers tonnes of Solid waste

Fertilizer runoff from farms and lawns is a huge problem for

coastal areas. The extra nutrients cause eutrophication - flourishing of algal blooms that deplete
the water's dissolved oxygen and suffocate other marine life.Eutrophication has created
enormous dead zones in several parts of the world, including the Gulf of Mexico and the Baltic
Sea.
 49

c) Seas of garbage
Solid garbage also makes its way to the ocean. Plastic bags, balloons, glass bottles, shoes,
packaging material – if not disposed of correctly, almost everything we throw away can reach the
sea.Plastic garbage, which decomposes very slowly, is often mistaken for food by marine
animals. Ocean trash can be broken into smaller pieces — known as microplastic — by sun
exposure and wave action, after which it can find its way into the food chain. When it eventually
degrades (which takes 400 years for most plastic), the process releases chemicals that further
contaminate the sea.High concentrations of plastic material, particularly plastic bags, have been
found blocking the breathing passages and stomachs of many marine species, including whales,
dolphins, seals, puffins, and turtles. Plastic six-pack rings for drink bottles can also choke marine
animals.This garbage can also come back to shore, where it pollutes beaches and other coastal
habitats.

Fig.2.10Different sources of marine pollution

d) Sewage disposal
In many parts of the world, sewage flows untreated, or under-treated, into the ocean. For
example, 80% of urban sewage discharged into the Mediterranean Sea is untreated.This sewage
can also lead to eutrophication. In addition, it can cause human disease and lead to beach
closures.
 50

e) Thermal pollution
Thermal pollution af - fects the ocean in a nega - tive way. An increase in water temperature
causes a change (lowering) of dissolved oxygen levels. This disrupts the body of water's
ecological balance, resulting in the suffocation of some plant and animal species while
encouraging the overgrowth of others. The overgrowth and suffocation causes a cascade reaction
with other organisms that are dependent on the ones that don't survive and with organisms that
now have to compete with the overgrow - ing organisms. Solid wastes

f) Toxic chemicals
Almost every marine organism, from the tiniest plankton to whales and polar bears, is
contaminated with man-made chemicals, such as pesticides and chemicals used in common
consumer products.Some of these chemicals enter the sea through deliberate dumping. For
centuries, the oceans have been a convenient dumping ground for waste generated on land. This
continued until the 1970s, with dumping at sea the accepted practise for disposal of nearly
everything, including toxic material such as pesticides, chemical weapons, and radioactive
waste.Chemicals also enter the sea from land-based activities. Chemicals can escape into water,
soil, and air during their manufacture, use, or disposal, as well as from accidental leaks or fires in
products containing these chemicals. Once in the environment, they can travel for long distances
in air and water, including ocean currents.

Evidence is mounting that a number of man-made chemicals can cause serious health problems -
including cancer, damage to the immune system, behavioural problems, and reduced fertility.

2.7.2. Marine environmental impacts

Depending upon the duration of pollutant

discharge into the marine environment and
the levels of pollutants being discharged, two
types of effects, can be expected on the
marine environment
 51

a) acute effects and

b) chronic,.effects
a) Acute effects
Major Marine Pollutants –
The short term exposure to high concentrations of pollutants can Solid Waste • A large portion
result in acute effects. Such effects include mass mortality of and great danger is
nonbiodegradable plastic
marine organisms or large scale damage to the marine ecosystem.
• 46,000 pieces of floating
Accidental discharges like oil spill or power plant blowouts
plastic/sq mile of ocean
usually cause such acute effects on the marine environment. surface off the N.E U.S. coast.

• Sea turtles mistake plastic

b) Chronic effects
bags for jellyfish and die from
internal blockages.
Long and continuous exposure to low concentrations of pollutants
• Seals and sea lions starve
can result in chronic effects in marine organisms including fishes.
after being entangled by nets
The chronic effects include retarded growth, outbreak of diseases, or muzzled by six-pack rings
(decomposition time 400
failure in reproduction etc., in marine organisms. Discharge of years).
untreated sewage and industrial effluents can cause chronic effects
• Plastic debris kills 100,000
on marine biota. Coastal marine environment all over the world are marine mammals and 2
million sea birds die annually
under unrelenting stress caused by urban development, hazardous
or toxic substances, habitat destruction and natural toxins. Several
environmental contaminants are being discharged into the coastal
environment causing serious threat to marine organisms and posing public health risk.

Elevated concentrations of contaminants including trace metals, polycyclic aromatic

hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) have been reported in waters,
sediment and biota at several locations from the coastal cities in Europe, America, Asia, Africa
and Middle East.

• A significant proportion of these chemicals have the potential to damage chromosomes or

DNA of marine organisms.

• Eggs and early developmental stages of fishes and other marine organisms are highly
vulnerable to the toxic effects of these genotoxic pollutants.
 52

• Usually, marine organisms including fishes accumulate pollutants in their body from the
contaminated seawater, sediments and through the food chains and this phenomenon is
called bioaccumulation. Bioaccumulation of contaminants in organisms from different
trophic levels leads to the biomagnification of pollutant.

• . Human activities resulting in the chemical contamination of the environment have

increased the potential stresses on marine organisms in most of their exposed habitats.
Even at very low concentrations, toxic pollutants can have drastic effects on their
physiology, immunology and ecology, and an increase in number and extent of disease
outbreaks in marine organisms was reported.

• Occurrences of cancers and preneoplastic conditions initiated and promoted by pollutant

exposure have been observed in marine taxa ranging from invertebrates to marine
mammals.

• Diseases caused by pathogenic agents and liver histopathology associated with cancer
were reported in marine fishes for several years.

• Elevated levels of organic and inorganic pollutants apparently resulted in high

prevalence of tumors in marine mammal populations

Fig.2.11 Pollution Creating nuaisance and harm to sea life

2.7.3. Marine pollution monitoring and control

United Nations (UN) has taken several initiatives to control the use and exploitation of the
oceans including coastal seas through several international conventions, treaties and agreements.
 53

• The UN Convention on the Law of the Sea (LOSC), which took place from 1973 to 1982,
lays down a comprehensive regime of law and order in the world's oceans and seas
establishing rules governing all uses of the oceans and their resources. It enshrines the
notion that all problems of ocean space are closely interrelated and need to be addressed
as a whole.

• The Convention on the Prevention of Marine Pollution by Dumping of Wastes and other
Matter (London-Dumping Convention) was agreed in 1972. Its purpose was to prevent
marine pollution caused by the deliberate disposal of wastes or other matter at sea,
including in areas beyond national jurisdiction. The 1996 Protocol adopted modifications
and included more stringent conditions.

• The United Nations Environment Programme (UNEP), particularly through its Regional
Seas Programme, acts to protect oceans and seas and promote the environmentally sound
use of marine resources.

• The International Maritime Organization (IMO) has developed and/or administers a wide
range of treaties, focusing, in particular, on preventing the pollution of the oceans and
seas. These include the landmark International Convention for the Prevention of Pollution
from Ships of 1973 (MARPOL), as modified by a 1978 Protocol (MARPOL), and the
1954 International Convention for the Prevention of Pollution of the Sea by Oil (the
“OILPOL Convention”).

Apart from this, every country, including India, has its own marine environmental monitoring
program to understand and assess the status of marine environment. A prominent example of this
is the National Oceanic and Atmospheric Administration (NOAA) National Status and Trends
Mussel Watch Program that started in 1986. Now contaminant monitoring programs similar to
mussel watch are being implemented throughout the world. At present, the disposal or dumping
of land-derived effluent, sewage and waste into the marine environment are controlled and
regulated.

Each country has its own environmental standards and guidelines for controlling the discharge
or dumping of pollutants into the sea. It is also mandatory to conduct Environmental Impact
Assessment (EIA) before starting construction and/or operation of any industrial activities in the
 54

coastal areas. In India, the Central Pollution Control Board (CPCB), a statutory organization
under the Ministry of Environment and Forest, formulates environmental standards and
guidelines for protecting the marine environment

2.8. WATER POLLUTION CONTROL

Water pollution can be controlled by diluting the water pollutants in a reservoir. The various
methods for the control of water pollution can be summarized as follows:

1. The sewage pollutants are required to be treated in sewage treatment plants before their
discharge in natural water bodies.

2. Water pollution due to organic insecticides and pesticides can be reduced by the use of
very specific and less stable chemicals in the manufacture of insecticides/pesticides.
Moreover, use of bio-fertilizers needs to be promoted.

3. Oxidation ponds can be useful in removing low level of radioactive wastes.

4. Hot water should not be disposed directly into the river, as it adversely affects the life
of aquatic organisms. Thermal pollution can be reduced by employing techniques such as
cooling, cooling ponds, evaporative or wet cooling towers and dry cooling towers.

5. Domestic and industrial waste waters should be treated properly in waste water
treatment plants, before discharge in the natural aquatic systems.

6. Strict implementation of legislations for water treatment should be done.

7. No solid waste should be dumped into water bodies.

8. Dead bodies of animals/human should not be floated in water sources.

9. Bathing, washing of clothes, and idol immersion should be strictly restricted in natural
water bodies.

2.9. SEWAGE TREATMENT

Sewage treatment is the process of removing contaminants from municipal wastewater,

containing mainly household sewage plus some industrial wastewater. Physical, chemical, and
 55

biological processes are used to remove contaminants and produce treated wastewater (or treated
effluent) that is safe enough for release into the environment. A by-product of sewage treatment
is a semi-solid waste or slurry, called sewage sludge. The sludge has to undergo further treatment
before being suitable for disposal or application to land.

Sewage treatment may also be referred to as wastewater treatment. However, the latter is a
broader term which can also refer to industrial wastewater. For most cities, the sewer system will
also carry a proportion of industrial effluent to the sewage treatment plant which has usually
received pre-treatment at the factories themselves to reduce the pollutant load. If the sewer
system is a combined sewer then it will also carry urban runoff (storm water) to the sewage
treatment plant. Sewage water can travel towards treatment plants via piping and in a flow aided
by gravity and pumps. The first part of filtration of sewage typically includes a bar screen to
filter solids and large objects which are then collected in dumpsters and disposed of in landfills.
Fat and grease is also removed before the primary treatment of sewage.

2.9.1. Primary treatment

Primary treatment removes material that will either float or readily settle out by gravity. It
includes the physical processes of screening, comminution, grit removal, and sedimentation.
Screens are made of long, closely spaced, narrow metal bars. They block floating debris such as
wood, rags, and other bulky objects that could clog pipes or pumps. In modern plants the screens
are cleaned mechanically, and the material is promptly disposed of by burial on the plant
grounds. A comminutor may be used to grind and shred debris that passes through the screens.
The shredded material is removed later by sedimentation or flotation processes.

Fig.2.12. sewage treatment plant

 56

2.9.2. Secondary treatment

Secondary treatment removes the soluble organic matter that escapes primary treatment. It also
removes more of the suspended solids. Removal is usually accomplished by biological processes
in which microbes consume the organic impurities as food, converting them into carbon dioxide,
water, and energy for their own growth and reproduction. The sewage treatment plant provides a
suitable environment, albeit of steel and concrete, for this natural biological process. Removal of
soluble organic matter at the treatment plant helps to protect the dissolved oxygen balance of a
receiving stream, river, or lake.

There are three basic biological treatment methods: the trickling filter, the activated sludge
process, and the oxidation pond.

a) Trickling filter

A trickling filter is simply a tank filled with a deep bed of stones. Settled sewage is sprayed
continuously over the top of the stones and
trickles to the bottom, where it is collected for
further treatment. As the wastewater trickles
down, bacteria gather and multiply on the
stones. The steady flow of sewage over these
growths allows the microbes to absorb the
dissolved organics, thus lowering the
biochemical oxygen demand (BOD) of the
sewage. Air circulating upward through the
spaces among the stones provides sufficient
oxygen for the metabolic processes.

b) Activated sludge

The activated sludge treatment system consists of an aeration tank followed by a secondary
clarifier. Settled sewage, mixed with fresh sludge that is recirculated from the secondary
clarifier, is introduced into the aeration tank. Compressed air is then injected into the mixture
through porous diffusers located at the bottom of the tank. As it bubbles to the surface, the
 57

diffused air provides oxygen and a rapid mixing action. Air can also be added by the churning
action of mechanical propeller-like mixers located at the tank surface.

Under such oxygenated conditions, microorganisms thrive, forming an active, healthy

suspension of biological solids—mostly bacteria—called activated sludge. About six hours of
detention is provided in the aeration tank. This gives the microbes enough time to absorb
dissolved organics from the sewage, reducing the BOD. The mixture then flows from the

Fig. 2.13.Activated sludge process

aeration tank into the secondary clarifier, where activated sludge settles out by gravity. Clear
water is skimmed from the surface of the clarifier, disinfected, and discharged as secondary
effluent. The sludge is pumped out from a hopper at the bottom of the tank. About 30 percent of
the sludge is recirculated back into the aeration tank, where it is mixed with the primary effluent.
This recirculation is a key feature of the activated sludge process. The recycled microbes are well
acclimated to the sewage environment and readily metabolize the organic materials in the
primary effluent. The remaining 70 percent of the secondary sludge must be treated and disposed
of in an acceptable manner.

c) Oxidation pond

Oxidation ponds, also called lagoons or stabilization ponds, are large, shallow ponds designed to
treat wastewater through the interaction of sunlight, bacteria, and algae. Algae grow using energy
from the sun and carbon dioxide and inorganic compounds released by bacteria in water. During
the process of photosynthesis, the algae release oxygen needed by aerobic bacteria. Mechanical
aerators are sometimes installed to supply yet more oxygen, thereby reducing the required size of
 58

the pond. Sludge deposits in the pond must eventually be removed by dredging. Algae remaining
in the pond effluent can be removed by filtration or by a combination of chemical treatment and
settling.

Fig.2.14. oxidation ponds

 59

SELF ASSESMENT
A) Long Answer Type Question
Q.NO.1. Define water pollution. What are different sources of water pollution?
Q.NO.2.Explain impacts of water pollution on different components of environment.
Q.NO.3.Explain the control measures for water pollution.
Q.NO.4.Discuss Eutrophication in detail.
Q.NO.5Define Sewage. Explain its primary and secondary treatment.

B) Short Answer Type Questions

Q.NO.1 Explain biomagnification and its impact on the ecosystem
Q.NO.3.Explain how Eutrophication affects aquatic ecosystems?
Q.NO.4. What are the sources of oil spills and their impacts on marine ecosystem?

C) Very Short Answer Type Questions

Q.NO.1.What is Activated Sludge?
Q.NO.2.What is a dystrophic lake?
Q.NO.3. What is BOD?

D) Multiple choice questions

Q.1. Eutrophication is caused by
A) Phosphorus (B) Potassium C) Oxygen D) CO
Q.2. Dissolved organic matter is broken down in water in
A) Primary treatment B) Secondary treatment
C)Tertiary treatment D) sedimentation tanks
Q.3. Increased BOD means
A) Less Pollution B) More dissolved oxygen
C) Pure water D) High organic pollution
 60

REFRENCES
1. Text book of environmental science 11th class by vidhi oberoi.
2. Ecology and environment 2018 edition by P.D Sharma
3. Prespectives in environmental science sixth edition by C.P.kaushak and
A.kaushak.
4. Ecology and environment by S.V.S Rana.

5. Principals of Environmental Science- William P. Cunninghan and Mary Ann

Cunninghan. McGraw Hill Education (India) Pvt.Ltd., New Delhi.
 61

Unit-3 :Soil Degradation.

❖ Learning outcomes:
After reading this chapter the s tudents will be able to

• understand the basic concept of soil and its composition .

• acquaint about different soil layers like O,A etc
• develop the understanding of soil Erosion, its impact and control
• Able to know about different classes of soil like,black soil, laterite soil etc
• develop the concept of Soil pollution and it’s control

3.1. INTRODUCTION

Soil is the upper part of earth’s crust,which contains organic as well as inorganic mineral matter
necessary for growth and development of plants. Soil often called the skin of earth is a mixture
of decaying organic matter (Humus), minerals ,liquids and many countless micro Organisms a
medium for plant growth and means of water storage.

Soil is the covering of the solid crust of the earth,s land

mass. Soil is made up of broken down rock materials of
varying degree of fineness and changed in varying degrees
from the parent rocks by the action of different agencies
such that the growth of vegetation made possible. Soil is
derived from the Latin word solum which means floor or
ground. What a scientist calls soil,a geologist calls
fragmented rock,and an engineer calls earth,while an
economist may call land. There are two basic concepts of the soil.

a) According to the first concept soil is a body of biochemically weathered and

synthesized product of nature. In other words, pedology considers soil as a entity, a
biologically weathered and synthesized product of nature. Pedologists study soils which
includes the study of origin of the soil,it’s Classification and it’s discription.
 62

b) According to the second concept soil is considered to be a natural habitat for plants
and other living Organisms and justifies soil studies primarily on that basis. In other
words,edaphology considers the soil as a natural habitat for plants.edaphology is the
study of soil from the stand point of higher plants. It considers the various properties of
soil in relation to growth, nutrition and yield of crops.

1.1: Soil Composition Or constituents of

soil.

The constituents of soil are:

• Mineral Matter
• Organic Matter
• Soil Air
• Water content
• Living Organisms

Fig. 3.1. composition of soil

i) Mineral Matter:

Mineral Matter of various sizes at different

stages of chemical decomposition compose of

a) Gravel – 2-50 mm
b) Course sand- 2-0.2mm
c) Fine sand –0.2-0.02mm
d) Silt – 0.02-0.002mm
e) Clay – under 0.002mm

It comprises 40-45% of soil volume.

ii) OrganicMatter:
Organic Matter gives brown or black colour to the soil.It is called Humus.It adds nitrogen,
phosphorus, sulphur, magnesium, calcium,iron,molebidenium and potassium,to the soil and
 63

plants.The organic matter is broken by fungi and bacteria or consumed by insects.They excrete
it as faecal pallets called frass. It comprises 5% of soil volume.

iii) Water Content: Soil contain water between the soil particles,it is very important for
transpiration, maitainence of cell content, turgidity and photosynthesis. Water that
moves down under the influence of gravity is called gravitational water.It becomes
unavailable to plants and forms underground water table. Capillary water present in very
small pores that act like capillaries is called capillary water. It is the only water available
and utilised by plants,whereas the water that remains bind with soil and does not move is
called hygroscopic water.water combining chemically with soil is called as combined
water.
iv) SoilAir:
soil air is the gaseous phase of the soil.soil air plays an important role in plants growth and the
activity of soil organisms.soil pores are filled with air and water,and there is a dynamic
equallibrium between water and air content within a Soil.

v) Living Organisms: Living Organisms comprise of

• 1.Micro fauna: Amoeba,Euglena, paramecium

• Macro fauna: nematodes, earthworm, millipedes, termites, snails,moles etc.
• 3.Micro Flora: Rhizobium,pseudomonas etc.
• 4.Macro Flora: Moulds, mushroom etc.

3.1.2: Soil profile

When a pit or a trench is dug into soil, especially where the soils are having a considerable
depth, we observe characteristic layers differing in colour, texture, structure, thickness
composition and biological properties. These superimposed layers are known as soil horizons
and are collectively designated as soil profile. The zonation is brought about largely by the action
of rain water, which removes materials from surface layers by leaching and deposits them in sub-
layers at different depths. A typical soil consists of the following horizons.
 64

O Horizon:- Which consists of plant litter on the surface. The recently fallen litter with little
decomposition is designated by O1 and partly decomposed organic matter derived from litter
having lost its identity is designated as O2.O- horizon is usually absent in deserts because of
scarce plant cover.

A Horizon:- It represents topsoil. Is the zone of

extraction or leaching where clay and easily soluble
salts like Fe, Al and organic colloids are leached by
downward movement. It is further divided into A1 –
the zone with maximum humans, granular structure
and dark colour, A2- zone of maximum eluviations
with light colour due to loss of Al, Fe and clay, and
A3 – a transition zone to B horizon.

B. Horizon :- Represents the zone of deposition or

illuviation. It receives the soluble salts from A
horizon along with clay minerals, oxides of Al and Fe
carried by percolation waters. This zone has heavy
texture, higher clay content and greater density than A
horizon .It I also known as sub- soil.

C Horizon: - Contains the parent weathered material

lying just below B layer excluding parent bed rock. Its
formation is little affected by pedogenisis. This layer
is rich in mineral matter but devoid of any organic
component Both A and B layers may or may not be from the material of C horizon and
frequently it contains weathered parent material to some extent.
D Horizon :- Consists of the bed rock which is unweathered and may not be the material form
which A, B, O, C layers are formed. Young soils have only few horizons like A and C while as
deserts do not have O horizon due to scare vegetation.
Fig.3.2. soil horizons

3.2: Classification of Soils:-

 65

As per ICAR the Indian soils are classified into following eight categories as:
3.2.1: Alluviall soils:- The soils which are brought about /carried out and deposited by
running water are known as alluvial soils. These are formed in coastal; plains, Indo- gaga
Brahmaputra plains and river valleys. Such soils contain different menial matter constituents like
sand, clay and silt in different proportions. The alluvial soils which are newer and are deposited
by rivers every year are known as khaddar and are very fertile, which are the old alluvial soils
contains pebbles and Ca CO3 are known as Bahnger. The colour of the alluvium soils may be
grey, brown or yellowish and are very rich in potash, phosphorus, lime and carbon compounds
but may be deficient in Nitrogen.

2. Black Soils:- The back soils also called as Regar or black cotton soils because cotton being
the most important crop grown in it. These soils are formed by the solidification of lava spread
over Deccan plateau. Dark Black colour of such soils is due to the presence or high organic
matter or titaniferous magnetite – a compound of Iron and Aluminum. Regur soils show swelling
on wetting and high shrinkage on drying. There soils are rich in Ca, Mg, Al, potash and time but
deficient in N2and humus.

3. Red soils:- These soils form the disintegration of crystalline and metamorphic rocks in heavy
rainfall areas. The red colour of these soils is due to the presence of iron oxide. These are rich in
ferromagnesian minerals and have low moisture retaining capacity. Thus these soils require
frequent irrigation when put under crop cultivation. These soils are rich in Fe, Mg, Al but
deficient in humus, N2 and phosphates.

4. Laterite Soils:- These are residual soils found, under typical monsoon conditions by leaching
process hence are mainly found on hill tops. The heavy rainfall in these areas washes away the
lime and silica content in humid climates and sloppy terrains. Hence these soils are deficient in
siliceous minerals but rich in oxides of Fe and Al. Such soils are only suitable for the growth of
bushes and pastures.

5. Forest Soils:- Also known as mountain soils formed by deposition of organic matter from
woodlands and forests. These are spread over Himalayas and are yet under formation process.
These contain stone pieces and pebbles and differ from place to place due to varied climate and
 66

ecological conditions of the area. Due to the excessive presence of organic matter and less
decomposed humus, these are acidic in nature.

Fig. 3.3. Major soil types in India (source.www.pmfias.com)

6. Arid and Desert soils:- It contains large quantities of sand and are mainly distributed in arid
and semi-arid regions or Rajasthan. These soils are less fertile, light in colour, containing high
concentration of soluble salts, and phosphorus, but lack in carbon compounds and N2. Such soils
are suitable for the growth of salt tolerating and drought resistant crops.

7. Saline and Alkaline:- The weathering and decomposition of various rock and mineral
fragments release Sodium, Magnesium and Calcium salts which are transported in solution by
water and hence making the soils alkali or saline. Sometimes the silks as a result of evaporation
and making the accumulation of these salts in surface layers possible. In other areas like coastal
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areas, the sea tides also deposit salts in the nearby areas which makes the soils unfit for
agriculture.

8. Peaty and Marsh Soils:- These are black, highly acidic with high proportion of vegetable
matter especially found in humid regions. Most of these are under water during rainy season and
are different in potash and phosphate. The colour of Marshy soils is gray or dark black due to
presence of organic matter.

3.3: Soil Erosion

The top layer of the soil serves as a feeding zone to the plants as all the nutrients required by the
plants are present in this layer. It is a vital natural resource that usually lies upto the depth of 25
cm. When the particles of soil get loose, these can easily be carried away by either wind, water
or gravity- the process being known as erosion. Thus the process of detaching, carrying away
and disposing the carried soil particles from their place

3.4. Soil Erosion

of origin to some other place is known as soil erosion (erosion=loss). Erosion is an important
natural process that redistributes the products of geological weathering and hence is a part of
both soil formation as well as soil loss. All the world’s landscapes have been sculptured by
erosion process and when it worn down mountains and spread soil over the plains or over river
bottoms in terms of rich alluvial soil, these are happily being farmed. But erosion is a disaster
only when it occurs in the wrong place at wrong time and hence is known as creeping death of
soil. Erosion is a comprehensive natural process of detachment and removal of loosened rock
materials and soils by exogenetic factors such as running water, sea waves, wind, glacier etc.
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Soil erosion involves mainly two processes viz. Loosening and detachment of soil particles from
the parent surface and removal and transport of detached particles down slope, downstream or
down wind. Soil erosion, if a slow process which occurs naturally without the interference of
man and there occurs an equilibrium between soil loss and soil formation is known as geological
erosion and the erosion that is intensified by the human activities where soil loss out passes the
soil formation process is known as accelerated erosion.

3.3.1: Causesof soil Erosion:

Soil Erosion is basically of two types based upon the cause of erosion

1)Normal Erosion or geological erosion: It is caused by the gradual removal of top soil by
natural processes which bring an equallibrium between physical,biological, and hydrological
activities and maintain a natural balance between erosion and renewal.

2) Accelerated erosion: This is mainly caused by anthropogenic activities and the rate of erosion
is much faster than the rate of formation of soil. overgrazing, deforestation and mining are some
of the important activities causing accelerated erosion.

Agents of Soil Erosion:-There are two types of agents which cause soil erosion

I)Climatic Agents: water and wind are the Climatic agents of soil erosion.water effects soil
erosion in the form of torrential rains,rapid flow of water along slopes,runoff,wave action and
melting and movement of snow.

A) Water erosion:-When soil erosion takes place by the action of water which detach and
remove the soil particles either by falling action as rain drops or by surface flow, it is
referred to as water erosion. It may be further distinguished into following forms viz;
• Sheet erosion:- When a thin covering of soil from large area is removed often from
an entire field more or less uniformly run off after a rainfall, it is known as sheet
erosion. It generally seems less prominent but its occurrence can be felt by the
muddy colour of the run off.
• Rill erosion:-If the run off water moves rapidly with full force over the soil surface
forming well defined, minute finger like grooves or rills over the entire field, it is
known as rill erosion.
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• Gully erosion:-When several rills converge and develop into deeper and wider
channels (gullies) down slope assuming a huge size which tend to deepen and widen
with every heavy rainfall, it is known as gully erosion. These gullies are the
prominent features of land degradation as they cut large fields into small fragments
making it unfit for cultivation.
• Slip Erosion:- when a heavy rainfall causes a downward movement of the slope
forming material composed of natural rocks and soil due to hydraulic pressure, it is
referred to as slip erosion. The fundamental cause of this type of erosion is
topography, geological structure and rock types.
• Stream bank erosion:-The flowing water systems during floods strike their water
swiftly with the banks and cuts through them and the bank caves in alongside taking
away the debris and hence is called as stream bank erosion.
• Splash erosion:-In absence of any vegetation cover, the raindrops against the open
and bare ground surface with greater speed resulting in the breaking of the soil
aggregate into fine particles which are thrown up in air by the impact of falling
raindrops and resettle on the ground surface. Such type of erosion is known as splash
erosion.
B) Wind Erosion:-
Wind also acts as an agent of carrying away the soil particles especially in dry areas or areas
devoid of vegetation. The high velocity winds blow away the soil particles in the form of dust
storms or sand storms. Wind is responsible for three types of soil movements which are;

• Saltation:- Saltation means when soil carried by the wind is moved in small bounces.
The direct pressure of wind causes saltation and their collusion with other particles. In
saltation the particles leap vertically after being pushed by wind along the ground.
• Suspension:- The smallest particles of 0.1mm size are thrown away by wind in air and
these particles move as dust with the wind and are carried to long distances from their
original location causing a complete loss to the eroded area.
• Surface creep:-The heavier particles of the soil larger than 0.5mm are too heavy to be
thrown up by the wind and are pushed or spread along the surface to form a surface
creep.
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ii)Biotic Agents:
Excessive grazing, mining and deforestration are the major biotic agents responsible for soil
erosion.Due to these processes the top soil is disturbed or rendered devoid of vegetation cover.so
the land is directly exposed to the action of various physical forces facilitating
erosion.overgrazing accounts for 35% of the world’s soil erosion while deforestation is
responsible for 30% of the earth's seriously eroded lands.Unsustainable methods of farming
cause 28% of soil erosion.
Deforestration without reforestation, overgrazing by cattle, surface mining without land
reclamation, irrigation techniques that lead to salt build up,water logged soil,farming on land
with unsuitable terrain,soil compaction by agricultural machinary, action of cattle tramping
etc.make the top soil vulnerable to erosion.

3.3.2: Impacts of soil Erosion:

• 1.The erosion of top layer(fertile soil) or wash away leaves soil infertile and
reduced yield.
• Soil erosion leads to textual changes of soil,less fine clay and humus,makes soil
sandy.
• Soil erosion makes disastrous effects on soil micro-organisms.
• 4.Due to soil Erosion the productive lands gets converted into deserts.
• 5.Loss of top soil decreases percolation of water into soil thus leads to increase in
floods.
• 6.Soil Erosion leads to landslides,loosening of rocks and river banks which cause
land degradation.

3.3.3: Control of Soil Erosion:-

There are certain basic principles that will reduce the impacts of chief agents of soil erosion like
wind and water. These include reducing the impact of raindrops on soil particles, slowing down
the movement of water moving down the slope, increasing the water percolation, reducing the
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wind velocity near the ground surface and to grow cover vegetation that will arrest the moving
soil particles. All these principles could be achieved by employing the following methods for
erosion control as:
A) Mechanical Method:- These are engineering methods designed to check soil erosion. these
include;
• .Contour terracing where a channel is constructed along the slope to intercept the run off
water and to reduce its speed. It may be done by; bench terracing-where a number of
platforms are constructed along the contours; channel terracing-where channels are dug at
suitable intervals and the excavated oil is deposited on the lower edge of the channel;
ridge terracing- where ridges along both sides of the channel mare constructed.
• Basin listing that involves construction of small basins along the contours to reduce the
velocity of running water and to retain it.

B) Biological method:-Those methods which employ the use of biological agents like plants
and vegetation cover to control the erosion by wind and water are known as biological methods.
These involve;

• Mulching- Where a protective layer is left on the surface made up of crop

residues to act against wind as well as water erosion and to encourage the
retention of soil moisture by reducing evaporation.
• Contour farming- Where the field is prepared with alternate ridges and furrows
and water is caught and stored in these furrows thus reducing water erosion.
• Crop rotation- It involves growing different crops in different seasons especially
legumes in order to reduce the impact of monoculture and to enhance the soil
fertility as well as productivity of land.
• Strip cropping-Here crops are grown in rows or strips to check the flow of water
along with the movement of soil particles being carried by water.

C) Agrostological methods:- This method involves the utilization of grasses as erosion resisting
plants where these are grown in strips between the main crops. The grasses act as stabilisers as
they stabilise the soil surfaces and keep the particles intact. Sometimes the grasses are grown in
rotation with the main field crops to build the soil structure and to improve its fertility. Grasses
are also grown on those lands which are devoid of vegetation and where a considerable portion
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of soil has been removed.In addition plants are also grown along river banks to check the cutting
and caving of river banks by fast flowing water. Trees are also planted as wind breaks in arid
areas to reduce the wind speed and to check the spread of sand dunes or to reduce the blowing
away of top soil by wind.

3.4: Soil Pollution:- The contamination of the soil system by considerable amounts of chemical
or other substances that cause reduction in its fertility and productivity so that its overall crop
yield is reduced both qualitatively and quantitatively is known as soil pollution. Soil pollution is
the introduction of substances, biological organisms, or energy into the soil, resulting in a change
of the soil quality, which is likely to affect the normal use of the soil or endangering public
health and the living environment. Any physical or chemical change in soil that adversely affects
the growth of plants and other organisms is also referred to as soil pollution or the presence of
toxic chemicals in soil in high enough concentration to pose a risk or threat to human beings or
soil environment may also be referred to as soil pollution.

Fig. 3.5. soil pollution

3.4.1: Causes of Soil Pollution:- Soil can be polluted by a number of ways, but the major causes
of soil pollution are:

a. Erosion: Soil erosion can be defined as the loss of surface litter and topsoil from one place to
another by means of erosive agents like wind and water. It is negative pollution of soil caused
naturally often by wind and flowing water, accelerated by human activities such as farming,
 73

mining, construction, overgrazing by livestock, burning of vegetation cover and deforestation.

Once the soil gets loose, it is easily transported by wind and water and hence reducing its
productive capacity at the place where from a part or whole of it gets eroded.

b. Excess use of Agrochemicals:- Due to increasing demands for food and reduction in the
amount of agriculture land, the soils are supplied with chemical fertilizers to replenish it with the
necessary nutrients and to increase its fertility. Most of the fertilizers are loaded with heavy
metals and other chemicals which accumulate in top soil as these are not absorbed by plants.
These accumulated metals prove to be toxic to the biodiversity of soil and hence cause reduction
of soil productivity. Most of the fertilizers with nitrates and phosphates often pollute ground
water through percolation and stimulate algal blooms in surface water resources. Besides,
continuous use of fertilizers increases the concentration of various salts in soil leading to its
Salinisation. Excessive salts form a white crust on the surface and are very injurious to the
survival of plants. Application of pesticides in the agricultural fields also leads to damage to soil
biota because of the toxic nature of various chemical constituents of these pesticides leading to a
considerable damage to soil properties.

c.Waste disposal:- Millions of tons of solid waste are spilled onto the surface through many
different activities involving deliberate disposal or accidents involving the vehicles that are
transporting waste material from the generation site to the site at which it is to be deposited.
These wastes pose various threats to the structure and fertility of soil and damage its
productivity. Others involve accidental release of oil and other chemicals to the soil surface alter
the basic composition of soil and make the soil toxic for plants. Besides, radioactive wastes from
nuclear processes may also reach the soil through direct disposal or through fallout which
intensifies the problem of soil pollution.

c. Air borne pollutants:- Pollutant are released into atmosphere from factories, automobiles,
thermal power plants and residential areas in solid or gaseous form. These pollutants may be
drifted away by prevailing winds from their source and might be washed away by precipitation
or their fallout deposits them to the soil causing toxic effects. Sulphur emitted from factories
form acid rain in the atmosphere which lowers the pH of the soil making it acidic and injurious
for plant growth. Besides, huge amounts of particulate matter and dust are emitted from cement
 74

industries, lime kilns, coal mining and transportation and thermal power plants which reach the
soils and thus pollute them by altering its chemical and physical properties.

d. Fertilizer Use:- Although fertilizers are used to enrich the soil by essential nutrients, but
excessive use can not support the microbial life which is so important to enrich the humus
essential for soil health and plant growth. Soil chemistry is changed by either making soil acidic
or alkaline and hence destroying the overall structure of the soil. Moreover, the incidences of
heavy metal accumulation also increase due to excessive use of synthetic fertilisers in the
agricultural fields.

e. Deforestation:- Removal of vegetation for getting wood, timber, forest land or mining is a
serious cause of negative soil pollution as soil gets devoid of organic matter and prone to wind
and water erosion.

3.4.2: Effects of Soil Pollution:- The main effects of soil pollution are as under:

• Pollutants cause reduction in soil fertility leading to reduced food production and
ultimately the shortage of food.

• Loss of soil that is washed awaycauses water pollution, clogging of lakes, increasing
turbidity of water and siltation of water bodies that ultimately causes loss of life.

• The destruction of natural vegetation results in accelerated rate of erosion of top fertile
soil transforming the land into sandy and rocky in nature that results in loss of
productivity and formation of deserts making the soil unsuitable for cultivation. Hence
there is decrease in the extent of agricultural land.

• Excessive use of chemical fertilizers makes the soil more acidic and saline that proves to
be harmful for soil biota and plant life.

• Nitrogen and phosphorus from the fertilizers in soil reach nearby water bodies with
agricultural runoff and cause eutrophication.

• Damage to the natural beauty and aesthetic sense of the landscape.

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• Sewage sludge has many types of pathogenic bacteria, viruses and intestinal worms
which may cause various types of diseases.
• Radioactive fallout on vegetation is the source of radioactive isotopes entering the food
chain in grazing animals cause various abnormalities.
• Chemicals or their degradation products from soil may percolate and contaminate ground
water resources.

3.5: Control of soil pollution

The process of soil formation being very slow, hence control of its pollution becomes very
important which can be achieved by taking the following measures;
• Proper soil conservation measures to minimize the loss of top soil.

• Effluents should be properly treated before discharging them on the soil

• Solid wastes should be properly collected and disposed of by appropriate methods.eg

sanitary landfills

• From the wastes, recovery of useful products should be made.

• Biodegradable organic waste should be used for generation of biogas.

• Cattle dung should be used for methane generation.Night soil (human faeces) can be used
in the biogas plant to produce inflammable methane gas.

• Microbial de gradation of biodegradable substances is also one of the scientific approches

for reducing soil pollution.

• One of the techniques for cleaning polluted soils is bioremediation.

3.5.1. Bioremediation:- it can be can be defined as any process that uses microorganisms,
fungi, green plants or their enzymes to treat contaminated soils by naturally occurring
biodegredative processes.
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Phytoextraction:- In this method inorganic contaminants are extracted and then dispersed into
atmosphere by volatilization from aerial parts through transpiration. This technique is useful in
removing mercury and selenium from polluted soils.
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SELF ASSESMENT
Short Answer Type Questions

Q.1: Explain how soil erosion can be controlled?

Q.2: Explain different sources of soil pollution.

Q.3: Write a short note on soil composition.

Q.4: Write a short note on wind erosion.

Q.5: Briefly explain different methods of soil pollution control.

Very Short Answer Type Questions

Q.1: What is bioremediation?

Q.2: Define mulching?

Q.3: what are residual soils?

Q.4: Define soil profile?

Q.5: Define strip farming,?

Objective Type Questions

1. New alluvial soils deposited by rivers every year are known as a) Khadder
b) Bhangar C) Residual soils d) Laterite soils
2. Black soils are most feasible for growing …………………..
3. Completely decomposed organic matter in soil is known as………………….
4. O horizon is usually absent in
a) Forest b) Desert c) Marsh d) Grassland
5. The name subsoil is given to
a) A horizon b) O horizon c) B horizon d) C horizon
6. Colour of red soils is due to
a) Sludge b) Iron oxide c) Humus d) Calcium
7. Vulnerability of soil to get eroded is known as
a) Erosivity b) Erodibility c) Erosion potential d) Erosion
8. Protective crop residue layer left on the surface against wind or water is
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a) Terracing b) Contour farming c) Crop rotation d) Mulching

9. Use of biological agents to treat contaminated soils is
a) Bioremediation b) Oxidation c) Skimming d) Biomagnification

References:
1. Prespectivesin environmental studies(sixth edition) by Anubha kaushik and CP

Kaushik.

2. Soil chemistry by B.K. Sharma.

3. Environmental science by Botkin and Keller.

4. Soil Analysis by P.K. Gupta.

5. Ecology and environment (2018- edition) by P.D. Sharma.

6. Internet.
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UNIT -4

Solid and Hazardous Waste Management

❖ Learning Outcomes:

Upon successful completion of this course, students will be able to:

• Learn basic concepts of solid waste management, beginning from source generation to waste
disposal in a system of municipality organizational structure.

• Develop understanding on various technological applications for processing of waste and their
disposals in various ways.

• Acquire knowledge on waste to energy productions in the perspectives of sustainable

development.

• Apply basic concepts in hazardous waste management and integrated waste management for
urban areas.

• To acquire a fair amount of knowledge on waste characterization and its management

4.0. INTRODUCTION

All living organisms like humans and other animals generate wastes in one form or other in
nearly every activity. Even in life processes
at cellular level, waste generation is a
common activity in living organisms. Any
matter that is discarded directly or indirectly
as useless, unwanted by products or residues
which no longer holds a value to the owner
is known as a waste. Solids waste is a
general term used for discarded materials
other than liquid and gaseous wastes.
Municipal solid waste (MSW), also called
Urban Solid Waste, is a waste type that
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includes predominantly household waste (domestic waste) with sometimes the addition of
commercial wastes, construction and demolition debris, sanitation residue, and waste from
streets collected by a municipality within a given area. They are in either solid or semisolid
form and generally exclude industrial hazardous wastes.

4.1.Classification of wastes
Various basis can be used to classify wastes like their origin, hazard or composition.
However, conveniently these may be classified into following categories as

• Garbage: – These include vegetable residues, meat, fruit residues which

decompose rapidly under warm weather conditions.

• Rubbish:– These include crockery, metals, glass, rubber, leather, plastic wastes
which do not decompose rapidly.

• Agricultural wastes:– These include crop residues from agricultural fields, farm
manure e.g., Rice straw, jute, cotton, sugarcane wastes etc.

• Industrial wastes:– These are produced as a result of industrial operations

e.g. sewage,paints, toxic metals flyash etc.

• Hazardous waste:– Those wastes which have an adverse effect on human, plant
and animal health because of their ignitibility, corrosivity, reactivity, toxicity etc
e.g. radioactive or nuclear wastes, explosives heavy metals etc.

• Junk :– Used things like machines, automobiles, their parts etc.

• Construction or demolition wastes:– The wastes which are generated as a result

of construction, repair or demolition of industrial, commercial or domestic
buildings such as bricks stones, dust, plaster etc. are known as construction &
demolition wastes.

• Municipal Solid Waste (MSW):– The total of all the material commonly called
trash, refuse or garbage thrown away from homes and small commercial
establishments, collected by local governments like municipalities or other local
authorities is known as a municipal waste. It is different from hazardous waste.
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• Biomedical waste:– It refers to any waste that includes anatomical waste,

pathological waste, infectious waste and other waste generated in health care
facilities and medical labs that require special handling.

4.2. Sources, composition and characterization of the solid waste

Municipal solid waste (MSW) is one of the important challenges to the environment.
Municipalities; generally; are responsible for the waste management. They have to provide an
effective and efficient system to the inhabitants. Nevertheless, they are; often; facing with
many problems beyond the ability of the municipal authority to handle the MSW . This is
essentially due to financial resources, lack of organization and complexity.

Based on the source of contributors, four common categories of solid waste are:
1. Municipal waste. 2. Industrial waste
3..Agriculture and Animal waste. 4. Hazardous waste.

3.5.2. Municipal Waste

Municipal solid waste (MSW) mainly consists of:
(a) Food wastes, commonly called garbage, are prone to decompose. They originate
from food products of animal and vegetable origin, arising out of preparation,
processing, handling, catering, and eating.
(b) Rubbish is combustible and non-combustible rejected materials other than those
mentioned above. The combustible portion (trash) consists of paper, cardboard, textiles,
plastics, rubber, etc. The non-combustible portion consists of glass, ceramics, metals, etc.
(c) Ashes and cinders originate mainly from coal, firewood, and burnt residues of other
combustible materials.
(d) Construction and demolition wastes include wide varieties of materials, mostly non-
combustible in nature. Civil works of construction, remodeling, repair works and demolition
of building structures and others that include broken pieces of bricks, stones, plasters, dirt,
sand, wooden articles, metal pieces, electrical parts, etc.
(e) Water treatment plant wastes are obtained from the water treatment plants in solid or
semisolid form, such as resins, organic waste, inorganic waste, etc.
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(f) Special wastes are uncommon materials accumulated from unpredictable and infrequent
sources, i.e., abandoned vehicles, dead animals, limbs, blood, etc. from hospitals; and that
found from street sweepings.

2.1.2.Industrial Wastes
They include the wastes produced during various industrial operations. Even though our
discussion has more emphasized on typical MSW and not the major industrial wastes, one
can not afford to overlook the contribution of some minor or small scale operations which are
located within the municipal territories to meet the daily requirements of the residents. These
are candle making, plywood manufacturing, bakeries, leather goods, rubber industries
,pharmaceutical products, canned goods, laundry trades, dairy products and photographic
products, etc. The spent solution and solid waste of these industries contains major organic
constituents. Every company should have their own solid waste handling and treatment
systems as otherwise they produce bad odour and cause problems to public health authorities.

2.1.3 Agriculture and Animal Wastes

The agriculture wastes are usually of plant origin. Plants that remain after harvesting are in huge
quantities. India has the highest livestock population in the world. Animal wastes
include the remains after slaughter and animal fascias, etc. A survey in Bombay has found that
the animal waste (1500 tons per month) constitutes the largest share followed by mineral waste
(1100 tons per month), and agriculture waste (550 tons per month).

2.1.4 Hazardous Wastes

Hazardous substances, depending on their quantity, concentration (physical or chemical),

infectious characteristics, is of potential hazard to human health. They may cause or significantly
contribute to an increase in mortality and to serious, irreversible or reversible but incapacitating
illnesses. It will also affect the animal and plant lives on a short or long-term basis. Hazardous
waste may include (a) radioactive substance (b) fuming, odorous, corrosive and toxic chemicals,
and (c) biological wastes, combustibles, flammable and explosive wastes.

Household or municipal wastes are usually generated from variable sources where different
human activities are encountered. Several studies reported that the municipal solid waste
that are generated from the developing countries are mainly from house- holds (55–80%),
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followed by market or commercial areas (10–30%). The later consists of variable

quantities generated from industries, streets, institutions and many others . Generally,
solid waste from such sources is highly; heterogeneous in nature. Thus, they have variable
physical and chemical characteristics depending on their original sources. Their
composition are yard waste, food
waste, plastics, wood, metals, papers,
rubbers, leather, batteries, inert
materials, textiles, paint containers,
demolishing and construction materials
as well as many others that would be
difficult to classify. The heterogeneity
of such generated solid waste is the
major setback in sorting and its
utilization as material. Therefore, there
is a proper need for fractionation and
sorting of these wastes before any
meaningful treatment process. Sorting and separating of such wastes are one of the most
important and traditional methods as essential steps in solid waste management to provide
data on the quality of the separated fractions for any potential utilization. Nevertheless,
the success of any designed for solid waste segregation depends mainly on the public
aware- ness and the active participation of such waste generators in the different
communities (i.e., how they follow the fundamental and principles of waste sorting and
separation).

The composition of MSW varies significantly from one municipality to another and from
country to country significantly. Such variation depends mainly on the life style,
economic situation, waste management regulations and industrial structure. The quan- tity
and the composition of the municipal solid waste are critical for the determination of the
appropriate handling and manage- ment of these wastes. Such information is essential and
useful to put up the solid waste to energy conversion facility within the municipality.
Based on the calorific value and the elemental com- position of MSW the engineers and
scientists can decide upon its utility as a fuel. Meanwhile, such information will help in
 84

predict- ing the makeup of gaseous emissions. Thereafter, this MSW is subjected to the energy
conversion technologies including gasification, incineration etc. However, the possible
hazardous substances occurring in the ash should be considered carefully. In this
respect, the composition of the waste will provide valuable information on the utility of the
material for either composting or for biogas production as fuel via biological conversion.

Meanwhile, the time has a great effect on the composition of MSW. Biodegradation
of such MSW according to the time is an important factor that governs the amount of
recyclable material particularly the organic contents.

4.3. Impacts of solid waste on environment

Solid waste can create significant health problems and a very unpleasant living environment if
not disposed of safely and appropriately. If not correctly disposed of, waste may provide
breeding sites for insect-vectors, pests, snakes and vermin (rats) that increase the likelihood of
disease transmission. It may also pollute water sources and the environment.

• Disease transmission
Decomposing organic waste attracts animals, vermin and flies. Flies may play a major role in the
transmission of faecal-oral diseases, particularly where domestic waste contains faeces (often
those of children). Rodents may increase the transmission of diseases such as leptospirosis and
salmonella, and attract snakes to waste heaps.

Solid waste may also provide breeding sites for mosquitoes. Mosquitoes of the Aedes genus lay
eggs in water stored in discarded items such as tins and drums; these are responsible for the
spread of dengue and yellow fevers. Such conditions may also attract mosquitoes of the
Anopheles genus, which transmit malaria. Mosquitoes of the Culex genus breed in stagnant water
with high organic content and transmit microfilariases (Médecins Sans Frontières, 1994),
appropriate conditions are likely to arise where leachate from waste enters pooling water.

In times of famine or food scarcity, members of the affected population may be attracted to
waste heaps to scavenge for food; this is likely to increase the risk of gastro-enteritis, dysentery
and other illnesses.
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• Pollution

Poor management of the collection and disposal of solid waste may lead to leachate pollution of
surface water or groundwater. This may cause significant problems if the waste contains toxic
substances, or if nearby water sources are used for water supplies. Where large quantities of dry
waste are stored in hot climates this may create a fire hazard. Related hazards include smoke
pollution and fire threat to buildings and people.

• Effect on morale
The effect of living in an unhygienic and untidy environment may lead people to become
demoralized and less motivated to improve conditions around them. Waste attracts more waste
and leads to less hygienic behavior in general.

7.4. Disposal of Solid Waste

The Union Ministry of Environment, Forests and Climate Change has recently notified
Solid Waste Management Rules 2016 that have replaces the old Municipal Solid Waste
management and Handling rules 2000. As per the reports of MOEF, 62 million tonnes of solid
waste is generated annually in India out of which 5.6 million tons is plastic, 0.17 is biomedical,
7.90 is hazardous and 15 lakh tonnes is e–waste. 80 % of this waste gets collected and only 22 %
of this gets treated. The new rules are now applicable beyond municipal areas and include urban
agglomerations, industrial townships, census town areas under Indian railways, airports, special
economic zones, pilgrimage, religious and historical areas etc. Some of the highlights of these
new rules are;

• Waste Segregation at source.

• Collection and disposal of Sanitary waste.

• Back Scheme for packaging waste.

• User fees to be paid by the waste generator.

• Processing and treatment of waste.

• Promotion of waste to energy.

• Promotion of waste to compost.

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• Revision of existing standards.

• Waste management in hilly areas.
• Monitoring committee to check the implementation of these rules.
• To see a way ahead.

These are the sixth category of waste management rules as it has earlier notified biomedical,
plastic, e–waste, hazardous and construction and demolition waste management rules. Solid
waste management means to minimize the amounts as well as the adverse effects of solid waste
on the environment and health before it becomes difficult to deal with it in the future. So it
involves the application of a series of ordered processes like collection, separation, processing,
disposal and utilization of solid waste. Getting rid from the solid waste generated on daily basis
is the greatest challenge for mankind. The orderly execution of the functions of collection,
processing and disposal of solid waste (SW) is a manifold task involving the following series of
activities.

7.4.1. Initial steps

In order to establish effective solid waste management in the affected area the following process
should be used
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Identify the types of waste

Identify the sources of waste

Determine the potential health hazards from waste

Determine the volume of waste generated

Identify safe collection method/s

Identify safe transportation method/s

Identify safe disposal method/s

fig.4.2. Initial steps in solid waste management

4.4. Key components of solid waste management

Solid waste management can be divided into following key components:
b) Generation
Generation of solid waste is the stage at which material become valueless to the owner and since
they have no use for them and require them no longer, they wish to get rid of them. Items which
may be valueless to one individual may not necessarily be valueless to another. For example,
waste items such as tins and cans may be highly sought after by young children.
 88

Fig.4.3. key components of solid waste management

c) Storage
Storage is a system for keeping materials after they have been discarded and prior to collection
and final disposal. Where on-site disposal systems are implemented, such as where people
discard items directly into family pits, storage may not be necessary. In emergency situations,
especially in the early stages, it is likely that the affected population will discard domestic waste
in poorly defined heaps close to dwelling areas. If this is the case, improved disposal or storage
facilities should be provided fairly quickly and these should be located where people are able to
use them easily. Improved storage facilities include:
• Small containers: household containers, plastic bins, etc.
• Large containers: communal bins, oil drums, etc.
• Shallow pits
• Communal depots: walled or fenced-in areas
In determining the size, quantity and distribution of storage facilities the number of users, type of
waste and maximum walking distance must be considered. The frequency of emptying must also
be determined, and it should be ensured that all facilities are reasonably safe from theft or
vandalism.
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d) Collection:
Waste collection is the collection of solid waste from point of production (residential, industrial
commercial, institutional) to the point of treatment or disposal. Municipal solid waste is collected
in several ways:

➢ House-to-House: Waste collectors visit each individual house to collect garbage. The user
generally pays a fee for this service.
➢ Community Bins: Users bring their garbage to community bins that are placed at fixed
points in a neighborhood or locality.
MSW is picked up by the municipality,
or its designate, according to a set
schedule.

➢ Curbside Pick-Up: Users leave their

garbage directly outside their homes
according to a garbage pick-up schedule set
with the local authorities (secondary house-
to- house collectors not typical).

➢ Self Delivered: Generators deliver the

waste directly to disposal sites or transfer
stations, or hire third-party operators (or
the municipality).

➢ Contracted or Delegated Service:

Businesses hire firms (or municipality with
municipal facilities) who arrange collection schedules and charges with

Collected MSW can be separated or mixed, depending on local regulations. Generators can be
required to separate their waste at source, e.g., into “wet” (food waste, organic matter) and “dry”
(recyclables), and possibly a third stream of “waste,” or residue. Waste that is un-segregated could
be separated into organic and recycling streams at a sorting facility. The degree of separation
can vary over time and by city. ‘Separation’ can be a misnomer as waste is not actually
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separated but rather is placed out for collection in separate containers without first being
‘mixed’ together. Often, especially in developing countries, MSW is not separated or sorted
before it is taken for disposal, but recyclables are removed by waste pickers prior to
collection, during the collection process, and at disposal sites.

e) Transportation
After collection, waste is transported to suitable places (disposal sites) for further processing. The
waste needs to be transported to the disposal sites in covered trucks in order to prevent
environmental contamination. There are various modes of transport which may be adopted and
the chosen method depends upon local availability and the volume of waste to be transported.
Types of transportation can be divided into three categories

Figure 4.4. Refuse collection containers and vehicles

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➢ Human-powered :open hand-cart, hand-cart with bins, wheelbarrow, tricycle

➢ Animal-powered : donkey-drawn cart
➢ Motorised : tractor and trailer, standard truck, tipper-truck

f) Separation or Segregation

The wastes from different sources are heterogeneous in nature and hence need to be segregated
either at the source or after collection. Usually wastes are segregated manually into organic and
inorganic category. Organic waste like leftover food, fruits, vegetables, biomass, paper,
disintegrate naturally under the influence of sun, rain, living organisms etc. while as inorganic
wastes like glass, plastic etc. need to be placed in separate containers before disposal.
Generally separation helps in recovery and reuse of materials out of the solid waste or safe and
compatible disposal of disposable materials.

g) Processing

After separation of reusable or disposable articles, various activities are applied to the waste to
prepare it for subsequent operation. Since solid waste has a great demand for space and in order
to accommodate huge amounts of solid waste, its volume needs to be reduced. Compactors are
used to reduce the volume of the waste by compressing it directly into containers. This is known
as the compaction or mechanical volume reduction. In addition the combustible wastes like
cardboard, paper rubber, food wastes, floor sweepings, plastics are subjected to incineration
(burning at very high temperature). But proper control equipment needs to be installed to avoid
contamination of environment as a result of incineration. This is known as thermal volume
reduction.
h) Disposal
The final stage of solid waste management is safe disposal where associated risks are minimized.
There are four main methods for the disposal of solid waste:
➢ Open dumping
➢ Composting
➢ Burning or incineration
➢ Recycling (resource recovery)
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i) Open Dumping

It means simply dropping the waste at some place away from the residential areas or near low–
lying areas or outskirts of the towns. This is the cheapest and most prominent method of disposal
in developing countries especially India. The organic waste disposal by such method tend to
break down and mix with top soil over a period to time and poor people who collect some reusable
or edible items sorting through the garbage earn their livelihood. But such practice encourages
public health problems caused by breeding of flies, mosquitoes, rodents or obnoxious gas
production. Moreover, open dumping requires large land areas which further intensifies the
problem of land shortage for human use.

Fig.4.5.open dumping
ii) Ocean Dumping

Oceans bring vast, huge amounts of solid waste is dumped in them every year. About 25,000
million tons including bottles, cans, and plastic containers are dumped in oceans per year.
Coastal areas including beaches are littered with non–biodegradable substances especially in
industrialized countries causing hazards to oceanic life especially the fur seals. Although the
deep ocean dumping in the abyssal zone is considered to be on the safe side but still many people
argue that little is known about such remote areas and the rare spices those inhabit such areas.
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iii) Sanitary Landfills

A sanitary landfill is a dumping pit or excavation made on the earth’s crust with of base lined
with leak proof material to prevent leaching. This method of waste disposal is controlled and
monitored very closely.This type of disposal started in 1935, in Fresno, California.
For sanitary landfills, the process starts by digging a large hole in the ground that is then lined
with thick plastic (normally 2-4 feet thick) and a layer of impervious clay. The bottom of the
landfill is also lined with a network of plumbing that functions as a collection system for any
liquids. Leachates is the term used to describe liquids that leach or leak from the landfill, and
this system collects the leachates. These components of the sanitary landfill help prevent
materials and liquids from spreading to the surrounding ground and waterways. Usually the
sanitary landfills should be cited at high grounds where water table is quite below, waste filling in
the landfill is done in the shape of pyramids to minimize the infiltration of water into the land
fill and monitoring wells to check periodically the ground water quality is encouraged

Fig.4.6. cross section of a sanitary land fill

Once the landfill is set up, waste can then be added to the landfill. Instead of simply filling the
landfill completely with waste, the landfill is organized in layers. The layers alternate between
waste and soil. This alternation of materials reduces odors and allows for more rapid decomposit
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-on which is the breakdown of materials. When a landfill is full, it is sealed and covered in a
thick layer of clay. Once the landfill has been evaluated and considered safe, it can be converted
into a park or open space for human use. It is interesting to think that a location where we put our
unwanted materials can then be turned into a location for recreation and fun.
• Issues with sanitary land fill
The largest issue associated with sanitary landfills is the risk of pollution. As waste breaks
down, Co2, CH4, H2S,NH3 gas is created, and if it escapes from the landfill, it could

pollute the air. In addition, methane gas can be dangerous if it builds up in the landfill
because it is flammable and could be explosive. Along with air pollution, sanitary landfills
also pose a threat to water systems systems. If the lining of the landfill is punctured or the
collection system breaks, leachates could travel from the landfill to the surrounding ground
and contaminate the groundwater.

Fig.4.7.different parts/components of sanitary land fill

iv) Composting

Bacterial or worm decomposition of the organic wastes in oxygen rich conditions results in the
formation of humus, manure or compost is known as composing. The organic compost
resulting from this process improves the water retaining capacity of soil, prevents soil erosion
and results in better crop yield. In this method all the organic waste, including leaves, vegetables,
wood chips lawn chippings are piled up with alternate layers of soil and turned up every week to
allow aeration to facilitate aerobic bacterial decomposition. Within a few weeks, naturally
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occurring microbes will decompose the organic matter into rich compost which is used as an
efficient soil amendment.Hence, composting is an easy and inexpensive way to dispose off
organic waste in an environment friendly way.
a. Design of composting facilities

The process model of composting facilities based on typical plant components is shown in
figure.4.8
• Conditioning of coarse input material:
The material will be crushed and seperated from contraries.
• Degradation / Decomposition unit:
Different types of process are available depending on operational capacity of the biowaste
unit (see Static operations / processes and Dynamic operations / processes).
• Conditioning of finest output material:

It is neccessary because of seperating the material from the remaining contraries.

Fig. 4.8: Process modell of the basic elements of a composting facility

At first there are waste receiving, storage (bunkers) and proportioning in the process chain
of biowaste composting. After that, the main biowaste processing starts with a visual
inspection. By the visual inspection major waste elements, which interruped the operating
procedure, should be achieved to separate. Because of health contamination by odours and
germs, a manual sorting is not recommended. 98% of all contraries are found in screening
fractions with diameters of >60 mm. Screen types are round or flat screens with round,
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square, rectangular or diamond-shaped holes. The elimination of ferrous components can be

achieved by drum magnets, overhead magnets and roller magnets with an electric or
permanent magnetc field. They can be adapted to the operating conditions because of their
flexibility in operation, design and configuration. Size reduction serves to increase the
specific surface of biowaste elements. In this way the biowaste will be decomposed for
microbial degradation and the absorption of water will be improved. For biowaste
composting, mixers can be used for efficient mixing when bulking material is processed. By
using a dynamic initial biodegradation system, the bulking material will be added to the
rotary drum directly

a) Utilisation and Quality

There is a wide range of application for fresh or finished compost, e.g. in the following fields

• Fertilizer in agriculture
• Erosion protection and land improvement in gardening and landscaping
• As a component for substrate production
• As a component for substrate for recultivation and in landscaping

Compost has many beneficial qualities:

• High level of organic substances
• High level of nutrients N, P, K, Ca and Mg
• Increasing of humus content and erosion resistance
• Increasing of soil living organisms
• Improvement of soil structure, thermal, water and nutrients balance
• Increasing of ability to retain water and reduces desiccation (sandy soils)
• Enhance soil porosity  Increasing of air and water movement 
Reducing surface erosion ( Heavy or loamy soil)

b) Benefits
The composting process as a natural waste treatment process results in al volume reduction
and has a lot of other benefits. The composting product improves the soil structure, can be
used as fertilizer and the process is very simple and sost efficient.. Some advantages have
been listed in Table 4.1
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Table.4.1.Benefits of composting process

Area Benefits
Waste treatment • natural waste treatment process
• reduces disposed waste volume and weight to be landfilled
Environmental • Improvement of the soil structure
• Fertilizer
• Volume reduction
Other benefits • cost-efficient
• decentralised applicable
• flexible process for a wide range of substrates
• no / low service
• simple incomplex application
v) Recycling
It involves collection and separation of the materials from the waste stream and their subsequent
reuse or processing to produce a marketable product. The best way to get rid from or to
minimize the effects of inorganic (non–biodegradable) wastes and to reduce the demand of raw
materials, is the recycling which means reprocessing of discarded material into new and useful
products. It is a better alternative to dumping or burning as it saves money, raw materials,
energy and space. Some recycling process involve using recycled materials for the same
process e.g. old aluminium cans are melted and recast into new cans while as other process turn
old materials into new products such as turning of old steel cans into new automobile materials.
For better recycling of the waste we need to segregate the waste into separate colour bins
because colour coding helps waste disposal agencies to distinguish different types of wastes and
easily sort them to different categories. However, some of the drawbacks of recycling are:
➢ Low cost of the virgin material than the recycled one.
➢ The recycling process depends upon waste production which can be recycled but not on
the demand.
➢ The energy consumption in recycling an item may be greater than raw material
production and some substances recovery may be beneficial for environment e.g. in
paper recycling emissions of gases like Sox, Nox may be greater than incinerating paper

waste.
➢ It needs sponsorship and large space to store recyclable material.
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vi) Incineration
Given under hazardous waste management

4.5. Hazardous Waste: Definition and characteristics

Hazardous waste is a waste with properties that make it potentially dangerous or harmful to
human health or the environment. The universe of hazardous wastes is large and diverse.
Hazardous wastes can be liquids, solids, or contained gases. They can be the by-products of
manufacturing processes, discarded used materials, or
discarded unused commercial products, such as cleaning fluids
(solvents) or pesticides. In regulatory terms, a hazardous waste The F-list (non-specific source
wastes):.The F-listed wastes are
is a waste that appears on one of the four hazardous wastes known as wastes from non-specific
sources. (Non-specific meaning
lists (the F-list, K-list, P-list, or U-list) or that exhibits one of they don't come from one specific
industry or one specific industrial
the four characteristics of a hazardous waste - ignitability, or manufacturing process.)
corrosivity, reactivity, or toxicity. However, materials can be
• The K-list (source-specific
hazardous wastes even if they are not specifically listed or wastes): This list includes certain
wastes from specific industries,
don't exhibit any characteristic of a hazardous waste. such as petroleum refining or
pesticide manufacturing, waste ater
or treatment facility
A solid waste, or combination of solid waste, which because of . • The P-list and the U-list
its quantity, concentration, or physical, chemical, or infectious (discarded commercial chemical
products): These lists include
characteristics may specific commercial chemical
products that have not been used,
(a) cause, or significantly contribute to, an increase in but that will be (or have been)
discarded. Industrial chemicals,
mortality or an increase in serious
pesticides, and pharmaceuticals are
irreversible, or incapacitating reversible, illness; or example.
• M-listed Wastes (discarded
(b) pose a substantial present or potential hazard to mercury-containing products):
This list includes certain wastes
human health or the environment known to contain mercury, such as
fluorescent lamps, mercury
when improperly treated, stored, transported, or
switches and the products that
disposed of, or otherwise managed house these switches, and mercury-
containing novelties
A useful listing of hazardous characteristics is that provided by
the United Nations (1989) as part of recommendations relating
to the transport of dangerous goods. Examples from this listing
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are given in Table -4.2

Table 4.2 - Examples of Hazardous Characteristics: Extracted From U.N. Listing (1989)

Hazardous Characteristic
U.N. Class Number
1 Explosive
3–4 Flammable
5 Oxidising
6 Poisonous/Infectious
7 Radioactive
8 Corrosive
9 Toxic (Delayed or Chronic)/Ecotoxic

4.5.1. Characteristic Hazardous Wastes

Wastes may be hazardous wastes if they exhibit any of the four characteristics of a hazardous
waste (ignitability, corrosivity, reactivity, and toxicity) .These four characteristics are:

a. Ignitability – Ignitable wastes can create fires under certain conditions, undergo
spontaneous combustion, or have a flash point less than 60°C (140°F) . A solid,
under standard temperature and pressure, that can cause fire through friction,
absorption of moisture, or spontaneous chemical changes and burn vigorously and
persistently that it creates a hazard.. Examples include waste oil and used
solvents.
b. Corrosivity – Corrosive wastes are materials, including solids, that are acids or
bases, or that produce acidic or alkaline solutions. Aqueous wastes with a pH less
than or equal to 2.0 or greater than or equal to 12.5 are corrosive. A liquid waste
may also be corrosive if it is able to corrode metal containers, such as storage
tanks, drums, and barrels.Spent battery acid is an example.
c. Reactivity – Reactive wastes are unstable under normal conditions. They can
cause explosions or release toxic fumes, gases, or vapors when heated,
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compressed, or mixed with water. Examples include lithium-sulfur batteries and

unused explosives.
d. Toxicity – Toxic wastes are harmful or fatal when ingested or absorbed (e.g.,
wastes containing mercury, lead, DDT, PCBs, etc.). When toxic wastes are
disposed, the toxic constituents may leach from the waste and pollute ground
water.

Fig. 4.9. Different types of hazards wastes

4.6. Management of hazardous wastes

Hazardous waste management involves reducing the amount of hazardous substances produced,
treating hazardous wastes to reduce their toxicity, and applying sound engineering controls to
reduce or eliminate exposures to these wastes. From a chemical engineering perspective, any
wastes, but especially hazardous wastes, are produced unintentionally. Facilities that generate the
chemicals are attempting to produce substances demanded by the marketplace, but in the process
and under the wrong circumstances these substances or their components become hazards. If the
same substance were produced intentionally, it would be a hazardous material, but not a
hazardous waste.

On generation hazardous waste is stored in safe places or containers till transported to

treatment and disposal facility. Treatment includes any method, technique, or process intended to
change the physical, chemical, or biological character or composition of any hazardous waste to
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such extend that hazardous waste is rendered less hazardous and safer to transport, store, or
dispose. Thermal Treatment is commonly used method for managing hazardous wastes. During
thermal treatment high temperature is applied to
convert hazardous waste into such a form that is
considerably less toxic, have lesser volume, and
is ready for safe disposal. Incineration is the best
examples of thermal treatment.

4.6.1. Incineration:
Incineration involves the combustion of waste in
the presence of oxygen. Incinerators are used
primarily for waste destruction and energy
recovery. Incineration converts hazardous waste
into gases and incombustible solid residue. Gases
are released into the atmosphere after passing
through a gas–cleaning system and solid residue finally dumped in a landfill. The typical
wastes that should be incinerated include waste oils, pesticide wastes, refinery wastes etc.
Incineration not only destroys the toxicity of wastes but also yield products of combustion that
are harmless. Typical incinerators include rotary kilns, Controlled air incinerators, and plasma
arc incinerator ( plasma torches).

Fig. 4.10. different components of incinerator.

a) Rotary-kiln
The rotary-kiln incinerator is used by municipalities and by large industrial plants. This design of
incinerator has two chambers: a primary chamber and secondary chamber. The primary chamber
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in a rotary kiln incinerator consists of an inclined refractory lined cylindrical tube. The inner
refractory lining serves as sacrificial layer to protect the kiln structure. This refractory layer
needs to be replaced from time to time. Movement of the cylinder on its axis facilitates
movement of waste. In the primary chamber, there is conversion of solid fraction to gases,
through volatilization, destructive distillation and partial combustion reactions. The secondary
chamber is necessary to complete gas phase combustion reactions.
The clinkers spill out at the end of the cylinder. A tall flue-gas stack, fan, or steam jet supplies
the needed draft. Ash drops through the grate, but many particles are carried along with the hot
gases. The particles and any combustible gases may be combusted in an "afterburner".

b) Fluidized bed
A strong airflow is forced through a sandbed. The
air seeps through the sand until a point is reached
where the sand particles separate to let the air
through and mixing and churning occurs, thus
a fluidized bed is created and fuel and waste can
now be introduced. The sand with the pre-treated
waste and/or fuel is kept suspended on pumped air
currents and takes on a fluid-like character. The
bed is thereby violently mixed and agitated
keeping small inert particles and air in a fluid-like
state. This allows all of the mass of waste, fuel and
sand to be fully circulated through the furnace.

c) Plasma Torches

Thermal plasma torches convert electric energy to high–temperature thermal energy by

applying a high voltage across a flowing gas stream. Plasma Torch generates Plasma. Plasma is
a mixture of ions, electrons and neutral particles. It is created by the ionization of a gas due to
the formation of a sustained electric arc by an electric current flowing through a gas stream. The
gas molecules collide with charged electrons and creating charged particles. When enough
charged particles are created, both positive and negative, the gas starts to conduct electricity.
Collisions between charged particles also occur giving off heat and forming an arc of light that
 103

is specifically plasma. Plasma processes is widely used for the destruction of hazardous waste
but this requires a high consumption of electricity. The range of temperatures (up to 5,000°C
or greater) generated by plasma torches can destroy any chemical bond and reduce it to gas
and vitrified ash. The advantage of Plasma torch over other thermal methods is that it can
generate high temperature, smaller size of the installation, and rapid start–up, However high
electricity consumption is a disadvantage.

4.7. Disposal of Hazardous Waste:–

After treatment, solid residue of hazardous waste is sent to landfill. However liquid residue is
disposed by way of deep well Injections

a) Landfills as a disposal method :

As discussed above some of the treatment processes discussed above result in residues
thatthemselves require disposal. This disposal is best carried out in properly designed
andoperated landfills. Controlled quantities of specific hazardous wastes may be broken down to
nonhazardous substances, immobilised or adequately diluted by the physical, chemical and
biochemical processes which occur in landfills accepting predominantly normal municipal
refuse. Such a practice is known as co-disposal and entails a degree of management and
monitoring usually restricted to the modern larger regional landfills.

b) Deep well injection

Deep well injection is a disposal method for hazardous waste that was introduced in the 1930’s.
Well injection’s primary purpose was initially for petroleum companies to dispose of their brine
wastes that are produced from drilling operations. Around the 1950’s it was realized that well
injections can be used for a much broader spectrum of hazardous wastes than just petroleum by-
products. Deep well injection began to appeal to a larger audience as a method that made it easy
to get rid of your waste and never see it again. This translated to an out of sight, out of mind
approach to hazardous waste disposal. The first industrial disposal well was installed in Texas in
the 1950’s. After its first introduction, deep well injection quickly became an extremely popular
method for waste disposal onto the 1960’s and 70’s. In this period of time, injection wells began
to be used for a much broader range of hazardous wastes, including chemicals, steel mill by-
products, and pharmaceutical wastes. Deep well disposal quickly took flight as companies
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realized that it was the most economical way to dispose of their waste. To this day, deep well
injection remains one of the least expensive methods for disposing of large volumes hazardous
wastes. With the drastic increase in popularity, deep well injection has seen numerous disaster
scenarios, which has led to constant changing on how they’re regulated and monitored.

• Classification.
Deep well injection is a disposal method that can be used for many different types of wastes, so
the EPA has developed a classification system to differentiate between types of wells. The
division of injection wells also helps to regulate the different types of wells to standards that best
fit the given situation. The different classes of wells and their purpose is listed in the table below.

EPA DESCRIPTION
CLASSIFICATION
CLASS I Wells used to dispose of industrial and municipal waste

CLASS II Wells used to dispose of oil and gas related wastes

CLASS III Wells used for extraction of minerals

CLASS IV Shallow wells for disposal of hazardous wastes, or radioactive

injection wells
CLASS V Wells used to dispose of non-hazardous fluids either into or above
the underground drinking water source

CLASS VI Wells used for geologic sequestration

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Fig.4.11.. Different Classes of Injection Wells In-situ (Ground Water Protection Council)

• Advantages
Deep well injection offers many distinct advantages over some of the other methods that are
commonly used for waste disposal.
➢ when done correctly, it presents no threat to surface or groundwater. Other methods such
as landfilling, incineration, or traditional wastewater treatment regimes can have very
detrimental effects when introduced to the hydrologic cycle.
➢ If a well is monitored and constructed properly, it can have little to no effect on the
surface or ground water. Deep well injection can permanently remove liquid and other
hazardous wastes from our biosphere, theoretically making the planet a healthier place to
live.
➢ When properly drilled, there should be little to no risk of waste migration to any drinking
water aquifers. One of the biggest advantages of deep well injection is the cost. When
compared to other methods like incineration, landfilling, and wastewater treatment, deep
well injection has lower lifetime costs while being able to dispose of more waste safely
 106

• Dis-advantages

While deep well injection is very popular, there are growing concerns associated with it. The
“out of sight, out of mind” mentality that deep well injection was based on has started to come
into question in a couple of different areas. There are also some concerns as to long-lasting
geologic effects of deep well injection, such as seismic activity, that have been discovered in
recent years. There have also been numerous cases of deep wells failing and causing significant
damage to the environment. In this section of the report we will discuss some of the criticisms of
deep well injections that have been presented over the years.
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SELF ASSESMENT
Long Answer Type Question
Q.1. Define Solid waste. Describe its various sources in detail?
Q.2. Give detailed account of different methods of solid waste disposal.
Q.3. What is a hazardous waste? What are its different characteristics?
Q.4. Explain different methods employed for management of hazardous waste.
Q.5. Solid waste management is necessary. Explain.

Short Answer Type Questions

Q.1. Define a waste. Give its classification.
Q.2. Describe briefly the impacts of solid wastes on environment.
Q.3. Write a short note
(i) Composting (ii) Recycling
Q.4. Describe briefly a sanitary landfill.
Q.5. What is a biomedical waste? How it can be managed?
Q.6. Write short notes on
(i)Plasma torch incineration (ii) Deep well injection
Very Short Answer Type Questions
Q.1. What is garbage?
Q.2. Define e– waste.
Q.3. What do you mean by rubbish?
Q.4. Define incineration.
Q.5. Give two advantages of recycling?
Q.6. What are the impacts of open dumping?
Objective Type Questions
Q.1. The waste which can decompose easily under warm conditions is known as
(i) e–waste (ii) Garbage (iii) Rubbish (iv) Junk
Q.2. Waste that has substantial or potential threat to human health is known as……….
Q.3. Waste generated in medical facility or health care institutes is known as……………
Q.4. Dumping pit made in earth’s crust with a leak proof lining is
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(i) Sanitary landfill (ii) Mine(iii) Well (iv) overburden

Q.5. The reprocessing of discarded material into new and useful products is
(i) Reducing (ii) Re–using (iii) Replenishing (iv) Recycling
Q.6. Solid waste management and handling rules are designed by
(i) SPCB (ii) Municipal commission
(iii) MOEF (iv) Forest department
Q.7. Plasma torch is used to treat which type of waste
(i) Garbage (ii) Hazardous waste
(iii) Scrape (iv) Slag
Q.8. Which among the following is a suitable method for waste disposal
i) Sanitary landfill (ii) Open dumping
(iii) Combustion (iv) Ocean dumping
Q.9. Which colour dustbin is used for collecting hazardous wastes
i) White (ii) Yellow (iii) Red (iv) Black
Q.10. Sanitary landfills generate which type of gas
(i) Nitrogen (ii) Methane (iii) CO2 (iv) hydrogen

REFRENCES

1.Adams, John (1999) Managing Water Supply and Sanitation in Emergencies. Oxfam: Oxford.

2.Ali, Mansoor, Cotton, Andrew and Westlake, Ken (1999) Down to Earth: Solid waste
disposal for low-income countries. WEDC, Lougborough University: UK.

3.Cairncross, S. and Feachem, R. (1983) Environmental Health Engineering in the Tropics: An

introductory text. John Wiley & Sons, Chichester.

4.Davis, Jan and Lambert, Robert (1996) Engineering in Emergencies: A practical guide for
relief workers. RedR / IT Publications: London.Médecins Sans Frontières (1994) Public
Health Engineering in Emergency Situation. Médecins Sans Frontières: Paris.

5. Reed, R. and P.T. Dean, P.T. (1994) Recommended Methods for the Disposal of Sanitary
Wastes from Temporary Field Medical Facilities Disasters Vol 18, No 4.
 109

Unit 5 Biodiversity Management

❖ Learning outcomes;

After reading this chapter the students will be able to answer the following;

• Definition of biodiversity and its importance.

• Different threats posed to the present global biodiversity
• Different threat categories as specified by IUCN
• Methods of conserving biodiversity

5.1 Biodiversity:

According to IUCN. UNEP -1992 biodiversity is defined as totality of genes, species and
ecosystems of a region. Richness in variety and variability of species of all living organisms
present on this planet is also known as Biodiversity. All these verities of living organism, their
genes, ecosystem, tropic levels, niches, ecological process etc. make this world a beautiful place
to live. Areas which are having high endemism with greater degree of threat from humans. There
are three levels of biodiversity as;

a) Genetic diversity. It represents variety of different genes within individual species of

living organisms. The difference could be in alleles (different variants of same gene), in
entire genes (the traits for particular characters) or in chromosomal structures. Genetic
diversity enables a population to adapt to its environment and to respond to the natural
selection. More the genetic diversity, the better a species can adapt to the changed
environmental conditions. The amount of genetic variation stands a base for evolution of
a new species. It plays an important role in maintaining a diversity at species and
community levels
b) Species Diversity:- it represents the total number of different kinds of organisms ranging
from microorganisms to multicellular organisms together represent the species diversity.
It involves variety of species within a community or a region. Simplest measure of the
species diversity is the species richness i.e., a count of number of species present in an
area and species evenness i.e. the number and kind of species as well as the number of
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individuals per species. Thus every organism and their different varieties is included
under species diversity.
c) Ecosystem diversity:- It includes different types of ecosystems whether small or large
present on planet earth. Ecosystem diversity has three perspectives; alpha beta and
gamma diversity and it describes the number of niches, trophic levels and various
processes that sustain ecosystem functions in terms of energy flow and recycling of
nutrients. The number of habitats or ecosystems vary within a geographical area that
gives rise to different organisms inhabiting these areas. e.g. Rain forests, Savannas,
Deserts, Lakes etc. are different ecosystems where species evolve and live. Hence the
number of ecosystems present in a region is also a measure of biodiversity. About 1.8
million species are known and to the scientists in the present day world out of the total
which is believed to vary from 1.5 to 50 million. Hence most of the species are yet to be
identified and authenticated for further use and investigation by the scientific community.
d) Biodiversity hotspots: Areas with large number of endemic, rare and threatened species
found in relatively small area but facing serious threat of habitat loss from human actions is
known as a biodiversity hotspot (Mayers 1990) . it means area having maximum endemism
and threat. These hotspots now cover 1.4% of the earth’s land area and contain about 44% of
all vascular plants and 35% of all species in four major vertebrate groups. Some of these
hotspots are present in Madagascar, Brazil, West Ecuador, West Amazon, Malaysia, East
Himalaya, Australia, Central Chile, Tanzania, Philippines , Sri Lanka and India. Recently in
2005, nine more hotspots were added by conservation International making the total to 34
hotspots. These 34 hotspots now contain 75% of world’s most threatened mammals, birds,
amphibians, and about 50% of all plants. in the form of Mangroves, wetlands and swamps,
four areas in India like Eastern Himalayas, Western Ghats, Andaman and Nicobar islands are
considered as hotspots.

5.2 Importance of Biodiversity

Biodiversity is important in many ways as it gives food, medicines, drugs, rubber, fiber etc.
along with many ecological services free of charge that are responsible for maintaining
ecosystem health and human welfare. Biodiversity is essential for maintenance and utilization of
goods and services from ecosystems and from the individual species. These benefits include
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maintaining the composition of the atmosphere, climate control by oceanic and forest systems,
formation and protection of soil, conservation and purification of water etc. the importance of
biodiversity could be briefly summarised as;

• Consumptive use:- It involves goods such as fuel wood and other that are consumed
locally and do not appear in commercial markets whether national or international or
When biodiversity or its products are consumed by people locally and such products are
not assigned a price in the commercial markets, it is considered to be its consumptive
value.
• Productive use:- The products obtained by people from biodiversity and sold in markets
such as fruits, nuts, resigns, leaves etc. indicates the productive value of biodiversity.
• Scientific use:- many organisms are used in scientific research programs to know the
truth of nature and thousands of organisms provide us with useful drugs and medicines
like antibiotics from fungus, bacteria etc. it represents the scientific value of biodiversity.
• Aesthetic use:- The beauty of biodiversity attracts and provides relief, psychological and
emotional restoration is known as aesthetic value. Many people enjoy fishing, hiking,
wild life watching and other activities which are nature based observing and be in
contact with biodiversity has got religious significance for many people as they call it
natures creation.

5.3 Threats to Biodiversity

Due to human interventions, there are thousands of species becoming extinct in the present day
world. If such trend continues, millions of plants, animals and microbes may be destroyed in near
future as 1/3 rd to 2/3rd of all current species could be extinct by the mid of 21 current (biologist
Paul Ehrlich). Specialized habitat and food requirements, harvest pressures, specialized breeding
habits, body size, inability to fly etc. are also factors that endanger a species. However, the main
human impacts which threaten biodiversity are:

a) .Habitat destruction:- destruction of habitats by humans is the largest causes of loss

of biodiversity. The greatest destruction of biological communities is caused due to
expansion of human activities and human population. As per JUCN, UNEP- report
(1986), more than 50% of the wild life habitats have been destroyed in the old world
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tropical countries and there are high rates of destruction going on in Asian countries
like Sri Lanka, Bangladesh and India too. Most of the habitat destruction has been
caused in recent times due to rapid expansion of human population and human
activities like mining, deforestation, expansion of agriculture, constructions, all have
caused a great threat to the world biodiversity.
b) Pollution of the habitat:- Pollutants have a disastrous effect on biological
communities, the most common evident causes of which are linked to pesticides,
industrial and automobile emissions, wastes etc. and these factors have destroyed the
global biodiversity to a larger extent.

c) Introduction of exotic species:- species which are not the natural members of a
community but have been introduced into that community arte known as exotic species.
These may be free from diseases, parasites and competition in the newly introduced area
and may become super aggressive. Such successful establishment of the exotic species
may kill the native species to the point of extinction by aggressively dominating the area
or may change the habitat conditions of the new area so that the native species could no
more persist.

c) Diseases:- Organisms are more prone to diseases when under stress or under captivity
or are confined to a small geographical area. Human activities like plant introduction may
increase the incidences of diseases to wild species e.g. American chestnut which was
abundant on the Appalachian mountains once in 1940’s. A nursery stock from china
carried a fungal blight to US and within four decades the chestnut has almost disappeared
from these mountains because of the epidemic caused by the fungal blight. This has lead
to the removal of this valuable species from the global biodiversity list.

d). Over overexploitation:- overexploitation of valuable species usually causes the

extinction of that very species at a much greater pace. Market hunting gives rise to
smuggling of furs, Hades specimens, teeth, tusks, skin etc. to have maximum gains.
Unsustainable methods of harvesting, international trade of species also exploits the
species to the point of extinction or reduces the size of population to a point where from
its recovery is very much difficult e.g. 200 yrs ago, the Passenger pigeon, worlds most
abundant bird inhabiting Eastern North American was drawn to extinction in 1900
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because of hunting pressure and habitat destruction causing the complete removal of this
species from the globe.

e) Shifting cultivation:- people in several developing countries earn their lively hood
through shift cultivation or ‘Jhum’ cultivation where plots of natural vegetation are burnt
and the cleared patches are cultivated continuously for 2-3 years and no inputs like
fertilizers and manures are used to maintain its fertility. As a result the plots are
abandoned as the fertility of the plot goes down and new patches are cleared and used in
the similar fashion for cultivation. Thus more and more plots are cleared and used for
cultivation and abandoned after few years. This also leads to loss of so many species
from the vegetation of that area.

5.4 Concept of Threatened species

A threatened species is defined as any species which is likely to become an endangered one
within the foreseeable future. These are continuously reduced in number. some species of
animals, plants, fungi etc. which are vulnerable to endangerment in the near future. The IUCN
prepares a list (Red List) that are facing the risk of extinction right from 1963. It uses a set of
criteria relevant to all species and all regions of the world, to evaluate the extinction risk of the
species and subspecies. It provides information about the degree of need of conservation to the
public and the policy makers. It is important in providing awareness about the importance of
threatened biodiversity, identification of endangered species, providing a global index of decline
of biodiversity so that conservation is done at an earliest possible time.

According to IUCN threatened species are of following categories as;

a) Extinct:- Species is extinct when the last individual on earth has died or when the last
surviving member of a species dies, it is said to be extinct. None of its members occurs in
the world.
b) Critically Endangered:- these face high risk of extinction in the immediate future, e.g.
Asiatic cheetah, Red wolf, Chinese alligator, Kashmiri stag, African wild Ass etc, or
when the best available evidence indicates that its population size is not more 250
individuals and has suffered a considerable reduction in its geographical range and is
therefore facing a high degree of threat.
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c) Endangered species:- The species whose population is facing a high risk of becoming
extinct because of its few in number or threatened by changing environmental conditions
or predication parameters or the taxa which are in danger of extinction and whose
survival is unlikely if the casual factors continue to operate. This group includes the taxa
whose numbers have been reduced to a critical level or whose habitats have been so
drastically reduced that they are deemed to be in immediate danger of extinction.
Example of endangered species are snow leopard, Asiatic lion, African penguin, Blue
whole, African wild dog etc.
d) Vulnerable:- species which are likely to be endangered in the near future if the casual
factors continue operating are known as vulnerable. Included are taxa of which most or
all populations are decreasing because of over-exploitation, extensive or habitat
destruction. e.g. clouded leopard, polar bear.
e) Near threatened:- those species which do not fit for either vulnerable, endangered or
critically endangered but are very close to qualify for a threatened category in the near
future are known as near threatened.
f) Data Deficient:- When the data about a species is so much deficient that it is difficult to
make a direct or indirect assessment of its risk of extinction or it is difficult to put it in
any of the categories.

5.4.1. Causes of threat:

Extinction and endangerment can occur naturally as a normal process in the course of evolution.
It can be the result of a catastrophic event such as natural disasters, environmental heating and
cooling, diseases. Today the endangerment and extinctions of species caused by humans are 100
to 1000 times the nature’s normal rate. So most of the threat to the modern living world are
caused by humans. Several species are becoming endangered or extinct each year either due to
natural reasons or by human activities. Through evolutionary processes, new species arise by
speciation, thrive well when they are able to find and exploit an ecological niche and older
species which are no longer able to survive in changing condition or superior competitions
become endangered or eventually extinct.

Some of the major causes of loss of species are as follows;

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a. Habitat loss:- Dwelling place of an organism is its habitat. But habitat is not simply a
home, it also is the place where an individual finds food, and raises its off springs. Them
of course those babies need room to grow up, spread out and live their own lives. The
trouble is humans take up a lot a space not only build houses in wild habitats but clear
forests, make fields where farming can be done to feed the ever increasing population,
drain water bodies, use chemicals in the agricultural practices which enter into the food
chains and disturb the ecosystems. So, due to overpopulation most of the habitats are
snatched from the organisms leading to sacristy of food or endangerment or even
extinction.
b. Introduction of exotic species:- Exotic species are the species which are not the natural
members of the population under consideration. They are introduced into the new
environment by way of human activities either intentionally or accidently. They appear to
be foreign to the native species, may cause no problem or may start causing catastrophes
to the native species by preying on them or by competing for resources which ultimately
can endanger the survival of native species and can cause their extinction.
c. Over exploitation; some species are threatened with danger of extinction because of
over exploitation as the rates at which species are used for commercial, domestic or trade
purposes are quite higher that the rates of their renewal e.g. rhino and tigers are being
over exploited for traditional medicinal purposes. Moreover, hunting for trade purposes
also causes a ruthless decline in the wild populations of species and making them more
vulnerable to extinction.
d. Diseases:- Disease can also drive the species to become endangered. Presence of man
and higher machinery in wild areas make sp to abandon those occupied areas even if the
habitat is not destroyed disturbance during nesting period causes profound harm to the
species and ultimately the species faces endangerment and severe threat in future.
5.5 Biodiversity Conservation;
Biodiversity is very important for the survival of the mankind. It is extremity important for the
ecosystem services and goods that human societies derive from the natural world. Therefore
biodiversity loss threatens the achievement of all the millennium development goals as well as
the very existence of mankind. As we gradually come to know, how serious the biodiversity
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losses have become we have to adopt policies to protect these irreplaceable loss of valuable
species.

Conservation may be defined as the management of biosphere so that it may yield sustainable
benefits to both present generation as well as future generations. Thus, conservation is the
practice of preservation, maintenance, wise utilizations, restoration and enhancement of the
natural environment.
Objectives of conserving Biodiversity:
• Protection of biodiversity from extinction.
• Wise use of biodiversity services
There are two methods used for rehabilitation and conservation of biodiversity as;
1. On site conservation:- This type of conservation method includes conservation and
maintenance of plants and animals in their native ecosystems or natural habitats where they
naturally occur. In- situ conservation includes declaring such natural habitats as protected areas
of different categories such as National Parks, Sanctuaries Biosphere reserves, Sacred groves,
Heritage sites etc. as per IUCN. A protected area is an area of land/sea specially set aside or
dedicated to the maintenance and protection of biodiversity and for natural and associated
cultural resources and managed through legal or other effective measures.

A. National Park:- National park is a geographical area which is important from ecological
faunal, floral, economic, geomorphological and zoological point of view for the purpose of
protecting and propagation or developing wild life and its environment there in. national
parks are hitched to the habitat for a particular wild animal species and such ecosystem are
not heavily altered by humans, protected by national governments and the boundaries
circumscribed by the state legislation. It ensures high degrees of protection as the activities
like hunting, fuel wood collection, extraction of other resources, grazing or agricultural
activity are not permitted in such area. There are about 104 National parks in Indian.
Organisms are under full protection in these areas.
b. Sanctuaries:- A sanctuary is meant for the conservation of the wild animals, only. It is an
area where killing, hunting, shooting, capturing of any species of bird or animal is prohibited
except by or under the control of the highest authority and whose boundaries should be
sacrosanct as far as possible. Hence, the sole aim of sanctuary is the provision of maximum
protection, preservation and conservation of the wild animals as it is generally species
oriented. The degree of protection in a sanctuary is less than that of National park as the
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activities like grazing, wood collection, resources extraction, agriculture or even human
settlements are permitted in such an area. There are about 516 sanctuaries presently in India
established in different states.
Table.5.1Details of national parks and sanctuaries MOEF 2012.

S.No. Name of the state/ UT Number of Number

national parks of sanctuaries
1. Andhra pradesh 6 21
2 Arunachal Pradesh 2 11
3 Assam 5 18
4 Bihar 1 12
5 Chattisgrah 3 11
6 Goa 1 6
7 Gujarat 4 23
8 Haryana 2 8
9 Himachal Pradesh 5 32
10 Jammu Kashmir 5 15
11 Jharkhand 1 11
12 Karnataka 5 22
13 Kerela 6 16
14 Madhya Pradesh 9 35
15 Maharashtra 6 35
16 Manipur 1 1
17 Meghalaya 2 3
18 Mizoram 2 3
19 Nagaland 2 18
20 Orsisa 2 18
21 Punjab 0 12
22 Rajasthan 5 25
23 Sikkim 1 7
24 Tamil nadu 5 21
25 Tripura 2 4
26 Uttar pradesh 1 23
27 Uttrakhand 6 6
28 West Bengal 5 15
29 Andman and nicobar 9 96
30 Chandigrah 0 1
31 Dadar and nagar haveli 0 1
32 Lakshadweep 0 1
33 Daman and diu 0 1
34 Delhi 0 1
35 Puducherry 0 1
Total 103 515
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c. Biosphere Reserves:- Biosphere reserve programme was launched by UNESCO in 1971

under its MAB (Man & biosphere) programme to conserve in situ all forms of life along with
its support systems in totally. A biosphere reserve is an international network of preserved
areas designated by UNESCO as these are important centres of biodiversity with research
and monitoring activities being conducted with local community participation with the aim to
protect and preserve healthy natural systems threatened by anthropogenic activities.
Presently, 425 biosphere reserves have been established in 95 countries with 14 being setup
in our country e.g. Nilgiris, Nandadevi, Kaziranga, Manas, Kanha, Sunderbans, Gulf of
mannar etc. Hence, it includes protected areas with characteristic ecosystems and
surrounding lands managed to ensure conservation and sustainable use of natural resources.
These may be terrestrial or coastal ecosystem which are internationally recognized within the
framework of UNESCO and managed for their protection and study.

B. Ex- Situ Conservation:- When the conservation is ensured outside its habits under human
care, it is termed as ex-situ conservation. Here the organism is assured of water, food, shelter,
health care etc. by human interventions as organism is kept under human captivity. This method
involves the following ways;
a. Botanical Gardens:- these are those areas where plants are kept safe when these face
a severe threat in the wild. There are 1500 botanical gardens and arboreta in the world
containing more than 80000 species. Many of these now have seed bank and tissue
culture facilities and other ex-situ technologies. The conservation of wild relatives of
crop plants and other threatened species provides the plant breeders a readymade source
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of genetic material. These plants can latter on be used to restore degraded lands and can
be reintroduced in their wild habitats to restock their depleted populations in those
degraded areas.
b. Seed Banks: - Seed banks are places where seeds are deposited into secure storage
with the intention of withdrawing them in the future when needed i.e. when certain crops
die out or are destroyed a seed bank stores seeds to preserve genetic diversity of genes
that plant breeders need to increase yield of crops, disease and pest resistance drought
tolerances nutritional quality of plants used in agriculture seeds are living parts of a crop
plant and keeping them viable for a long time requires proper storage conditions such as
temperature and moisture.
c. Gene Banks: - The genetic diversity of our crops is preserved in the form of seeds or
cuttings in case of vegetatively reproducing plants and subsequently this material is made
available together with other important information for use in research and plant breeding
in future. Thus, gene banks are biorepositories where biological material is collected,
stored and catalogued to be made available for distribution. The gene banks may be in the
form of seed banks where seeds and spores are preserved, tissue banks where buds
meristematic cells (in case of seedless plants) are preserved through arrangements of light
and temperature in a specific nutrient medium, cryobank where plant material like seeds
or embryos is preserved at a very low temperature of -1960C in liquid Nitrogen and field
gene banks where plants are planted for conservation of genes in a man engineered
ecosystem.
d. Cryopreservation:- Cryopreservation is a technique where cells, tissues, organelles,
organs etc susceptible to damage are preserved by cooling to very low temperatures (-
80oc using solid CO2 or mostly using liquid Nitrogen at -1960C). At such temperatures,
most of the enzymatic activities which might cause damage to the biological material are
effectively stopped and the genetic material is stored with an aim to conserve the breed
and to preserve structurally intact cells and tissues. Thus, all the biomaterial preserved by
this technique could be very useful for future as basis of ex-situ conservation of
threatened plants and animals species.
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SELF ASSESMENT

Short Answer Type Questions

Q.1: Write short notes on a) sanctuary b) sacred grove

Q.2: Give a brief account of conservation.

Q.3: What is ex-situ conservation? How it can be achieved?

Q.4: Give the concept of endangered species.

Q.5: Write short notes on a) species diversity b) habitat destruction

Very Short Answer Type Questions

Q.1: Define exotic species.

Q.2: Write the names of two critically endangered species of plants?

Q.3: What is a hot spot?

Q.4: Name few national parks of your state.

Q.6: What is a shifting cultivation?

References

1. Ecology and Environment- P D Sharma. Rastogi Publications, Meerut.

2. Ecology- P N Michael.CBS Publishers & Distributors Pvt. Ltd, India.

3. Environment and Ecology – Majid Hussain. Access Publishing India Pvt.Ltd., New Delhi.

4. Environmental Biology- P S VERMA and V K Agarwal. S.Chand& Company Ltd., New

Delhi.

5. Fundamental Concept in Environmental Studies- D D Mishra. S.Chand& Company Ltd.,

New Delhi.

6. Living in the Environment-G. Tyler Miller and Scott E. Spoolman. Brooks/Cole,

Belmont,USA.
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UNIT 6

Module: Global Environmental Issues

Learning Outcome
❖ The module will help in developing the understanding in students about
Global environmental Problems, its causes, effects, & control measures
❖ The module will help in developing the understanding in students about
the possible control measures of Global Environmental Problems at local,
regional, national and international level

6. The Atmosphere and Ozone Layer

The small blue and green planet we call home is a very special and unique place. We live on the
only planet in our solar system and possibly in the galaxy where life is known to exist. All life
exists within thin film of air, water, and soil about 15 km deep. This spherical shell of life is
known as the biosphere. The biosphere can be divided into three layers; the atmosphere (air), the
hydrosphere (water), and the lithosphere (rock and soil). It is the unique attributes of the Earth’s
atmosphere that allow it to be a habitable place for humans, animals, microbes and plants as we
know them

Our Mother Earth is currently facing lot of environmental concerns. The environmental
problems like global warming, acid rain, air pollution, ozone layer depletion, water pollution,
and climate change. These environmental problems affect every human, animal, religion and
nation on this planet.

6.1 Ozone Layer Depletion as a Global Environmental Concern

6.1.1 History of ozone Discovery

In 1785, the Dutch chemist Martinus van Marum was conducting experiments involving
electrical sparking above water when he noticed an unusual smell, which he attributed to the
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electrical reactions, failing to realize that he had in fact created ozone. A half century later,
Christian Friedrich Schönbein noticed the same pungent odour and recognized it as the smell
often following a bolt of lightning. In 1839, he succeeded in isolating the gaseous chemical and
named it "ozone", from the Greek word ozein (ὄζειν) meaning "to smell". For this reason,
Schönbein is generally credited with the discovery of ozone. The formula for ozone, O3, was not
determined until 1865 by Jacques-Louis Soret and confirmed by Schönbein in 1867.

6.1.2 Ozone is a gas that is naturally present in our atmosphere. Each ozone molecule contains
three atoms of oxygen and is denoted chemically as O3.

(Figure6.1) The ozone molecule . (Source: UCAR (Randy Russell)

Ozone is a gas that is naturally present in our atmosphere. Because an ozone molecule contains
three oxygen atoms, it has a chemical formula of O3. The word ozone is derived from the Greek
word ozein, meaning “to smell.” Ozone has a pungent odor that allows ozone to be detected
even in very low amounts.
Ozone is 1.5 times as dense as oxygen; at -112° C (-170° F) it condenses to a dark blue liquid,
which freezes at -251.4° C (-420° F). The gas decomposes rapidly at temperatures above 100° C
(212° F) or, in the presence of certain catalysts, at room temperatures. Although it resembles
oxygen in many respects, ozone is much more reactive; hence, it is an extremely powerful
oxidizing agent, particularly useful in converting olefins into aldehydes, ketones, or carboxylic
acids. Because it can decolorize many substances, it is used commercially as a bleaching agent
for organic compounds; as a strong germicide it is used to sterilize drinking water as well as to
remove objectionable odours and flavours.
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6.1.3 Ozone location. Most ozone (about 90%) is found in the stratosphere, a region that
begins about 10-16 kilometers (6-10 miles) above Earth’s surface and extends up to about 50
kilometers (31 miles) altitude . The stratosphere begins at higher altitudes (16 kilometers) in the
tropics than in the Polar Regions (10 kilometers). Most ozone resides in the stratosphere in what
is commonly known as the “ozone layer.” The remaining ozone, about 10%, is found in the
troposphere, which is the lowest region of the atmosphere between Earth’s surface and the
stratosphere.
6.1.4 Ozone Abundance. Ozone molecules have a relatively low abundance in the
atmosphere. In the stratosphere near the peak of the ozone layer, there are up to 12,000 ozone
molecules for every billion air molecules (1 billion = 1000 million). Most air molecules are
either oxygen (O2) or nitrogen (N2) molecules. In the troposphere near Earth’s surface, ozone is
even less abundant, with a typical range of 20 to 100 ozone molecules for each billion air
molecules. The highest surface values are a result of ozone formed in air polluted by human
activities.
As an illustration of the low relative abundance of ozone in our atmosphere, one can consider
bringing all the ozone molecules in the troposphere and stratosphere down to Earth’s surface
and uniformly distributing these molecules into a gas layer over the globe. The resulting layer of
pure ozone would have a thickness of less than one half centimeters (about one-quarter inch).
6.1.5 Ground-level ozone
Tropospheric, or ground level ozone, is not emitted directly into the air, but is created by
chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds
(VOC). This happens when pollutants emitted by cars, power plants, industrial boilers, refineries,
chemical plants, and other sources chemically react in the presence of sunlight. Ozone is most
likely to reach unhealthy levels on hot sunny days in urban environments, but can still reach high
levels during colder months. Ozone can also be transported long distances by wind, so even rural
areas can experience high ozone levels.
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(Figure 6. 2): Sources of emissions responsible for the formation of Ozone in troposphere
6.1.6 Bad ozone. Ozone is also formed near Earth’s surface in natural chemical reactions
and in reactions caused by the presence of human-made pollutant gases. Ozone produced by
pollutants is “bad” because more ozone comes in direct contact with humans, plants, and
animals. Increased levels of ozone are generally harmful to living systems because ozone reacts
strongly to destroy or alter many other molecules. Excessive ozone exposure reduces crop yields
and forest growth. In humans, ozone exposure can reduce lung capacity; causes chest pains,
throat irritation, and coughing; and worsen pre-existing health conditions related to the heart and
lungs. According to the Environmental Protection Agency, exposure to ozone levels of greater
than 70 parts per billion for 8 hours or longer is unhealthy. Such concentrations occur in or near
cities during periods where the atmosphere is warm and stable. The harmful effects can include
throat and lung irritation or aggravation of asthma or emphysema.
6.1.7 Stratospheric ozone. Stratospheric ozone is naturally formed in chemical reactions
involving ultraviolet sunlight and oxygen molecules, which make up 21% of the atmosphere.
The existence of ozone layer was discovered by the French Physicists, Charles Fabry and
Henri Buisson in 1913. It is located in the lower part of the stratosphere approximately between
the altitudes of 15 and 35 km. Concentration of ozone at its maximum is 10 ppm at an altitude of
25-30 km. Between the altitudes of 15 and 40 km, its concentration ranges from 2 to 8 ppm.
Concentration of ozone is maintained at their levels in the above altitudes by “ozone-oxygen”
cycle. Photochemical mechanisms in ozone- oxygen cycle were studied by the British Physicist,
Sidney Chapman in 1930.
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(Figure 6.3) Stratospheric ozone production.

When ultra-violet radiation strikes the oxygen molecule, O2, it splits the molecule into two
individual oxygen atoms (O and O). The reactions and wavelengths of the ultra violet radiation
in which the reactions take place are described below:

The atomic oxygen thus produced will combine with un-split oxygen molecule (O2) to produce
ozone molecule (O3) once again. In this reaction a third body, M plays a crucial role in absorbing
the excess energy liberated. This M may be a N2 or another O2

Thus formed ozone will be split by striking ultra- violet radiation at the wavelength around 308
nm into a molecule of O2 and an atom of oxygen.

By this ozone-oxygen cycle, the concentration of ozone is maintained. The actual concentration
of ozone is determined by the rate of its formation and its destruction.

The amount of ozone present in the stratosphere is measured by simple spectrophotometer from
the ground. This instrument was developed by the British meteorologist, G.M.B. Dobson who
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explored the properties of ozone layer in detail. Total amount of ozone in a column overhead is
measured and expressed in “Dobson units” named in honour of G.M.B. Dobson

6.1.8 Good ozone. Stratospheric ozone is considered “good” for humans and other life
forms because it absorbs ultraviolet (UV)-B radiation from the Sun. The ozone layer resides in
the stratosphere and surrounds the entire Earth. UV-B radiation (280- to 315-nanometer (nm)
wavelength) from the Sun is partially absorbed in this layer. As a result, the amount reaching
Earth’s surface is greatly reduced. UV-A (315- to 400- nm wavelength) and other solar radiation
are not strongly absorbed by the ozone layer. Human exposure to UV-B increases the risk of skin
cancer, cataracts, and a suppressed immune system. UV-B exposure can also damage terrestrial
plant life, single cell organisms, and aquatic ecosystems. If not absorbed, UV-B would reach
Earth’s surface in amounts that are harmful to a variety of life forms. In humans, as their
exposure to UV-B increases, so do their risk of skin cancer cataracts, and a suppressed immune
system increases.

(Figure 6.4)UV-B protection by the ozone layer.

The UV-B exposure before adulthood and cumulative exposure are both important factors in the
risk. Excessive UV-B exposure also can damage terrestrial plant life, single-cell organisms, and
aquatic ecosystems. Other UV radiation, UV-A, which is not absorbed significantly by ozone,
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causes premature aging of the skin. The absorption of UV-B radiation by ozone is a source of
heat in the stratosphere. This helps to maintain the stratosphere as a stable region of the
atmosphere with temperatures increasing with altitude. As a result, ozone plays a key role in
controlling the temperature structure of Earth’s atmosphere.

6.2 Ozone Depletion:-

In 1974, Mario Molina and Sherwood Rowland pointed out the potential for O3loss associated
with rising atmospheric concentrations of chlorofluorocarbons (CFCs). CFCs are not found in
nature; they were first manufactured for industrial purposes in the 1930s and their use increased
rapidly in the following decades. During the 1970s and 1980s, atmospheric concentrations of
CFCs rose by 2-4% yr-. CFC molecules are inert in the troposphere; they are therefore
transported to the stratosphere, where they photolyze to release Cl atoms. For example, in the
case of CF2Cl2 (known by the trade name CFC-12):

Reactions

The Cl atoms then trigger a catalytic loss mechanism for O3 involving cycling between Cl and
ClO (the ClOx family). The sequence is similar to that of the NOx-catalyzed mechanism:

The catalytic cycle is terminated by conversion of ClOx to non-radical chlorine reservoirs, HCl
and ClNO3. The lifetime of HCl is typically a few weeks and the lifetime of ClNO3 is of the
order of a day. Eventually these reservoirs return ClOx

Ozone depletion means reduction or thinning of the ozone layer due to both anthropogenic as
well as natural activities. But so far as natural process is concerned, there exists a dynamic
equilibrium between production and decomposition of ozone molecules and this therefore does
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not upset the ozone equilibrium. However, if present situation is concerned, the balance has been
upset mainly by anthropogenic processes which share a general mechanism

Second and third Chlorine radical may get formed which in turn may further cause ozone
destruction. The first signs of ozone depletion were observed over Antarctica in 1985 and were
called as ozone hole i.e. thinning of O3 over the South Pole. The main cause of the ozone
depletion is the wide spread use of CFC’s which were first introduced in 1930 in USA to replace
toxic and inflammable refrigerants like methyl chloride, propane etc to serve refrigeration, air
conditioning, clean solvents in fast food packing, dry cleaning, sterilizing surgical equipment’s
etc. In addition CF2ClBr were used as fire extinguishers and they cause 10 times greater damage
to ozone as compared to CFC’s .Besides burning coal, oil and increased used on nitrogenous
fertilizers, supersonic jets and space shutters are also contributing to the ozone layer depletion.
CFC’s are inert in troposphere, but upon reaching to stratosphere under the influence of UV
radiations, these release Cl atoms that convert thousands of ozone molecules to oxygen.

(Figure 6.5) CFCs destroy ozone (O3) when a chlorine atom breaks loose from the CFC
and interacts with the oxygen atoms in the ozone molecule.

6.3 Emissions from human activities which lead to ozone depletion

Unfortunately, the ozone layer that protects life on Earth from harmful UV light has been
depleted due to human activities. The ozone depletion process begins when CFCs
(chlorofluorocarbons) and other ozone-depleting substances (ODS) are emitted into the
atmosphere. CFCs were used by industry as refrigerants, degreasing solvents, and propellants. In
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the lower atmosphere, CFC molecules are extremely stable chemically and do not dissolve in
rain, and thus can linger for long periods. After several years, ODS molecules eventually reach
the ozone layer in the stratosphere, which starts at about 10 kilometers above the Earth’s
surface..

6.3.1 Ozone depleting substances (ODS)

“Ozone depleting substances are the substances such as chlorofluorocarbons, halons, carbon
tetrachloride, hydrofluorocarbons, etc. that are responsible for the depletion of ozone layer.”

▪ Scientific evidence indicates that stratospheric ozone is being destroyed by a group of

manufactured chemicals, containing mainly chlorine or bromine, called “ozone-depleting
substances” (ODS).

▪ ODS are very stable, nontoxic, non-flammable and environmentally safe in the lower
atmosphere, which is why they became so popular in the first place

▪ Chlorine and bromine demolish ozone at an alarming rate, by stripping an atom from the
ozone molecule

Ozone-Depleting Substances Sources

Chlorofluorocarbons Refrigerators, air-conditioners, solvents, dry-cleaning
(CFCs) agents, etc.
Halons Fire-extinguishers
Carbon tetrachloride Fire extinguishers, solvents
Methyl chloroform Adhesives, aerosols
Hydrofluorocarbons Solvent cleaning, fire extinguishers, solvent cleaning
Table 1: list of some of the main ozone depleting substances and the sources from where they are released

1. Chlorofluorocarbons (CFCs)
The most widely used ODS, accounting for over 80% of total stratospheric ozone depletion.

• Used as coolants in refrigerators, freezers and air conditioners in buildings and cars
manufactured before 1995.
• Also found in industrial solvents, dry-cleaning agents and hospital sterilants.
• Also used in foam products — such as soft-foam padding (e.g. cushions and
mattresses) and rigid foam (e.g. home insulation)
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2. Halons & Hydrobromofluorocarbon (HBFC)

• Halons, unlike CFCs, contain bromine, which destroys ozone 100 times more than
chlorine
• Halons are used primarily in fire extinguishers & methyl bromide (Pesticide)
3. Methyl Chloroform
• Used mainly in industry as cleansing solvent — for vapour degreasing, cold cleaning,
adhesives and chemical processing.
4. Carbon Tetrachloride
• Mainly used as solvent & in fire extinguishers.
5. Hydro fluorocarbons (HCFCs)
• Major, “transitional” substitutes for CFCs- much less harmful to stratospheric
ozone than CFCs
• But still cause some ozone destruction and are potent greenhouse gases

6.4 Stratospheric Ozone and Ultraviolet Radiation (UVR)

There are three types of UV rays, classified according to their wavelengths and measured in
‘Nanometres, nm’. All three differ in terms of their biological activity and their penetration
levels to our skins. UV’s with shorter wavelengths are the most destructive and dangerous,
although they are completely filtered by the atmosphere level, and do not reach the earth’s
surface.
Here is how the sun’s UV affects life on earth. When the sun comes up, its’ energy is emitted
at different wavelengths. What we see is visible light. There are also infra-red (felt as heat)
and ultraviolet (UV) rays (which we do not see or feel).
Let us consider the three basic types: UV-A UV-B and UV-C.

(Figure 6.6)Three basic types: UV-A UV-B and UV-C

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1. UV-A
UV-A has a long wavelength (315-399nm) and reaches the earth all the time. It makes up about
95% of UV radiation reaching the earth’s surface. It helps generate vitamin D for living things.
In recent studies, prolonged exposures UV-A is known to enhance skin cancer development.

(Figure 6.7) The ozone layer absorbs UV-B and UV-C light, protecting life on Earth
from its harmful effects

2. UV-B
UV-B is not as long as UV-A (280-314nm). Because it is shorter, it is more damaging to
human and plant cells. Not all UVB reaches the earth, as some of it is filtered by the
ozone layer. The little that reaches earth causes sunburns and can also damage our cells
and DNAs (DNA is the basic building blocks of our cells). This is why it can cause skin
cancer and cataracts in our eyes. The amount of UV-B that reaches us on earth depends
on factors like the time of the day, the time of the year and the amount of stratospheric
ozone available to block it. It is also known that altitude, weather conditions and
reflective surfaces such as sand, snow and water reflect some of the UV radiation, and
that means shady areas can have higher UV effect.

3. UV-C

UV-C has the shortest wavelength (100-279nm). It is the most dangerous but all of it is
usually absorbed by the ozone layer.
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6.5 Health and Environmental Effects of Ozone Layer Depletion

With the direct connection between Ozone depletion and UV-B, there is enough research of its
effects on life on earth.
1. Effects on Aquatic Ecosystems: - Life in oceans is also Vulnerable to UV-
radiations. The critical effect of UV-rays depends on the depth to which it penetrates
more than 20m to 30 m in clear water and 5 meter in unclear water. Damage is caused to
aquatic organisms like zooplanktons, larval crabs and shrimp and fish as well as slowing
of photosynthesis in phytoplankton.

(Figure 6. 8) Fauna and flora present in aquatic ecosystems

• UV-B penetrates water columns to depths of 30m
• Increased UV-B exposure in water columns can lead to

Reduces productivity by interfering with processes of photosynthesis

Damages DNA
Alters nitrogen metabolism
Inhibits mobility
Studies (1993) conducted in the Weddle Sea

2. Terrestrial plants: Plant are adopted to present levels of U B R but they are not
adapted to increased levels of U V B. In presence of ultra-violet radiations plants show
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reduced growth and smaller leaves, Unable to photo synthesize as efficiently as other
plants yield smaller amounts of seeds and fruits

The influence of the UV-B radiation on plant process

(Figure 6. 9) Flow Chart showing the influence of UV-B radiations on Plant Process

3. Human Health: - The link between UV-B and the incidence of skin cancer is clear.
Skin cancer is predominantly a disease of white skinned people and the dark pigment
melanin is known to be an effective filter of Ultraviolet beta radiations. Ultraviolet
radiations influence the occurrence of the disease in human population.

◼ Over exposure may of U- VB :

◼ Increase risk of non-melanoma and malignant melanoma

skin cancer

◼ Higher risks of malignant melanoma from severe

sunburns – especially in childhood
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◼ Risk of malignant melanoma has increased 10%

◼ Risk of nonmalignant melanoma has increased 26%
(Figure 6.10 a &b) Effect of UV radiations on Skin causing non-melanoma and malignant
melanoma skin cancer

◼ Melanoma – The particular form of skin cancer as reported in many areas is much rarer
than other.

Over exposure of UB V on skin

❑ Suppress immune system
❑ Accelerate aging of skin due high exposure
❑ Cause an outbreak of rash in fair skinned people due to photo allergy – can be
severe

(Figure 6.11 ) Aging of skin due high exposure of UV B Radiations

4. Over Exposure to UV-B on eyes

UV-B radiation can damage several parts of the eye, including the lens, the cornea, and
the membrane covering the eye (conjunctiva). "Snow blindness" is the result of
overexposure to UV-B and occurs in areas of the world with high levels of UV exposure,
including snowy regions at high altitudes. Snow blindness is not unlike sunburn, and if
repeated, can cause damage to eye over the long term.
Cataracts are a clouding of the eye's lens and are the leading cause of permanent
blindness worldwide. They are a result of overexposure to UV. A sustained 10% thinning
of the ozone layer is expected to result in nearly two million new cases of cataracts per
year globally.
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(Figure 6.12) Effect of UV B radiations on eyes

5. Effects on Climate: - Due to ozone depletion the earth heats up. This warms the
stratosphere and produces the temperature inversion at the troposphere; there would be
no stratosphere without ozone layer. Depletion of stratospheric ozone is predicted to cool
this region and hence change the temperature.

6. Effects on biogeochemical cycles

The power of higher UL levels affect the natural balance of gasses (and greenhouse
gases) in the biosphere: e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl
sulfide (COS) and ozone. Changes in UV levels can cause biosphere-atmosphere
feedback resulting from the atmospheric build-up of these gases.

6.6 Control of Ozone Depletion :- In order to prevent further damage to ozone

layer, a large number of substances are now being used as substitutes for ODS that are being
phased out under Montreal Protocol. These ozone friendly chemicals are now widely being
manufactured as alternatives to CFCs in refrigeration, foam sector, industry and fire
extinguishing by both developing as well as developed countries.

1. Refrigeration Sector: - As an alternative in the new refrigeration units,

Hydrocarbons, Hydro-fluorocarbons (HFC-134a), HCF blends and Ammonia are used
which are less effective in ozone depletion than CFCs. Air conditioning units, automobile
air conditioners and coolers have HFC-134a and blends as safe refrigerant substances to
be used.
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2. Fire fighting: - Halons are usually used for firefighting systems in control rooms,
aircrafts etc. but today fire fighting is done by means of CO2 or dry powder, water mist
technologies and combustion generated aerosols are best alternatives to halons. Currently
these ozone friendly products like FCs, HCFCs, HFAs and HFCs are being tested for
their toxicity and global warming effect and global observations suggest that their
contribution in warming effects are currently increasing despite being ozone friendly.

6.6.1 International efforts in saving the ozone layer

To halt the depletion of the ozone layer, countries around the world agreed to stop using
ozone-depleting substances. This agreement was formalized in the Vienna Convention for the
Protection of the Ozone Layer in 1985 and the Montreal Protocol on Substances that Deplete
the Ozone Layer in 1987. In 2009, the Vienna Convention and the Montreal Protocol became
the first treaties in the history of the United Nations to achieve universal ratification.
Substances covered by the protocol are referred to as 'controlled substances'. The main
substances include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons,
carbon tetrachloride, methyl chloroform and methyl bromide. The damage to the ozone layer
caused by each of these substances is expressed as their ozone depletion potential (ODP).

2007, governments made an additional commitment, agreeing to freeze production of

HCFCs in developing countries by 2013 and to bring forward the final phase-out date of these
chemicals to 2030. These international agreements helped to greatly reduce the worldwide use
of ozone-depleting substances in Europe and around the World. Scientific monitoring shows
signs that the ozone layer is starting to recover. Full recovery is not expected to occur before
the middle of the 21st century.

6.6.2 Montreal Protocol: - Vienna Convention on protection of the ozone layer was
adopted in 1985 that led to a series of international agreements on the elimination and reduction
of CFCs and other ozone depleting substances. Montreal Protocol was signed at Montreal
Canada in 1987 by 27 industrialized countries as a landmark international agreement to protect
the stratospheric ozone. It was agreed to limit the production and use of ozone depleting
substances, phasing out of ozone depleting substances and providing a helping hand to the
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developing countries to adopt the use of alternative substances to CFCs that cause minimal
damage to ozone than CFCs. The protocol was amended with additional requirements at London
1990, Copenhagen 1992, Montreal 1997 and Beijing China 1999. Presently 189 countries are
signatories to the protocol with their commitment to protect the ozone layer and to ensure
environmentally sustainability. Since 1995, 16th September of every year is celebrated as world
ozone day that marks the signing of Montreal Protocol. At Beijing meeting it was impressed and
agreed upon to phase out all types of ozone depleting substances like methyl bromide, HCFCs
and bromo-chloromethane in near future in accordance with the agreement. The developed
countries have already phased out production and use of CFCs and Halons by 1996 and that of
methyl bromide by 2005 and will phase out HCFCs by January 2030. However, developing
countries were to freeze CFC consumption as of 1 July 1999 based on 1995-1997 averages,
reduce the consumption by 50% by January 2005 and complete elimination by 2010. But methyl
bromide was to freeze out by 2015 and HCFs by January 2040. The overall effect would be to
freeze consumption of the Halons at 1986 levels in 1992 and to cut consumption of CFCs to 50%
of 1986 levels by 2000. The overall highlights of the protocol are;

• CFCs to be phased out by the year 2000, with 50% by 1995 and 85% by 1997.
• Halons to be phased out by 2000, with 50% cut by 1995.
• CCl4 to be phased out by 2000, with 95% cut by 1995.
• Methyl chloroform to be phased out by 2005, with a cut of 30% of 1990 levels by

6.7 Acid Rain:

The phrase acid rain was first used in 1852 by Scottish chemist Robert Angus Smith during his
investigation of rainwater chemistry near industrial cities in England and Scotland. The
phenomenon became an important part of his book Air and Rain: The Beginnings of a Chemical
Climatology (1872). It was not until the late 1960s and early 1970`s however, that acid rain was
recognized as a regional environmental issue affecting large areas of western Europe and eastern
North America. Acid rain also occurs in Asia and parts of Africa, South America, and Australia.
As a global environmental issue, it is frequently overshadowed by climate change. Although the
problem of acid rain has been significantly reduced in some areas, it remains an important
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environmental issue within and downwind from major industrial and industrial agricultural
regions worldwide.

Acid rain refers to a mixture of deposited material, both wet and dry, coming from the
atmosphere containing more than normal amounts of nitric and sulfuric acids. Simply put, it
means rain that is acidic in nature due to the presence of certain pollutants in the air due to cars
and industrial processes. It is easily defined as rain, fog, sleet or snow that has been made acidic
by pollutants in the air as a result of fossil fuel and industrial combustions that mostly emits
Nitrogen Oxides (NOx) and Sulfur Dioxide (SO2). Acidity is determined on the basis of the pH
level of the water droplets. Normal rain water is slightly acidic with a pH range of 5.3-6.0,
because carbon dioxide and water present in the air react together to form carbonic acid, which is
a weak acid. When the pH level of rain water falls below this range, it becomes acid rain

6.8 Forms of Acid Rain

There are two forms in which acid deposition occurs – wet and dry.

1. Wet Deposition: When the wind blows the acidic chemicals in the air to the areas
where the weather is wet, the acids fall to the ground in the form of rain, sleet, fog,
snow or mist. It removes acid from the atmosphere and deposit them on the earth’s
surface. When this acid flows through the ground, it affects large number of plants,
animals and aquatic life. The water from drain flows into rivers and canals which is
them mixed up with sea water, thereby affecting marine habitats.

(Figure 6.13) Acid Depositions Forms

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2. Dry Deposition: If the wind blows the acidic chemicals in the air to the areas
where the weather is dry, the acidic pollutants slip into dust or smoke and fall to the
ground as dry particles. These stick to the ground and other surfaces such as cars,
houses, trees and buildings. Almost 50% of the acidic pollutants in the atmosphere
fall back through dry deposition. These acidic pollutants can be washed away from
earth surface by rainstorms.

6.9 Components of acid rain: The major components of acid rains are sulphur
dioxide/sulphur trioxide, carbon dioxide and nitrogen dioxide dissolves in rain water. These
components are deposited as dry and wet depositions. When these pollutants are dissolved in
water during rain it forms various acids .

The chemical reactions of these pollutants are discussed as follows.

• CO2+H2O → H2CO3 (carbonic acid)

• SO2+H2O → H2SO3 (sulphurous acid)
• NO2+H2O → HNO2 (nitrous acid) +HNO3 (nitric acid)

6.10 Formation of Acid Rain

Natural sources and human activities are the main causes for the formation of acid rain in the
world. Natural source causes are emissions from volcanoes and biological processes that occur
on the land, in wetlands, and in the oceans contribute acid-producing gases to the atmosphere;
and Effects of acidic deposits have been detected in glacial ice thousands of years old in remote
parts of the globe. Whereas, activities of human beings are burning of coal, using Oil and natural
gas in power stations to produce electricity, cooking purpose and to run their vehicles are giving
of oxide of sulphur, oxides of carbon, oxides of nitrogen, residual hydrocarbons and particulate
matters to the environment. These emissions mix with water vapour and rainwater in the
atmosphere producing weak solutions of sulphuric and nitric acids, which fall back as acid rain
to the ocean, lake and land.

The following reaction will clarify the acid formation reaction:

2SO2 (g) + O2 (g) + 2H2O (l) → 2H2SO4 (aq)

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4NO2 (g) + O2 (g) + 2H2O (l) → 4HNO3 (aq)

(Figure 6.14) Formation of acid rain and its interaction with environment.

6.11 Natural Acidity of Rainwater

Pure water has a pH of 7.0 (neutral); however, natural, unpolluted rainwater actually has a pH of
about 5.6. The acidity of rainwater comes from the natural presence of three substances (CO 2,
NO, and SO2) found in the troposphere (the lowest layer of the atmosphere). Carbon dioxide
(CO2) is present in the greatest concentration and therefore contributes the most to the natural
acidity of rainwater.

Gas Natural Sources Concentration

Carbon dioxide
Decomposition 355 ppm
CO2

Nitric oxide
Electric discharge 0.01 ppm
NO

Sulfur dioxide
Volcanic gases 0-0.01 ppm
SO2

NOTE: Parts per million (ppm) is a common concentration measure used in

environmental chemistry. The formula for ppm is given by:
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Table 3 . Sources of Natural Gases which Contribute to Natural Acidity Of water

Carbon dioxide reacts with water to form carbonic acid (Equation 1). Carbonic acid then
dissociates to give the hydrogen ion (H+) and the hydrogen carbonate ion (HCO3-) (Equation 2).
The ability of H2CO3 to deliver H+ is what classifies this molecule as an acid, thus lowering the
pH of a solution.

(1)

(2)

Nitric oxide (NO), which also contributes to the natural acidity of rainwater, is formed during
lightning storms by the reaction of nitrogen and oxygen, two common atmospheric gases
(Equation 3). In air, NO is oxidized to nitrogen dioxide (NO2) (Equation 4), which in turn reacts
with water to give nitric acid (HNO3) (Equation 5). This acid dissociates in water to yield
hydrogen ions and nitrate ions (NO3-) in a reaction analogous to the dissociation of carbonic acid
shown in Equation 2, again lowering the pH of the solution.

(5)
6.12 Causes of Acid Rain

Both natural and man-made sources are known to play a role in the formation of acid rain. But, it
is mainly caused by combustion of fossil fuels which results in emissions of sulphur dioxide
(SO2) and nitrogen oxides (NOx).

1 Natural Source: The major natural causal agent for acid rain is volcanic emissions.
Volcanoes emit acid producing gases to create higher than normal amounts of acid rain or any
other form of precipitation such as fog and snow to an extent of affecting vegetation cover and
health of residents within the surrounding. Decaying vegetation, wildfires and biological
processes within the environment also generate the acid rain forming gases. Dimethyl sulphide is
a typical example of a major biological contributor to sulphur containing elements into the
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atmosphere. Lightning strikes also naturally produce nitric oxides that react with water
molecules via electrical activity to produce nitric acid, thereby forming acid rain.

2 Man-made sources: Human activities leading to chemical gas emissions such as sulphur
and nitrogen are the primary contributors to acid rain.

Gas Non-Natural Sources Concentration

Nitric oxide
Internal Combustion 0.2 ppm
NO

Sulfur dioxide
Fossil-fuel Combustion 0.1 - 2.0 ppm
SO2

Table 3 : Man Made Sources of emissions of NO & SO2

The activities include air pollution sources emitting sulphur and nitrogen gases like factories,
power generations facilities, and automobiles. In particular, use of coal for electrical power
generation is the biggest contributor to gaseous emissions leading to acid rain. Automobiles and
factories also release high scores of gaseous emissions on daily basis into the air, especially in
highly industrialized areas and urban regions with large numbers of car traffic. These gases react
in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds
such as sulphuric acid, ammonium nitrate, and nitric acid. As a result, these areas experience
exceedingly high amounts of acid rain.

The existing winds blow these acidic compounds over large areas across borders and they fall
back to the ground in the form of acid rain or other forms of precipitation. Upon reaching the
earth, it flows across the surface, absorbs into the soil and enters into lakes and rivers and finally
gets mixed up with sea water.

The gases i.e. sulphur dioxide (SO2) and nitrogen oxides (NOx) are primarily gases occurring
from electric power generation by burning coal and responsible for acid rain.
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6.13 Measuring Acid Rain

Acidity and alkalinity are measured using a pH scale for which 7.0 is neutral. The lower a
substance's pH (less than 7), the more acidic it is; the higher a substance's pH (greater than 7),
the more alkaline it is. Normal rain has a pH of about 5.6; it is slightly acidic because carbon
dioxide (CO2) dissolves into it forming weak carbonic acid. Acid rain usually has a pH between
4.2 and 4.4

(Figure 6.15)The pH Scale

6.14 Effects of Acid Rain

Acid rain has significant effects on the world environment and public health.

1. Effects of Acid Rain on Fish and Wildlife

The ecological effects of acid rain are most clearly seen in aquatic environments, such as
streams, lakes, and marshes where it can be harmful to fish and other wildlife. As it flows
through the soil, acidic rain water can leach aluminium from soil clay particles and then flow
into streams and lakes. The more acid that is introduced to the ecosystem, the more
aluminium is released. Some types of plants and animals are able to tolerate acidic waters and
moderate amounts of aluminium. Others, however, are acid-sensitive and will be lost as the
pH declines. Generally, the young of most species are more sensitive to environmental
conditions than adults. At pH 5, most fish eggs cannot hatch. At lower pH levels, some adult
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fish die. Some acidic lakes have no fish. Even if a species of fish or animal can tolerate
moderately acidic water, the animals or plants it eats might not. For example, frogs have a
critical pH around 4, but the mayflies they eat are more sensitive and may not survive pH
below 5.5.

2 Effect on Aquatic Environment: Acid rain either falls directly on aquatic bodies or gets
run off the forests, roads and fields to flow into streams, rivers and lakes. Over a period of time,
acids get accumulated in the water and lower the overall pH of the water body. The aquatic
plants and animals need a particular pH level of about 4.8 to survive. If the pH level falls below
that the conditions become hostile for the survival of aquatic life. Acid rain tendency of altering
pH and aluminum concentrations greatly affects pH concentration levels in surface water,
thereby affecting fish as well as other aquatic life-forms. At pH levels below 5, most fish eggs
cannot hatch. Lower pH can also kill adult fish. Acid rain runoff from catchment areas into rivers
and lakes has also reduced biodiversity as rivers and lakes become more acidic. Species
including fish, plant and insect types in some lakes, rivers and brooks have been reduced and
some even completely eliminated owing to excess acid rain flowing into the waters.

3 Effect on Forests: It makes trees vulnerable to disease, extreme weather, and insects by
destroying their leaves, damaging the bark and arresting their growth. Forest damage due to acid
rain is most evident in Eastern Europe – especially Germany, Poland and Switzerland.

(Figure 6.16) Acid Rain Damage to a Forest in the Czech Republic. Trees and many other
plants are sensitive to aluminum and other metals in groundwater. Acid rain increases the
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concentration of Al3+ in groundwater, thereby adversely affecting plant growth. Large

sections of established forests have been severely damaged.

3. Effect on Soil: Acid rain highly impacts on soil chemistry and biology. Acid rain
also disturbs the microbial activity of soil. The microorganism is very sensitive to
change in soil pH. Change in pH due to acid rain may cause a shift in the community
of the microorganisms. The pH optima of most bacteria and protozoa are near
neutrality, most fungi prefer an acidic environment, and most blue-green bacteria
prefer an alkaline environment.
4. Effect on Microorganisms
Acid rain results in shifting of bacterial community to fungal community. This
causes imbalance in the micro flora.
Decay in the decomposition of soil organic material due to loss of bacterial
community. The fungi are not as good decomposers as bacteria.
• Increased incidence of fungal diseases.
• Inhibition of mycorrhizal activity.
5. Vegetation Cover and Plantations: The damaging effects of acid rain on soil
and high levels of dry depositions have endlessly damaged high altitude forests and
vegetation cover since they are mostly encircled by acidic fogs and clouds. Besides,
the widespread effects of acid rain on ecological harmony have led to stunted growth
and even death of some forests and vegetation cover.
6. Effects on Angiosperms

Growth of the leaves is suppressed due to high acidity.

Result in stunted and abnormal growth of the plant.
Discoloration and loss of foliar biomass.
Decreased annual increment (width of growth rings).
Increased susceptibility to secondary root and folia pathogens.
Death of herbaceous vegetation beneath affected trees.
Premature falling of leaves while still green.

7. Effects on Gymnosperms

Loss of feeder – root biomass in conifers.

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Premature senescence of older needles in conifers.

Shedding of whole green shoots, especially in spruce.
Formation of stork’s nest crown in young white fir.
Excessive seed and cone productions, year after year.
8. Effect on Architecture and Buildings: Acid rain on buildings, especially
those constructed with limestone, react with the minerals and corrode them away.
This leaves the building weak and susceptible to decay.

(Figure 6.17) Acid Rain Damage to Taj Mahal. Both marble and limestone consist of
CaCO3, which reacts with acid rain in an acid–base reaction to produce CaSO4.

Modern buildings, cars, airplanes, steel bridges and pipes are all affected by acid rain.
Irreplaceable damage can be caused to the old heritage buildings. Taj Mahal, one of the 7
wonders of the world, is largely affected by acid rain. The city of Agra has many industries
which emit the oxides of sulphur and nitrogen in the atmosphere. People continue to use low-
quality coal and firewood as a domestic fuel, adding to this problem.

(Figure 6.18) Acid Rain Damage to a Statue of George Washington. Both marble and limestone consist of
CaCO3, which reacts with acid rain in an acid–base reaction to produce CaSO4. Because CaSO4 is somewhat
soluble in water, significant damage to the structure can result.
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9. Effect on Human Health

Walking in acid rain, or even swimming in a lake affected by acid rain, is no more dangerous
to humans than walking in normal rain or swimming in non-acidic lakes. However, when the
pollutants that cause acid rain —SO2 and NOX, as well as sulphate and nitrate particles— are
in the air, they can be harmful to humans.

SO2 and NOX react in the atmosphere to form fine sulphate and nitrate particles that people
can inhale into their lungs. Many scientific studies have shown a relationship between these
particles and effects on heart function, such as heart attacks resulting in death for people with
increased heart disease risk, and effects on lung function, such as breathing difficulties for
people with asthma.

10 Other Effects of SO2 and NOX

In the atmosphere, SO2 and NOX gases can be transformed into sulphate and nitrate particles,
while some NOX can also react with other pollutants to form ozone. These particles and ozone
make the air hazy and difficult to see through. This affects our enjoyment of national parks
that we visit for the scenic view such as Shenandoah and the Great Smoky Mountains

6.15 Area of the world is affected by Acid Rain

There are several places around the world affected by acid rain and here are the main ones. The
North-eastern section of the United States where acid rain is caused by high numbers of factories
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and power plants is one affected area. Also in that same region, the Southeastern section of
Canada is affected and the main cause is factories in the Toronto-Hamilton area. Central Europe
and Scandinavian (Sweden, Norway and Finland) are also affected, here being the British and
other European factories doing the damage. One more main area that is affected is parts of Asia,
specifically India and China, where acid rain is caused by large numbers of factories.

6.16 Possible solutions for Acid rain

There are many possible solutions to the acid rain problem. One is to use fuels that burn more
cleanly. Another solution is to burn coal more efficiently.
Power plant and factory chimneys can be fitted with scrubbers
that release 90-95% sulphur free smoke and also produce sludge
from which gypsum, a building material, can be produced. This
problem can also be solved by enforcing tight emission
standards on vehicles that burn gas and diesel. One other
solution is fitting devices such as a catalytic converter into car exhaust pipes to minimize the amount
of sulphur dioxide in car exhaust. The main steps to be taken to combat Acid Rain are:

a. Cleaning up Exhaust Pipes and Smokestacks

b. Restoring Damaged Environments
c. Alternative Energy Sources
d. Individual, National/State, and International Actions
6.17 Heat budget
The balance of incoming and outgoing heat on Earth is referred to as its heat budget. As with
any budget, to maintain constant conditions the budget must be balanced so that the incoming
heat equals the outgoing heat.
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(Figure 6.19 ) Earth’s heat budget.

Of all of the solar radiation reaching Earth, 30% is reflected back to space and 70% is absorbed
by the Earth (47%) and atmosphere (23%). The heat absorbed by the land and oceans is
exchanged with the atmosphere through conduction, radiation, and latent heat (phase change).
The heat absorbed by the atmosphere is eventually radiated back into space (PW).

Of all of the solar energy reaching the Earth, about 30% is reflected back into space from the
atmosphere, clouds, and surface of the Earth.
Another 23% of the energy is absorbed by the water vapour, clouds, and dust in the atmosphere,
where it is converted into heat.
Just under half (47%) of the incoming solar radiation is absorbed by the land and ocean, and this
energy heats up the Earth’s surface. The energy absorbed by the Earth returns to the atmosphere
through three processes; conduction, radiation, and latent heat (phase change).
Conduction is the transfer of heat through direct contact between the surface and the atmosphere.
Air is a relatively poor thermal conductor (which means it is a good insulator), so conduction
represents only a small part of the energy transfer between the Earth and the atmosphere; equal
to about 7% of the incoming solar energy.
All bodies with a temperature above absolute zero (-273oC) radiate heat in the form of longwave,
infrared radiation. The warmed Earth is no exception, and about 16% of the original solar energy
is radiated from the Earth to the atmosphere. Some of this radiated energy will dissipate into
space, but a significant amount of heat will be absorbed by the atmosphere.
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When the radiation is re-emitted by the Earth, it is now in the form of long wavelength, infrared
radiation, which does not easily pass through the atmosphere. Instead, this infrared radiation is
absorbed by the atmosphere, particularly by the greenhouse gases such as CO2, methane, and
water vapour. As a result, the atmosphere heats up.

6.18 Concept of Green House

(Figure 6.20) Illustration of a Green House

The transparent walls and roof of the greenhouse are such that these allow the visible sunlight to
enter but prevent the long wave radiations to go out.
• Thus, the sunlight is absorbed by the soil and structure of the green house.
• It is then re-emitted as heat which cannot pass through the glass.
• The amount of energy in the greenhouse thus increases until its temperature is high
enough for the slight leakage of heat through the glass to take away as much energy
as gets in as sunlight.
• Subsequently walls and roof re-emit absorbed radiation into the house.
• Thus, during the day time, infra-red radiation passes into the green house and warm
the atmosphere and the ground on which the greenhouse stands.
• Coating of glass with a non-heat radiation film transparent to sunlight further
maximizes heating effect of the radiation.
6.19 The Greenhouse Effect.
• The existence of the greenhouse effect, while not named as such, was proposed by
Joseph Fourier in 1824. The argument and the evidence were further strengthened
by Claude Pouillet in 1827 and 1838. John Tyndall was the first to measure the
infrared absorption and emission of various gases and vapours. From 1859 onwards,
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he showed that the effect was due to a very small proportion of the atmosphere, with
the main gases having no effect, and was largely due to water vapour, though small
percentages of hydrocarbons and carbon dioxide had a significant effect. The effect
was more fully quantified by Svante Arrhenius in 1896, who made the first
quantitative prediction of global warming due to a hypothetical doubling of
atmospheric carbon dioxide. However, the term "greenhouse" was not used to refer to
this effect by any of these scientists; the term was first used in this way by Nils
Gustaf Ekholm in 1901

Greenhouse effect, a warming of Earth’s surface and troposphere (the lowest layer of the
atmosphere) caused by the presence of water vapour, carbon dioxide, methane, and certain other
gases in the air. The exchange of incoming and outgoing radiation that warms the Earth is often
referred to as the greenhouse effect because a greenhouse works in much the same way.

(Figure 6.21) The Earth`s Green House Effect

◼ Importance of Natural Greenhouse Effect

The green-house effect is a natural phenomenon and has been occurring for millions of years on the
earth.
• Life on the earth has been possible because of this natural greenhouse effect which is
due to water vapor and small particles of water present in the atmosphere.
• Together, these produce more than 95 percent of total greenhouse warming.
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• Average global temperatures are maintained at about 15°C due to natural greenhouse
effect.
• Without this phenomenon, average global temperatures might have been around –
17°C and at such low temperature life would not be able to exist.
◼ Green House Effect Contributors
Water vapour is the biggest contributor to the greenhouse effect; However CO2 & other
greenhouse gases are increasing the amount of water vapours in the air by boosting the rate of
evaporation

These gases are

• Carbon dioxide (CO2),
• methane (CH4)
• Nitrous oxides (NOx)
• chlorofluorocarbon (CFC)
· Out of these four gases,
➢ Carbon dioxide contributes about 55%,
➢ Chlorofluorocarbon contributes about 24%,
➢ Methane (about 15%)
➢ Mitrous oxide (about 6%)

◼ Major Sources
• Electricity , Transportation Industry , Commercial & Residential

( Figure 6.22) Major Sources of Green Houses Gases

• Black carbon stays in the atmosphere for only several days to weeks, whereas carbon
dioxide (CO2) has an atmospheric lifetime of more than 100 years

• Together, black carbon, methane & ozone are responsible for 30 – 50% of human effects
on global warming. However, unlike CO2which lasts over 100 yrs once released, these
pollutants are short lived.
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• Major co-benefits of reducing these air pollutants will include immediate improvements
in public health, agricultural productivity and economic development for the rural
populations in developing nations.

6.20 Consequences of Greenhouse effect:

• It is estimated that if the present rate of increase in CO2 level continues, it will result
in rise of atmospheric temperature by 20C to 30C by end of 21st century.

• This will result in receding many glaciers; melting of icecaps in the Polar Regions
and disappearance of deposits of ice on the other parts of world in large scale.

• According to an estimate, if all the ice on the earth would melt, about 60M of water
would be added to surface of all oceans and low lying coastal areas.

• A rise in sea-level of only 50-100 cm caused by global warming would flood low
lying areas of the world such as Bangladesh, West Bengal as well as densely
populated coastal cities from Shanghai to San-Fancisco.

• Because of increased concentration of CO2 and due to much warmer tropical oceans,
there may occur more cyclones and hurricanes.

• Early snow melt in mountains will cause more floods during monsoon.

• According to United Nations Environment Programme (UNEP), within about three

decades, rising levels of seas will be able to and flood coastal cities like Bombay,
Boston, Chittgang and Manila.

• A slight increase in global temperature can adversely affect the world food
production.

• Thus the wheat production zones in the northern latitudes will be shifted to north of
temperate latitudes.

• The biological productivity of the ocean would also decrease due to warming of the
surface layer, which in turn reduces the transport of nutrients from deeper layers to
the surface by vertical circulation.
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6.21 Control and Remedial Measures of Green House Effect:

• CO2 concentration can be reduced by drastic cut in the consumption of fossil fuels in
the highly developed and industrialized countries like USA and Japan and developing
country like China and India.

• Scientific efforts should be made to develop alternative efficient fuels. Methane may be
a substitute of petroleum.

• Development of hydro-electric better alternatives.

• There should be a restriction on the emission of dangerous CO2, CFCs, and as NO2
from the factories and automobiles.

• Limiting the driving days in megacities can be another option. Cities like singapore and
Mexico are following the practice.

• In tropical and sub-tropical countries, the solar energy may be developed as an

alternative to the fossil fuels.

• Biogas plants should be used which is another source of conventional energy for
domestic use.

• Enhancing afforestation will certainly reduce the CO2 level thereby decreasing the
greenhouse effect.

6.22 Global Warming: -

Global warming refers to a gradual rise of atmospheric temperature and consequent changes in
the radiation balance mainly due to human action leading to climatic change at different levels –
local, regional and global. As per recent estimates, it has been found that the surface air
temperature over the past 100 years has increased by about 0.50C to 0.70C. This is due to
greenhouse effect.
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It had led to many changes on the planet, such as a rise in sea level; massive melting of snow and
land ice, elevated heat content of the oceans, increased humidity, change in the timings of
seasonal events, and many others. For both land and ocean, the global mean surface temperature
indicates warming of 0.85°C from 1880 to 2012. During the period 1906-2005, the Earth’s mean
surface temperature had increased by 0.74±0.18°C. Hence, it is seen that the rate of warming
approximately doubled for the last half of that duration (0.13±0.03°C per decade, as compared to
0.07±0.02°C per decade).

6.23 Causes of Global warming

Global warming is primarily a problem of too much carbon dioxide (CO2) in the atmosphere—
which acts as a blanket, trapping heat and warming the planet. As we burn fossil fuels like coal,
oil and natural gas for energy or cut down and burn forests to create pastures and plantations,
carbon accumulates and overloads our atmosphere. Certain waste management and agricultural
practices aggravate the problem by releasing other potent global warming gases, such as methane
and nitrous oxide.

(Figure 6.23) Illustration of causes of Global warming

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6.24 Effects of Greenhouse Gases (GHGs) on Global Warming

The main greenhouse gases, namely: Carbon dioxide (CO2); Methane (CH4); Nitrous oxide
(N2O); Hydrofluorocarbons (HFCs); Perfluorocarbons (PFCs); and Sulphur hexafluoride
(SF6). The impact of any GHG is based on the magnitude of the rise in its concentration, its
duration in the atmosphere and the wavelength of radiation that is absorbed.
➢ Carbon dioxide is the GHG which is present in the largest concentration in the
atmosphere. Its emission chiefly comes from fossil fuel combustion. It is showing a rise
of about 0.5% per annum.
➢ Chlorofluorocarbons (CFCs) are produced due to anthropogenic activity. Ozone is
present in the stratosphere where ultraviolet (UV) radiations convert oxygen into ozone.
Hence, the UV rays do not reach the Earth’s surface. The CFCs which goes into the
stratosphere destroys the ozone, which is evidently seen over Antarctica. The reduction of
ozone concentration in the stratosphere is known as the ozone hole. This permits the UV
rays to pass through the troposphere.
➢ Nitrous oxide is naturally produced by oceans and rainforests. Man-made sources of
nitrous oxide include nylon and nitric acid production, the use of fertilisers in agriculture,
cars with catalytic converters and the burning of organic matter.
➢ Hydrofluorocarbons (HFCs) are used as refrigerants, especially after the ozone-
destroying CFCs had been under the Montreal Protocol.
➢ Per-fluorocarbons (PFCs): Emitted as a result of production of flourites, they have an
atmospheric lifetime of more than 1,000 years.
➢ Sulphur hexafluoride (SF6): The most powerful greenhouse gas yet discovered, it is
emitted as result of production of flourites.
6.25 Effects on environment and its components: - The consequent global
warming phenomena have a number of effects on the earth’s climate, ecosystems and
biospheric processes. The effects are briefly enlisted as below:

• There will be increased incidences of weather and climate change by means of increasing
the temperature of earth. It will disturb the precipitation patterns and increase the storm
intensities. Further the frequency of extreme events like droughts, floods etc will
substantially increase.
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• Glaciers in mountains and polar ice caps being sensitive to temperature changes will melt
causing a raised sea level and flooding of coastal areas.

(Figure 6.24) Melting of Glaciers due to rise in Global Temperature

• There will be a shift in the range of distribution and phenology of organisms. With
increasing global warming many species are expected to shift from lower altitudes to
higher altitudes and from lower latitudes to higher latitudes.
• It is likely that global warming may increase the decomposition of soil organic matter
and would lead to increased release of CO2 from soil pool which inturn would lead to
further warming and changes in soil organic pools.
• Sea level is expected to rise due to thermal expansion of water and melting of glaciers.

•
(Figure 6.25)Trophic Sea level rise due to rise in Global temperature
• Temperature rise will have a drastic effect on the coral reefs by means of coral bleaching
which represents a reduction in the algal pigments that makes the reef coral white in
appearance.
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• Increased CO2 concentration would result in immediate changes in CO2 concentration of

the oceanic surface layer and carbonate precipitation.
• Changes in rainfall patterns: In some areas, droughts and fires happen, whereas in
other areas, flooding takes place. This all is due to changes in rainfall pattern.

(Figure 6.26) Floods and droughts due to Global warming

6. 26 Efforts to tackle Global Warming: - It is necessary to have an immediate

reduction in manmade greenhouse gases to stabilize the atmospheric concentrations. Various
strategies that could be helpful in reducing the risk of global warming include reduction in the
energy consumption by developing efficient energy systems, use of alternate sources of energy
by replacing fossil fuels, increasing vegetation cover, minimizing the use of nitrogen fertilizers
and improving paddy cropping practices to reduce methane production etc. Some of the
mitigation strategies could be briefly described as;
1 Use of renewable sources of energy:- Better energy planning including reduced energy
consumption and exploiting pollution free sources of energy like solar, wind and geothermal
and switching to hydrogen fuel cells will surely reduce greenhouse gas emissions to a larger
extent. Besides eliminating the use of CFCs will not only reduce global warming but also will
protect ozone layer. Tapping CH4 produced from landfills will provide energy as well as will
reduce its contribution in global warming.
2 Trapping Carbon in geological formations: - It is another method to separate and
capture CO2 away from atmosphere that is produced by the combustion of fossil fuels.
Technology is available where carbon uptake in bicarbonate system in geological formations
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is done at depths of several kilometers that ultimately reduce the concentration of CO2 in
atmosphere.
3 Carbon trading:- It is another approach to mitigate the problem of rising concentrations
of CO2. Carbon trading means making the provisions of payments to the industries and other
communities for undertaking those activities which sequester CO2 from the atmosphere.
4 Carbon Tax: Nations have developed a mechanism where tax is imposed on greenhouse
gas emissions on input basis. Some European countries like Sweden, Finland etc have
imposed taxes on all types of fossil fuels like coal, oil and gas. Such practices motivate the
industries to look for the means to reduce CO2 emissions by means of improving energy
efficiency and CO2 capturing techniques.

6.27 Control: The most important aspect of stabilizing atmospheric concentrations of

greenhouse gases is to lower the global emissions significantly. Risks from the potential
global warming are quite evident and there is a need to act at international level. Some of the
international policies which are recent are briefly discussed as:

◼ Intergovernmental Panel on Climate Change (IPCC)

• The World Meteorological Organisation (WMO) and the UN Environment

Programme (UNEP) founded the IPCC to provide for a mechanism to study the
effects of global warming at a governmental level.
• IPCC is a UN body that assesses the science related to climate change.
• It provides the policymakers with regular scientific assessments on climate
change, its implications and potential future risks while also providing adaptation
and mitigation options.
• It complements UNFCCC and vice versa.

◼ United Nations Framework Convention on Climate Change (UNFCCC )

• It came to force on 21st March 1994.

• The 195 countries that have ratified it are called the Parties to the Convention.
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• The UNFCC is a Rio Convention, one of the three adopted at the Rio Earth Summit
in 1992. The others include the UN Convention on Biological Diversity and the UN
Convention to Combat Desertification.
• The Joint Liaison Group was established to ensure cooperation among the three
Conventions.
• Currently, it also consists of the Ramsar Convention on Wetlands.
• The ultimate aim of the Convention is to stabilize the greenhouse gas concentration
“at a level that would prevent dangerous anthropogenic interference with the climate
system”.
• It also aims to achieve the said level within a specific period so that the ecosystem is
allowed to adapt naturally to climate change while also ensuring food security and
sustainable economic development.

Following its establishment, the COP1 (first Conference of Parties) was held in Berlin, COP2
was held in Geneva and the COP3 was held in Kyoto to adopt the “Kyoto Protocol” that ensures
the implementation of the UNFCCC’s objective.

◼ Kyoto Protocol:

• Kyoto Protocols was adopted in Kyoto, Japan on 11th December 1997 and came to
force on 16th February 2005
• Its signatories are committed towards the achievement of emission reduction targets.
• COP 7 held in Morocco in 2001 saw the adoption of the detailed rules for the
implementation of the protocol. These are referred to as “Marrakesh Accords”.
• This protocol holds the developed countries are accountable for the current high
levels of GHG emissions into the atmosphere due to their role in the industrial
revolution.
• Kyoto Mechanism, also known as Flexible Mechanism, is defined under the Kyoto
Protocol to lower the overall cost of achieving the emission targets. It includes
Emission Trading, the Clean Development Mechanism and Joint Implementation.
• On December 2012, the Doha Amendment to the Kyoto Protocol was adopted. The
changes made include:
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• New commitments were made by Annex I Parties (developed nations and Economies
in Transition) to be implemented between the period of 1st January 2013 and 31st
December 2020.
• A revised list of GHG that is to be reported by the Parties during the second
commitment period
• Amendments were made to update several articles of the Kyoto Protocol to be on par
with the second commitment period.

The Kyoto Protocol is a significant step towards the reduction of global emission regime that
will allow the stabilisation of GHG emissions.

◼ Paris Agreement:

Signed in 2016, it is considered to be the world’s first comprehensive climate agreement.

It aims to:

• Keep the global temperature well below 2°C above preindustrial times and endeavor
to limit them even more to 1.5°C.
• Strengthen the nations’ ability to combat the adverse impacts of climate change.
• The Paris Accord calls for a reduction of the GHGs emitted due to human activities
equal to that of the trees, soil and oceans so that they can be absorbed naturally.
• As per the Agreement, each country’s contribution towards cutting emission must be
reviewed every 5 years.
• It also states that rich countries must help the poorer nations by providing them with
“Climate finances” to make them shift towards renewable energy usage.
• The agreement is binding in some elements like reporting requirements. Other
elements of the agreement are non-binding like the emission targets of the individual
nations.
• The Paris Agreement necessitates all Parties to put forth their best efforts through
Nationally Determined Contributions (NDCs) and to strengthen these efforts in the
future.
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• This also includes the need for regular reporting emissions and implementation by the
parties.
• India’s Intended Nationally Determined Contribution (INDC) includes the reduction
in the intensity of its GDP by 33 to 35% by 2030 from 2005 level. Additionally, it has
pledged to increase the share of non-fossil fuel-based electricity by 40% by 2030. It
has also agreed to enhance its forest cover, which will absorb 2.5 to 3 billion tonnes
of CO2 by 2030.

◼ REDD+

Reducing Emissions from Deforestation and Forest Degradation (REDD+) is a mechanism

developed by Parties of the UNFCCC.

• It creates financial value for the carbon stored in forests to offer incentives for the
developing nations to reduce emissions from forested lands and invest in low-carbon
paths.
• The developing nations will receive results-based payments for results-based actions.
• The REDD+ goes beyond simply deforestation and forest degradation by including
the role of conservation, sustainable management of forests and enhancement of
forest carbon stocks.
• It is estimated that the financial flows for the GHG emission reduction from REDD+
could reach up to $30 billion per year.
• This improved North-South flow of funds can ensure a significant reduction of carbon
emissions and the promotion of inclusive development. It could also improve
biodiversity conservation and secure vital ecosystem services.
• Forests are vital carbon sink and thus, it is vital to increase its resilience to climate
change.

◼ US – China sign pact on emission reductions

• China and the United States in November 2014 agreed on a timetable to limit
emission of greenhouse gases.
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• In a joint announcement, the U.S. agreed to reduce by 2025 its emission of

greenhouse gases by 26 per cent to 28 per cent below its 2005 level.
• China stated its intent to peak emissions of carbon dioxide in 2030, if not earlier. It
also agreed to raise the share of non-fossil fuels to 20 per cent, in its primary energy
mix, in the next 16 years. This would entail China shifting towards clean energy
generated by nuclear, wind, solar and such zero-emitting resources.
• The agreement on a timetable for emission cuts to combat climate change has
brightened prospects for a climate deal in Paris next year.
• The joint announcement could impose fresh pressure on India not to become a deal
breaker in the run up to the Paris talks. India’s per capita emissions are estimated at
one-tenth of the United States and one-fourth of China.

◼ India’ Efforts to Counter Climate Change

• India is the world’s third largest economy and fifth largest greenhouse gas (GHG)
emitter, accounting for about 5% of global emissions. India’s emissions increased
65% between 1990 and 2005 and are projected to grow another 70% by 2020.
• By other measures, India’s emissions are low compared to those of other major
economies. India accounts for only 2% of cumulative energy-related emissions since
1850. On a per capita basis, India’s emissions are 70% below the world average and
93% below those of the United States.
• India is also at the frontlines of facing the impacts of climate change. Shifting rainfall
patterns, recurring floods, stronger cyclones and droughts or soil erosion are
exacerbating the challenge of poverty eradication and necessitate the allocation of
scarce national resources for preventing loss of human life.
• Despite resource constraints, India is undertaking ambitious actions to undertake
adaptation and mitigation actions, including thorough lowering of the energy intensity
of our economic growth, increasing energy efficiency across sectors and making
greater use of renewable.
• India has doubled the Clean Energy Cess on coal, which very few countries have, and
the Clean Energy Fund already has over 3 billion US dollars to be used for promoting
clean technologies
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• India’s National Solar Mission is being scaled up five-fold from 20,000 megawatts to
100,000 megawatts. This will mean an additional investment of 100 billion dollars
and savings of about 165 million tonnes of CO2 emissions per year.
• India is releasing 6 billion US dollars in one go for intensive afforestation which will
result in more carbon sinks.
• India has allocated about 200 million US dollars for the ‘National Adaptation Fund’,
setting-up of Ultra Mega Solar Projects, Ultra-Modern Super Critical Coal Based
Thermal Power Technology, and the development of Solar Parks on canals.
• Another initiative is “100 Smart Cities’ with integrated policies for adaptation and
mitigation to reduce the vulnerability and exposure of urban areas to climate change
and also to improve their energy efficiency for which 1.2 billion US dollars have been
allocated.
• India has put in place stringent norms for cement industry. Our Action Plan for
cleaning one of the longest rivers in the world, River Ganga will bring multiple
benefits of pollution reduction and climate adaptation. We have also taken initiatives
for protecting coastal, Himalayan, and forest areas.
• India has initiated preparations to develop a National Air Quality Index and have
launched a National Air Quality Scheme.
• Setting-up of Ultra Mega Solar Projects in Tamil Nadu, Rajasthan, Gujarat, Andhra
Pradesh and Ladakh to promote renewable energy

◼ National action plan on climate change (NAPCC)

Government of India has launched eight Missions as part of the National Action Plan on
Climate Change (NAPCC) in specific areas which include assessment of the impact of
climate change and actions needed to address climate change.

1. National Solar Mission:

• The NAPCC aims to promote the development and use of solar energy for power
generation and other uses with the ultimate objective of making solar competitive
with fossil-based energy options.
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• The plan includes: specific goals for increasing use of solar thermal technologies in
urban areas, industry, and commercial establishments; a goal of increasing
production of photovoltaic to 1000 MW/year; and a goal of deploying at least 1000
MW of solar thermal power generation.
• Other objectives include the establishment of a solar research centre, increased
international collaboration on technology development, strengthening of domestic
manufacturing capacity, and increased government funding and international
support.

2. National Mission for Enhanced Energy Efficiency:

• Initiatives based on increasing the energy use efficiency were expected to yield
savings of 10,000 MW by 2012.
• Building on the Energy Conservation Act 2001, the plan recommends:
• Mandating specific energy consumption decreases in large energy-consuming
industries, with a system for companies to trade energy-savings certificates;
• Energy incentives, including reduced taxes on energy-efficient appliances; and

• Financing for public-private partnerships to reduce energy consumption through

demand-side management programs in the municipal, buildings and agricultural
sectors.

3. National Mission on Sustainable Habitat:

• To promote energy efficiency as a core component of urban planning, the plan calls
for:
• Extending the existing Energy Conservation Building Code;
• A greater emphasis on urban waste management and recycling, including power
production from waste;
• Strengthening the enforcement of automotive fuel economy standards and using
pricing measures to encourage the purchase of efficient vehicles; and
• Incentives for the use of public transportation.
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◼ India’s Stand on climate change negotiations

• Clean air, clean energy and clean power balanced with growth were the priorities for
India in its mission to combat climate change. The government had pursued
voluntarily set targets with commitment, conviction and followed-up action and had
played an active and positive role in tackling the Climate Change.
• India’s stand is based on its domestic obligations of addressing the basic development
needs of poverty eradication, food security and nutrition, universal access to
education and health, gender equality and women empowerment, water and
sanitation, clean energy, employment, sustainable cities and human settlement and its
commitment to fight climate change.
• India is of the view that historical emissions of developed countries as laid down in
the Conventions should be the basis for differentiation. The developing countries’
need for inclusive growth, sustainable development, poverty eradication, and energy
access to all must be recognized as fundamental to the approach to differentiation
• India is of the view that Announcement of contributions for Green Climate Fund
(GCF) and its actual deposit should be ensured by developed countries. GCF could be
used to purchase Intellectual Property Rights (IPRs) of climate friendly technologies.
The non-capitalization of the Green Climate Fund was a matter of concern and could
affect the 2015 Climate agreement.
• India grows into a regional power, which can only be accomplished if India is given
sufficient development space to grow its economy and eliminate poverty. It is in
India’s interest to diversify its energy portfolio — a prospect that can be strengthened
with the U.S.’s assistance. The way to achieve these objectives is to forge an “India
exception” at the global climate talks in Paris; doing so is the only realistic pathway
to a global climate deal and will cement the growing ties between the two critical
actors in an evolving international order.

6.28 Climate Change:

Climate change is the global phenomenon of climate transformation characterized by the changes
in the usual climate of the planet (regarding temperature, precipitation, and wind) that are
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especially caused by human activities. As a result of unbalancing the weather of Earth, the
sustainability of the planet’s ecosystems is under threat, as well as the future of humankind and
the estability of the global economy.

or
Climate change is the periodic modification of Earth’s climate brought about as a result of
changes in the atmosphere as well as interactions between the atmosphere and various other
geologic, chemical, biological, and geographic factors within the Earth system.
NASA’s definition of climate change says it is “a broad range of global phenomena created
predominantly by burning fossil fuels, which add heat-trapping gases to Earth’s atmosphere.
These phenomena include the increased temperature trends described by global warming, but
also encompass changes such as sea-level rise; ice mass loss in Greenland, Antarctica, the Arctic
and mountain glaciers worldwide; shifts in flower/plant blooming; and extreme weather events.”
In 2013 The Intergovernmental Panel on Climate Change (IPCC) IPCC provided more clarity
about the role of human activities in climate change when it released its Fifth Assessment
Report. It is categorical in its conclusion: climate change is real and human activities are
the main cause.
Fifth Assessment Report of IPPC: The report provides a comprehensive assessment
of sea level rise, and its causes, over the past few decades. It also estimates cumulative
CO2 emissions since pre-industrial times and provides a CO2 budget for future emissions
to limit warming to less than 2°C. About half of this maximum amount was already
emitted by 2011.
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The report found that:

From 1880 to 2012, the average global temperature increased by 0.85°C.
Oceans have warmed, the amounts of snow and ice have diminished and the sea level has
risen. From 1901 to 2010, the global average sea level rose by 19 cm as oceans expanded
due to warming and ice melted.
The sea ice extent in the Arctic has shrunk in every successive decade since 1979, with
1.07 × 106 km² of ice loss per decade.
Given current concentrations and on-going emissions of greenhouse gases, it is likely that
by the end of this century global mean temperature will continue to rise above the pre-
industrial level. The world’s oceans will warm and ice melt will continue.
Average sea level rise is predicted to be 24–30 cm by 2065 and 40–63 cm by 2100
relative to the reference period of 1986–2005.
Most aspects of climate change will persist for many centuries, even if emissions are
stopped.

6.29 Global Warming of 1.5°C

In October 2018 the IPCC issued a special report on the impacts of global warming of 1.5°C,
finding that limiting global warming to 1.5°C would require rapid, far-reaching and
unprecedented changes in all aspects of society. With clear benefits to people and natural
ecosystems, the report found that limiting global warming to 1.5°C compared to 2°C could go
hand in hand with ensuring a more sustainable and equitable society. While previous estimates
focused on estimating the damage if average temperatures were to rise by 2°C, this report shows
that many of the adverse impacts of climate change will come at the 1.5°C mark.
The report also highlights a number of climate change impacts that could be avoided by limiting
global warming to 1.5ºC compared to 2ºC, or more. For instance, by 2100, global sea level rise
would be 10 cm lower with global warming of 1.5°C compared with 2°C. The likelihood of an
Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C,
compared with at least once per decade with 2°C. Coral reefs would decline by 70-90 percent
with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost with 2ºC.
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6.30 SMOG

The term "smog" was first used in London during the early 1900s to describe the
combination of smoke and fog that often blanketed the city. According to several sources,
the term was first coined by Dr. Henry Antoine des Voeux in his paper, “Fog and
Smoke,” which he presented at a meeting of the Public Health Congress in July 1905.
The type of smog described by Dr. des Voeux was a combination of smoke and sulphur
dioxide, which resulted from the heavy use of coal to heat homes and businesses and to
run factories in Victorian England.

Smog is a mixture of air pollutants, mainly nitrogen oxides and some organic
compounds, which combine in presence of sunlight to form Ozone. The Volatile Organic
Compounds can come from various products we use daily such as paint, hairspray,
charcoal starter fluid, chemical solvents, and even packaging plastics.

6.31 Geographical and Climatic Conditions

• Smog occurs in places with higher temperatures, on bright sunny days with no winds.
• It is also common in cities that are in a geologic basin like area surrounded by mountains
on all sides. These areas naturally trap air and much air circulation does not occur.
• Smog occurs frequently in Mexico City in Mexico, Beijing in China, Delhi in India, Salt
Lake City in Utah, Tehran in Iran, London in UK, San Francisco to San Diego in
California and many others.
• Temperature Inversion a climatic phenomenon that occurs when the air closer to the
ground becomes cooler than the air above. We know that warmer air always rises up and
there is a natural mixing of the layers in the troposphere. Thus reducing the concentration
of pollutants and also carrying them away in winds.
• When temperature inversion occurs, the cold air stays where it is, trapping the air
pollutants with it, close to the Earth’s surface. There is a heavy concentration of pollutant
laden air which causes adverse effects on the human health and environmental damage.
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• Smog also occurs in places away from the source of pollution, because of the pollutants
being carried away by wind and air currents to other cities or even countries. For E.g.
China is said to generate a large quantity of air pollutants which cause much damage not
only in China, but in nearby countries like India and even up to the US across the Pacific
Ocean.

6.32 Causes of Smog

Smog is an air pollutant mixture of nitrogen oxides and some organic compounds that reacts with
the sunlight to create an ozone layer in the ground level. The main causes of smog are:

• Coal emissions: the smoke that emits on burning the coal adds to formation of smog. The
areas where coal emission is happening on a large scale will be sure shot of smog.

• Vehicular emissions: the emissions from the vehicles or automobiles are the factors that
cause smog. Such emissions include carbon monoxide, sulphur dioxide, nitric oxides etc.
that are the reasons for smog.

• Industrial emissions: the toxic emissions are also the contributor for the formation of
smog. These smokes also contain the volatile organic compounds and nitric oxides that
can make smog.
• Natural phenomenon: Natural phenomenon such as volcanic eruption that emits a large
amount of sulphur dioxide is also a contributing factor of smog.

• It is also said that some plants that have radiocarbon content emits more smog causing agents
than that of fossil fuels. Being it a natural phenomenon, humans are not responsible for it.

• Photochemical reactions: it is the reactions that cause photochemical smog.

Photochemical smog is the brown mist like layer that is found above the cities. It is
caused due to the reaction of nitrogen oxides and volatile organic compounds with the
sunlight giving out photochemical smog. This is mainly seen during summer due to the
presence of sunlight all through.
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6.33 Effects of Smog

• Smog causes health problems affecting the respiratory system. There is an increase in
Asthma, Emphysema, Chronic Bronchitis, Chronic Obstructive Pulmonary Disease
(COPD)and lung cancer

(Figure 6.27) Effects of smog on human Health ( Source:www.image.slidesharecdn.com)

Smog is not only harmful to humans but also to plants, animals and the nature as a whole.
Exposure to it can lead to various health problems which include:

• Symptoms of Asthma will become worse and can lead to asthma attacks.
• Cardiovascular (heart) disease. Due to bronchial disease many people are dying.
• Production of natural element vitamin D will be less which will lead to rickets among
people.
• Chest irritation, coughing, pneumonia and throat cancer or infection
• Breathing problem, pain when breathing, irritation in eyes and pulmonary disease like
lung cancer will increase.
• Feeling unusually tired, headache, low energy, wheezing.
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• It will cause immense damage to crops and forests. Vegetables and crops mainly soya
beans, wheat, tomatoes, peanuts and cotton are subject to infection when they are
exposed to smog.
So, on smoggy days it is important to note that children, seniors and people with asthma need
to be especially careful. They should take proper precautions.
Although smog affects each and every one of us, it is especially harmful to:

• Children: As children lungs are still in developing stage and in summers they
spend lot of time outdoors while playing which will increase their risk of inhaling
more polluted air.
• People those who have lung disease like asthma problem etc.
• People those who have heart problem and diabetic patients are also more
sensitive because they are more likely to have heart disease.
• Seniors are also at higher risk not only because of their age but also due to their
weaker heart, lungs and immune system.
• People with allergies, pregnant women and smokers need to be careful.

6.34 Types of Smog

1. The Great Smog of London
The Great Smog of London, or Great Smog of 1952, was a severe air-pollution event that
affected the British capital of London in early December 1952. A period of cold weather,
combined with an anticyclone and windless conditions, collected airborne pollutants—mostly
arising from the use of coal—to form a thick layer of smog over the city. It lasted from
Friday 5 December to Tuesday 9 December 1952, and dispersed quickly when the weather
changed.

(Figure 6.28) Trafalgar Square in London during the Great Smog of 1952
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It caused major disruption by reducing visibility and even penetrating indoor areas, far more
severely than previous smog events experienced in the past, called "pea-soupers".
Government medical reports in the following weeks, however, estimated that up until 8
December, 4,000 people had died as a direct result of the smog and 100,000 more were
made ill by the smog's effects on the human respiratory tract. More recent research suggests
that the total number of fatalities may have been considerably greater, one paper suggesting
about 6,000 more died in the following months as a result of the event.

London has suffered since the 13th century from poor air quality, which worsened in the
1600s,but the Great Smog is known to be the worst air-pollution event in the history of the
United Kingdom, and the most significant in terms of its effect on environmental research,
government regulation, and public awareness of the relationship between air quality and
health. It led to several changes in practices and regulations, including the Clean Air Act
1956.

(Figure 6.29) In December 1952, London was trapped in a deadly cloud of fog and pollution for five
days — what became known as the Great Smog of 1952.

II. Effect on London Smog on London

Although London was accustomed to heavy fogs, this one was denser and longer-lasting than
any previous fog. Visibility was reduced to a few meters making driving difficult or
impossible. Public transport ceased, apart from the London Underground, and the ambulance
service stopped, forcing users to transport themselves to the hospital. The smog was so dense
that it even seeped indoors; resulting in cancellation or abandonment of concerts and film
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screenings as visibility decreased in large enclosed spaces, and stages and screens became
harder to see from the seats.
III. Health effects
There was no panic, as London was infamous for its fog. In the weeks that ensued, however,
statistics compiled by medical services found that the fog had killed 4,000 people. Most of
the victims were very young or elderly, or had pre-existing respiratory problems. In February
1953, Marcus Lipton suggested in the House of Commons that the fog had caused 6,000
deaths and that 25,000 more people had claimed sickness benefits in London during that
period. Mortality remained elevated for months after the fog. A preliminary report, never
finalised, blamed those deaths on an influenza epidemic. Emerging evidence revealed that
only a fraction of the deaths could be from influenza. Most of the deaths were caused by
respiratory tract infections, from hypoxia and as a result of mechanical obstruction of the air
passages by pus arising from lung infections caused by the smog. The lung infections were
mainly bronchopneumonia or acute purulent bronchitis superimposed upon chronic
bronchitis. More recent research suggests that the number of fatalities was considerably
greater than contemporary estimates, at about 12, 00
2. Photochemical smog
Photochemical smog is a type of smog produced when ultraviolet light from the sun reacts
with nitrogen oxides in the atmosphere. It is visible as a brown haze, and is most prominent
during the morning and afternoon, especially in densely populated, warm cities. Cities that
experience this smog daily include Los Angeles, Sydney, Mexico City, Beijing, and many
more.

(Figure 6.30) Photochemical smog over Shanghai

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1. Formation of Photochemical Smog

Photochemical smog forms from a complex process, however the source of it is quite
apparent. The largest contributor is automobiles, while coal-fired power plants and some other
power plants also produce the necessary pollutants to facilitate its production. Due to its
abundance in areas of warmer temperatures, photochemical smog is most common in the
summer.

It forms in the morning when a tremendous number people are driving their vehicles to work.
Nitrogen oxides produced in the car engine are introduced into the atmosphere, which may
combine with water to form nitric acid or react with sunlight to produce singular oxygen
atoms, which then combine with molecular oxygen to produce ozone. The nitric acid may
precipitate to the Earth resulting in acid rain, or remain in the smog. Due to the direct
production of it by vehicles, the smog forms over cities where many people may encounter its
adverse health effects. Hotter days mean more photochemical smog, especially in the densely
populated cities such as those mentioned above. As more and more urban populations arise
around the globe, this problem is only expected to increase.

2. Composition of Photochemical Smog

Nitric oxide (NO) and nitrogen dioxide (NO2) are emitted from the combustion of fossil
fuels, along with being naturally emitted from things such as volcanoes and forest fires (it
is the immense concentration of these pollutants within cities that is of the most concern
however, as natural emissions tend to spread out over larger areas). When exposed to
ultraviolet radiation, NO2 goes through a complex series of reactions with hydrocarbons to
produce the components of photochemical smog—a mixture of ozone, nitric acid,
aldehydes, peroxyacyl nitrates (PANs) and other secondary pollutants.

NO2, ozone and PANs are called photochemical oxidants because they can react and
oxidize certain compounds in the atmosphere or within a person's lungs that are not
normally oxidized. Even small traces of these chemicals can affect the respiratory tract of
humans and animals, and damage crops and trees.
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(Figure 6.31) Photochemical smog formation; sunlight reacts with NO2 which then
interacts with other molecules in the air to form smog.

3. Effects
Photochemical smog has many adverse effects. When combined with hydrocarbons, the
chemicals contained within it form molecules that cause eye irritation. Radicals in the air
interfere with the nitrogen cycle by preventing the destruction of ground level ozone. Other
effects include reduced visibility and respiratory ailments.

Ground level ozone is also produced which has various effects on the human body .

6.35 Smog Control

• The Environmental Protection Agency (EPA), the US federal agency has set Air
Quality standards to assess the levels of air pollutants in various places and
provide guide lines for the effects of that pollution on human health.
• The Pollutant standard Index is another relative scale of air quality that applies to
all pollutants.
• The pollution monitoring agencies have set guidelines and strict regulations to
control the emission of air pollutants.
• Keeping track of weather forecasts the weather department may be able to
forecast the occurrence of smog in an area.
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6.36 Desertification

The word ‘desert’ originates from an ancient Egyptian hieroglyph pronounced ‘tesert’, meaning
a place that was ‘forsaken’ or ‘left behind’. Later, it was used as a Latin verb ‘deserturn’ to
signify abandonment. The earliest usages suggest that the deserts were initially vibrant places
that eventually became wastelands.

‘Desertification’ was first popularized by French botanist André Aubréville in 1948, who used it
to describe how tropical forest regions in Africa were being transformed into “desert-like
regions”. This definition suggested the expansion of deserts to new places as desertification.
Strangely enough, this limited understanding played a crucial role in drawing the world’s
attention towards desertification.

The official definition by the United Nations Convention to Combat Desertification (UNCCD)
that has been widely used since it’s formulation in 1994 is: “desertification is land degradation in
arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic
fluctuations and human activities.” UNCCD also highlights that it is important to note that
desertification is not a natural process of deserts expanding to new regions; it is a form of land
degradation caused primarily by human activity in vulnerable areas. In the 1970s, scientists
mistakenly believed the long spells of droughts in the Sahel region in Africa was desertification.
This prompted the establishment of the United Nations Conference on Desertification (UNCOD)
in 1977.

On the back of an ineffective UNCOD, in 1994, the United Nations Convention to Combat
Desertification (UNCCD) was established, which defined desertification as land degradation in
dry land areas due to various factors, including climatic variations and/or human activities.

It predicts that by 2040, over 70 per cent of the big cities (more than 0.3 million people)
currently in non-dryland areas will grow drier in the business-as-usual scenario. In contrast, 43
per cent of the big cities in dryland areas will be hit by desertification.

According to the 2018 World Atlas of Desertification (WAD) population growth and changes in
human consumption patterns have resulted in unprecedented pressures being applied to Earth's
natural resources.
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To date, desertification has resulted in (information courtesy of reliefweb.int and WAD): -

• Over 75% of the Earth's land area is already degraded, and over 90% could become
degraded by 2050.
• Globally, a total area half of the size of the European Union (4.18 million km²) is
degraded annually, with Africa and Asia being the most affected.
• The economic cost of soil degradation for the EU is estimated to be in the order of tens of
billions of euros annually.
• Land degradation and climate change are estimated to lead to a reduction of global crop
yields by about 10% by 2050. Most of this will occur in India, China, and sub-Saharan
Africa, where land degradation could halve crop production.
• As a consequence of accelerated deforestation, it will become more difficult to mitigate
the effects of climate change
• By 2050, up to 700 million people are estimated to have been displaced due to issues
linked to scarce land resources. The figure could reach up to 10 billion by the end of this
century.

• It should also be noted that while land degradation, and desertification, are a global issue;
the effects are local and require localized remediation. Groups like the UNCCD stress the
need for greater commitment and more effective cooperation at the local level to stop the
loss of habitat and stave off potential catastrophe for societies around the world.
• At present, desertification is affecting many parts of the world. It is most notable,
however, in India, China, and sub-Saharan Africa. These areas share the characteristic of
being dry lands.

• Dry lands comprise around 40-41% of the Earth's total land surface and are occupied by
around 2 billion people. Some estimates show that 10–20% of dry lands are already
degraded to date. "The total area affected by desertification being between 6 and 12
million square kilometers, that about 1–6% of the inhabitants of dry lands live in
desertified areas, and that a billion people are under threat from further desertification."
But more temperate regions, like Europe, are not immune to this problem. According to
the WAD, EU nations have around 8% of their territory affected by desertification. The
main areas of concern are Southern, Eastern and Central Europe. These regions comprise
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around 14 million hectares (140,000 km2) and show high sensitivity to desertification.
Under definitions set by the UNCDD, thirteen Member States have declared themselves
affected by desertification

6.37 Process of desertification

Land desertification, as we have already seen, is the gradual, yet continuous, process of
ecosystem degradation in an affected area. During this process, plants and animals, and
geological resources like water and soil, are stressed beyond their ability to adapt and change.
The process occurs gradually and the causes for it are well understood. For this reason, it is
possible for it to be avoided or reversed before the problem gets too serious. Desertification is
characterized by: -

• The progressive loss of mature, stabilizing vegetation in the ecosystem;

• Loss of agricultural crop cover during periods of drought or economic infeasibility
• A resulting loss of unconsolidated topsoil. This process is called deflation.

6.38 Causes of desertification

Desertification is a complex process with multiple causes with climate being an inevitable
dominant factor along with other cultural factors such as over- grazing, over –cultivation
deforestation (usually prompted by over- population). According to sites like greenfacts.org,
the current major factors that contribute to or drive desertification are:

⇨ Overgrazing 35%

⇨ Deforestation 30%

⇨ Agricultural activities 28%

⇨ Overexploitation for biofuels 7%

Table: Factors drive desertification Source: Global Mechanism of the UNCCD, 2016.
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Lands turn to desert due to a number of reasons, but much of the desertification that is
occurring around the world today is caused by human activity on lands that are extremely
vulnerable to overexploitation and improper agricultural methods.

The following are some of the primary causes of desertification in our world.
1. Overgrazing
Overgrazing and desertification have been always closely linked together.
In dry regions, grass and other small vegetation is necessary to keep the soil in place to prevent
erosion and further damage to the soil. However, it is the paradox of life that especially in these
vulnerable regions, animal herding is often the only livelihood people can have and there are no
restrictions in place that would regulate the maximum number of animals for a given space.
When people gather and keep too many animals in one area, grasses start dying because their
roots are often weakened by animals constantly stepping on them and plucking out newly re-
growing parts before plants have time to grow resistant enough and to multiply. After some
time, no vegetation remains to prevent soil from blowing or washing away. So, people move the
livestock to another piece of land where the process repeats. If this occurs long enough, it leads
to extensive desertification.

(Figure: 6.32) Overgrazing of land leading to desertification

There have been numerous cases when overgrazed areas of land became severely damaged.
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Scientists have, for example, confirmed that overgrazing is the primary reason why around
70 percent of the once pasture rich Mongolian steppe is slowly overtaken by the Gobi Desert
now.
2. Unsustainable agriculture techniques
The world’s dry lands cover approximately 40 percent of the total land mass. They are home to
more than 2 billion people, so it is clear that many of these areas are farmed, even though they
are very fragile and can easily turn barren.
Through inconsiderate farming methods like heavy tilling, planting of unsuitable crops and
leaving soils exposed to wind and rain erosion, farmers only speed up the process of
desertification in exchange for poor quality crops with low economic value. Besides, while
preparing the soil for sowing, natural vegetation that holds the brittle soil in place is removed,
letting the last bits of the productive soil layer fully wear away in just a few short seasons.
Another common problem of the crop cultivation in vulnerable areas is the employment of
improper irrigation methods, such as canal irrigation. These irrigation methods often lead to a
build-up of salt in soils. Increased salinity happens because irrigation water mobilizes naturally
occurring salt in these soils. Additionally, artificially added water also rises otherwise low
groundwater level which in turn dissolves even more salts. Salt build up on cultivated lands,
then, makes it difficult for crops and other plants to grow, further exacerbating degradation of
these lands.
3. Deforestation
Deforestation is one of the leading human causes of desertification. Forests are being cut down at
much larger scale than ever before, to be used as fuel, to provide products we use in our daily
life, or to simply create more space for agriculture to sustain growing human population. When
the trees and other vegetation in an area are gone, there are no roots that would hold soils in
place; there is no canopy that would shield the ground from the direct rainfall or from the sun’s
heat. The bare soil then easier dries out and turns to dust, which can be blown and washed away
in a single storm.
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(Figure 6.33) Deforestation is one of the leading human causes of desertification

Once the soil is degraded and the precious nutrients are lost, only infertile and lifeless swaths of
land are left behind. And what’s more, without trees, even the local climate becomes drier due to
the lack of water evapo-transpiration from tree canopy, which reduces cloud formation in the
region and results in less rain.

6.39 The effects of desertification

In the introduction of a document called ‘Desertification: The invisible frontline’ from UNCCD
is stated: “Desertification is a silent, invisible crisis that is destabilizing communities on a global
scale.”
The document further goes on examining the serious and complex web of problems that have
arisen from worsening land degradation of the earth’s dry lands, which are home to 2,000 million
people, comprise of 44 percent of the entire world’s cultivated land and should sustain 50 percent
of the world’s livestock.

1 Vegetation is damaged or destroyed

Desertification reduces the ability of land to support plant life. Loose soil buries plants or
exposes their roots to the sun, so they cannot fulfil their function. With plants dying, already
scarce rainwater gets washed away instead of being drawn into the soil, which only scales up the
problem as remaining plants do not have enough moisture to survive dry spells as they used to.
2 Soil becomes infertile
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Topsoil is crucial for plant growth because it contains most of the organic matter and 50 percent
of important nutrients such as phosphorus and potassium. It is in topsoil where large pores and
soil aggregates form, allowing for proper water infiltration and aeration.
As desertification occurs, this most productive layer of the soil gets blown or washed away from
the surface rather quickly because there is no vegetation that would protect it, and nutrients with
organic material are lost for good. As the soil dries out, it hardens, and it becomes difficult for
any rainfall that does occur to penetrate below the soil’s surface.
3 Soil erosion gets worse
As you may have noticed, desertification problems are often related and lead to one another. The
link between soil erosion and other consequences of desertification only confirms this, as erosion
is another negative outcome but also a catalyst of previously mentioned problems.
In many cases, increased water runoff from desertified areas wreaks havoc on neighbouring
lands, eroding soils, damaging vegetation and making soils extremely vulnerable to encroaching
desert.
When this happens, weakening soils get also directly exposed to wind, which often picks up last
pieces of drying topsoil and mixes them with dust from already degraded parts, exacerbating the
problem and creating far-reaching dust storms.
According to the newest data, the Sahara Desert has been gradually spreading over the
grasslands in the neighbouring Sahel area. Compared with the data from 1920s, Sahara has
already expanded by 10 percent.
4 Increased vulnerability to natural disasters
Desertification makes natural disasters worse because it reduces natural resilience of ecosystems.
This means that affected areas and even adjacent areas have compromised capacity of
withstanding extreme weather events. Desertification also increases vulnerability of whole
regions to the unpredictable effects of climate change.
Events such as flash floods, landslides and dust storms, become stronger in areas with heavily
degraded soils. Without plants stabilizing the soil and slowing down the runoff, rainwater flows
faster and floods human settlements in the blink of an eye.
5 Extinction of species
Extended droughts, prolonged flooding or sudden extreme changes in temperature can deplete
food sources of species causing starvation. Species that once lived in a fertile and productive
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climate may not survive in a newly desertified region. With a changing ecosystem, species must
adapt to their new climate or migrate to a more favorable climate. If they fail to do so, they will
become extinct for their inability to cope with a sudden change of their environment.
.
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SELF ASSESMENT

Long Answer Type Question

Q.1. What is global warming? Explain its causes and consequences.
Explain desertification and its impacts on land resources

Q.2. What is ozone? What are the causes and mechanism for its depletion?
Q.3. How is acid rain formed? What are its causes and impacts on the ecosystem?
Q.4. Describe desertification and its control in detail.

Short Answer Type Questions

Q.1. What do you mean by Kyoto Protocol? What is its importance?
Q.2. Write down the role of some green house gases in global warming.
Q.3. What is climate change? Write down its different causes.
Q.4. Montreal protocol is a global effort to protect ozone layer. Discuss briefly.
Q.5. Write down the impacts of ozone depletion.
Q.6. What is smog? What are its different types?

Very Short Answer Type Questions

Q.1. Define photochemical smog.
Q.2. What do you mean by climate change?
Q.3. Expand IPCC.
Q.4. How can desertification be minimised?
Q.5. What are the impacts of global warming?
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UNIT 7: ENVIRONMENTAL MANAGEMENT AND

LEGISLATION
Learning Outcomes
a) Understand the basic idea of Sustainable Development and the measures for
attaining sustainability.
b) Acquaint with the meaning, scope and key elements of Environmental Impact
Assessment (EIA).
c) Have an understanding of the salient features of different environmental laws
in India namely Water (Prevention and Control of Pollution) Act, 1974; Air
(Prevention and Control of Pollution) Act, 1981; Environment (Protection)
Act, 1986.

7.1 Concept of Sustainable Development

Sustainable development can be defined as an approach to the economic development of a

country without compromising the quality of the environment for future generations. In the name
of economic development, the price of environmental damage is paid in the form of land
degradation, soil erosion, air & water pollution, deforestation, etc. This damage may surpass the
advantages of having more quality output of goods and service.

Brundtland Report, also called Our Common Future, a publication released in 1987 by the World
Commission on Environment and Development (WCED) introduced and defined the concept
of Sustainable Development as “meeting the needs of the present without compromising the
ability of future generations to meet their own needs.” Sponsored by the United Nations and
chaired by Norwegian Prime Minister Gro Harlem Brundtland, the WCED explored the causes
of environmental degradation, attempted to understand the interconnections between
social equity, economic growth, and environmental problems, and developed policy solutions
that integrated all three areas.
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Fig. 7.1: Sustainable Development (Venn diagram).

Today sustainable development has become a buzz word and hundreds of programmes have been
initiated in the name of sustainable development. A clear discussion on sustainable development
emerged on an international level in 1992, in the UN Conference on Environment and
Development (UNCED), popularly known as The Earth Summit, held at Rio de Janeiro, Brazil.
The Rio Declaration aims at “a new and equitable global partnership through the creation of new
levels of cooperation among states ….” Out of its five significant agreements Agenda-21
proposes a global programme of action on sustainable development in social, economic and
political context for the 21st century. This was followed by UN World Summit on Sustainable
Develpment (WSSD) or “Rio + 10” in Johannesburg, South Africa in 2002 (26 August - 4
September 2002) to review progress since the Rio conference in 1992, and to agree a new global
deal on sustainable development and emphasize on national strategies for sustainable
development.

Some of the important measures for sustainable development are as follows:

(i) Technology: Using appropriate technology is one which is locally adaptable, eco-
friendly, resource efficient and culturally suitable. It mostly involves local resources
and local labour. Indigenous technologies are more useful, cost-effective and
sustainable. Nature is often taken as a model, using the natural conditions of that
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region as its components. This concept is known as “design with nature”. The
technology should use less of resources and should produce minimum waste.

(ii) Reduce, Reuse, and Recycle Approach: The 3-R approach advocating minimization
of resource use, using them again and again instead of passing it on to the waste
stream and recycling the materials goes a long way in achieving the goals of
sustainability. It reduces pressure on our resources as well as reduces waste
generation and pollution.

(iii) Promoting Environmental Education and Awareness: Making environmental

education the centre of all learning process will greatly help in changing the thinking
pattern and attitude of people towards our earth and the environment. Introducing
subject right from the school stage will inculcate a feeling of belongingness to earth
in small children. ‘Earth thinking’ will gradually get incorporated in our thinking and
action which will greatly help in transforming our lifestyles to sustainable ones.

(iv) Resource Utilization as Per Carrying Capacity: Any system can sustain a limited
number of organisms on a long-term basis which is known as its carrying
capacity. Sustainability of a system depends largely upon the carrying capacity of the
system. If the carrying capacity of a system is crossed (say, by over exploitation of a
resource), environmental degradation starts and continues till it reaches a point of no
return.
Carrying capacity has two basic components:
(a) Supporting capacity i.e. the capacity to regenerate

(b) Assimilative capacity i.e. the capacity to tolerate different stresses.

In order to attain sustainability it is very important to utilize the resources based upon the above
two properties of the system. Consumption should not exceed regeneration and changes should
not be allowed to occur beyond the tolerance capacity of the system.
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(v) Improving Quality of Life Including Social, Cultural and Economic Dimensions:
Development should not focus just on one-section of already affluent people. Rather
it should include sharing of benefits between the rich and the poor. The tribal, ethnic
people and their cultural heritage should also be conserved. Strong community
participation should be there in policy and practice. Population growth should be
stabilized.

7.2 Environmental Impact Assessment (EIA): Scope and Key Elements

7.2.1 INTRODUCTION

There has been a remarkable interest in environmental issues over the past few years. A major
impetus was provided by the 1987 Report of the World Commission on the Environment and
Development (the Brundtland Report); the Earth Summit in 1992 sought to accelerate the
impetus. Much of the discussion on environmental issues and on sustainable development is
about the better management of current activity in harmony with the environment. However,
there will always be pressure for new development. How much better it would be to avoid or
mitigate the potential harmful effects of future development on the environment at the planning
stage. Environmental impact assessment (EIA) assesses the impacts of planned activity on the
environment in advance, thereby allowing avoidance measures to be taken: prevention is better
than cure.

EIAs commenced in the 1960s, as part of increasing environmental awareness. The USA was the
first country to enact legislation on EIA. In the United States, EIAs obtained formal status in
1969, with enactment of the National Environmental Policy Act (NEPA). This was the first time
that EIA became the official tool to be used to protect the environment. The United Nations
Conference on the Environment in Stockholm in 1972 and subsequent conventions formalized
EIA. The EIA process really took off after the mid-1980s. It spread worldwide and received a
significant boost in Europe with the introduction of an EC Directive on EIA in 1985. In 1989, the
World Bank adopted EIA for major development projects, in which a borrower country had to
undertake an EIA under the Bank's supervision.
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The Indian experience with Environmental Impact Assessment started in 1976-77 when the
Planning Commission asked the Department of Science and Technology to examine the river-
valley projects from an environmental angle. This was subsequently extended to cover those
projects, which required the approval of the Public Investment Board. Till 1994, environmental
clearance from the Central Government was an administrative decision and lacked legislative
support.

On 27 January 1994, the Union Ministry of Environment and Forests (MoEF), Government of
India, under the Environmental (Protection) Act 1986, promulgated an EIA notification making
Environmental Clearance (EC) mandatory for expansion or modernisation of any activity or for
setting up new projects listed in Schedule 1 of the notification.

Environmental Impact Assessment (EIA) may be defined as a formal process used to predict the
environmental consequences of any developmental project. EIA thus ensures that the potential
problems are foreseen and addressed at an early stage in the planning and design of a project.

Environmental Impact Assessment (EIA) is a planning tool that is generally regarded as an

integral component of sound decision making. As a planning tool, it has both an information
gathering and decision making component which provides the decision maker with an objective
basis for granting or denying approval for a proposed development. Hence, as a decision making
tool, EIA compares various alternatives for a project and seeks to identify the one which
represents the best combination of economic and environmental costs and benefits.

7.2.2 Scope of Environmental Impact Assessment (EIA)

EIA systematically examines both beneficial and adverse consequences of the project and
ensures that these effects are taken into account during project design. It helps to identify
possible environmental effects of the proposed project, proposes measures to mitigate adverse
effects and predicts whether there will be significant adverse environmental effects, even after
the mitigation is implemented. By considering the environmental effects of the project and their
mitigation early in the project planning cycle, environmental assessment has many benefits, such
as protection of environment, optimum utilisation of resources and saving of time and cost of the
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project. Properly conducted EIA also lessens conflicts by promoting community participation,
informing decision makers, and helping lay the base for environmentally sound projects. Benefits
of integrating EIA have been observed in all stages of a project, from exploration and planning,
through construction, operations, decommissioning, and beyond site closure.

The purpose of EIA may be summarized as under:

(a) It is an instrument for achieving the goals sustainable development

(b) It helps in integrating environmental protection and economic decisions at the earliest
stages of planning an activity.

(c) It is a basic tool for predicting physical, chemical, biological, social, economic and
cultural consequences of a proposed activity and to assess plans to mitigate any adverse
impacts resulting from the proposed activity.

(d) EIA provides for the involvement of the public, Government departments and agencies in
the review of the proposed activities.

7.2.3 Key elements of EIA

The environment impact assessment (EIA) consists of various steps with each step equally
important in determining the overall performance of the project. Typically, the EIA process
begins with screening to ensure time and resources are directed at the proposals that matter
environmentally and end with some form of follow up on the implementation of the decisions
and actions taken as a result of an EIA report. The steps of the EIA process are briefly presented
below:

(1) Screening: Project screening is the first stage of EIA which determines whether the
proposed project requires an EIA and if it does, then the level of assessment
required. Guidelines for whether or not an EIA is required are country specific
depending on the laws or norms in operation (see Appendix-I).
 192

(2) Scoping: This stage identifies the key issues and impacts that should be further
investigated. It also defines the boundary and time limit of the study. This stage is very
wide and extensive because consultations, discussions, experts’ opinions etc. are very
important, useful and essential at this stage. It should involve all interested groups such as
the proponents and planning or environmental agencies and members of the public.

Fig. 7.2: Process of Environmental Impact Assessment (EIA)

(3) Impact Analysis: This stage of EIA identifies and predicts the likely environmental
impact of the proposed project and evaluates the significance.
 193

a. Impact Identification: It includes the details of project characteristics and

baseline environmental characteristics to ensure the identification of full range of
environmental impacts. During identification process, the positive and negative,
direct and indirect, significant and insignificant impacts are considered.

b. Impact Prediction: Here, magnitude of changes going to occur due to the project
is predicted by using mathematical models, mass balance models, etc. The
magnitude of the identified change in the environment is predicted with a
project/action in comparison with the situation without that project/action.

c. Impact evaluation: Impact evaluation is done by considering the costs and

benefits of the project. Long-term effects and side-effects of the project are also
evaluated. Indirect valuation of environmental parameters is also done e.g. loss of
a rare species, degradation of a lake etc.

(4) Mitigation: This step in EIA recommends the actions to reduce and avoid the potential
adverse environmental consequences of development activities. Mitigation is defined as
not only taking action, limiting the proposed action and its implementation but also
repairing, rehabilitating or restoring the affected environment, preventive maintenance
actions during the life of the project and replacing or providing substitute resources for
protecting the environment.

(5) EIS Presentation (Reporting the findings of EIA): An Environmental Impact

Statement (EIS) is a document or a report which contains the findings of EIA like the
environmental impacts of the proposed project and/or alternatives and mitigating
measures, etc.

(6) Review of EIS: It examines the adequacy and effectiveness of the EIA report and
provides the information necessary for decision-making. It ensures that all relevant
information has been analysed and presented. Public participation can be used effectively
in ensuring that the EIS is objective, truthful and complete.
 194

(7) Decision-making: It decides whether the project is rejected, approved or needs further
change.

(8) Monitoring and Auditing. It involves the measuring and recording of different
environmental variables associated with development project. It compares the impacts
predicted in EIS with those that actually occur after the implementation, in order to assess
whether the impact prediction performs satisfactorily. Monitoring and auditing can make
important contributions to the better planning and the EIA of the future projects. So, it
helps in providing the constant feedback in order to learn from the experiences.

7.3 Salient features of Water (Prevention and Control of Pollution) Act, 1974

‘Water’ being a ‘state subject’, the Parliament can exercise the power to legislate on “water”
only under Articles 249 and 252 of the Constitution of India. Under Article 252 (1) of the
Constitution, resolutions were passed by all the Houses of the Legislatures of the States of
Assam, Bihar, Gujarat, Haryana, Himachal Pradesh, Jammu & Kashmir (erstwhile J&K State),
Karnataka, Kerala, Madhya Pradesh, Rajasthan, Tripura and West-Bengal and Union Territories
to the effect that the matters relating to prevention and control of water pollution should be
regulated by the Parliament by Law. Accordingly, the Parliament enacted the Water (Prevention
and Control of Pollution) Act, 1974. The Water Act represents one of the India’s first attempts to
deal with an environmental issue comprehensively.

The purpose of the legislation is not only the prevention and control of Water Pollution but also
the maintenance and restoration of the wholesomeness of water. This specialized legislative
measure is meant to tackle one facet of environmental pollution. The provisions of the Act are as
follows:

(a) To provide for the prevention and control of water pollution and the maintaining or
restoring of wholesomeness of water.

(b) To establish Central and State Boards for the prevention and control of water pollution.
 195

(c) To provide for conferring on and assigning to such Boards powers and functions relating
thereto and for matters connected therewith (i.e., It confers them with powers and
functions to control pollution).

(d) To provide penalties for the contravention of the provisions of the Water Act.

(e) To establish Central and State water-testing laboratories to enable the Board to assess the
extent of pollution, lay down standards and establish guilt or default.

Chapter IV deals with the powers and functions of the Central and State Boards. Under this Act,
the Central and State Boards have been established and assigned distinct functions to promote
the cleanliness of the water bodies like streams, wells in the different areas of the states.

7.3.1 Central Pollution Control Board (CPCB):

The Central Board may perform all or any of the following functions namely:

(i) advise the Central Government on any matter concerning the prevention and control
of water pollution;

(ii) coordinate the activities of State Boards and resolve disputes among them;

(iii) provide technical assistance and guidance to the State Boards, carry out and sponsor
investigations and research relating to problems of water pollution and prevention,
control or abatement of water pollution;

(iv) organize through mass media a comprehensive programme regarding the prevention
and control of water pollution;

(v) to perform the functions of the State Board where the State Board where the State
Board has defaulted in complying with the directions of the Central Board resulting
into grave emergency and where it is required to do so in the public interest;
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(vi) plan and cause to be executed a nationwide programme for the prevention, control or
abatement of water pollution;

(vii) Collects, compiles and publishes technical and statistical data related to pollution;

(viii) Establishes and recognizes laboratories for analysis of water, sewage or trade
effluents.

7.3.2 State Pollution Control Boards (SPCB):

These boards also have similar functions to be executed at state level and are governed by the
directions of CPCB. A State Board shall have the following functions:

(i) To plan a comprehensive programme for the prevention, control or abatement of

water pollution.

(ii) To advise the State Government on matters concerning the prevention, control and
abatement of water pollution.

(iii) To collect and spread information relating to prevention, control and abatement of
water pollution.

(iv) To encourage and conduct investigations and research resulting to problems of water
pollution.

(v) To collaborate with the Central Board in organizing training programmes relating to
the prevention, control or abatement of water pollution and to organize mass
education programme relating thereto.

(vi) It lays down standards for effluents and is empowered to take samples from any
stream, well or trade effluent or sewage passing through an industry.

(vii) To evolve economical and reliable methods for treatment of sewage and trade
effluents.
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(viii) To advise the State Government with respect to the location of any industry which is
likely to pollute a stream or well.

(ix) The Board suggests efficient methods for utilization, treatment and disposal of trade
effluents on land or in any particular stream.

The Water Act has ample provisions for preventing and controlling water pollution through legal
measures.

7.4 Salient features of Air (Prevention and Control of Pollution) Act, 1981

The Air (Prevention and Control of Pollution) Act, 1981 has been enacted by the Parliament
under Article 253 of the Constitution to make laws for implementing decisions taken at
international conferences. The preamble to the Air Act states that the Act represents an
implementation of the decision made at the United Nation Conference on the Human
Environment held in Stockholm in June 1972. In this conference, India participated and was a
party to the decision taken at the conference, to take appropriate steps for the preservation of the
natural resources of the earth which, among other things, include the preservation of the quality
of air and control of air pollution. The main objectives of the Act are as follows:

(1) To provide for the prevention, control and abatement of air pollution.

(2) To provide for the establishment of central and State Boards with a view to implement
the Act.

(3) To confer on the Boards the powers to implement the provisions of the Act and assign to
the Boards functions relating to pollution.

Structurally, the Air Act is similar to the Water Act-with a Central board and State boards
administering a system of consent orders, monitoring activities and enforcement through fines
and criminal prosecution. Chapter III of the Air Act deals with the powers and functions of the
boards.
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7.4.1 Powers and Functions of the Central Board:

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. The Board advises the Central
Government on matters concerning the improvement of air quality and also coordinates
activities, provides technical assistance and guidance to State Boards and lays down standards
for the quality of air. It collects and disseminates information in respect of matters relating to air
pollution and performs functions as prescribed in the Act.
7.4.2 Powers and Functions of the State Boards:
The State Boards have the power to advise the State Government on any matter concerning the
prevention and control of air pollution. They have the right to inspect at all reasonable times any
control equipment, industrial plant, or manufacturing process and give orders to take the
necessary steps to control pollution.
They are expected to inspect air pollution control areas at intervals or whenever necessary. They
are empowered to provide standards (in consultation with the Central Board) for emissions to be
laid down for different industrial plants with regard to quantity and composition of emission of
air pollutants into the atmosphere.

A State Board may establish or recognize a laboratory to perform this function. The State
Governments have been given powers to declare air pollution control areas after consulting with
the State Board and also give instructions to ensure standards of emission from automobiles and
restriction on use of certain industrial plants.

The Central Board and State Board are bound by such directions in writing as the Central
Government and State Government respectively may give to them. Where a direction by the
State Government is inconsistent with the direction given by the Central Board the matter has to
be decided by the Central Government.

It is evident that the framework of the Air Act is similar to the one adopted by its predecessor,
the Water Act. The Air Act expands the authority of the Central and State Boards established
under the Water Act to include air pollution prevention, control and abatement. All industries
operating within designated air pollution control areas are required to obtain a 'permit' from the
 199

State Board under the Air Act. Emission standards for industry and automobiles are to be
prescribed .by the states after consulting the Central Board and noting its ambient air quality
standards. Under the Act boards are empowered to close down a defaulting industrial unit or may
stop its electric or water supply. A board has the option to apply to a court to restrain emissions
that exceed prescribed standards. The stiff penalties, citizens' suit provision and inclusion of
noise pollution have made the Air Act more purposeful and effective.

7.5 Salient features of Environment (Protection) Act, 1986

The Environment (Protection) Act , 1986 or EPA, 1986 was enacted under Article 253 of the
Constitution of India to implement the decisions made at the United Nations Conference on
Human Environment held at Stockholm in 1972. India participated in the conference and in order
to fulfill its commitment at the conference relating to the protection and improvement of
environment and the prevention of hazards to human beings, other living creatures, plants and
property passed the aforesaid enactment.
The Environment Protection Act is the umbrella legislation to provide framework for central
government to coordinate activities of various central and state authorities established under
previous laws. The objectives of the Environment Protection Act are:

(1) To implement the decisions which were made at the United Nation Conference on the
Human Environment held at Stockholm in June 1972.
(2) To provide for the protection and improvement of environment and for matters connected
therewith.
(3) Coordinating the activities of various regulating agencies which are done under the
existing law.
(4) Providing deterrent punishment to those who inculcate in endangering the human
environment, safety and health.
(5) To enact general laws for environmental protection which could be unfolded in areas of
severe environmental hazards.

7.5.1 Scope and commencement of the Act

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The Act is a special law and extends to the whole of India. It came into force on the 19
November 1986. Section 2 of the Environmental protection Act, 1986 (EPA) deals with some of
the information about the definition of the Act and these definitions are as follows:

(a) ‘Environment' includes water, air and land and the inter-relationship which exists among
and between water, air and land and human beings, other living creatures; plants, micro-
organism and property.
(b) The 'environmental pollutant', according to the Act, means any solid, liquid or gaseous
substance present in such concentration as may be, or tend to be, injurious to
environment.
(c) 'Environmental Pollution' means the presence in environment of any environmental
pollutant.
(d) 'Hazardous substance' means any substance or preparation which, by reason of its
chemical or physico-chemical properties or handling, is liable to cause harm to human
beings, other living creatures, plants, microorganism, property or the environment.

Thus, from the above definitions it shows that the EPA is the overall National legislation
covering a wide range of the subject matters pertaining to the environment.

7.5.2 Central government: Measures to protect and improve the Environment

The central government has the powers to take all the steps and measures for the
protection and improvement of the quality of the degrading environment. These
measures are taken for the prevention, control and abatement of environmental
Pollution. Such measures may include:

(1) Laying down the standards for the emission or discharge of environmental pollutants.
(2) Planning and execution of the nationwide programme for the prevention, controlling and
the abatement of environmental pollution.

(3) Restrictions of areas in which any industry or any operation shall be carried out.
(4) To lay down the procedure and safeguards for the prevention of many inevitable
accidents which may result in more environmental pollution
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(5) To lay down the procedures and safeguards for handling hazardous substances.
(6) Inspection of any premises, equipment, material and directing the authorities to take
appropriate measures for the prevention and control of environmental pollution.
(7) Preparation of the manuals, codes, guides required for controlling environmental
pollution.
(8) Establishment and recognition of environment laboratories.

The central government in the exercise of powers of the Act can issue the directions to any
occupier or any person for the closure, prohibition or the regulation of any industry and its
operational process and also the stoppage of the supply of electricity or any other service. The
occupier or the owner of the industry or any plant has to comply with the directions failing which
their act shall be punishable and the services provided are liable to be taken back leading to the
closure of the industry.

7.5.3 Penalties for the Contravention of the Act

One of the most important goals of the environment protection act is to provide for the
punishment of the offence of endangering human environment, safety and health. Any person
who is not complying with the provisions of the act or the rules made thereunder or any set of
directions thereof will make him punishable under the Act with imprisonment for a term which
may extend to five years or a fine upto one lakh rupees or both and if the failure continues, then
an additional fine of 5000 rupees can also be levied every day. The punishment under the Act is
harsher if compared with the penal provision given under the water Act or Air Act. This is the
first time that very heavy penalties like imprisonment for periods up to 5 years and fine up to Rs.
1 lakh have been prescribed for environmental violation.
A complaint can be filed under this Act by two parties:

(i) The Central Government or any authority or officer authorised in the behalf by that
Government; or
(ii) Any person who has given notice of not less than sixty days of the alleged offence
and of his intention to make complaint, to the Central Government or the authority or
officer authorised as aforesaid.
7.5.4 Power to Delegate and Make Rules
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The Act empowers the Central Government to make rules for carrying out the purposes of the
Act. Such rules define:
(a) the standards for environmental pollutants;
(b) the handling of hazardous substances;
(c) the procedure to take samples;
(d) the functions etc. of environmental laboratories;
(e) the qualifications of Government Analyst;
(f) the manner in which notice of the offence and of the intention to make a complaint to the
Central Government shall be done;
(g) the authority or officer to whom any reports or any information shall be furnished.

Every rule made under the Environment Act is required to be laid before each House of
Parliament. Rules can be accepted, modified or rejected by both the House of Parliament.

So far various rules have been notified by the Central Government in the exercise of the powers
conferred under the Act. These Rules includes:

(1) The Environment (Protection) Rules, 1986

(2) The Hazardous Wastes (Management and Handling) Rules, 1989
(3) The Bio-Medical Waste (Management and Handling) Rules, 1998
(4) The Recycled Plastics Manufacture and Uses Rules, 1999.
(5) The Municipal Solid Waste (Management and Handling) Rules, 2000. ·
(6) Noise Pollution (Control and Regulation) Rules, 2000.

Thus, the environment Act being an 'umbrella' legislation intends to provide a framework for
Central Government to coordinate the activities of various Central and State authorities
established under previous enactments, such as the Water Act and Air Act. The Act empowers
the Centre to take all such measures as it deems· necessary or expedient for protection and
improvement of the quality of the environment and prevention, control and abatement of
environmental pollution.
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SELF ASSESSMENT
(A) Answer the following questions

1) What do you mean by EIA? Why is it required and what are its key elements?
2) What are the different measures for achieving sustainable development?
3) What are the objectives of Air (Prevention and Control of Pollution) Act, 1981?
4) What are the salient features of EPA, 1986? Why is it called umbrella legislation?

(B) Fill in the blanks

5) UN Conference on Human Environment was held at Stockholm in………..

6) The term Sustainable Development was introduced in……………….commission.
7) ……………… is the first stage of EIA.
8) In India, the process of EIA started in the year……………….
9) Water (Prevention and Control of Pollution) Act was enacted in the year……
10) NEPA stands for………………………………………………………

(C) Choose the correct option

11) Air pollution control Act was enacted in the year

(i) 1986 (ii) 1974 (iii) 1981 (iv) 1971

12) Indian parliament passed various laws for environmental protection in response to
(i) Earth Summit (ii) CITES (iii) Stockholm Conference (iv) Kyoto protocol
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REFERENCES
1) J. Glasson, R. Therival and A. Chadwick. Introduction to Environmental Impact
Assessment. London: London UCL Press, 1994.
2) A. Ogola (2007). “Environmental Impact Assessment, General Procedures”. Lake
Naivasha: UNU-GTP and KenGen.
3) Armin Rosencranz et al (ed), “Environmental Law and Policy in India”, (1991) Tripathi,
Bombay.
4) Chakrabarti, Dr. N.K. (1995) “Environmental Protection and the Law”, New Delhi.
5) Kaushik A. and Kaushik, C.P. Perspectives in Environmental Studies, New Age
International (P) Ltd. Publishers, New Delhi 2008. 3rd edition.
6) D.J. Kalita (2016). EIA in India: An Appraisal. Dimorian Review
7) Mani, S. Bansal, A. “Environmental Science, Centre for Science and Environment”,
Foundation Books, New Delhi (2012).

Internet Sites
www.cseindia.org
www.brittanica.com
www.yourarticlelibrary.com
www.byjus.com
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Glossary

Acid deposition: Acidic material that falls from the atmosphere to the earth in either wet
(rain, sleet, snow, or fog) or dry (gases and particles) forms.
Acid Rain Program: A program run by the U.S. Environmental Protection Agency with the
goal of reducing emissions of sulphur dioxide and nitrogen oxides.
Acid rain: A popular expression for the deposition by rainfall of various airborne pollutants
(especially SO2 and NO2) that have harmful effects on vegetation, soils, buildings and other
external structures. Toxic gases like SOx and NOx dissolve in rain water to form sulphuric acid
and nitric acid and come down as acid rain.

Acidic: A term used to describe substances that have a value lower than 7 on the pH scale.
Acidic pollutants: Harmful particles, such as sulphur dioxide and nitrogen oxides, that turns
into acid when they mix with water and oxygen in the sky.
Aeration tank: A tank that is used to inject air into water

Aerosol: Minute particles and droplets suspended in the air.

Algal bloom: An unusual, sudden or excessive abundance of algae. Algal blooms can adversely
affect water quality.

Alkaline: A term used to describe substances that have a value higher than 7 on the pH
scale.
Ambient air: The air surrounding us.

Anthropogenic: Human generated; caused by humans.

Atmosphere: The mass of air surrounding the earth.

Biodiversity: Living organisms and their varieties present on earth are collectively known as
biodiversity.

Biological Oxygen Demand: The amount of oxygen required by aerobic microorganisms to

decompose the organic matter in sample of water. Used as a measure of the degree of water
pollution.

Climate: Long term pattern of weather in a particular area.

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Compost: A nutrient rich material produced by biological degradation of organic material under
aerobic conditions.

Conservation tillage farming: Crop farming where soil is least disturbed.

CPCB: Central Pollution Control Board

Cryopreservation: Technique where living cells is preserved in liquid nitrogen at extremely low
temperatures.

Earth Summit: United Nations Conference on Environment and Development held at Rio de
Janeiro in 1992.
Effluent: Liquid flowing out of a system, such as a discharge of liquid waste from a factory or
water leaving a sewage treatment plant.

Endangered species: Species which are likely going to be extinct in near future.

Environment: All external conditions that affect an organism or other specified system
during its lifetime.
Environmental Impact Assessment (EIA): A systematic analysis of the effects of a major
developmental project.
Eutrophication: Over nourishment of water bodies due to excessive nitrates and phosphates
received through runoff. The aging process by which lakes are fertilized with nutrients.

Exotic species: That species which is not the natural member of a community.

Gully Erosion: Removal of layers of soil creating large channels.

Habitat: The dwelling place of an organism represents its habitat.

In-Situ Conservation: Conservation of biodiversity in its natural habitat.

Leaching: Process in which various nutrients in upper layers of soil are dissolved and carried to
lower layers.

Nitrogen oxides (NOx): Gases consisting of one molecule of nitrogen and varying numbers
of oxygen molecules. Nitrogen oxides are produced, for example, by the combustion of
fossil fuels in vehicles and electric power plants. In the atmosphere, nitrogen oxides can
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contribute to formation of photochemical ozone (smog), impair visibility, and have health
consequences; they are considered pollutants.

Nitrous oxide (N2O): A powerful greenhouse gas with a global warming potential evaluated
at 310. Major sources of nitrous oxide include soil cultivation practices, especially the use of
commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and
biomass burning.
Non-Point pollution source: Polluted runoff sources not discharged from a single point, such as
runoff from agricultural fields or feedlots.

Oxidation pond: A man-made body of water in which waste is consumed by bacteria.

Particulate matter: Solid particles or liquids droplets suspended in air.

Pesticides: Chemicals used to kill or control pests, such as weeds, insects, fungus, mites, algae,
rodents and other undesirable agents.

pH: A way of measuring the acidity of an object. Values of pH can range from 0-14, with 0
being the most acidic, and 14 being the least acidic. For more information on pH see Acid
Rain and the pH Scale.
Phytoplankton: Free-floating, mostly microscopic aquatic plants.

Point pollution source: A single identifiable source that discharge pollutants into the
environment. Pollution arising from a well-defined origin, such as a discharge from an industrial
plant.

Pollutant: Any substance which causes pollution.

Pollution: Environmental condition in which certain substances (including the normal

constituents in excess) are present in concentrations that can cause undesirable effects on man
and his environment.

Precipitation: The collection of water molecules that falls from the sky as rain, sleet, hail,
or snow.
Primary pollutant: Pollutants released directly into the air.
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Reduce, Recycle and Reuse (3-R Approach): An approach towards reducing waste generation
and pollution.
Runoff: That portion of precipitation or irrigation water that flows off a field or paved area and
enters surface water. The excess of precipitation that does not evaporate or infiltrate.

Secondary pollutant: Pollutants formed by the reaction of two or more primary pollutant in the
air.

Sewage: Waste fluid in a sewer system.

Sludge: A semi-solid residue, containing micro-organisms and their products, from any water
treatment process.

SPCB: State Pollution Control Board

Sustainable Development: An approach to the economic development of a country without
compromising the quality of the environment for future generations

Terracing: Shaping the land to create level shelves on hill slopes.

Zooplankton: Tiny aquatic animals eaten by fish.

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Appendix-I
Environment and Social Screening

Part A: General Information

Name of the sub-project

2.Type of proposed activity (tick the applicable option and provide details)

▪ Road X
▪ Bridge X
▪ Fire Station X -

▪ Hospital/Health Facility X

▪ Educational Institute ✓

▪ Building for Livelihoods X

▪ Flood Infrastructure Related X

▪ Other Public Building X

▪ Any Other (Please Specify) X

3. Location of the proposed sub-project

▪ Name of the Region

▪ Name of the District

▪ Name of the Block

▪ Name of the Settlement

▪ Latitude

▪ Longitude

4a. Proposed Nature of Work (tick the applicable options)

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▪ Minor Repairs

▪ Major Repairs/Rehabilitation

▪ Upgrading/Major Improvement

▪ Expansion of the facility

▪ New Construction
▪ Any Other
4b. Size of the sub-project
(approx. area in sq. mt/hac or length in
mt/km, as relevant)
5. Land Requirement (in hac./sq.mt.)

▪ Total Requirement

• Private Land

▪ Govt. Land

▪ Forest Land

6. Implementing Agency Details (sub-project level)

▪ Name of the Department/Agency

▪ Name of the contact person

▪ Designation
▪ Contact Number
▪ E-mail Id
7. Screening Exercise Details

▪ Date on which it was carried out

▪ Name of the Person

▪ Contact Number

▪ E-mail Id
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Part B (1): Environment Screening

Question Yes No Details

1. Is the sub-project located in whole or part within 1 km of the following

environmentally sensitive areas?

a. Biosphere Reserve

b. National Park

c. Wildlife/Bird Sanctuary

d. Wildlife/Bird Reserve

e. Important Bird Areas (IBAs)

f. Habitat of migratory birds .

(outside protected areas)

g. Breeding/Foraging/Migratory
route of Wild Animals (outside
protected areas)

h. Area with threatened/rare/

endangered fauna (outside
protected areas)

i. Area with threatened/rare/

endangered flora (outside
protected areas)

j. Reserved/Protected Forest

k. Other category of Forest

.
l. Wetland

m. Natural Lakes
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n. Rivers/Streams

o. Swamps/Mudflats

p. Zoological Park

q. Botanical Garden

a. World Heritage Sites

b. Archaeological monuments/
sites (under ASI’s central/state
list)
c. Historic Places/Monuments/
Buildings/Other Assets (not
listed under ASI list but
considered locally important or
carry a sentimental value)
d. Religious Places (regionally or
locally important)
e. Reservoirs/Dams
f. Canals

g. Public Water Supply Areas from

Rivers/Surface Water
Bodies/Ground Water Sources
4. What is the High Flood Level in
the sub-project area?

5. Is any scheduled/protected tree

like Chinar, Mulberry or Deodar
likely to be affected/ cut due to
the project?
6. Is the sub-project located in a
landslide/heavy erosion prone
area or affected by such a
problem?
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7. Is sub-project located in an area

that faces water paucity or water
quality issues?

Part B (2) : Result/Outcome of Environmental Screening Exercise

1. Environment Impact
Assessment Required

2. Environment Clearance
Required
3. Forest land
Clearance/Diversion Required
4. Tree Cutting Permission
Required
5. ASI (Centre/State) Permission
Required

6. Permission from ULB/Local

Body/Department Required

7. Any other
clearance/permission required

Part C (1): Social Screening

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1. Does the sub-project activity require acquisition of land?

Yes No

Private Land (sq mts/hac.)

Give the following details: Govt. Land (sq mts/hac.)

Forest Land (sq mts/hac.)

2. Does the proposed sub-project activity result in demolition/removal of

existing structures?

Yes

If so, give the following details:

▪ Number of public structures/buildings

▪ Number of common property

-
resources (such as religious/cultural/
drinking water/wells/etc.)
▪ Number of private structures (located
-
on private or public land)

3. Does the proposed project activity result in loss of crops/trees?

Yes No

4. Does the proposed Project activity result in loss of direct livelihood/

employment?

Yes No

5. Does the proposed activity result in loss of community forest/pastures

on which nearby residents/local population are dependent?

Yes No
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If yes, give the details of the extent of

area to be lost (in acres/hac).

6. Does the proposed Project activity affect scheduled tribe/caste

communities?

Yes No

Part C (2): Result/Outcome of Social Screening Exercise

S.No. Result/Outcome Outcome

Answer to all the questions is ‘No’ and only forest

1.
land is being acquired

Answer to any question is ‘Yes’ and the sub-project

2. does not affect more than 200 people (i.e. either
complete or partial loss of assets and/or livelihood)

Answer to any question is ‘Yes’ and the sub-project

3. affects more than 200 people (i.e. either complete or
partial loss of assets and/or livelihood)
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