Pollution

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In today’s Biology class, We will be learning about Environmental Pollution. We hope you enjoy the class!

CONTENT

Definition of Pollution
Air Pollution
Noise Pollution
Land Pollution
Water Pollution

POLLUTION

Definition: Pollution is defined as the release of toxic or harmful substances into the environment by their natural forces or man and other animals to an extent that causes biological damage to man and his resources. In other words, pollution is the release of harmful substances into the environment, i.e., water, air and land in quantities or to the level that is harmful to man, animals and plants.

The harmful substances that cause pollution in the environment are called pollutants.

There are four main types of pollution. These are

(a)Air pollution

(b)Noise pollution

(c) Land pollution

(d) Water pollution

Air Pollution

The major air pollutants, their sources, harmful effects and their control

Air Pollutants

Sources

Effects

Carbon monoxide

Burning of fuel in cars

other combustion engines

and some industrial processes

It causes suffocation because it combines

with haemoglobin and reduces its ability

to carry oxygen which results in death

Sulphur dioxide

Burning from vehicle’s exhaust,

coal mining and cement factory

It causes impaired health such as the

irritation of eyes, lungs and other respiratory tract diseases. It can cause acid rain.

Nitrogen oxides

Electrical discharge in air and

Industrial processes

It forms nitric acid with water in air form acid rain which corrodes metallic objects. It irritates the skin and respiratory system.

Smoke and soots

Burning of substances from industries, machines and coal into the air.

Particles can damage lungs and cause discomfort. Soot can cover the leaves of plants thereby reducing photosynthesis. Smoke reduces visibility. It makes buildings black.

Dust particles

Mining, quarries, machines and industrial processes

It irritates the respiratory system and causes respiratory diseases such as catarrh and cough.

It reduces visibility. Pollen grains containing dust can affect the lungs resulting in asthma.

Control of Air Pollution

Conditions must be created for complete combustion of fuel in internal combustion engines.
Chemical waste should be discharged into the air through fumes chambers.
Industries should be sited far away from residential areas.
There should be a provision of filters or absorbers to be worn around mining and industrial areas so as to reduce pollution from waste gases.
Legislation should be made against indiscriminate burning that may bring about smoke.

Evaluation

What is environmental pollution?
Mention five sources of air pollution.

Noise pollution

Noise Sources include

Factory or industrial noise.
Aeroplane or aviation noise.
Railway engine noise.
Car horns and sirens.
High pitched musical sound from loudspeakers.
Noise from heavy guns or cannon shots.
Thunder noise.
Noise from generators.

Effects of Noise Pollution

It causes loss of hearing or deafness.
Noise can cause emotional disorder, anxiety or lack of concentration.
Noise can also cause high blood pressure or hypertension.
It causes general irritation or short tempers.
It can also cause changes in behaviour.

Control of Noise

There should be a reduction in noise from loudspeakers and sirens.
Legislation should be made against the use of loudspeakers in public places
Installation of soundproof in industries.
Heavy guns must be banned.
Railways and airports should be sited far away from residential areas.

Land Pollution

Land Pollutants	Sources	Effects
(1) Refuse	Home, offices, industries and markets	(i) It causes offensive odour when the decay.
(2) Sewage	Homes and offices	(i) It can cause respiratory disorder. (ii) It results in offensive odour. (iii) It serves as breeding ground for disease causing organisms.
(3) Metal Scraps	Abandoned vehicles and machines	(i) It occupies land space (ii) It prevents proper land us.
(4) Pesticides and fertilizes	Pesticides sprayed on crops and fertilizers used in soils	(i) They destroy useful soil organisms. (ii). Excess fertilizers can cause soil acidity. (iii). It can cause the death of aquatic organisms, e.g. fishes
(5) Chemicals, eg. Toxic waste	Chemical waste from industries	(i) 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.
(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.

Control of Land Pollution

Refuse should be burnt in incinerators.
Urban wastes should be properly burnt or buried
Metal scraps, tin cans, bottles, motor vehicle parts and other related materials should be recycled.
Pesticides and fertilizers should be applied as instructed.
Legislation should be made against dumping of harmful wastes.
Proper treatment of sewage before disposal.
Proper maintenance and checking of oil pipelines.

Evaluation

Mention five common land pollutants.
Suggest ways of controlling the pollutants mentioned

Water Pollution

Water Pollutants	Sources	Effects
(1) Sewage	City sewage system	(i). It supports the growth of pathogens that can cause diseases, eg. Cholera. (ii). It make water unfit for human consumption. (iii). It can kill aquatic organisms. (iv). It produces unpleasant odours.
(2) Pesticides and Fertilizers	Washed by erosion from farms to rivers, streams or ponds	(i) It makes water unfit for human consumption. (ii). It leads to rapid vegetative growth of water plants which makes fishing and movement impossible, eg. Algae bloom. (iii). It can destroy aquatic organisms, eg. Fish and sea birds.
(3) Chemical Wastes	Industries and ships at harbours	(i). It can kill aquatic organisms. (ii). It makes water unfit for human consumption. (iii). It can accumulate in human body and become toxic later, eg. Lead and mercury.
(4) Excreta or faeces	Humans and animals	(i). It produces unpleasant odour (ii). It serves as a medium for the breeding of pathogens
(5). Crude oil (Oil spillage)	Oil drilling, loading and unloading of oil tankers	(i) It destroys aquatic plants and animals. (ii). It makes water unfit for human consumption. (iii). Food chain is affected. (iv). It leads to migration of animals.

Control of Water Pollution

(I) There should be efficient and proper sewage disposal system.

(ii) Dumping of refuse or petro-chemical byproducts into rivers, streams or seas should be avoided.

(iii) There should be efficient techniques to deal with or prevent oil spillage.

(iv) Industries should be sited far away from residential areas.

(v) Government or local authorities should strictly monitor all industrial wastes.

(vi) There should be public enlightenment on waste disposal.

(vii) Industrial effluents should be recycled. ‘

Methods of Purifying Water

Methods involved in purifying water include: (i) Boiling (ii) Addition of chemicals, e.g. alum or chlorine (iii) Filtration (iv) Distillation (v) Sterilization using UV light (vi) Boiling (vii) Sedimentation

General Evaluation

Define the term pollution.
State four types of pollution.
Mention three air and noise pollution.
State the effect of air and land pollution.
What is sewage?

Weekend Assignment

The unfavorable alteration of environment due to the addition of impurities is A. pollution B. pollutant C. global warming D. poisoning
These are causes of water pollution except A. Insects B. Fertilizers C. Sewage D. Petroleum.
Which of the following air pollutant depletes the ozone layer? A. Oxides of sulphur B. Carbon dioxide C. Dust D. Chlorofluorocarbons (CFC)
These are the effects of noise except A. Calmness B. Anxiety C. Short temper D. High blood pressure.
Which of the following pollutants cause suffocation? A. CO2 B. No2 C. CFC D. sewage.

Theory

What are the effects of the following pollution on man? (a) carbon monoxide (b) dust (c) sewage
Highlight five dangers of water pollution.

Reading Assignment: College Biology by idodo Umeh. Chapter 24 page 565-572

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