department of zoology, university of

ZOOLOGY Principles of Ecology

Applied Ecology: Pollution

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Paper : 12 Principles of Ecology Module : 37 Applied Ecology: Pollution

Development Team

Paper Coordinator: Prof. D.K. Singh Department of Zoology, University of Delhi

Principal Investigator: Prof. Neeta Sehgal Department of Zoology, University of Delhi

Content Writer: Dr. Kapinder Kirori Mal College, University of Delhi Content Reviewer: Prof. K.S. Rao Department of Botany, University of Delhi

Co-Principal Investigator: Prof. D.K. Singh Department of Zoology, University of Delhi



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Description of Module

Subject Name ZOOLOGY

Paper Name Zool 012; Principles of Ecology

Module Name/Title Applied Ecology

Module Id M37; Pollution

Keywords Pollution, water pollution, air pollution, noise pollution, land

pollution, acid rain, global warming, ozone depletion.

Contents

1. Learning Outcomes

2. Introduction

3. Air Pollution

3.1. Causes of air pollution

3.2. Acid rain

3.3. Consequences of air pollution

3.3.1. Effects on health

3.4. Green house effect and global warming

3.5. Ozone depletion

3.5.1. Protection of the ozone layer

4. Water Pollution

4.1. Causes of water pollution

4.1.1. Sources of water pollution

4.2. Consequences of water pollution

5. Land Pollution

6. Noise Pollution

6.1. Effects of noise

7. Control of Pollution

8. Summary



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1. Learning Outcomes

After studying this module, you shall be able to

List the major pollutants and their sources.

Understand various human activities resulting in pollution and deterioration of environment

Know the causes of air, water and land pollution and explain with examples.

Describe the causes and consequences of noise and discuss the control of pollution.

2. Introduction

Pollution is an undesirable change in the physical, chemical or biological characteristics of air, land

and water that will adversely affect human life land or that of desirable species directly or indirectly

(Odum, 1971). In general, the term pollution is used to refer introduction of harmful substance into

the environment by humans. According to Southwick (1976), the problem of pollution arises because

of human population explosion. The higher population leads to utilize excessive energy, produce more

waste, more sewage and exploited natural resources. Figure 1 explains the various sources that lead to

pollution.

Figure 1: Different sources of Pollution

After the Industrial Revolution, human has developed various technologies and progressed in

economic, medical, social and industrial spheres. There is significant increase in coal production,

petrochemicals, energy generation, pesticide, fertilizers etc. which leads to degradation of the

environment due to release of large quantities of gaseous, liquid and solid wastes generated by

Sources of

Pollution

Biogenic sources Industrial sources

Antropogenic sources Agricultural sources



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industry and other human activities. The pollution directly or indirectly affects human health (Figure

2) by deteriorating the life support systems of our biosphere.

Figure 2: Effect of pollution on human health

A substance or chemicals which causes the pollution is called as called as pollutant. The pollutants

can be divided into two types:

i) Biodegradable pollutants: Those pollutants which can be easily broken down into simpler

elements or forms by various microbes and other decomposing organisms. For e.g. Organic waste,

animals and human waste, agriculture waste etc.

ii) Non-biodegradable pollutants: Those pollutants which cannot be broken down into simpler

forms. For e.g. Heavy metals like lead and mercury, pesticides etc.

In this module we will discuss how human activities responsible for the degradation of environment by

creating pollution such as air, water and soil. In addition, the higher intensity of noise and radiation is also

detrimental to human life and called as noise pollution and radiation pollution respectively.

3. Air Pollution

Air pollution can be defined as the presence of undesired chemicals in the atmosphere at higher

concentrations which is harmful to the organisms, materials and to alter climate.



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Figure 3: Air pollution generated from natural human manufactured

The source of air pollutants can be from both natural and human generated (Figure 3). Natural sources

consist of dust, forest fires, volcanic eruptions etc. Air pollution generated from human activities is not

new but it starts since the discovery of fire. But the situation becomes alarming when the human started

extracting and burning coal. Most outdoor pollutants released in the atmosphere from the burning of fossil

fuels in the industries and vehicles. Figure 1 explains the various sources of air pollution.

The air pollutants can be classified into two categories.

i) Primary pollutants: Pollutants which are released into the environment as a result of natural

and/or human activity. For e.g., carbon dioxide, carbon monoxide, oxides of nitrogen, sulphur

dioxide, suspended particulate matter and hydrocarbons.

ii) Secondary pollutants: Pollutants which formed when some primary pollutants react with one

another or with the basic components of air. The pollutants which formed due to chemical

interaction of primary pollutants are further catalyzed by sunlight. For eg., ozone (O3),

peroxyacyl nitrates (PAN), sulphuric acid and nitric acid.

The threat due to air pollution became evident only when some severe incidences caused human

casualty. In 1952, nearly 2,500 people died in London due to presence of sulphuric acid vapours,

sulphur dioxide and particulate matters. In India on 3rd

December, 1984 at Union Carbide in Bhopal,

approximately 36 tonnes of methyl isocyanate leaked from the tank in midnight over the city. It

caused death of around 10,000 people and more than 2, 00,000 were injured. Many surviving people

suffered from permanent respiratory illness and impairment of vision.

According to the World Health Organization (WHO) 24% of global diseases and 23% of all deaths

are caused by environmental exposure. In addition, one of every six individuals on the earth lives in

an urban area where the air is unhealthy to breathe. Most of these individuals live in highly populated

cities in developing countries where air pollution control laws do not exist or are poorly enforced.



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3.1. Causes of Air Pollution

The major constituents of air are N2, O2 and inert gases that comprises about 99.9% of total

atmospheric gases. Some minor gases like sulphur dioxide (SO2), methane (CH4), nitrogen dioxide

(NO2) chlorofluorocarbons (CFCs) along with carbon dioxide (CO2) unburned hydrocarbon and

suspended particulate matter (SPM) have increased which are responsible for the pollution. The

common atmospheric pollutants along with their major source are presented in table 1.

Table 1: Various pollutants commonly present in atmosphere

Common atmospheric pollutants

Primary Secondary Industrial process Natural process

CO2, CO, NOX, SO2, NH3,

H2S, hydrocarbon

PAN,O3 CFC, acid, aldehyde,

fluoride, chloride

CO2, CO, O3, CH3, H2S, SO2,

NOX, NH3

Particulates

Smoke, dust, lead particles etc., grit, dust, smoke, fumes, mist (liquid droplets), aerosol (suspended)

The major causes of air pollution include the following human activities:

(i) Fossil fuel consumption (ii) Motor transport (iii) Modern agriculture and (iv) Industry.

Fossil fuels are the source of energy for cooking, transport, power generation, manufacturing, cooling,

and heating and for many other purposes. Fossil fuel (including coal) on complete combustion

produces CO2 but incomplete combustion yields carbon monoxide and a variety of hydrocarbons. In

addition, burning of coal also produces SO2 and ash. About 60% of SO2 releases due to burning of

coal.

Transport vehicle including trucks, buses, cars, two wheelers and three wheelers contributes NO2, CO

and hydrocarbon emission. These vehicles also releases lead because of tetramethyl lead in petrol

which acts as antiknock agent. Agricultural activities like burning of forest for agriculture also

produces carbon dioxide and 40% of methane is produced from rice fields, guts of livestock due to

breakdown of organic matter by anaerobic bacteria and burning of biomass.



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Figure 4: Air pollution caused by transport vehicles

Industrial activities like smelting of metal ores produces large quantities of SO2, chemical plants

produces number of hazardous chemicals including CFCs and many more. These are non-

biodegradable pollutants with half life ranging from 7 to 10 years. Other major sources of pollutants

are rubber, dioxine, paper, plastic, pesticides, automobile industry, asbestos fibers, tobacco smoke,

nitrosamine and polychlorinated biphenyls and are the major environmental contaminants.

Figure 5: Air pollution caused by gases released from industries

Dust is generated from various sources such as coal dust-from power plants, cement dust from cement

factories, silica dust from stone crushing, building construction, etc. The transport vehicles are also

causes production of large amount of dust. In India, about 80 million tonnes of fly-ash is produced

annually by power plants running through coal. About 10,000 tonnes of stone dust is generated by

over 10,000 stone crushers in India.



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The economic development of a nation depends upon the availability of energy. The living standard

of USA, Japan, Russia, Germany, and some other industrialized nations is largely dependent on

energy access and consumption. These countries use more than 70% of the total world's commercial

energy. The share of energy for developing nations is very small. But now there is increase in the

energy consumption in developing countries that indicates increase in levels of SO2, CO2, NO2, CO

and particulate matter. Similarly, industrialization, modern agriculture, transport vehicles have also

increased sharply and have contributed enormously to air pollution.

3.2. Acid rain

It refers to several ways in which acids from the atmosphere reaches to surface of earth. Acid rain

includes dry and wet deposition. Dry deposition refers to settle down of windblown acidic gases and

atmospheric particles on the earth surface. However, wet deposition refers to acidic water received

from the rain, fog and snow. About half of the acidity in the atmosphere is transferred on earth

through dry deposition.

Various gases like NO2, SO2 and VOCs are generated from the burning of coal and petroleum.

Lightening in the sky also produces NO2 naturally. These gases are highly reactive in the air which

oxidized into acids like H2SO4 and HNO3. These gases dissolved in the water very easily and is

washed down to earth surface as acid rain. Usually, rain water is slightly acidic (pH 5.6-6.5) as the

water and CO2 combined in air to form weak acid. The pH of acid rain is less than 5.6 can be goes

down as 4 or below. Acid rain can damage building material (Taj Mahal), furnishing fabrics,

terrestrial and aquatic vegetation. Fish cannot tolerate pH less than 5. Low pH of acid rain also

damages soil minerals.

Human health

a. In dry gaseous forms, acid rain causes respiratory problems. In severe condition, it can lead to

death.

b. Acid rain when fall on body may cause itching or burning sensation

3.3. Consequences of air pollution

The physiological effects of toxic pollutants on living beings can be of two types:

i) Acute effect: This effect is immediate but short-lived. It occurs when the individual is exposed to

a high concentration of toxic pollutant for a shorter period of time. For example, we experience



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headache during travelling on a busy road. It is due to exposure to carbon monoxide released from

vehicles. Acute effects result when a pollutant is released in abnormally large quantities e.g.

release of methyl isocyanate gas accidently from the pesticide plant in Bhopal.

ii) Chronic effects: It is the exposure of small amount of pollutants for a long period of time and the

effect appears after several months or years. For example, prolong exposure to SO2 may leads to

chronic bronchitis, pulmonary fibrosis, exposure to coal dust leads to black lung.

3.3.1. Effects on health

The air pollutants when inhaled during respiration, they enter into the blood circulatory system and

through which reaches to the target organs. The extent of damage of the organ is depends upon a

particular pollutant, its concentration in the air and exposure time. The air pollutants are generally

linked with respiratory and some other diseases (Figure6) as mentioned below:

1. Sulphur dioxide is mainly responsible for lung diseases. It causes irritation to nose and mucous

lining. The acute effects include shortness of breath, bronchospasm, edema and tissue fluid

accumulation. However, chronic effects may result in respiratory diseases like-chronic bronchitis,

asthma, emphysema and pulmonary fibrosis.

Figure 6: Respiratory and cardiovascular disease caused by air pollution

2. Oxides of nitrogen released from the buses, trucks and other vehicles causes irritation in eye and

lung. Inhalation of these gases in large amounts may results in gum inflammation, internal

bleeding and cancer.

3. Carbon monoxide can compete and binds with the hemoglobin. Its affinity for hemoglobin is 200

times more than oxygen. So, even when it is present at low levels, it is not safe. High



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concentrations of CO slow down physical and mental activities and may cause asphyxiation, heart

and brain damage.

4. Ozone and peroxyacyl nitrate (PAN) causes irritation of eyes. Ozone causes dry throat, cough,

headache, difficulty in breathing and weakens the lung tissues.

5. The particulate matter depends upon its nature and size cause irritation reactions.

6. Fumes of toxic metals like lead damages brain of child and can cause death. In adults it affects

kidneys and liver. Chronic exposure to mercury vapours causes lesions of the mouth and skin and

neurological problems.

7. Dust of coal, asbestos etc. cause respiratory problems.

8. Hydrocarbons like chlorinated hydrocarbons, benzypyrene, polybiphenyl chloride, benzene and

many other compounds cause cancer.

3.4. Green house effect and global warming

Various gases in the atmosphere like CH4, CO2, NO2, O3, and CFC's and water vapours prevent heat

from escaping. The gases are known as green house gases and the effect is called green house effect.

It makes the earth warm and provides the conditions for the existence of life. In the absence of the

greenhouse effect, the average temperature of the earth would be about –18oC. But due to human

activities the temperature of earth is continuously increasing. The following human activities

contributing increase in greenhouse gases:

1. Excessive use of fossil fuels in vehicles and industries which releases large amount of carbon

dioxide, carbon monoxide and methane gas.

2. Clearing and burning of forests and grasslands for agricultural crops.

3. Growing rice in agricultural field and use of inorganic fertilizers releases release N2O.

It is believed that increased concentration of CO2 and other greenhouse gases will increase the earth’s

natural greenhouse effect and will increase the earth temperature. This increased greenhouse effect is

called as global warming. According to IPCC report (2001), the global warming in the last 50 years

has been occurred due to enhanced human activities and it is believed that the earth’s average

temperature will increase by 1.4 to 5.80

C by 2100. According to Bush administration report (2002),

expect rising temperature of earth surface is by 3oC and the sea level by 9-88 cm. The increased sea

level results in flooding of coastal wetlands, low lying islands and heavily populated coastal cities.

These changes would affect 50% of the earth's populations that inhabits coastal regions.



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3.5. Ozone depletion

The ozone layer in the stratosphere is dynamic which is constantly formed and destroyed. The ozone

is formed when some molecules of the oxygen interact with the UV radiations. Initially, the UV

radiations (UV-B) break the oxygen molecules (O2) into oxygen atom (O). The oxygen atom (O) then

combines with molecular oxygen (O2) to form the ozone.

O2 + UV-B → O + O

O + O2 → O3

However, at the same time, some of free oxygen atom (O) also combines with ozone to form two

molecules of oxygen.

O + O3 → 2O2

Moreover, ozone when absorbs UV-B radiations, it is broken down into oxygen (O2) and free oxygen

atom (O).

O3 + UV B → O2

+ O

So, there is continuous formation as well as destruction of ozone. The ozone concentration is

measured in Dobson Units and its normal value ranges from of 400-600 DU.

When chlorofluorocarbons (CFCs) concentration is higher in the air, it moves to the stratosphere by

convection current and turbulent mixing of the air and react with the ultraviolet radiations to form free

chlorine:

CFCl3 + UV → Cl + CFCl2

This chlorine react with ozone to form oxygen (O2):

Cl + O3 → ClO + O2

ClO + ClO → 2Cl + O2

The chlorine is continuously regenerated and each chlorine atom can convert upto 100,000 molecules

of ozone to oxygen. As a result the thickness of ozone decreased significantly called as Ozone hole

but accurately it is thinning of ozone hole. The thinning of ozone (O3) layer results in the reaching of

UV-A and UV-B on earth’s surface and causing adverse effect on living organisms as follows.

1. In human beings UV radiations causes sunburns, skin cancers and eye cataracts. The cancer

spreads to other organs and is lethal to the human.



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2. UV radiations cause suppression of the immune system and make the body susceptible to

infections.

3. UV radiation causes higher mortality of aquatic species and reduces the population of

phytoplankton on the surface.

4. There may be reduced yield of some crops and decreased forest productivity from UV sensitive

tree species.

5. It also contributes to global warming due to decreased uptake of atmospheric CO2 by the

phytoplankton.

3.5.1. Protection of the ozone layer

Due to the awareness of harmful effect of ozone, the use of ozone depleting chemicals is banned.

There are various other chemical are now available like hydrochlorofluorocarbon (HCFC), which

releases much less chlorine molecule. Ray Turner in California has developed citrus-based solvents to

clear the circuit boards replacing the CFCs.

In 1987, Montreal Protocol was presented to reduce CFCs emission by about 50% between 1989 and

2000. Later, Copenhagen, Denmark in 1992 was passed to accelerate the phasing out of the ozone

depleting chemicals.

4. Water Pollution

Water is one of the important components of living organisms. It is for agriculture, industries,

household and various other purposes. The used water when released into the environment consists of

many undesired toxic and innocuous matter and many disease causing microbes which adversely

affect environment and health (Figure7). The pollution in rivers, lakes, estuaries is continuously

increasing all over the world and becoming nightmare to human beings.



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Figure 7: River pollution due to dumping of industrial waste and domestic waste

The water pollutants can be distinguished into two types.

i) Point source: It involves the release of undesired substances into water bodies from a specific

site such as sewage, oil wells, power plants, factories and coal mines.

ii) Non-point source: It involves the inflow of pollutants into water body in a different manner over

a larger area such as various agricultural lands, water drainage from roads, streets etc, farm

animals and many more. These sources are diffuse and are poorly defined.

4.1. Causes of water pollution

Most of the human activities are the prime cause of water pollution. Rapid increase in population,

intensive agriculture, growing industrialization and urbanization has resulted in deterioration of water

in the natural reservoirs.

Water pollutants

Water pollution can occur on any one or more of the following agents:

i) Biological: The growth of various living microbes such as bacteria, virus, protozoa and

helminthes.

ii) Chemical:

a) Inorganic: Various Inorganic chemicals such as nitrates, phosphates, chloride and fluoride etc.

b) Organic: Pesticides, dyes, chloro-compounds, phenols etc.

c) Heavy metals: Presence of heavy metal ions such as mercury, lead, arsenic, zinc, cadmium,

copper etc.

iii) Physical: Waste heat released from thermal plants.



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4.1.1. Sources of water pollution

The pollution caused by various human activities can broadly group into four categories:

1) Domestic effluents

The waste produced in kitchen, bathroom and toilet are discharged directly or through canal into the

river, pond or other water body. Most of the Indian rivers are polluted at stretches on account of

indiscriminate discharge of liquid effluents. This occurs due to inadequate facilities of sewage

collection and treatment. For example, Dal Lake in Kashmir has been polluted due to the dumping of

sewage and domestic effluents from house boats, hotels and from neighboring localities into the lake.

The Hooghly estuary is also heavily polluted with domestic waste and effluents released from various

industries located on its shore.

2) Industrial effluents

Most industries discharge their effluents into nearby river which consists of heavy metals like

mercury, cadmium, lead, arsenic etc. Other chemical pollutants include polychlorinated biphenyls,

phenols, dyes, paints, varnishes, and plastics.

The Rhine River in Europe becomes one of the most polluted rivers due the accumulation of heavy

metals and toxic chemicals at the base of the river. In India also river Ganga receives sewage and

noxious effluents from chemical factories.

3) Surface Run-off

The surface run-off occurs from the cultivated lands where inorganic fertilisers, pesticides, and

insecticides are used. Pesticides such as DDT (Dichloro-diphenyl tetrachloro-ethene) 2,4D

(Dichlorophenoxy acetic acid), dieldrin, malathion, carbaryl etc are used for crop protection. India

alone uses approximately 1, 00,000 tonnes of pesticides annually. Application of nitrogen fertilizers,

nitrates and ammonia released from manure increase nitrate content of water bodies.

4) Waste Heat

Water is a good cooling agent which is used in thermal power plants, refineries and various other

industries. The waste heat in the form of hot water is discharged into the river or other water body.

For example, nuclear power station in Kota uses water as a coolant from the Chambal river. The

temperature of water released from power plant is about 8 oC to 10

oC which is much higher than



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normal river water. The disposal of waste heat into water increases the temperature of the water body;

adversely affect the amount of dissolved oxygen and the aquatic community present in it.

4.2. Consequences of water pollution

The water pollution adversely affects the flora and fauna of aquatic system and also human health.

1) Effects on aquatic organisms

Toxic water pollutants such as heavy metals, insecticides and other harmful chemicals directly affect

aquatic organisms whereas non-toxic organic materials eliminate some aquatic species indirectly by

reducing the dissolved oxygen of water (Figure 8).

Figure 8: Death of fishes due to river pollution

The species like Trout and Bass are sensitive that require high level of oxygen. These species are

eliminated first when oxygen level is low. With further decrease in dissolved oxygen, leeches, catfish

and carp get killed. Trout and salmon are excellent indicators of pollution. The aquatic flora of lakes

and ponds is also affected by slight variations in temperature.

Hot water released from power plants cause ecological imbalance by death of some fish species and

other aquatic organisms. Different species have different optimum temperature for growth,

development and reproduction. Stenothermal species die due to slight increase in the temperature.

Warm water can causes premature reproduction in some species but the young ones are not able to

survive in the absence of desirable living conditions such as availability of food. Increased

temperature due to thermal pollution at stretches of water body interfere the migration of fish species

and thus affects their life cycle.

https://www.flickr.com/photos/blmurch/1481423813



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2) Effects on health

Polluted water deteriorates the water quality which is used for drinking, bathing, swimming and

various other purposes. Drinking water polluted with sewage is a source of viruses, bacteria, protozoa,

worms and also have foul smell. It causes various water born diseases like cholera, dysentery,

typhoid, jaundice and various other infection.

Presence of heavy metals such as mercury, lead, cadmium, zinc and copper are harmful to health.

Mercury compounds are converted into methyl mercury by bacterial action which is highly toxic to

body. In 1952, mercury poisoning in Japan caused "Minamata” disease due to eating of fish taken

from mercury polluted Minamata Bay. It causes numbness of limbs, lips and tongue. It also caused

deafness, blurring of vision, apathy and mental retardation.

Cadmium pollution caused another disease called Itai-Itai occurred in Japan due to the consumption

of rice affected with cadmium. It is a painful disease of bone and also causes cancer of liver and

lungs. Excess of nitrate in water causes methamoglobinemia. Nitrate converts haemoglobin to its

oxidized form methaemoglobin which is nonfunctional. Nitrate can be fatal to human, especially

infants under three months. Such infants are called "blue babies".

Fluoride when present in excess causes mottled teeth, stiffening of joints and hardened bones called

skeletal fluorosis or knock knees disease. It leads to total inability to move. In India, excessive

fluoride affected states are Tamil Nadu, Kerala, Gujarat, Rajasthan, Punjab, Haryana and Bihar.

Chlorination of water produces chlorinated organic compounds which can be carcinogenic or

teratogenic. Pesticides which enter into water body such as DDT, aldrin and dieldrin get accumulated

in the animals and causes cancer and teratogeny. It also causes tremors, convulsions causing damage

to kidneys.

5. Land Pollution

Land pollution occurs due to dumping of solid wastes generated in the household and manufacturing

units. Domestic wastes include kitchen garbage, waste tin cans, plastic bottles, cloth rags, waste

papers, straw-board boxes, ash etc. However industrial wastes are fly-ash, lime sludge, brine mud,

metal scraps and copper slag from large industries, dyes, plastics and lots of other wastes from small

scale industries (Figure9).



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Figure 9: Plastics and other solid wastes disposed into land

The amount of garbage generated is proportional to affluence in the society. For example the solid

waste generated in affluent areas in Delhi is around 800-1000 gallon/day, whereas in MCD areas it is

about 300 gl/day and in rural areas it is significantly very low. In India, average per capita waste

generated is 300400 gallon/day. Industries in India also generate a number of wastes in large

quantities. For example, the amount of slag generated by the blast furnace used for integrated iron and

steel mills is about 35 million tonnes/ year and fly-ash produced from coal based power station is 80

million tones/year. The fertility of soil also decreases due to acids and alkali, insecticides, fumigants

and herbicides (Figure 10).

Figure 10: Soil contaminated by chemicals which decrease the fertility of soil

6. Noise Pollution

Noise pollution is the production of excessively high levels of sound which may cause loss of hearing.

The main sources of noise pollution originated from human activities (fig, 11, 12, 13). The major

sources of pollution are:



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1. Transport which includes road traffic, railways, aircraft.

2. Industries having generators, pile drivers, pneumatic drills, road roller etc.

3. Special events include loud speakers, music performance, marriage party, religious festival etc.

The human ear is sensitive to the sound of frequency in the range of 20 to 2000Hz. Loudness is

measured in decibel scale (dB). It is not linear but a logarithmic scale. For example, a change from

40dB to 80 dB represents a 10,000 increase in loudness. In New Delhi, the noise levels ranges from

28-71 dB at different area at different times, Mumbai 64-102 dB, Rourkela 70-104 dB and

Ahmadabad on average is 62 dB.

Figure 11: Noise pollution caused due to loudspeaker in religious festival

Figure 12: The noisy machines have given every third person hypertension and hearing problems



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Figure 13: Noise level during Ganpati 2013, one of the loudest festivals in Mumbai

6.1. Effects of noise

The noise pollution is increasing tremendously due to development of new technologies. It causes

psychological and physiological changes and also affects the health. The noise has following adverse

affect on the body:

1. Noise produces temper tantrum, irritation, anxiety, fatigue and even nausea. Prolonged exposure

of excessive noise cause lack of concentration, sleeplessness, headache, constriction in blood

vessels, change in heart beat, increase of blood pressure, pale skin, nervous breakdown, etc.

2. Noise results in decrease sensitiveness to hearing, finally leading to deafness.

3. According to WHO report noise pollution contribute to hundreds of thousands of deaths per year

by causing the high risk of coronary heart disease.

4. Underwater noise pollution produced by ships disturbs whale’s navigation systems and kill other

species. The excessive noise makes wild species to communicate louder, which can decrease their

lifespan.

The methods of noise control are:

The noise pollution can be reduced by decreasing the sources that produces sound. For example, the

number of trucks, vehicles and loud speakers etc. from residential areas can be reduced by legislation.

However, there is a limitation to this type of solution. If it is not feasible to reduce such sources,

efforts can certainly be made to reduce noise production. Proper oiling of the wheels and redesigning

of the machinery and regular servicing can be done in this connection. In 1980s and 1990s there were

several court judgment in India to reduce the noise from industries, fire crackers, vehicle horns etc. In

http://www.livescience.com/13656-noise-pollution-injures-squid-octopus.html

http://www.livescience.com/6705-whales-shout-noise-pollution.html



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2000, Indian government notifies the noise regulation rules under the environment protection act of

1986. The rule regulate the noise level in industry ( 75dB), commercial (65dB), and residence (55dB)

and also establish zone of silence (100m) near school, hospital, court etc. there is no permission by

any authority for use of public address system in the open after 10 PM and before 6 AM. In 2010,

there was amendment to the rules to make it stricter and specific.

7. Control of Pollution

The pollution adversely affects human health, crop yield, fisheries, forests, buildings, archaeological

monuments and tourism. Pollution can be controlled at two levels: i) technological and ii) legal.

Air pollution can be reduced by using bag filters, gravity settling chamber, centrifugal collectors like

cyclone collector and dynamic precipitators, wet scrubbers (spray tower and venture scrubber),

electrostatic precipitators and fabric filters that removes smaller and larger particulate matter and

pollutant gases from emission gases. Sewage treatment plants can be used for the purification of

water. These technologies require large investments. Studies have shown that in industrial sector

waste reduction makes tremendous economic sense and helps in restriction pollution. Pollution can

also be controlled by effective legislation. The Constitution of India has provision to make

environmental legislation. Like USA, Japan, Germany and many other countries a comprehensive

legislation for prevention and control of water pollution has also been enacted in India. The Water Act

1974 and Air Act in 1981 are being implemented through the Central Board and State Boards. The

Central Board coordinates the regulatory norms and enacts strategies to be undertaken for effective

prevention, control or abatement of water and air pollution in the country. It also looks after the

pollution control activities in the Union Territories. The Air

Act is meant to regulate and control the emissions from automobiles and industrial plants. The state

government can declare certain areas as "Air pollution control areas" and the industries cannot operate

in such areas without prior permission from the State Board. The Water Act prohibits the dumping of

poisonous metals, hazardous chemicals and other pollutants into stream and wells. For dumping of

sewage and industrial effluents in water, prior consent of the State Board is necessary.

In addition to these legislative measures, a nationwide network was set up in 1984 for monitoring

ambient air quality. Now it has 85 stations covering 24 cities. For monitoring the quality of rivers

about 170 stations have been set up. Central Board and Department of Ocean Development have

jointly identified 173 monitoring stations all along the Indian coast for the purpose of water quality



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standards. Likewise, in 1968, Insecticide Control Act was enforced to regulate import, manufacture,

sale, transport, distribution and use of insecticides. There are also provisions for the regulation of

nuclear installation and control on disposal of nuclear wastes.

8. Summary

Pollution is an undesirable change in the physical, chemical or biological characteristics of air, land

and water that will adversely affect human life land or that of desirable species directly or indirectly.

Pollution can be categorized as air, water, land and noise pollution.

Air pollution is the presence of undesired chemicals in the atmosphere which is harmful to the

organisms, materials and to alter climate. The source of air pollutants can be from both natural like

dust, forest fires, volcanic eruptions and human generated which includes industries and vehicles etc.

Various gases like NO2, SO2 and VOCs are generated from the burning of coal and petroleum. These

gases are highly reactive in the air which oxidized into acids like H2SO4 and HNO3 and washed down

to earth surface as acid rain. The air pollutants when inhaled are generally linked with respiratory and

some other diseases like asphyxiation, heart and brain damage, cancer etc.

Water is one of the important components of living organisms when released into the environment

after industrial or domestic use, consists of many undesired toxic and innocuous matter and many

disease causing microbes which adversely affect environment and health. Drinking water polluted

with sewage is a source of viruses, bacteria, protozoa, worms which causes various water born

diseases like cholera, dysentery, typhoid, jaundice and various other infection. Presence of heavy

metals such as mercury, lead, cadmium, zinc and copper are also harmful to health.

Land pollution occurs due to dumping of solid wastes generated in the household and manufacturing

units. The fertility of soil is decreases due to acids and alkali, insecticides, fumigants and herbicides.

Noise pollution occurs due to excessively high levels of sound produced through various means. The

main source of noise pollution is originated from human activities which include road traffic,

railways, industrial operations, construction work, aircrafts etc. Noise can affect through interferes

with communication, diminishes hearing and affects health and even behavior. All these pollutions are

dangerous to human beings. Its far-reaching consequences for coming generations are feared. Control

of pollution is economically beneficial. Pollution can be controlled by appropriate technology and

effective legislation.

department of zoology, university of

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