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GE1204 –ENVIRONMENTAL SCIENCE AND ENGINEERING

UNIT – 2 ENVIRONMENTAL POLLUTION

LECTURE PLAN

Section 1 - Pollution
2.1) Air pollution – Causes, Effects, Control
2.2) Water pollution – Causes, Effects, Control
2.3) Soil pollution – Causes, Effects, Control
2.4) Solid waste management – Urban and Industrial wastes, e-waste
2.5) Marine pollution – Causes, Effects, Control
2.6) Noise pollution – Causes, Effects, Control
2.7) Thermal pollution – Causes, Effects, Control
2.8) Nuclear pollution – Causes, Effects, Control
2.9) Role of individual in prevention of pollution
Section 2 – Disaster Management
2.10) Floods
2.11) Earthquake
2.12) Tsunami
2.13) Cyclone
2.14) Land slides.
2.15) Field / Case studies related to disaster
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 UNIT – 2 ENVIRONMENTAL POLLUTION

Pollution : Entry of unwanted materials into the environment causing hazards to human
being and their properties is called environmental pollution.
(e.g) Air pollution , water pollution, soil pollution, marine pollution, noise pollution
Types of pollutants: If the pollutants decompose rapidly by natural process, they are bio-
degradable pollutants. It the pollutants do not decompose or very slowly decompose in the
environment, they are non-biodegradable pollutants.The slowly decomposed materials are
more dangerous because it is more difficult to remove them.
2.1) AIR POLLUTION – CAUSES, EFFECTS AND CONTROL MEASURES
Entry of unwanted contaminants into the atmosphere which are injurious to human beings,
plants, animals is called Air pollution.
Broadly air pollution sources are classified as
i) Industrial air pollution ii) Automobile air pollution
If the pollutants are emitted directly in the atmosphere in harmful form, they are primary
pollutants. (e.g.) CO, NO, SO2
Some of the primary pollutants may react with one another or with the basic components of
air to form new pollutants as „secondary pollutants’. (e.g.) NO3 , smog etc.,
Common air pollutants and their effects:
1. Carbon monoxide:
2C + O2  2CO
Formed due to incomplete combustion of carbon fuels. It reacts with heamoglobin in RBC
and reduces O2 transportation. Causes headache, anemia, and brain cell damage.
2. Nitrogen dioxide:
NO2 + moisture  HNO3 : N2 + 2 O2  2NO2
NO2 and hydrocarbons combine to form photochemical smog. It reduces visibility. The
main sources are motor vehicles and power industrial plants. It causes lung irritation and
damages also.
3. Sulphur dioxide:
It is formed from the combustion of sulphur containing fossil fuels. In presence of moisture,
it is converted to sulphuric acid and causing breathing problems and reduced visibility, eye
irritation. Nitric acid from nitrogen dioxide and sulphuric acid from sulphur oxide
dissolved in the rain water causing „Acid rain‟ which corrodes marble buildings, makes the
lands infertile and cause some health hazards. 2
4. Ozone (O3) :
It is the major component of photochemical smog. It is formed due to chemical reaction
between volatile organic compounds and nitrogen oxides. They cause climatic changes.
5. Lead and mercury:
These solid and mercuric vapours are mainly emitted by industrial activities like paint,
smelters and battery industries. They cause cancer, mercury poison, suffocation and
respiratory diseases.
6. Photochemical smog
The brownish smoke like appearance that frequently forms on clear, sunny days over large
cities with significant amounts of automobile traffic. It is mainly due to chemical reactions
among nitrogen oxides and hydrocarbon by sunlight. Breathing problems, cough, eye, nose
and throat irritation, heart diseases, reduces resistance to colds and pneumonia.
7. Suspended particulate matter (SPM)
It includes variety of particles and droplets (aerosols).They can be suspended in atmosphere
for short periods to long periods. Burning coal in power and industrial plants (40%),
burning diesel and other fuels in vehicles (17%), agriculture, unpaved roads, construction.
Nose , throat irritation, lung damage, bronchitis, asthma, reproductive problems and cancer.
Effects of air pollution:
1 Effects on Cancer - Asthma - Lung disorder - respiratory diseases
human health Eye irritation - reduced visibility - convulsions.
2 Effects on i) Chlorosis (lose of chlorophyll and yellowing of leaves)
plants ii) Premature fall of leaves,
iii) Yield reduction
iv) Necrosis (dead areas on laves)
v)Epinasty ( downward curvature of leaves)
3 Effects on i) Discolouration and deterioration of limestone and building
materials materials
ii)Reduction in tensile strength of textiles
iii) Cracking and strength loss of rubber
iv) surface erosion and soiling of paints
v) disintegration and strength loss of leather
4 Effects on i) Global warming
environment ii) Green house effect
iii) Ozone layer depletion
iv) Acid rain 3
Control of air pollution:
The air pollution can be controlled by three ways.
1. Source control
2. Control measures in Industrial centres
3. Control by Emission control equipments

1. Source control
In this principle, the pollution is controlled or reduced from the source itself.
i) Proper use of the existing equipments
ii) Modifications or replacement of equipments
iii) Using unleaded and low sulphur content petrol.
iv) Reducing the number of private vehicles on the road by developing an efficient public-
transport system and encouraging people to walk or use cycles.
v) Planting trees along busy streets because they remove particulates , CO and absorb noise.
vi) Use catalytic converters to control the emissions of carbon monoxide and hydrocarbons.

2. Control measures in industrial centers

i) The emission rates should be restricted to permissible levels by each and every industry.
ii) Industries and waste disposal sites should be situated outside the city center.
iii) Continuous monitoring of the atmosphere for the pollutants.
iv) Incorporation of air pollution control equipment in the design of the plant layout.
v) Maintaining sufficient O2 and adequate temperature in the combustion chamber to carry
out complete combustion. This eliminates much of the smoke consisting of partly burnt
ashes and dust.

3. Control by Emission control equipments

S.No Equipment Process to control air pollution
1 Electrostatic precipitator Principle of electro deposition.
2 Bag house filter applying varying velocity
3 Cyclone separator High velocity settles the particles down
4 Wet scrubber wet precipitation
5 Gravitational settling chamber By gravitational force. 4
. 5
2.2) WATER POLLUTION – CAUSES, EFFECTS- CONTROL MEASURES

Water Pollution:
The entry of unwanted and harmful materials into water bodies which alter the physical,
chemical and biological characteristics of water and hazardous to human health is known as
water pollution.

Sources of water pollution:

1. Point sources 2. Non point sources

1. Point sources (e.g.) Factory outlets, power plant outlets, oil wells
They discharge pollutants at a specific place through pipelines, sewer lines or ditches into
water bodies. Identification, monitoring and control of point source discharge are easy.
The amount of discharge is predictable.

2. Non point source (e.g.) urban streets, agrilands, leachates from municipal and industrial
landfill sites, soil erosion.
They discharge pollutants from large and scattered area. They have no specific location.
Identification, monitoring and control of non-point source discharge is not easy.

Common water pollutants:

S.No Pollutants examples

1 Infectious agents Bacteria, viruses, parasitic worms
2 Oxygen demanding Animal manure, plant debris, sewage, paper/food
wastes industrial wastes
3 Inorganic chemicals Acids, lead, arsenic, selenium, fluorides
4 Organic chemicals Oil, gasoline, pesticides, detergents
5 Plant nutrients Water soluble nitrates, phosphates, ammonium salts
6 Radioactive materials Radon, cesium wastes
7 Thermal pollutants Industrial sewages, thermal power plant sewages

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Effects of water pollution:
1. Decrease in oxygen content
2. Eutrophication
3. Water borne diseases
4. Biomagnifications
5. Genetic disorders
1. Decrease in oxygen content:
Organic matter in sewage requires lot of dissolved oxygen for their decomposition. It leads
to decrease in dissolved oxygen content in the water bodies. It may arise biological oxygen
demand (BOD) or chemical oxygen demand (COD).
BOD: It is the amount of dissolved oxygen required by microorganisms to breakdown
organic matter present in water, over a period of 5 days at 20 degree Celsius.
COD: It is the amount of oxygen required for oxidation of organic compounds present in
water by means of chemical reactions.
2. Eutrophication:
Excess nitrogen and phosphorous enhance the growth of algae. They decay and consume
large amount of oxygen causing BOD. It will produce foul smell also. It alters the Carbon
di oxide amount and changes PH of water.

3. Water borne diseases:

Pathogenic viruses and micro-organisms cause water borne diseases like cholera, dysentery,
typhoid, jaundice etc.

4. Biomagnification:
Bioaccumulated pesticides, mercurates buildup at successive levels of food chain. The
mercury poisoning leads to vision, hearing problems, abnormal mental behaviour. This
disease is called “minamata disease”, found in a coastal hamlet “Minamata” in Japan.
Calcium poisoning leads to „Itai-Itai‟ disease. Nitrate excess leads to „Blue baby syndrome‟
and „methaemoglobinemia‟. Excess fluorine causes „flourosis‟.

5. Genetic disorders:
Radioactive pollutants cause genetic disorders, birth defects and certain cancers. 7
Control of water pollution:

1. Farmers can reduce the running of fertilizers from their agricultural lands to the water
bodies by providing buffer zones between surface water and agro lands.
2. Over fertilization and improper applications of pesticides can be avoided.
3. Proper treatment of effluents and sewages.
4. Soil erosion is minimized by watershed management.
5. by reuse of treated waste water for irrigation purposes.
6. 3R‟s principle should be implicated as Reduce, Recycle, Reuse.
7. Preventing ground water contamination.
8. Waste water industrial treatment steps:

No Treatment To remove Methods employed

1 Preliminary coarse solids and suspended Screening and filtering
impurities using mesh screens.
2 Primary (Settling process) Major proportion of Coagulation by adding
suspended solid impurities alum
3 Secondary (Biological biodegradable organic Trickling filter process
treatment) impurities Activated sludge process
4 Tertiary Residual BOD causing Flocculation
organic impurities
5 Sludge disposal Sludges Dumping
Incineration

(a) Trickling filter process

It is a circular tank and is filled with either coarse or crushed rock. Sewage is sprayed
over this bed by means of slowly rotating arms.
When sewage starts percolating downwards, microorganisms present in the sewage grow
on the surface of filtering media using organic material of the sewage as food. After
completion of aerobic oxidation the treated sewage is taken to the settling tank and the
sludge is removed. This process removes about 80-85% of BOD.

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(b) Activated sludge process
Activated sludge is biologically active sewage and it has a large number of aerobic
bacteria‟s, which can easily oxidize the organic impurities.
The sewage effluent from primary treatment is mixed with the required amount of
activated sludge. Then the mixture is aerated in the aeration tank. Under these conditions,
organic impurities of the sewage get oxidized rapidly by the microorganisms.
After aeration, the sewage is taken to the sedimentation tank. Sludges settle down in this
tank, called activated sludge, a portion of which is used for seeding fresh batch of the
sewage. This process removes about 90-95% of BOD. The residual BOD can be removed
by flocculation process using lime and charcoal. This process removes ammonia, phosphate
and minute organic wastes. The unwanted deposits, known as sludge can be cleared by
incineration , burning or can be used as low grade fertilizers.

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2.3) SOIL POLLUTION – CAUSES, EFFECTS AND CONTROL MEASURES
Soil Pollution: Entry of unwanted materials into soil which changes the soil quality and
affects the public health and environment is termed as „soil pollution‟.
Sources of soil pollution:
1. Industrial wastes 2. Urban wastes 3. Agricultural practices
4. Radioactive pollutants 5. Biological agents 6. e-waste
1. Industrial wastes:
a. Paper mills – chloride, sodium
b. sugar mills – nitrogen, phosphorous
c. Steel, coke industry – cyanide, carbon, fly ash
d. refineries - P, S, Cr, phenol
e. fertilizers and pesticides – sulphates, Cl, N, P, K, organic wastes, BHC, DDT, lindane
2. Urban wastes:
a. Domestic wastes: food waste, cloth, waste paper
b. Commercial wastes: Cans, bottles, bag, polythene
c. Construction wastes: wood, concrete, debris
d. Bio medical wastes: Syringe, bottles, waste cottons
3. Agricultural practices:
Modern agricultural practices pollute the soil to a large extent. Huge quantities of fertilizers,
pesticides, herbicides, and weedicides are added to increase the crop yield. Apart from these
farm wastes, manure, slurry, debris are causing soil pollution.
4. Radioactive pollutants:
Radioactive substances and radioactive wastes are produced by nuclear testing laboratories
and industries. They penetrate the soil and accumulate there by creating land pollution.
Radio nuclides of radium, thorium, uranium, strontium, lanthanum are very common
radioactive pollutants causing soil pollution.
5. Biological agents:
Pathogens in contaminated soil, sewage sludge, large quantities of human, animal and
bird‟s excreta are the biological agents causing soil pollution. Faulty sanitations, municipal
garbage, waste water and wrong methods of agricultural practices also induce heavy soil
pollution.
6. E-waste (Electronic waste)
The discarded electronic and electrical equipment is called e-waste. (e.g) Mobile phones,
television, refrigerator, home appliances etc. are some of the examples of the e-waste.
The toxic chemicals present in the e-waste releases into the atmosphere when it warms up.
The lead, zinc, barium etc, found in electronic waste tend to harm human health. Also, when
e-waste meets the landfills, the toxic chemicals seep into the soil and water, leading to
groundwater pollution that further impacts human health. 10
Effect of soil pollution:
1. Contamination of ground water level.
2. Destruction of ecosystems and food chains.
3. Pesticide induces congenital birth defects.
4. Soil degradation and soil acidification.
5. Arsenic poison leads to loss of appetite, weight, gastro intestinal problems.
6. Cadmium poison leads to kidney problems, chronic poisons.
7. Mercuric poison leads to neurological and renal problems.
Control of soil pollution:
1. Control of soil erosion:
Soil erosion can be controlled by forestation, proper agricultural practices, green manuring.
2. Proper dumping of unwanted materials:
The improper dumping of unwanted materials are causing severe soil pollution. Open
dumping is most commonly practiced method. Recently controlled tipping is followed for
solid waste disposal. The surface so obtained then can be used for housing or sports field.
3. Production of natural fertilizers and biopesticides:
Excessive use of chemical fertilizers and insecticides should be avoided. Bio pesticides
should be used in place of toxic chemical pesticides. For example, instead of throwing
animal dung pollutants in soil, they can be used to prepare compost manure and biogas.
4. Proper hygienic condition: People should be trained regarding the sanitary habits.
Lavatories should be equipped with quick and effective disposal methods.
5. Public awareness:
Informal and formal public awareness programs should be imparted to educate people on
health hazards by environmental pollution. Mass media, educational institutions and
voluntary agencies can achieve this.
6. Recycling and reuse of wastes.
To minimize soil pollution, the wastes such as paper, plastics, metals, glasses, organics,
petroleum products and industrial effluents etc. should be recycled and reused. For example,
Industrial wastes should be properly treated at source. Integrated waste treatment method
should be adopted.
7. Ban on toxic chemicals: Ban should be imposed on chemicals and pesticides like DDT,
BHC etc. which are fatal to plants and animals. Nuclear explosions and the improper
disposal of radioactive wastes should be banned. 11
2.4-a) SOLID WASTE MANAGEMENT

The population explosion and urbanization have produced enormous quantities of

solid wastes and environmental degradation. An estimated 7.6 million tones of municipal
solid waste is produceD per day in developing countries. These wastes are disposed in open
dumps creating environmental problems. So, the management of solid waste is become very
important in order to minimize the adverse effects of solid wastes.

Effect of improper solid waste management:

1. Decomposition of biodegradable materials produce foul smell and breeds insects which
spoil the land value.
2. Industrial wastes are sources of toxic metals and hazardous wastes, which affect soil
productivity.
3. They contaminate ground water.
4. Burning solid wastes cause air pollution.

Steps involved in solid waste management:

1. 3R principle
2. Discarding waste (Landfill, incineration, composting, acid bath)
Flow chart for the solid waste management:

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1. 3R Principle – Reduce, Reuse, Recycle
a. Reduce:
If the usage of raw materials is reduced, the generation of waste also gets reduced.
b. Reuse of waste materials:
For example, the refillable containers, which are discarded after use, can be reused. The
rubber rings can be made from the discarded cycle tubes, which reduce the waste generation
during manufacturing of rubber bands.
c. Recycle:
It is the reprocessing of the discarded materials into new useful products. As example, old
aluminium cans and glass bottles are melted and recast into new cans and bottles.
Mechanical recycling is the most efficient and eco-friendly method. Here we use dry
physical separation to recover used circuit boards, ICs, motherboard, etc from the e-waste
and recycle them. In this method, precious metals like copper, lead, etc., are separated from
the e-waste using a PCB recycling machine without harming the environment.
2. Discarding wastes: (Landfill, incineration and composting)
a. Land fills:
Landfill system consists of alternate layers of 80cm thick refuse, 20 cm earth fill. After 2 or
3 years, the waste volume is reduced by 25-30% and the land is used for parks and roads. It
is simple and economical. There is no need of prior segregation of biodegradable and non-
degradable materials. Land reclamation is easy. But, it requires large area and longer
transportations. Sometimes, due to methane gas formation, fire hazard happens.
b. Incineration:
The solid wastes are burnt in a furnace called incinerator. The combustible materials alone
can be allowed for incineration. They result in ashes and clinkers. They are reduced by
volume of 10 -20% which can be then discarded to landfills. The heat produced can be used
for steam-electricity generation. Larger incinerators of capacity 150 tones are called as
„destructors‟.They maintain the temperature of 700-1000oC. It is a hygienic way of
disposing wastes. But it is costlier process. It needs skilled persons. It causes air pollution.
c. Composting:
Here, bulk organic waste is converted into fertlilsing manure by biological action. The
compostable waste is dumped in underground earthen trenches in layers of 1.5m and
covered with earth of about 20 cm. Microorganisms like actinomycetes are introduced for
active decomposition. Within 2-3 days, biological action starts and heat is
liberated .Around at 75 degree Celsius, the refuse is converted into browny humus for
agricultural field. It is rich is nitrogen. 13
2.5) MARINE POLLUTION – CAUSES, EFFECTS - CONTROL MEASURES

Marine Pollution:
Entry of unwanted, harmful materials into the marine environment resulting in damage to
living resources, affecting human health , hindrance to marine activity is called as „ marine
pollution‟.
Sources of marine pollution:
1. Land based sources 2. Air based sources 3. Maritime transportation
4. dumping of wastes 5. Coastal accidents and wars 6. Ballast drainage
1. Land based sources:
This includes storm water, urban runoff, drains, heavy metal contaminated water bodies,
protozoa, pipelines and radioactive materials.
2. Air based sources:
Industrial activities that create air pollution which eventually drifts over and falls onto ocean.
3. Maritime transportation:
This pollution is created either accidentally or purposively from ships as part of the travel
process. (e.g.) Disposal of oil during the normal cleaning process, accidental spill of oil,
disposal of garbage.
4. Dumping of wastes:
Deliberate dumping of land bases wastes at sea causes marine pollution.
5. Coastal accidents and wars:
Iran – Iraq war caused extensive marine pollution.
6. Ballast drainage: After delivering the oil through sea-route, earlier empty tankers used to
be filled with water known as „ballast water‟ to maintain the balance, It contains residual oil
which is released into the sea on completion of journey.

Effects of marine pollution:

1. Organic matter decomposition decrease oxygen content.
2. Nitrogen excess effluents cause eutrophication.
3. Pathogenic micro-organisms cause infectious diseases.
4. Oil spillage affects respiration of plants and animals.
5. Oil spillage affects the process of photosynthesis.
6. Pesticides pollution cause reproductive failure in aqua culture. 14
7. Ships often paint their walls with anti-fouling paint of tributyl tin (TBT) to prevent the
growth of marine organisms. These leach into water and affect aqua culture.
8. Any leakage in radioactive waste containers causes severe skin effects.
9. Thermal pollution alters the normal life of aquatic lives.
10. Oil disturbs the insulating capacity of feathers. Death occurs due to loss of buoyancy
and drowning of birds.
11. Many marine birds ingest plastic that causes gastro-intestinal disorders.

Control measures of marine pollution:

1. Careful handling of oil and petroleum products
2. Ban of ocean dumping of sludge and hazardous materials.
3. Disposing only treated wastes.
4. Regulating coastal development
5. Hygienic and aesthetic maintenance of recreational beaches.
6. controlled use of pesticides and chemicals.
7. Separating sewage and storm water lines.
8. Providing double hull for oil tankers.
9. Recreational beaches should be maintained to meet hygienic and aesthetic standard.
10. The split oil layer should be immediately removed by suitable methods.

Methods of removal of oil

Several methods have been devised to deal with oil floating on the sea,
1. Physical Methods
a) Skimming the oil off the surface with a suction device appears to be the simplest methods
b) The floating oil can be absorbed using a suitable absorbing material like polyurethane
foam.
c) Chopped straw and saw dust can also be used to absorb oil from the sea water.
d) Chemicals can be used to coagulate the oil.
2. Chemical Methods
a) Dispersion.
b) Emulsification
c) Using Chemical additives.
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2.6) NOISE POLLUTION – CAUSES, EFFECTS - CONTROL MEASURES
Noise Pollution: The unpleasant and unwanted sound is called noise. So, the unwanted,
unpleasant and disagreeable sound causing discomfort for living beings is called „Noise
pollution‟. The sound intensity is measured in decibel (dB). 1dB to 70dB is of tolerance
level. 70 to 130 dB is of warning tolerance level. 140 dB is threshold of pain. Even for
crackers, the allowed limit is 125dB. The Ambient Noise Level dB is given below.
Zone Day-time Night-time
Silent zone 50 40
Residential zone 55 45
Commercial zone 65 55
Industrial zone 70 70
Types of noise pollution:
1. Industrial noise pollution
2. Transport pollution
3. Neighborhood noise pollution.
Industrial noise pollution:
This includes sound and noise caused by machines of factories, industries, saw mills,
pneumatic drillers. In steel industry, 112 dB exposures caused some hearing problems to
the employers. Construction, demolition activities are also there.
The Institute of Oto-Rino Laryngology reported enormously increasing industrial pollution
has damaged the hearing of about 20% workers.

Transport noise pollution:

It includes road, rail and aircraft, jet noises. Noise level in the residential areas in
metropolitan cities is already hovering on the border line because of this pollution, which
gradually deafen them. A survey conducted in metropolitan cities has shown that noise level
in Delhi, Bombay and Calcutta is as high as 90dB. Inhabitants of cities are subjected to this
most annoying form of transport noise which gradually deafens them.

Neighbourhood noise:
This includes musical instruments, TV, VCD, radios, loud speakers and other gadgets from
household appliances. Elections, social-religious functions also come under this category.
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Effects of noise pollution:
1. Continuous exposure to noise results in hypertension, insomnia, gastro-intestinal and
digestive disorders, blood pressure changes etc.
2. Severe noise pollution leads to mental distress, heart attacks and seriously of birth defects,
abortion.
3. When exposed to very loud and sudden noise, acute damage occurs to the ear drum.
4. It leads to psychological and pathological disorders.
5. It leads to visionary problems as a side effect. Pupillary dilation, impairment of night
vision and decrease in the rate of colour perception are some of its severe effects.
6. Ultrasonic sound can affect the digestive, respiratory, cardio vascular systems
semicircular canals of the internal ear. The rate of heart beat may also be affected.
Control of Noise pollution:
It can be done in three aspects.
(i) Noise control at source
ii) Noise control at path (medium)
iii) Noise control at Receiver end
Control at source:
1. Sources of noise pollution like heavy vehicles, old vehicles may not be allowed to ply in
the populated areas.
2. Source modification such as acoustic treatment to machine surface, design changes,
limiting the operational timings can be done.
3. The noise producing sources can be incorporated with noise barrier, sound absorbing
materials, insulators etc.
4. Proper oiling will reduce the noise from the machines.
Control at path:
1. More plantations of trees is an excellent natural way of noise absorption.
2. Proper acoustics plans, screens in the auditorium can minimize sound pollution.
Control at receiving end:
1. Personal protective devices such as ear-plugs can be used.
2. Strict laws should be enforced to minimize the sound in functions, Blowing horns in
congested, residential, hospital, school zones must be banned.

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2.7) THERMAL POLLUTION – CAUSES, EFFECTS - CONTROL MEASURES

Thermal Pollution:
Addition of excess, undesirable heat to water systems affecting the aquatic life and in turn
the human life is called „Thermal pollution‟.
Sources:
1. Power plants (Nuclear, coal field, hydro electric)
2. Soil erosion
3. Deforestation
4. Hot runoff
5. Effluents and sewages
6. Natural factors such as forest fire, volcanic eruptions and lava emissions.

1. Power Plants:
Nuclear power plants and reactor operation involves a large amount of hot water as process,
coolant and moderators. During the installation period also, it results in huge quantity of
hot water. This results in 10oC rise in the water body. Hydro electric power plants and coal
fired power plants also increase the water body temperature as by 8 to 10oC.
2. Soil erosion:
During soil erosion, the leached soil makes the water so muddy that it absorbs and holds the
sunlight for a long period which causes thermal pollution.
3. Deforestation:
Due to deforestation of shore lines, shade to water is prevented and hence causing rise in
temperature.
4. Hot runoff:
The excess rainwater and other runoff from hot tar streets, parking lots reaching the surface
water bodies cause thermal pollution.
5. Effluents and sewage:
Sewages and effluents, turbo generators spent also contribute 6-9 oC increase in the water
surfaces.
6. Natural factors:
Forest fire, volcanic eruptions also significantly contribute to the thermal pollution.
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Effects of thermal pollution:
1. Reduction in dissolved oxygen:
Concentration of dissolved oxygen (DO) decreases with increase in temperature of water.
2. Increase in toxicity:
The rising temperature increases the toxicity of the poison present in water. A 100c rise in
temperature doubles the toxic effect of potassium cyanide, while an 800C rise in temperature
triples the toxic effects of O-xylene causing massive mortality of fish.
3. Interference with the biological activities:
Temperature is considered to be vital significance to physiology metabolism and
biochemical process in controlling respiratory rates, digestion, excretion and overall
development of aquatic organisms. The temperature changes totally disrupt the entire
ecosystem.
4. Interference with reproduction:
In fishes and marine birds, several activities like nest building, spauning, hatching,
migration and reproduction etc., depend on optimum temperature.
5. Direct mortality:
Unutilized heat in water is responsible for direct mortality of aquatic organisms. The
increase in temperature exhausts the micro-organisms and shortens their life span. Above a
particular temperature, death occurs to fish due to failure in respiratory system, nervous
system process.
6. Food storage for fish:
Change in temperature alters the seasonal variation in the type and abundance of lower
organisms. The fish may lack the right food at the right time.

Control of thermal pollution:

1. Cooling towers
2. Cooling ponds
3. Spray ponds
4. Artificial lakes
1. Cooling towers: Cooling towers are designed to control the temperature of water. They
transfer most of the heat from the hot water to the surrounding by evaporation. In wet
cooling tower, the hot water from factories is sprayed through baffles and cool air is passed
from sides to cool the water. 19
In dry cooling tower, water is passed through spiral pipes and cooled by a fan. In wet
method, evaporation loss is high and also causes fog formation. In dry method, no water
loss, but it is costlier process.

2. In cooling ponds, water from condensers is stored in ponds where natural evaporation
cools the water, which can be recycled or discharged to nearby water body.

3. In spray ponds, hot water is passed through sprayers and nozzles as fine droplets. Heat
from the fine droplets gets dissipated to the atmosphere.
4. In artificial lakes, the heated effluents can be discharged into the lake at one end and the
water for cooling purposes may be withdrawn from the other end. The hot water is also
used as such for frost protection of land during high cold seasons in western countries.

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2.8) NUCLEAR HAZARDS – CAUSES, EFFECTS - CONTROL MEASURES
Nuclear Pollution:
Pollution due to radioactive materials is known as „nuclear hazard‟ or „nuclear pollution‟.
Sources of nuclear hazards
Various sources of nuclear hazards are grouped into two types
1.Natural source 2. Man-made (Anthropogenic) sources.
1. Natural sources of nuclear pollution:
It involves cosmic rays, UV rays, Radon 222 emitted from soil, rocks, common
radioactivity from air and water.
2. Anthropogenic nuclear pollution:
a. Nuclear power plants – Nuclear reactors produce cleaner and safer nuclear energy either
by fission or fusion. But, it possesses serious hazard of radioactive pollutants and wastes. It
may be due to nuclear test, underground nuclear explosions, Nuclear power plant accidents,
improper disposal of radioactive wastes, accidents during transport.
b. Atom bombs cause destruction of bio diversity. A large number of living beings are
totally destroyed by nuclear war. This phenomenon is known as „Nuclear holocaust‟.
c. Diagnostic kits : Without proper technical procedures and due to faulty operations, X
rays and testing labs are posing a high risk of radioactive pollution.
Effects of nuclear pollution:
1. Genetic damages, DNA mutation, disorders in genes, chromosomes and heredity carriers.
2. Somatic damages, burns, skin cancer, eye cataract, bone cancer, Thyroid, lungs problems.
3. Mining of Uranium enters into crops and to human beings.
4. On contact with water, these pollutants affect the environment severely.
5. Radioactive Iodine - 131 cause Thyroid glands malfunctions.
6. Radioactive Strontium – 90 causes bone diseases and leukemia.
7. Low dose radiations (100 – 250 rads) cause fatigue, vomiting and loss of hair.
8. High dose radiations (400 -500 rads) - problems in bone marrow, blood cells, clotting.
9. Very high dose of radiation (10,000 rads) kills the organisms by damaging the tissues of
heart and brain.
11. Nuclear bombardment cause combustion of wood, plastics and produce black soot.
Black soot absorbs all UV- radiations. Therefore, cooling will result. This is opposite to
„global warming‟ known as ‘nuclear winter’. It leads to freezing temperature and famine.
12. Chernobyll disaster (1986) and World war II (1945) are the examples of nuclear hazards.
21
Control of nuclear pollution:

1. The important step in controlling nuclear pollution is the proper disposal of nuclear waste.
It involves three major principles.
a. Dilute and disperse
b. Delay and Decay
c. Concentrate and contain.
If the nuclear wastes are of minimum amount, it can be diluted with other impurities
and can be dispersed. It the half life period is greater, then the materials have to be kept
upto their half life period and can be dispersed. Otherwise, they have to be kept under a
proof seal material and deep burial method is to be adopted.

Classification of radioactive wastes

a. High level wastes (HLW) - (e.g) Spent nuclear fuel
HLW have a very high radioactivity per unit volume. They have to be cooled and
stored for several decades by its producer before disposal. Since they are too dangerous,
must be contained either by converting them into inert solids (ceramics) and then buried
deep into earth or stored in deep salt mines.
b. Medium level wastes (e.g) Filters, reactor components, etc.,
MLW is mixed with concrete in steel drums before being buried in deep mines or below
the sea bed in concrete chambers.
c. Low level wastes (e.g) Solids or liquids contaminated with traces of
radioactivity. LLW are disposed of in steel drum in concrete-lined trenches.
2. Erection stage analysis for nuclear reactor should be carried out properly.
3. Proper disaster management system should be maintained.
4. Radiation therapy should be applied only as a last irresistible method even then with a
minimum dosage.
5. Always using less harmful isotopes in industries.
6. Regular checks for power plants.
7. Constant monitoring of radiation level inside and outside the plant.
8. Proper training of operators.
9. Ban on nuclear weapons.
22
2.9) ROLE OF INDIVIDUAL IN PREVENTION OF POLLUTION

1.Plant more trees.

2.Help more in pollution prevention than pollution control.
3.Use water, energy other resources effectively.
4.Purchase recyclable, recycled and environmentally safe products.
5.Use CFC free refrigerators.
6.Use natural gas than coal
7.Reduce deformation.
8.Increase use of renewable resources.
9.Remove NOx from motor vehicular exhaust.
10.Use office machines in well ventilated areas.
11.Use less polluting substituted for harmful cleaning agents, paints and other products.
12.Use of ecofriendly products.
13.Don‟t use polystyrene cups that have chloro fluoro carbon (CFC) molecules, which
destroy ozone layer.
14.Use rechargeable batteries. Rechargeable batteries will reduce metal pollution.
15.Reduce garbage by recycling and reuse.
16.Slow population growth.

Role of women in environmental protection

Women play an important role in environmental protection, considering their status in
social production, consumption and their influence to future generation at home.
Various roles of women are
1.In rural areas, women plant trees and grass, grow vegetables with the drip-irrigation
method in order to save water.
2.In urban areas, they go shopping using cloth bags to reduce white pollution.
3.Women refuse to use disposable products to save energy and resources.
4.Women choose green products instead of poor quality that harm the environment.
5.Women buy non-phosphate detergents to reduce the incidence of water pollution.
6.They refuse to eat the meat, so variety of animals is preserved.
7. They value paper and thus protect trees.
23
2.10) DISASTER MANAGEMENT
Disaster is defined as a hazardous event that causes human causalities and property
damages in a particular time and area. Disaster management (emergency management)
is the creation of plans through which communities reduce vulnerability to hazards and
cope with disasters. There are two types of disasters.
(i) Natural disaster – (e.g) Floods, earthquakes, cyclones, landslides, volcanoes, Tsunami
(ii) Man-made disaster – (e.g) Accidents, Pollution, fire accidents
FLOODS;
If the amount of water flow exceeds the storage capacity of the river banks , then the water
come out of the banks, it is called „flood‟.
Reasons of flood:
i) Increased runoff in the catchment area
ii) Removal of dense and uniform forest cover hill zones
iii) Heavy rainfall
iv) Melting of ice, snow melt
v) Sudden or excess release of dam water
vi) Encroachment on the river banks
Effects of flood:
i) Submergence of the surrounding area
ii) Water borne diseases
iii) Plain surfaces have been eroded with mud and sand
iv) Cultivable lands get affected.
v) Extinction of coastal area civilization.
Control measures of flood:
i) By building check-in dams, reservoirs
ii) Proper management of channels – Diverting excess water through channels to
areas like lake, rivers where water is not sufficient.
iii) Removing encroachment from river banks
iv) Proper afforestation which reduces run-off
v) Weather forecasting and warning can save and minimize the damage.
vi) Restoring wetlands, replacing ground cover on water-course.
vii) River-networking in the country also reduce flood.
viii) Satellite pictures of pre-flood, flood and post flood with other information
contribute to the flood management process.
24
2.11) EARTH-QUAKES

1. Sudden fractures in solid rocks of earth crust, thus producing a faulty movement is known
as „earthquake‟. The focus point of origin is called as „epicenter‟.
2. Earthquakes are recorded by seismograph in Richter scale.
Richter scale Nature of the earthquake
Less than 4 insignificant
4 to 4.9 minor
5 to 5.9 damageable
6 to 6.9 destructive
7 to 7.9 major
8 and above great
3. Earthquake releases energy in the form of P– wave (Primary) and S- wave (secondary).
4. P waves pass through solids and fluids and it is faster.
5. S waves pass through only through solids and are comparatively slower.
6. Earthquakes are followed by aftershock, primary and secondary effects.

Causes of earthquakes:
1. Tectonic forces – Earth-quakes are arising when the equilibrium is disturbed in any part
of the earth crust. These disturbance causes displacement of tectonic plates and their uneven
and sudden movements cause earthquake.
2. Volcanic eruptions.
3. Hot steam tremors at deeper earth.
4. Underground nuclear tests
5. Water level reduction
6. Reservoir Induced seismicity (RIS) of dams.

Effects of earthquakes:
1. Land slides
2. Mortality
3. Deformation of ground surface
4. Tsunami
25
Earthquake management:
1. Earthquake resistant building
2. Wooden house mechanism of Japan
3. Using seismic hazard map predictions
4. Maintaining the proper ground water level.
5. Aforestation
6. Minimizing underground nuclear test.
7. Proper engineering prevention of RIS.
Case studies of Earthquakes:
1. 1906 – Sanfrancisco – 7.8 Richter
2. 1976 – Tangshan, China – 8.0 Richter
3. 1995 – Kobe, Japan – 8.0 Richter
4. 2001 – Bhuj, India – 6.3 Richter

2.12) TSUNAMI
In Japanese language, Tsu = harbour nami = waves. When the earthquake occurs beneath
the sea, the water above the deformed area is displaced from its equilibrium position,
generating the waves called „Tsunami‟.
1. Due to seismic activity, sea floor is deformed and large waves are created. This is called
„Tsunami‟.
2. It is a series of waves of very high wavelengths with high velocity.
3. But, nearing shores, its velocity decreases and height and energy drastically increases as
15 – 65 m.
Effects of Tsunami:
1. Devastating properties, loss of life.
2. Killing livestock.
3. Water borne diseases.
Tsunami management:
1. Step – 1: Monitoring by sensors.
2. Step – 2: Sending messages from sensors to buoys.
3. Step – 3 : Relay to satellite and then earth stations.
4. Step – 4: Warning to member nations.
5. Step – 5 : Domestic alertment. 26
2.13) CYCLONES
1. Spiral movement of wind towards a low pressure centre is called „cyclone‟.
2. The wind movement is anticlockwise in northern hemisphere and clockwise in south.
3. The central area where the pressure changes occur is called „Eye‟. Area surrounding the
eye is called as „wall cloud region of gales‟.
4. The cyclone storm is accompanied by heavy rains with thunder, lightning and moves at a
speed of 100 – 400 km / day.
5. The frequency of cyclone is high in Bay of Bengal than Arabian Sea and Indian Ocean.
6. Depending on areas it is given different names. In USA, it is Hurricane, China it is
typhoons, India as cyclones and in Australia it is Willy willies.

Effects of cyclones:
1. Sea level increases - Leads to inundations of seashore.
2. Death toll increases due to drowning.
3. Agricultural fields are getting collapsed.
4. Disturbances in power supply.
5. Disturbances in communication systems.
6. Affecting the road side, rail and air traffics.
7. Hinders the developmental activities.

Control measures of cyclone:

1. Meteorological information should be advanced informed.
2. Development activities should be done in par with environmental aspects.
3. Modification of constructional techniques.
4. Radar detection.
5. Planting coastal belt trees, embankments, wind breaks.
Case studies of cyclones:
1. 1964 December - Rameswaram
2.1970 November - Bangladesh
3. 1977 November – Andhra, Nizampattnam
4. 1999 October - Orissa
5. 2018 November - Pudukkottai
27
2.14) LANDSLIDES
Defintion:
The movement of earthy materials such as rocks, soil, mud and debris from higher region to
lower region due to gravitation pull is known as landslides. It may be a natural process or
manmade process.
Causes of landslides:
1. Downhill movement of earth is mainly caused by rain. The heavy rain may lubricate
the various layers and make the slope too steep.
2. Movement of heavy vehicles/heavy loaded transportation.
3. Earthquakes, shocks, vibrations and cyclone.
4. Soil erosion
5. Underground mining.
6. Deforestation.
7. Dumping of debris – construction of heavy structures.
8. Deep excavations on sloppy areas for buildings, roads, and canals.
Effects of landslides:
1. Blockage of road and diversion of passage
2. Soil erosion
3. Damage of houses, crop yield and life stocks
4. Makes soil infertile
5. Rivers are filled with sand and mud and they become unfit for boating.
Control measures and management of landslides:
1. The cultivation of plants in the sloppy region whose root help to provide cohesion
and slows down the flow of the water and its erosion capacity
2. Concrete support at the base of the slope
3. Proper drainage of water from weak sloppy region
4. Soil stabilization by quick lime
5. Aforestation
6. Controlling constructional activities in the heavy slide prone areas

Case studies of landslides:

1. 1998 August – Malpa Village – Uttar Pradesh – 180 people died. 28
2.15) CASE STUDIES / FIELD STUDIES OF POLLUTION & DISASTERS

No Pollution Case study – 1 Case study – 2

1 Nuclear Hazards Second world war Chernobyl disaster
2 Air Pollution Bhopal gas tragedy, Taj Mahal Pollution
3 Marine Pollution Miniamatta Epidemic, Gulf war
4 Water Pollution Palar river, Arsenic Pollution Noyyal Pollution
5 Soil pollution Coco-cola unit (Kerala), Hindustan Lever Ltd (TN)
1. Nuclear Hazards:
E.g. 1. Second World War
1945 – World War II – Hiroshima (6th August), Nagasaki (9th August) bomb blast caused
severe genetic and somatic damages for a very long period. – More than 100,000 people
died.
E.g. 2 – Chernobyl disaster
1. Chernobyl, Ukraine in USSR in 26th April, 1986. The power plant was designed to
produce 1000MW electrical energy. It was shut down for maintenance operations on April
25, 1986. Due to faulty operations, an explosion occurred at 1.23 hrs on April 26. Three
seconds later another explosion occurred. 1000 tones steel concrete lid of the reactor blew
off. Temperature rose to 2000o C. The debris and gases drifted over most of the northern
hemisphere. Iodine, Cesium were the important radioactive components. More than 2000
people were killed. People suffered due to the illness such as degeneration of the cells,
severe bleeding, anaemia, skin cancer. Animals, plants are also affected by nuclear radiation.
2. Air pollution:
E.g.1 – Bhopal gas tragedy
The world‟s worst industrial accident occurred in Bhopal, Madhya pradesh on the night of
3rd December 1984. It happened at Union Carbide India Ltd, who manufactures some
carbonate pesticides using methyl isocyanides (MIC). Methyl-iso-cyanate is a toxic gas
lower concentrated of which affects lungs and eyes and causes irritation in the skin. Higher
amounts of MIC, remove oxygen from the lungs and can cause death. The gas (MIC) spread
over 40sq. km area. About 5000 person were skilled and 65,000 people suffered from severe
eye, respiratory, neuromuscular, gastrointestinal disorders. Nearly 1000 persons become
blind. 29
E.g.2 – Taj Mahal, Agra
The Taj Mahal- Agra, one amongst the world wonders, represents the most refined aesthetic
value and one of the most priceless national monuments in architecture and engineering.
The foundries, chemical and the hazardous industries, refineries at Mathura are the major
sources of damage to Taj. The SO3, emitted by the Mathura refineries, combine with oxygen
along with moisture in the atmosphere forms sulphuric acid, called acid rain. This has a
corroding effect on the clean white marble. Industrial waste, refinery emissions, brick kilns,
vehicular traffic and generator sets are primarily responsible for polluting the ambient air
around the Taj Trapezium Zone (TTZ). Both inside and outside, the marble has decayed and
yellow pallor is affecting the entire monument. M.C. Mehta filed a case against those
industries. The Supreme Court agreed with the petitioner and ordered many industries to
close down. Numerous other industries switched over from the use of coke/coal and
obtained gas connections from the Gas Authority of India Ltd (GAIL). The judgment
vigorously applied the “Precautionary Principle” and in May 1999, the Central Government
constituted the Taj Trapezium Pollution Authority.
3. Marine pollution:
E.g.1 – The Miniamatta Epidemic (1953)
Miniamatta is a small coastal village in Japan. The Chisso Chemical Company, which
produces vinyl polymer plastics used organo-mercurial compound. The industry released its
effluent into Miniamatta sea. The effluent containing mercury ions is converted into methyl
mercury, which is highly toxic. The marine organisms like phytoplankton and zoo-plankton
easily absorb the toxic methyl mercury compound. These organisms are consumed by small
fishes and these are in-turn consumed by human beings. Thus the poisonous chemical
(methyl mercury) entered into the body of human beings though food chain. It damages the
central nervous system, which cause various disorders such as Loss of vision and hearing,
Loss of muscular co-ordination and severe headache and nervous disorders.
E.g.2 – Gulf War (1991)
Gulf war took place in Kuwait from January 16 to February 26, 1991 between Iraq
and USA. During the war America fighters dropped nearly a lakh of bombs, and forced the
Iraqi army to withdraw from Kuwait. During the retreat of Iraqi, they have set fire on nearly
700 oil wells of Kuwait. Since most of the oil wells are on shore of the sea, oil from the oil
well spills out into the sea. The floating oil over sea water covered nearly 80 km long and
25km wide area. The burning of oil wells continued nearly for 10 months. The burning of
oil wells released huge amounts of pollutants like CO2 and SO2 into the atmosphere. Nearly
one million birds have been killed due to the oil slick. The oil slick in the sea made the
desalination plants ineffective. 30
4. Water pollution
E.g 1 - Palar River-pollution
Palar river originates in Nandidurgam of Karnataka state and flows for about 350 km
through Karnataka, Andra Pradesh and Tamil nadu. Pala supply drinking water for several
municipalities, towns and villages in Vellore district, Tamil Nadu. Now the Palar is polluted
by the effluent of various leather industries which in-turn affecting the agriculture
productivity in 40,000 hectares of croplands. Chrome tanning industries discharge large
amount of chemicals like chromium, calcium, ammonium salts, organic dyes and acids
which cause severe pollution in the river.
E.g 2 - Arsenic pollution
West Bengal, Bihar and Bangladesh are severely contaminated by the toxic heavy
metal arsenic pollution in the ground water. Excessive use of lead arsenic and copper
arsenic as pesticides in summer paddy and jute seems to be the major cause of arsenic
pollution. The states lying in the downstream side of the river Ganga are facing the problem
of arsenic content. Nearly 350 million residents in Ganga basin are exposed to dangerous
levels of the arsenic elements in their drinking water. The local people, who were ingesting
low dose of arsenic for 10-14 years, were affected from white or back spots on the skin,
called melanosis. Long exposures lead to bladder lung cancer. Children are more badly
affected by arsenicosis.
E.g 3 - Noyyal River pollution – Thirupur Industries
There are nearly 500 dying units and 195 bleaching units operating in and around Tirupur.
They consume large quantity of water for processing and later discharge waste water. The
effluent from the above industries affect the surface and underground water and make the
water unfit for domestic work. The effluent also increases the pH of the soil and affects the
cultivation. The rivers like Bhavani, Noyyal and cavery get polluted due to mixing of
effluent from the above industries. TamilNadu Pollution Control Board (TNPCB) has
directed all textile printers and dyes of Thirupur to not allow the effluent to mix in the river
systems. These effluents are generally coloured, high in BOD, COD, and suspended solids,
highly alkaline and have a fairly high temperature. They also contain toxic metals and
chemicals like sulphides, chlorides, chromium salts etc., The high alkalinity and salinity are
harmful to several crops and impair their growth. The soluble dyes and colours in waste
water inhibit the process of sunlight penetration and photosynthesis. 31
5. Soil pollution
E.g 1 - Coca-Cola bottling unit – Lead waste
The coca-cola‟s bottling unit at Plachimada, plalakkad district, Kerala, discharged large
amount of sludges. These sludges are used as fertilizers by the nearby farmers. But, analysis
of the sludges showed that it contains toxic metals like cadmium and lead. The scientists
warned that the level of these toxic elements would pollute the land, local water supplies
and the food chain.
E.g 2 - Hindustan Lever Ltd. – Mercury waste
Mercury is an extremely toxic metal. Hindustan Lever Ltd (HLL), Kodaikkannal, is
manufacturing thermometer, disposed its mercury laden glass waste into the nearby area and
created land pollution. By the intervention of local people and environmental groups, HLL
transferred large quantities of mercury contaminated glass wastes from Kodaikkanal to USA.
6 Field Study Of Local Polluted Sites
Pallavaram in Chennai- Pallavaram in Chennai, is the place in which a number of leather
factory and tanneries are situated. These factories and tanneries process the raw leather
items and convert them into useful products.
The various process involved are
1.Tanning 2. Washing 3. Neutralizing 4. Finishing operation.
The sources of air pollution are
1.Products of combustion from heating plants
2.Incinerators
3. Automobile flue gases
4. Fumes and smokes from industrial processes.
Important air Pollutants are
1) CO 2)SOX 3)NOX 4) Particulates matter 5)Hydrocarbon
Effect of air pollution
1.Material damage. 2. Vegetation damage. 3. Damage to human health and animals
4. Reduction in visibility and darkening of sky
5.Acid rain, greenhouse effect, ozone layer depletion, photochemical smog, etc.,
Control measures
1.Selecting proper raw materials and equipment
2. Recovering or recycling the waste.
3.Use of granites settling chamber, cyclone separators, wet scrubber, filters and electrostatic
precipitators. 32