2. DEFINITION OF POLLUTION
Pollution is a process in which the
quality of the environment is lowered
when some materials known as
pollutants are injected or released into
the environment at concentrations
above the accepted level.
3. DEFINITION OF POLLUTANT
Pollutant is any substance
introduced into any environment by
man which causes the destruction or
impairs the purity of the
environment and causing harm to
4. Pollutants that can be broken down by
microorganisms are called
BIODEGRADABLE pollutants while
pollutants that can not be decomposed
naturally by bacteria are called NON-
BIODEGRADABLE pollutants. The most
effective method of getting rid of them is
by RECYCLING them e.g., plastics, metal
scraps, glass, etc
5. EXAMPLES OF POLLUTANTS
Heavy metals (such as mercury,
zinc, nickel, lead), oil spillage from
pipelines or tank, improper refuse
disposal, untreated sewage,
herbicides and pesticides, noise
6. MAJOR TYPES OF POLLUTION
1. Land pollution
2. Water pollution
3. Air pollution
4. Noise pollution
8. LAND
POLLUTANTS
SOURCES EFFECTS
1. Refuse Home, offices and industries It causes offensive odour when
the refuse decay.
2. Sewage Homes and offices i. It can cause respiratory
disoder
ii. It results in offensive odour
iii. It serves as a breeding
ground for disease causing
organisms.
9. 3. Metal scraps Abandoned
vehicles and
machines
i. It occupy space
ii. It prevents
proper land use
4. Pesticides and
Fertilizers
Pesticides sprayed
on crops and
fertilizers used in
soils
i. They destroy
useful soil organisms
ii. Excess fertilizer
can cause soil
acidity
iii. It can cause the
death of aquatic
organisms, e.g.
fishes
10. 5. Chemicals, e.g.
toxic wastes
Chemicals waste
from industries
These are
poisonous to
plants and
animals
6. Glass particles Glass
manufacturing or
industries using
bottles
i. It can cause
injury to human
skin or body .
ii. It does not
decay hence it
prevents proper
land use.
11. 7. Crude oil (
Oil spillage)
Oil drilling,
loading or
unloading of
oil tankers
i. It destroys
soil and
renders it
infertile
ii. It destroys
plants and
animals’ life
in water.
12. CONTROL OF LAND POLLUTION
1. Indiscriminate dumping of refuse should
be discourage.
2. Refuse should be burnt in incinerators.
3. Urban wastes should be properly treated
before disposal.
4. Sewage should be properly treated before
disposal.
13. 5. Legislation should be made by government
against dumping of harmful or toxic wastes.
6. Pesticides and fertilizers should be applied
as instructed.
7. Metals scraps, tin cans, bottles, motor
vehicle parts should be recycled.
8. Oil pipelines should be maintained and
checked regularly to prevent sabotage or
natural oil spillage.
15. AIR
POLLUTANTS
SOURCES OF
POLLUTANTS
HARMFUL
EFFECTS
1. Carbon monoxide (CO): It
is a colourless and odourless
gas.
It is produced by incomplete
combustion of fuels like
coal, diesel and petrol. It is
emitted from motor vehicles,
charcoal stoves, cigarette
smoke and heaters.
i. It affects the central nervous system
(CNS).
ii. Inhaling of CO in large quantities
is fatal as it reduces the oxygen-
carrying capacity of blood. It
combines with haemoglobin and
forms an irreversible compound
called carboxyhaemoglobin.
iii. It is poisonous and causes
suffocation and in
extreme cases leads to death.
16. 2.
Hydrocarbons:
Compounds of
carbon and
hydrogen, e.g.
methane,
benzene
formaldehyde
They are
released from
the exhausts of
vehicles by
incomplete
burning of
fuels.
They are
carcinogenic
substances
(substances that
cause cancer)
17. 3. Sulphur oxides like
sulphur dioxide (SO2)
Produced by burning of
fossil fuels like petrol
and coal . These are
released in large
amount by oil refineries
and power plants
i. Inhaling such air can
cause respiratory
problems and can lead
to permanent lung
damage
ii. SO2 and SO3 react
with water in the
atmosphere and form
dilute sulphurous and
sulphuric acids
iii. These acids combine
with water vapours to
form acid rain which is
very harmful to plants,
animals and buildings.
18. 4. Nitrogen oxides (NO2) They are emitted from
the automobiles. They
are formed by
combining N2 and O2
with coal and petroleum
at high temperatus in
the engines.
i. They remain
suspended in the air in
the high traffic or
congested areas and
forms a reddish brown
haze called brown air.
ii. They are carcinogenic
and causes lung
problems and
respiratory disorders
iii. They form dilute
solution of nitric acid in
combining with water
vapour and come down
as acid rain.
19. 5. Particulate
matter: Very
small particles
that remain
suspended like
soot, smoke,
dust and
asbestos etc.
They are
released by
burning of fuels
from vehicles,
industries and
burning of
crops and
agricultural
stubble etc.
They cause
various
respiratory
disorders like
asthma,
chronic
bronchitis etc.
20. 6. Smog
(remains
suspended in
air during
winter)
It is produced
by reaction of
smoke from
exhausts with
fog or water
vapour in air.
i. It causes
breathing or
respiratory
disorders.
ii. It can lead
to asthma,
cough and
lung
disorders.
21. 7.
Chlorofluorocarbo
ns (CFC)
CFCs damage the
protective ozone
layer. CFCs are
used in
refrigerators, air
conditioners and
aerosol sprays
i. CFCs are
responsible for
creating a hole in
the ozone layer,
which is a
protective layer
around earth.
ii. As more of UV
rays reach the
earth, it leads to
increase in number
of skin cancers
22. CONTROL OF AIR POLLUTION
1. Conditions must be created for complete
combustion of fuel in internal combustion
engines.
2. Chemical waste should be discharged into the
air through fume chambers
3. Industries should be sited far away from
residential areas.
23. 4. There should be provision of
filters or absorbers to be won around
mining and industrial areas so as to
reduce pollution from waste gases.
5. Legislation should be made
against indiscriminate burning that
may bring about smoke.
24. NOISE POLLUTION
It is defined as unwanted
high-pitched sound. It can be
measured by a sound meter and
is expressed in a unit called
decibel (dB).
25. SOURCES OF NOISE POLLUTION
1. Electronic sound system
2. Car horn and Sirens
3. Generators
4. Airplanes
5. Factory /Industrial machines
26. 6. Canons shots/gun firing
7. Artillery firing
8. Quarry activity/ Construction site
9. Motor vehicles
10. High pitched loud speakers or
drumming
11. Dynamic blastings, bulldozers,
27. EFFECTS OF NOISE POLLUTION
1. It causes loss of hearing or deafness
2. It can cause emotional disoder, anxiety or lack
of concentration
3. It can also cause high blood pressure or
hypertension.
4. It causes general irritation
5. It can also cause changes in behaviours
28. CONTROL OF NOISE POLLUTION
1. Legislation should be made against the use of
loudspeakers in public places.
2. Education/public enlightenment
3. Siting factories, industries, railways and airports far
away from residential areas.
4. Use of sound proof/silent generators.
5. Reduction of noise from loudspeakers and car
29. WATER POLLUTION
This is the discharge into the
water bodies any substance which
may become harmful to living
organisms in the water and make
them unfit for human
30. POLLUTANTS OF WATER
1. Domestic waste/Sewage/Household waste
2. Industrial waste/dyes/detergents/lead/mercury
compounds
3. Agricultural
wastes/pesticides/insecticides/fertilizers.
4. Oil/oil spillage
5. Hot water/thermal plants
31. EFFECTS OF WATER POLLUTANTS
ON AQUATIC ORGANISMS
A. DOMESTIC WASTES
i. Bacterial breakdown of sewage reduces dissolved
oxygen in water/Eutrophication
ii. Aquatic animals suffocate and die
iii. Rapid growth of aquatic plants due to mineral rich
sewage
iv. Reduces light penetration and photosynthesis
v. Contaminated sewage spread disease-causing organism
32. B. INDUSTRIAL WASTES
i. They are poisonous to aquatic organisms
ii. Detergents foam on the water surface
tension causing floating animals animals to
sink.
iii. Phosphates cause rapid plant growth.
iv. Dyes from textile factories reduce light
penetration/photosynthesis
33. C. AGRICULTURAL WASTES
i. These may accumulate to toxic
levels thereby poisoning aquatic
organisms.
ii. Fertilizers residues stimulate growth
of aquatic plants which form a dense
mat on the surface of water leading to
depletion of oxygen/eutrophication
34. D. OIL SPILLAGE
i. Oil reduces surface tension of water causing floating
animals to sink
ii. Animals die due to lack of oxygen
iii. Coats feathers/fur of animals making them unable to
fly/causing affected animals to freeze/starve to death
iv. Coats gills of aquatic organisms
v. Reduces light penetration and decreases
photosynthesis
vi. Toxic to aquatic organisms
35. E. HOT WATER
i. Kills living organisms
ii. Upsets the balance of the
ecosystem
iii. Hot water increases the water
temperature thereby reducing the
oxygen content and leading to death.
36. CONTROL OF WATER POLLUTION
1. There should be an efficient and proper sewage disposal system
2. Dumping of refuse or petro-chemical by products into rivers, streams
or seas should be avoided
3. There should be efficient techniques to deal with or prevent oil
spillage
4. Industries should be sited far away from residential areas
5. Government or local authorities should striclty monitor all industrial
wastes
6. There should be public enlightenment on waste disposal
37. EFFECTS OF POLLUTION ON
AQUATIC ECOSYSTEMS
Amount of dissolved oxygen (DO) in
water is extremely important for the
survival of aquatic ecosystems. The
easiest way to establish the level of
pollution in a local stream is to measure
the level of dissolved oxygen (DO).
38. NOTE:
i. Normal value of DO in water bodies =
8.0 mg/litre.
ii. Polluted water bodies have DO content
< 8.0 mg/litre.
iii. Heavily polluted water bodies have DO
content < 4.0 mg/litre.
39. FACTORS THAT REDUCE DO CONTENT IN
WATER
1. Biochemical Oxygen Demand
(BOD).
2. Chemical Oxygen Demand
(COD).
3. Temperature.
40. BIOCHEMICAL OXYGEN DEMAND (BOD)
This is a measure of the amount of oxygen
bacteria need to break down the organic matter in
a water sample in a fixed period of time.
It enables us to test the degree of water
pollution in ponds, lakes and rivers.
Hence BOD is directly proportional to input of
organic wastes.
41. High input of organic wastes high
BOD
Higher BOD indicates a greater
degree of water pollution.
Higher amout of organic wastes
cause a drop in DO content of water.
Drinking water should have a low
BOD.
42. CHEMICAL OXYGEN DEMAND
Chemical Oxygen Demand is the
measure of oxygen requirement for
oxidation of total organic matter
(biodegradable + non-biodegradable)
present in water.
High COD low DO.
43. EUTROPHICATION
This refers to a condition caused by a
sudden increase in the amounts of organic
nutrients and minerals (nitrate and
phosphate) in a lake or pond whereby there
is an excessive growth of plant life/
algae/alga bloom leading to the death of
44. CAUSES OF EUTROPHICATION
1. Overuse of fertilizers
2. Sewage discharge
3. Wash from fish farming
4. Plant nutrients which drain off
into water bodies
