ENVIRONMENTAL POLLUTION

Pollution

• Pollution may be defined as an undesirable change in the physical, chemical

or biological characteristics of air, water and land that may be harmful to
human life and other animals, living conditions, industrial processes and
cultural assets. Pollution can be natural or manmade.
• The agents that pollute are called pollutants.
POLLUTANTS
• Pollutants are by-products of man’s action. The important pollutants are summarized
below:
• Deposited matter—Soot, smoke, dust and domestic wastes.
• Gases—CO, nitrogen oxides, sulphur oxides, halogens (chlorine, bromine and
iodine).
• Industrial pollutants—Benzene, ether, acetic acid etc., andcyanide compounds.
• Agriculture pollutants—Pesticides, herbicides, fungicides and fertilizers
• Photochemical pollutants—Ozone, oxides of nitrogen, aldehydes, ethylene,
photochemical smog and proxy acetyl nitrate.
• Radiation pollutants—Radioactive substances and radioactive fall-outs of the
nuclear test.
Classification of Pollutants
Nature of disposal: On the basis of natural disposal, pollutants are of two types:

1. Non-degradable pollutants: These are the pollutants, which degrade at a very

slow pace by the natural biological processes. These are inorganic compounds
such as salts (chlorides), metallic oxides waste producing materials and
materials like, aluminum cans, mercuric salts and even DDT. These continue to
accumulate in the environment.

2. Biodegradable pollutants: These include domestic sewage that easily

decomposes under natural processes and can be rapidly decomposed by
natural/ artificial methods. These cause serious problems when accumulated
in large amounts as the pace of deposition exceeds the pace of decomposition
of disposal.
Nature of form: On the basis of the form in which they persist after their release
into the environment, pollutants can be categorized under two types:
(i) Primary pollutants: These include those substances, which are emitted
directly from some identifiable sources. This include-
a. Sulphur compounds: SO2, SO3, H2S produced by the oxidation of fuel.
b. Carbon compounds: Oxides of carbon (CO+CO2) and hydrocarbons.
c. Nitrogen compounds: NO2 and NH3.
d. Halogen compounds: Hydrogen fluoride (HF) and hydrochloric acid (HCl).
e. Particles of different size and substances: These are found suspended in air.
The fine particles below the diameter of 100u are more abundant and include
particles of metals, carbon, tar, pollen, fungi, bacteria, silicates and others.
(ii) Secondary pollutants: The secondary pollutants are produced by the
combination of primary emitted pollutants in the atmosphere.
Ex: In bright sunlight, a photochemical reaction occurs between nitrogen oxides;
oxygen and waste hydrocarbons from gasoline that forms peroxy-acetyle nitrate
(PAN) and ozone (O3), both of them are toxic components of smog and cause
smarting eyes and lung damage.
 TYPES OF POLLUTION
Air Pollution-
The WHO defines air pollution as the presence of materials in the air in such
concentration which are harmful to man and his environment. A number of
ingredients find their way in the air and these are mostly gases, which rapidly
spread over wide areas.
It occurs when any harmful gases, dust, smoke enters into the atmosphere and
makes it difficult for plants, animals and humans to survive as the air becomes
dirty.
Causes of Air pollution:
1. Burning of Fossil Fuels: Sulfur dioxide emitted from the combustion of fossil
fuels like coal, petroleum and other factory combustibles is one of the major
causes of air pollution. Pollutants emitting from vehicles cause immense
amount of pollution. Carbon Monoxide produced by improper or incomplete
combustion emitted from vehicles is another major pollutant along with
Nitrogen Oxides that is produced from both natural and manmade processes.
2. Agricultural activities: Ammonia is a very common by product from
agriculture related activities and is one of the most hazardous gases in the
atmosphere. Use of insecticides, pesticides and fertilizers in agricultural
activities emit harmful chemicals into the air and cause water pollution.
3. Exhaust from factories and industries: Causes of Air pollution: Manufacturing
industries release large amount of carbon monoxide, hydrocarbons, organic
compounds, and chemicals into the air thereby depleting the quality of air.
Petroleum refineries also release hydrocarbons and various other chemicals
that pollute the air and also cause land pollution.
4. Mining operations: Mining is a process where in minerals below the earth are
extracted using large equipments. During the process dust and chemicals are
released in the air causing massive air pollution.
5. Indoor air pollution: Household cleaning products, painting supplies emit toxic
chemicals in the air and cause air pollution.
6. Suspended Particulate matter: Suspended particulate matter popular by its
acronym SPM, is another cause of pollution.
Types of Air Pollutants-
Primarily air pollutants can be caused by primary sources or secondary sources.
The pollutants that are a direct result of the process can be called primary
pollutants. A classic example of a primary pollutant would be the sulfur-dioxide
emitted from factories
Secondary pollutants are the ones that are caused by the inter mingling and reactions of
primary pollutants. Smog created by the interactions of several primary pollutants is known
to be as secondary pollutant.

Common air pollutants

1. Carbon Dioxide: CO2 content of air has increased by 20% during the last century. CO2
causes nausea and headache. Its increase in the air may cause green house effect,
rise in the atmospheric temperature. This may melt the polar ice resulting in rise in
level of oceans and flooding of coastal regions.
2. Carbon Monoxide: It is a very poisonous gas and is produced by incomplete
combustion of fuel. If inhaled. It combines with hemoglobin and reduces its oxygen-
carrying capacity. This leads to laziness, reduced vision and death.

3. Oxides of Nitrogen: These include NO and NO2, which are released by automobiles
and chemical industries as waste gases and also by burning of materials. These are
harmful and lower the oxygen carrying capacity of blood.
4. Oxides of Sulphur: SO2 and SO3 are produced by burning of coal and petroleum
and are harmful to buildings, clothing, plants and animals. High concentration
of SO2 causes chlorosis (yellowing of leaves), plasmolysis, damage to mucous
membrane and metabolic inhibition. SO2 and SO3 react with water to form
Sulphuric and sulphurous acids. These may precipitate as rain or snow
producing acid rain or acid precipitation.
5. Photochemical Oxidants: Formed by the photochemical reactions between
primary pollutants, viz. oxides of nitrogen and hydrocarbons. Nitrogen oxides in
the presence of sunlight react with un-burnt hydrocarbons to form peroxyacyl
nitrate (PAN), Ozone, aldehydes and some other complex organic compounds in
the air.
6. Hydrocarbons: These are un-burnt discharges from incomplete combustion of
fuel in automobiles. These forms PAN with nitrogen oxides, which is highly
toxic.
7. Particulate Matter: Industries and automobiles release fine solid and liquid
particles into the air. Fly ash and soot from burning of coal, metal dust
containing lead, chromium, nickel, cadmium, zinc and mercury from
metallurgical processes; cotton dust from textile mills; and pesticides sprayed
on crops are examples of particulate pollutants in the air. These are injurious to
respiratory tract.
8. Aerosols: Aerosols are chemicals released in the air in vapor form. These include
fluorocarbon (carbon compound having fluorine) present in emissions from the
Jet aero planes. Aerosols deplete the ozone layer. Thinning of ozone layer
results in more harmful ultraviolet rays reaching the earth, which are harmful
to skin, and can lead to skin cancer also.

9. Radioactive Substances: These are released by nuclear explosions and

explosives. These are extremely harmful for health.

10. Fluorides: Rocks, soils and. minerals containing fluorides release an extremely
toxic gas called hydrogen fluoride on heating. This gas is highly injurious to
livestock and cattle.
Control measures
1. Source control: Some measures that can be adopted in this direction are-
i. Using unleaded petrol
ii. Using fuels with low sulphur and ash content
iii. Encouraging people to use public transport, walk or use a cycle as opposed to
private vehicles
iv. Ensure that houses, schools, restaurants and playgrounds are not located on
busy streets
v. Plant trees along busy streets as they remove particulates, carbon dioxide and
absorb noise
vi. Catalytic converters should be used to help control emissions of carbon
monoxide and hydrocarbons
2. Control measures in industrial centres:
vii. Emission rates should be restricted to permissible levels by each and every
industry
viii. Incorporation of air pollution control equipment in design of plant layout
must be made mandatory
ix. Continuous monitoring of the atmosphere for pollutants should be carried
out to know the emission levels.
WATER POLLUTION

Introduction: Water pollution may be defined as “the alteration in physical,

chemical and biological characteristics of water which may cause harmful
effects on humans and aquatic life.”
Sources of water pollution-
1. Point sources: These are pollutants that are discharged at specific locations
through pipes, ditches or sewers into bodies of surface waters.
Ex: Factories, sewage treatment plants, abandoned underground mines and oil
tankers.
2. Non point sources: These pollutants cannot be traced to a single point of
discharge. They are large land areas or air-sheds that pollute water by runoff,
subsurface flow or deposition from the atmosphere.
Ex: Acid deposition, runoff of chemicals into surface water from croplands.
Types, effects and sources of water pollution-

Water pollution is any chemical, biological or physical change in water quality that
has a harmful effect on living organisms or makes water unsuitable for desired
uses.
S. No Pollutants Human sources Health Effects

1 Infectious agents Human and animal Variety of diseases

Ex: Bacteria, Viruses, wastes
Protozoa, and parasitic worms.
2. Oxygen demanding wastes Sewage, Animal feedlots, Degrade water
(Dissolved oxygen) paper mills and food quality by
Ex: Organic wastes such as processing facilities depleting water of
animal manure and plant debris dissolved oxygen.
This causes fish
and other forms of
oxygen-
consuming aquatic
life to die.
3. Inorganic chemicals Surface runoff, • Make freshwater
Ex: Water soluble inorganic industrial effluents unusable
and household for drinking and
cleansers irrigation
• Harm fish and
other aquatic life
S.No Pollutants Human sources Health Effects

chemicals: Surface runoff, • Cause skin cancer

Acids, Compounds of toxic industrial effluents and neck damage,
metals such as lead (Pb), and household Damage to
arsenic (As) and selenium (Se) cleansers nervous system,
and Salts such as NaCl in liver and kidneys
oceans and fluoride (F-) found • Lower crop yields
in some soils.

4. Organic chemicals Industrial effluents, • Can threaten

Ex: Oil, Gasoline, Plastics, household cleansers and human health by
Pesticides, Cleaning solvents surface runoff from causing nervous
and Detergents. farms. system damage
and some cancers.
• Harm fish and
wildlife.

5. Plant nutrients Sewage, manure and Can cause

Ex: Water soluble runoff of agricultural and excessive growth
compounds containing nitrate, urban fertilizers of algae and other
Phosphate and Ammonium aquatic plants,
ions.
S.No Pollutants Human sources Health Effects

decay, deplete
dissolved oxygen in
water thereby
killing fish
• Drinking water
with excessive
levels of nitrates
lower the oxygen
carrying capacity
of the blood and
can kill urban
children and
infants.

6. Sediment Land erosion • Causes cloudy

Ex: Soil, silt, etc. water there by
reducing
photosynthetic
activity
S. No Pollutants Human sources Health Effects

Sediment Land erosion • Disturb of aquatic

Ex: Soil, silt, etc. food
Chain
• Carries pesticides,
bacteria and other
harmful substances
• Carries pesticides,
bacteria and other
harmful substances
• Settles and destroys
feeding and spawning
grounds of fish

7. Radioactive materials: Nuclear power plants, • Genetic mutations,

Ex: Radioactive isotopes of: mining and processing of birth defects and
Iodine, Radon, Uranium, uranium and other ores, certain cancers.
Cesium and Thorium. nuclear weapon
production and natural
sources.
S. No Pollutants Human sources Health Effects

8. Heat (Thermal pollution) Ex: Water cooling of electric • Low dissolved oxygen
Excessive heat power plants and some levels thereby making
types of industrial aquatic organisms
plants. more vulnerable to
disease, parasites and
toxic chemicals.
Control measures of water pollution
1. Administration of water pollution control should be in the hands of state or
central government
2. Scientific techniques should be adopted for environmental control of
catchment areas of rivers, ponds or streams
3. Plants, trees and forests control pollution as they act as natural air
conditioners.
4. Trees are capable of reducing sulphur dioxide and nitric oxide pollutants and
hence more trees should be planted.
5. No type of waste (treated, partially treated or untreated) should be
discharged into any natural water body. Industries should develop closed loop
water supply schemes and domestic sewage must be used for irrigation.
6. Qualified and experienced people must be consulted from time to time for
effective control of water pollution.
7. Public awareness must be initiated regarding adverse effects of water
pollution using the media.
8. Laws, standards and practices should be established to prevent water
pollution and these laws should be modified from time to time based on
current requirements and technological advancements.
SOIL POLLUTION

Soil pollution is defined as, “contamination of soil by human and natural

activities which may cause harmful effect on living organisms”.
Types, effects and sources of soil pollution-
S. No Pollutants sources Health Effects

1. Industrial wastes Industrial pollutants are mainly These pollutants affect

discharged from various origins and alter the chemical
such as pulp and paper mills, and biological properties
chemical fertilizers, oil refineries, of soil. As a result,
sugar factories, tanneries, textiles, hazardous chemicals can
steel, distilleries, fertilizers, enter into human food
pesticides, coal and mineral mining chain from the soil or
industries, drugs, glass, cement, water, disturb the
petroleum and biochemical process and
engineering industries etc. finally lead to serious
effects on living
organisms.
SOIL POLLUTION

Soil pollution is defined as, “contamination of soil by human and natural

activities which may cause harmful effect on living organisms”.
Types, effects and sources of soil pollution-
S. No Pollutants sources Health Effects

2. Urban wastes Plastics, glasses, metallic cans, • Alter the constitution of

fibers, paper, rubbers, street soil
sweepings, fuel residues, leaves, • Cause Water logging
containers, abandoned vehicles Cause biomagnifications
and other discarded of toxic materials through
manufactured products. food chain

3. Agricultural fertilizers,pesticides, weedicides, Water logging,

practices farm wastes, manure debris, soil Salinisation, micronutrient
erosion imbalance,
loss of fertile soil
S. No Pollutants sources Health Effects

4. Radioactive pollutants Atomic reactor, nuclear Mutations, changes

radioactive devices, functions of living
Explosion of hydrogen weapons beings,
and cosmic Biomagnifications,
radiations cancers, Infant
mortality

5. Biological agents The human and animal wastes, Variety of diseases

garbage, waste water Cause nutrient
imbalance

6. Pesticides Chlorinated hydrocarbon Reduces the activity

insecticide Organic of sex hormones of
phosphorous pesticides male and female.
Causes diseases to
human beings.
S. No Pollutants sources Health Effects

7. Fertilizers Different fertilizers discharge N, The nitrate causes

Na, K, S, Nitrates etc cancer, blue baby
syndrome in infants.

8. Polymer, Plastics & Waste from different Biomagnifications,

other water sources water logging, create
cancers in animals
and human
beings.
Control measures of soil pollution

1. Soil erosion can be controlled by a variety of forestry and farm practices.

Ex: Planting trees on barren slopes
2. Contour cultivation and strip cropping may be practiced instead of shifting
cultivation
3. Reducing deforestation and substituting chemical manures by animal wastes also
helps arrest soil erosion in the long term.
4. Proper dumping of unwanted materials: Excess wastes by man and animals
pose a disposal problem. Open dumping is the most commonly practiced
technique. Nowadays, controlled tipping is followed for solid waste disposal.
The surface so obtained is used for housing or sports field.
5. Production of natural fertilizers: Bio-pesticides should be used in place of toxic
chemical pesticides. Organic fertilizers should be used in place of synthesized
chemical fertilizers. Ex: Organic wastes in animal dung may be used to
prepare compost manure instead of throwing them wastefully and polluting
the soil.
Control measures of soil pollution

6. Proper hygienic condition: People should be trained regarding sanitary habits

Ex: Lavatories should be equipped with quick and effective disposal methods.

7. Public awareness: Informal and formal public awareness programs should be

imparted to educate people on health hazards by environmental education.

8. 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.

9. 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
improper disposal of radioactive wastes should be banned.
NOISE POLLUTION

Noise is defined as, "the unwanted, unpleasant or disagreeable sound that causes
discomfort to all living beings". Sound intensity is measured in decibels (dB) ,
that is the tenth part of the longest unit Bel.
Types of noise:
1. Industrial Noise

It is sound with a high intensity sound caused by industry machines. Sources of

such noise pollution are caused by machines from machines in various
factories, industries and mills. Noise from mechanical saws and pneumatic
drills is unbearable and a nuisance to the public. The Indian Institute of Oto-
Rino Laryngology, Chennai reported that increasing industrial pollution
damages the hearing ability by at least 20%. Workers in steel industry, who
work close to heavy industrial blower, are exposed to 112 dB for eight hours
suffer from occupational pollution.
NOISE POLLUTION

2. Transport Noise:
Transport noise mainly consists of traffic noise from road, rail and aircraft. The
number of automobiles on roads like motors, scooters, cars, motor cycles,
buses, trucks and diesel engine vehicles has increased enormously in the recent
past further aggravating the problem of transport noise. Noise levels in most
residential areas in metropolitan cities are hovering around the border line due
to increased vehicular noise pollution. This high level of noise pollution leads
to deafening in the elderly.

3. Domestic noise:

This type of noise includes disturbance from household gadgets and community.
Common sources of noise are musical instruments, TV, VCR, Radios,
Transistors, Telephones, and loudspeakers etc. Statistically ever since the
industrial revolution, noise in the environment has been doubled every ten
years.
Effects of Noise pollution
Noise pollution affects both human and animal health. It leads to:
• Contraction of blood vessels
• Making skin pale
• Responsible for high blood pressure.
• Blaring sounds are known to cause mental distress
• Heart attacks, neurological problems, birth defects and abortion
• Muscle contraction leading to nervous breakdown, tension, etc
• The adverse reactions are coupled with a change in hormone content of
blood, which in-turn increases heart beat, constriction of blood vessels,
digestive spams and dilation of the pupil of the eye.
• Adverse affects health, work efficiency and behavior. Noise pollution may
cause damage to the heart, brain, kidneys, liver and may produce emotional
disturbance.
Effects of Noise pollution

• Impulsive noise may cause psychological and pathological disorders

• Ultrasonic sound can affect the digestive, respiratory, cardiovascular system and
semicircular canals of the internal ear.
• The brain is adversely affected by loud and sudden noise by jets and airplanes.
People are subjected to psychiatric illness.
• Recent reports suggest that blood is thickened by excessive noise.
Control measures:

1. SOURCE CONTROL : This includes source modification such as design changes,

and limiting operational timings, etc.

2. RECEPTOR CONTROL : This includes protection of the receiver by altering the

work schedule or provision of personal protection devices such as ear plugs for
operating noisy machinery.

3. OILING of machines : Proper oiling will reduce noise from the machine.

4. Other control measures:

• Prescribing noise limits for vehicular traffic

• Ban on honking (usage of horns) in certain areas

• Creation of silence zones near schools and hospitals

• Reduction of traffic density in residential areas

MARINE POLLUTION

The discharge of waste substances in to the sea resulting in harm to the living
resources, hazards to the human health hindrances to the fishery and
impairment of quality use of sea water.

Sources :

1. Dumping the wastes: Dumping of untreated wastes and sewages in the oceans
by coastal towns, cities and industries. Rivers on the way to sea carry huge
amount of sewage garbage agricultural discharge pesticide heavy metals. Huge
quantity of plastic dumped in to the sea.

2. Oil: This is discharged in to the sea as crude oil and as separate fraction. Oil and
it’s fractions are used in houses automobiles and industries. This causes
devastation of marine environment

3. Radioactive materials enter the ocean from nuclear weapon testing.

MARINE POLLUTION

4. Toxics: Toxic waste is the most harmful form of marine pollution. Once toxic
wastes affects an organism it quickly passes along the food chain and as sea
food which cause various problems.

5. Marine Debris: Garbage like plastic bags, ropes helium balloons

Effects of marine pollution-

1. Oil pollution causes damage to marine animals and plants including algae bird,
fish etc.

2. Oil films are able to retard the rate of oxygen uptake by water.

3. Hydrocarbon and benzpyrene accumulate in food chain and consumption of fish

by man may cause cancer.

4. Oil spilling in the sea causes abnormal low body temperature in birds.
MARINE POLLUTION

5. Many marine birds ingest plastic that causes gastrointestinal disorders.

6. Oil spills inhibit photosynthesis and the growth of planktons. All aquatic animals
depend either directly of indirectly on planktons the basis of tropic chain.

Control of marine pollution-

I. Nature and world conservation union suggest the principles:
1. The industrial unit on the coastal lines should be equipped with pollution control
instrument.
2. Urban growth near the coast should be regulated
II. Methods of removal of oil:

3. Physical methods.
• Skimming the oil off the surface with suction device
• Floating oil can be absorbed using absorbing materials like ploy urethane foam.
Chopped straw and saw dust also used to absorbed oil from the sea water.
MARINE POLLUTION

2. Chemical methods like dispersion, emulsification and using chemical additives

are used to coagulated the oil

3. Protective method –
• Municipal and industrial waste should be treated before disposing in to sea
• Coastal waste are periodically analyzed for detecting pollution level
• Soil erosion in the coastal land should be arrested be suitable techniques
• Recreation beaches should be maintained to meet hygienic and aesthetic
standard.
Thermal pollution
Thermal pollution is defined as the addition of excess of undesirable heat to water
thereby making it harmful to man, animal or aquatic life.
Sources of Thermal Pollution-
1. Nuclear power plants: Nuclear power plants including drainage from hospitals,
research institutions, nuclear experiments and explosions, discharge a lot of
heat that is not utilized along with traces of toxic radio nuclides into nearby
water streams. Emissions from nuclear reactors and processing installations
are also responsible for increasing the temperatures of water bodies. The
operations of power reactors and nuclear fuel processing units constitute the
major contributor of heat in the aquatic environment. Heated effluents from
power plants are discharged at 100 C higher than the receiving waters that
affect the aquatic flora and fauna.
2. Coal-fired power plants:
Coal fired power plants constitute a major source of thermal pollution. The
condenser coils in such plants are cooled with water from nearby lakes or
rivers.
Thermal pollution
The resulting heated water is discharged into streams thereby raising the water
temperature by 15oC. Heated effluent decreases the dissolved content of water
resulting in death of fish and other aquatic organisms.
3. Industrial effluents:
Industries like textile, paper, pulp and sugar manufacturing release huge amounts
of cooling water along with effluents into nearby natural water bodies. The
waters polluted by sudden and heavy organic loads result in severe drop in
levels of dissolved oxygen leading to death of several aquatic organisms.
4. Domestic Sewage: Domestic sewage is discharged into rivers, lakes, canals or
streams with minimal treatment or without any treatment. These wastes have
a higher organic temperature and organic load. This leads to decrease in
dissolved oxygen content in the receiving waters resulting in the set-up of
anaerobic conditions causing release of foul and offensive gases in water.
Eventually, this leads to development of anoxic conditions resulting in rapid
death of aquatic organisms.
Thermal pollution
5. Hydro-electric power:
Generation of hydroelectric power sometimes leads to negative thermal loading
in water systems. Apart from electric power industries, various factories with
cooling requirement contribute to thermal loading.
Effects of Thermal pollution-
1. Increase in toxicity: The rising temperature increases the toxicity of the
poison present in water. A 100C increase in temperature of water doubles the
toxicity effect like potassium cyanide.
2. Interference in biological activity: Temperature is considered to be of vital
significance to physiology, metabolism and biochemical processes that control
respiratory rates, digestion, excretion, and overall development of aquatic
organisms. Temperature changes cause total disruption to the entire
ecosystem.
3. Reduction in dissolved oxygen: Concentration of Dissolved Oxygen (DO)
decreases with increase in temperature.
4. Interference in reproduction: In fishes, several activities like nest building,
spawning, hatching, migration and reproduction depend on optimum
temperature.
Thermal pollution
5. Direct mortality: Thermal pollution is directly responsible for mortality of
aquatic organisms. Increase in temperature of water leads to exhaustion of
microorganisms thereby shortening the life span of fish. Above a certain
temperature, fish die due to failure of respiratory system and nervous system
failure.
6. Food storage for fish: Abrupt changes in temperature alter the seasonal
variation in the type and abundance of lower organisms leading to shortage
of right food for fish at the right time.
Control measures -
1. Cooling towers: Use of water from water systems for cooling systems for
cooling purposes, with subsequent return to the water way after passage
through a condenser, is called cooling process. Cooling towers transfer heat
from hot water to the atmosphere by evaporation.
2. Cooling ponds: Cooling ponds are the best way to cool thermal discharges.
Heated effluents on the surface of the water in cooling ponds maximize
dissipation of heat to the atmosphere and minimize the water area and
volume. The warm water wedge acts like a cooling pond.
Thermal pollution

3. Spray ponds: The water coming out from condensers is allowed to pass into the
ponds through sprayers. Here water is sprayed through nozzles as fine
droplets. Heat from the fine droplets gets dissipated to the atmosphere.
4. Artificial lakes:
Artificial lakes are manmade water bodies that offer once-through cooling. The
heated effluents can be discharged into the lake at one end and water for
cooling purposes may be withdrawn from the other end. The heat is
eventually dissipated through evaporation
Solid Waste Management:
Rapid population growth and urbanization in developing countries has led to
people generating enormous quantities of solid waste and consequent
environmental degradation. The waste is normally disposed in open dumps
creating nuisance and environmental degradation. Solid wastes cause a major
risk to public health and the environment.
Management of solid wastes is important in order to minimize the adverse effects
posed by their indiscriminate disposal.
Types of solid wastes- Depending on the nature of origin, solid wastes are
classified into
1. Urban or municipal wastes
2. Industrial wastes
Sources of urban wastes :
• Domestic wastes containing a variety of materials thrown out from homes.
• Commercial wastes: It includes wastes coming out from shops, markets, hotels,
offices, institutions, etc.
Ex: Waste paper, packaging material, cans, bottle, polythene bags, etc.
Solid Waste Management:
• Construction wastes: It includes wastes of construction materials. Ex:
Wood, Concrete, Debris, etc.
• Biomedical wastes: It includes mostly waste organic materials.
Ex: Anatomical wastes, Infectious wastes, etc.
Urban wastes are classified into:
1. Bio-degradable wastes - Those wastes that can be degraded by micro
organisms are called bio-degradable wastes
Ex: Food, vegetables, tea leaves, dry leaves, etc.
2. Non-biodegradable wastes: Urban solid waste materials that cannot be
degraded by micro organisms are called non-biodegradable wastes.
Ex: Polythene bags, scrap materials, glass bottles, etc.
Solid Waste Management:
Sources of industrial Waste: The main source of industrial wastes is chemical
industries, metal and mineral processing industries. Ex: Nuclear plants: It
generated radioactive wastes.
• Thermal power plants: It produces fly ash in large quantities
• Chemical Industries: It produces large quantities of hazardous and toxic
materials.
• Other industries: Other industries produce packing materials, rubbish, organic
wastes, acid, alkali, scrap metals, rubber, plastic, paper, glass, wood, oils, paints,
dyes, etc.
EFFECT OF IMPROPER SOLID WASTE MANAGEMENT
1. Due to improper disposal of municipal solid waste on the roads and
immediate surroundings, biodegradable materials undergo decomposition
producing foul smell and become a breeding ground for disease vectors.
2. Industrial solid wastes are the source for toxic metals and hazardous wastes
that affect soil characteristics and productivity of soils when they are dumped
on the soil
3. Toxic substances may percolate into the ground and contaminate the
groundwater.
Solid Waste Management:
4. Burning of industrial or domestic wastes (cans, plastics, radioactive materials
polythene and batteries) produce furans, dioxins and polychlorinated
biphenyls that are harmful to human beings.
Control measures of urban and industrial wastes-
Two important steps involved in solid waste management are- Reduce, Reuse and
Recycle of Raw Materials
1. Discarding wastes:
• Reduce - If usage of raw materials is reduced, the generation of waste also
gets reduced.
• Reuse - Refillable containers that are discarded after use can be reused.
Rubber rings can be made from discarded cycle tubes and this reduces waste
generation during manufacture of rubber bands.
2. Recycle: Recycling is the reprocessing of discarded materials into new useful
products
Ex: Old aluminum cans and glass bottles are melted and recast into new cans and
bottles, preparation of cellulose insulation from paper, Preparation of
automobile body and construction material from steel cans. This
method (Reduce, Reuse & Recycle)
Solid Waste Management
Discarding wastes
The following methods are adopted for discarding wastes:
1. Landfill- Solid wastes are placed in a sanitary landfill in which alternate layers
of 80 cm thick refuse is covered with selected earth-fill of 20 cm thickness.
After 2-3 years solid waste volume shrinks by 25-30% and land is used for
parks, roads and small buildings. This is the most common and cheapest
method of waste disposal and is mostly employed in Indian cities.
Advantages:
• It is simple and economical
• Land filled areas can be reclaimed and used for other purposes
• Converts low-lying, marshy waste-land into useful areas.
• Natural resources are returned to soil and recycled.
Disadvantage:
• Large area is required
• Land availability is away from the town, transportation costs are high
• Leads to bad odor, if landfill is not properly managed.
• Land filled areas will be sources of mosquitoes and flies requiring application
of insecticides and pesticides at regular intervals.
Solid Waste Management:
2. COMPOSTING:
It is another popular method practiced in many cities in our country. In this
method, bulk organic waste is converted into fertilizer by biological action.
Separated compostable waste is dumped in underground trenches in layers
of 1.5m and finally covered with earth of 20cm and left for decomposition.
Sometimes, Actionmycetes are introduced for active decomposition. Within
2 to 3 days, biological action starts. Organic matter is destroyed by
actinomycetes and lot of heat is liberated increasing the temperature of
compost by 750C and the refuse is finally converted into powdery brown
colored odorless mass called humus that has a fertilizing value and can be
used in agriculture. Humus contains lot of Nitrogen essential for plant
growth apart from phosphates and other minerals.
ADVANTAGES:
• Manure added to soil increases water retention and ion-exchange capacity
of soil.
• This method can be used to treat several industrial solid wastes.
• Manure can be sold thereby reducing cost of disposing wastes
• Recycling can be done
Solid Waste Management:

DISADVANTAGES:
• Non-consumables have to be disposed separately
• The technology has not caught-up with the farmers and hence does not have
an assured market.
Nuclear hazards:
Nuclear hazards refer to the incidents involving the release of significant levels of
radioactive materials and exposure of general public or the natural
environment to nuclear radiation. The nuclear hazards primarily affect public
health due to direct exposure to radioactive materials, inhalation of
radioactive waste, ingestion of contaminated food, water etc. and long term
exposure to radioactive materials in the environment that leads to acute or
chronic health and environmental damage.
SOURCE OF NUCLEAR HAZARD:
The sources of radioactivity are both natural and man-made -
1. Cosmic rays from outer space.
2. Emissions from radioactive materials in the earth’s crust (rocks, marine
sediments etc) Man-made sources include the nuclear wastes produced during
3. Mining and processing of radioactive ores.
4. Use of radioactive materials in power plants such as Carbon-14, Uranium-235,
Radium-226, etc.
5. Use of radioactive isotopes in medical technology (x-ray machines, radioisotopes
used in medicine)
6. Industrial applications include wastes from nuclear reactors.
Nuclear hazards:
7. Research applications: radioactive fallouts during nuclear weapons testing.
8. In a nuclear power plant, any leak or accident taking place emit nuclear
radiation. In either case it results in nuclear hazard.
9. Nuclear tests Conducted under the ground or under oceans which also
release radiation.
10. Uranium mining and milling, Nuclear reactors and reprocessing of nuclear fuel
cause nuclear pollution.
Effects:
1. Radioactive materials released from nuclear hazards cause mutations in the
DNA, thereby affecting genes and chromosomes. The genetic makeup of
future generations is affected due to these mutations. It leads to several
incurable birth defects.
2. Radiations can kill essential flora and fauna, important environmental species
and can make land soil, plants etc. toxic and critical species are also affected. It
results in huge damage to biodiversity.
3. Damages caused by different kinds of radiations also include direct physical
harms such as burns, miscarriages, cancer, bone defects, eye diseases etc.
Even a small exposure to radiation can cause adverse effects. Damages that
occur over longer periods are spread over for generations.
Nuclear hazards:
4. Natural resources such as land, soil, forests, water bodies like rivers, ponds, oceans
get affected by nuclear wastes and nuclear elements. Contamination of natural
resources affects large number of people living in urban as well as rural areas.
5. Children are at particular risk from nuclear radiations. High doses of radiation
increases cancer risk early in the life of children. Lifetime cancer risk significantly
increases among children due to exposure to radiation.
6. Nuclear hazards increases the pressure on land as soil and water resources are
contaminated and therefore lesser land is available for agricultural purposes. The
microorganisms present in land and soil also get killed due to insufficient oxygen
which reduces soil fertility.
Control Measure :
• Laboratory generated nuclear wastes should be disposed off safely
and scientifically.
• Nuclear power plants should be located in areas after careful study of the geology
of the area, tectonic activity and meeting other established conditions.
• Appropriate protection against occupational exposure
• Leakage of radioactive elements from nuclear reactors, careless use of radioactive
elements as fuel and careless handling of radioactive isotopes must be prevented.
Nuclear hazards:
• Safety measure against accidental release of radioactive elements must be
ensured in nuclear plants.
• Unless absolutely necessary, one should not frequently go for diagnosis by x-
rays.
• Regular monitoring of the presence of radioactive substance in high risk
area should be ensured.