Environmental Pollution-

Causes, Effects and Control

Measures

Prepared by

M.SHANMUGARAJ M.E.,

V.S.V.N Polytechnic College,

Virudhunagar

Tamil Nadu

India

Definition

“Pollution is the effect of undesirable

changes in our surroundings that have

harmful effects on plants, animals and

human beings”.

Pollutant

Any thing (solid, liquid or gas) that

cause pollution is called pollutant

Eg. Lead, sulphuric acid, carbon

monoxide,

Types of Pollution

Degradable Non-degradable

Degradable: Those can be readily broken down by natural

processes

Eg. Discarded vegetables

Non-degradable: Those can not be degraded by natural

processes

Eg.plastics

Types of Pollution

Noise

Air Water Land or Soil

Thermal Nuclear

Air Pollution

Air pollution occurs due to the presence of

undesirable solid or gaseous particles in the

air in quantities that are harmful to human

health and environment

Composition of Air

Composition of Air

Component Symbol Volume

Nitrogen N2 78.084%

99.998%

Oxygen O2 20.947%

Argon Ar 0.934%

Carbon Dioxide CO2 0.033%

Neon Ne 18.2 parts per million

Helium He 5.2 parts per million

Krypton Kr 1.1 parts per million

Sulfur dioxide SO2 1.0 parts per million

Methane CH4 2.0 parts per million

Hydrogen H2 0.5 parts per million

Nitrous Oxide N2O 0.5 parts per million

Xenon Xe 0.09 parts per million

Ozone O3 0.07 parts per million

Nitrogen dioxide NO2 0.02 parts per million

Iodine I2 0.01 parts per million

Carbon monoxide CO trace

Ammonia NH3 trace

Types of pollutants

Primary pollutants

Pollutants that are emitted directly from identifiable sources –produced by both natural events or human activities

Eg. Dust storms, emission from vehicles

Secondary pollutants

When certain chemical

reactions take place

among the primary

pollutants

Eg. Sulphuric acid

Primary pollutants

Carbon oxides (CO2 and CO)

Nitrogen oxides

Sulphur oxides

Volatile organic compounds – hydro

carbons

Suspended particulate matter

TERM MEANING EXAMPLES

Aerosol Particles suspended on air Sprays from pressurized

cans

Mist Aerosol consisting of liquid droplets Sulfuric acid mist

Dust Aerosol of solid particles that are blown

into the air

Dust storm

Smoke Aerosol of solid and liquid particles

produced by chemical reactions such as

fires

Cigarette smoke

Fume Condensation of hot vapors of metals Zinc, lead fumes

Plume Smoke coming out of chimney

Fog Aerosol of water droplets

Smog Mixture of smoke and fog

Sources of Air Pollution

Vehicles

Industries

Dust and storm

Air crafts, jet

Effects of air pollution

Prolonged smoking or exposure to air

pollutants can overload or break down the

natural defenses such as hair in our nose,

sticky mucas in the lining of the upper

respiratory tract causing diseases like lung

cancer, asthma, chronic bronchitis etc.,

Cigarette smoking is responsible for the greatest exposure

to carbon monoxide.Exposure to air containing even

0.001% of carbon monoxide for several hours can cause

collapse, coma and even death.

CO is attached to blood hemoglobin for a long time, it

accumulates and reduces the oxygen carrying capacity of

blood. This impairs perception and thinking, slows reflexes

and causes headaches, drowsiness, dizziness and nausea

and blurred vision.

Nitrogen oxides and suspended particles both can

irritate lungs, aggravate asthma or chronic

bronchitis and increase respiratory infections.

Many volatile organic compounds such as benzene

and formaldehyde and toxic particulates such as

lead and cadmium can cause mutations,

reproductive problems and cancer, breathlessness

and irritation of the eye, nose and throat.

Sulphur dioxide irritates respiratory tissues,

chronic exposure causes a condition similar

to bronchitis.

It also reacts with water, oxygen and other

materials to form sulphur containing acids –

The acids can become attached to particles

which when inhaled are very corrosive to

the lung.

Chronic exposure of the leaves to air

pollutants can break down the waxy coating

that helps prevent excessive water loss and

leads to damage from diseases, pests,

drought and frost.

It also affects photosynthesis, respiration

and other metabolisms.

Ozone depletion

The upper stratosphere consists of

considerable amounts of ozone which works

as an effective screen for UV light.

The ozone thus formed is constantly broken down by naturally occurring processes that maintain its balance in the ozone layer. But the presence of certain pollutants can accelerate the breakdown of ozone. (chloroflurocarbons, halons)

The Chloro-fluro-carbons (CFCs) are extremely stable, non-flammable, non-toxic and harmless to handle. It is ideal for air conditioners, refrigerators and fire extinguishers etc.

Halons are similar to the CFCs dangerous to ozone layer.

The CFCs and Halons migrate into the upper atmosphere after they are released. As they are heavier than air, they are carried by air currents and reach upper atmosphere. This is a slow process and even take few to many years.

In the stratosphere unfiltered UV radiation severs the chemical bonds releasing chlorine from CFCs.

This attacks the ozone molecule resulting in its splitting into oxygen molecule and an oxygen atom.

Thus leading to ozone depletion.

Effects of ozone depletion

On human- sunburn, cataract, skin cancer, weakens the immune system

Food production – uv radiation causes reduction in photosynthesis – reduces nutrient contents and the growth of plants

On materials- damages paints and fabrics causing them to fade faster.

On climate- global warming – Green house effect-

increase in concentration of certain gases like carbon di oxide, nitrogen oxides, methane, CFCs trap heat in the form of infra red radiation near the earth’s surface- Green house effect

Effects of Green house effect

Polar ice caps will melt causing rise in

ocean levels.

Fall in agricultural produce.

Changes in habitats – climatic conditions.

Smog is a type of large-scale outdoor

pollution. It is caused by chemical reactions

between pollutants derived from different

sources, primarily automobile exhaust and

industrial emissions. Cities are often centers

of these types of activities, and many suffer

from the effects of smog, especially during

the warm months of the year.

Control measures

Proper fuel and exhaust system in vehicles

Use of dry and wet collectors, filters,

electrostatic precipitators.

Providing greater height to the stacks –

discharge pollutants away from the ground.

Substitution of raw materials that cause

more pollution.

Water pollution

71% of earth’s surface is covered by water-but

only a tiny fraction is available as fresh water.

97% of total water is found in oceans and 3% is

fresh water.

Out of this 2.997% is locked in ice caps. The only

0.003% of total volume is available as soil

moisture, ground water, water vapour, water in

lakes, streams, rivers and wetlands.

Definition

When the quality or composition of

water changes directly or indirectly as

a result of man’s activities such that it

becomes unfit for any purpose it is

said to be polluted.

Types of water

Surface water- water found in streams,

rivers and lakes etc.

Ground water- that percolates into ground

Aquifers- porous water-saturated layers of

sand, gravel or bedrock through which

ground water flows. It is replenished

naturally by rainfall.

Point source – source is known-

eg. Municipal and industrial discharge pipes

Non-point source- source is unknown-

eg.agricultural runoff, acid rain

Sources of Water

Pollution

Water soluble radioactive isoptopes –

radioactive wastes- ionizing radiation cause

birth defects, cancer and genetic disorders.

Hot water- thermal plants, nuclear power

stations, power plants release water-

Oil-leakage

Water soluble inorganic chemicals-acids, salts and compounds of toxic metals such as mercury and lead.

Organic compounds-oil, gaseoline, plastics, pesticides, cleaning solvents, detergents etc.

Sediment of suspended water- insoluble particles of soil and other solids that become suspended in water

Industrial EffluentsWater is discharged from industries after having been used in production processes. This waste water may contain acids, alkalis, salts, poisons, oils and in some cases harmful bacteria.

Mining and Agricultural WastesMines, especially gold and coal mines, are responsible for large quantities of acid water.

Agricultural pesticides, fertilizers and herbicides may wash into rivers and stagnant water bodies.

Sewage Disposal and Domestic WastesSewage as well as domestic and farm wastes were often

allowed to pollute rivers and dams.

.

Causes of water pollution

Disease causing agents – bacteria, viruses,

protozoa and parasitic worms enter water from

domestic sewage and untreated human and animal

wastes.

Oxygen depleting wastes- large populations of

bacteria use up the oxygen present in water to

degrade wastes. The amount of oxygen required

to break down a certain amount of organic matter

is called Biological Oxygen Demand(BOD).

If too much organic waste is added, all the

available oxygen is used up and causes

organisms like fish to die.

Anaerobic bacteria begin to break down the

wastes producing chemicals that have a foul

and unpleasant odour.

Inorganic plant nutrients-water soluble nitrates

and phosphates that cause excessive growth of

algae and other aquatic plants- called

eutrophication.

Biomagnification- pesticides- reach water-

phytoplanktons-herbivorous fish-carnivorous fish-

water birds-animals-human beings.

At each stage the chemicals are concentrated

resulting biomagnifiction. Eg.DDT

Control measures

Prevention

Setting up treatment plants

Root Zone Process – using reefs

.

.

Soil pollution

Soil is s thin covering over the land

consisting of a mixture of minerals, organic

materials, living organisms, air and water.

Under ideal climatic conditions soft parent

material may develop into a centimeter of

soil in 15 years.

Soil profile

The top layer – O horizon- freshly fallen and decomposed leaves, twigs, animal wastes, fungi and other organic materials- brown or black in colour

Uppermost layer- A horizon-partially decomposed organic matter and inorganic mineral particles –darker and looser

B horizon – subsoil contains less aquatic material and fewer organisms than A zone.

C horizon – weathered parent material

Causes of soil degradation

Erosion

By wind and water accelerated by human

activities such as farming, construction,

overgrazing by livestock, burning of grass

cover, deforestation.

Excess use of fertilizers

Fertilizers, insecticides, herbicides,

pesticides, fungicides, rodenticides

Soil fertility is lost

Kill beneficial insects

Integrated Treatment

Methods

Continuous contour trenches or benches

Live check dams – planting grass, shrubs

and trees etc.

Bund constructed out of stones.

Earthen check bund- local soil,across the

stream

Integrated Pest Management

Organic farming

Use of biofertilzers

Earthworms- vermicomposting

Pest control through microbes – Bacillus

thrungiensis, Azadirachta indica- Neem

Marine Pollution

The introduction of substances to the

marine environment directly or

indirectly by man resulting in adverse

effects

Causes

Direct discharge of wastes into sea –

sewage

Washed off materials- fertilizers, pesticides

Petroleum, oils washed off from roads

Spill of Toxic substances from ships

Offshore oil exploration and extraction

Effects of marine pollution

Eutrophication-phytoplankton blooms

Oil slick – affect plants and fish

Destroys flora and fauna

Control Measures

Introduction of sewage treatment plants

Primary treatment-physical process such as

screening and sedimentation to remove

pollutants that will settle, float etc.

Secondary treatment- to remove BOD

Control measures for oil

pollution

Process of emulsification through chemical

dispersants-sprayed on the oil.

Biological methods- use of bacteria

Noise Pollution

Noise is unwanted and undesirable sound

Permitted noise level is 125 decibels

dB Environmental condition

0 Threshold of hearing

10 Rustle of leaves

20 Broadcasting studio

30 Bedroom at night

40 Library

50 Quiet office

60 Conversational speech

70 Average radio

74 Light traffic noise

90 Subway train

100 Symphony orchestra

110 Rock band

120 Aircraft takeoff

146 Threshold of pain

Decibel levels of common sounds dB

Ambient noise levels dB

Zone Day time Night time

Silent zone 50 40

Residential zone 55 45

Commercial zone 65 55

Industrial zone 70 70

Safe time exposure in dBDuration

(hrs/minutes/seconds)

dB

8 hrs 90

4 93

2 96

1 99

30 minutes 102

15 102

7 108

4 111

2 114

1 117

30 seconds 120

Instantaneous rupture of

membrane

150

Effects of noise pollution

Physical damage to ear- temporary thresh

hold shift-TTS – hearing loss

Mental fatigue

Control techniques

Reduce noise at source

Block the path of noise

Increase the path length and

protect the recipient

Thermal Pollution

Sources- discharge of warm water into river

Effects-changes the ecological balance of river

Death of fish

Effect on plants

Control- passing the heated water through a cooling pond or cooling tower after it leaves the condenser

Nuclear hazards

Nuclear fission –splitting of the nucleus of

the atom – resulting energy is used for a

variety of purposes

Hot water

Uranium waste – ionizing material

Effects of nuclear pollution

Lethal

Mutation

Plants and animals

Marine organisms-fish

Skin diseases, cancer, eye disorders etc.,

Control measures

Away from the cities

Proper disposal mechanisms

Safety measures

Role of an individual in

prevention of pollution Develop respect to all forms of life

Try to plant trees where ever you can

Reduce the use of paper and wood products where ever possible – use recycled paper

Do not buy furniture, doors etc., made from teak – forest based

Help in restoring a degraded area

Join in an aforestation program

Advocate organic forming

Avoid use of pesticides

Reduce fossil fuel – coal, petrol etc. save petrol

Shut of the lights and fans when not needed- save

electricity

Do not use aerosol spray products

do not pour chemicals, paints pesticides in the

drain

Use rechargeable batteries

Do not use cans, avoid plastics – plastic

carry bags

Recycle paper, aluminum, plastics

Set up compost bin in your garden

Start community composting

Keep you and your place clean

Environmental protection

begins with

YOU!!!

Thank you