CLASS: SS1

SUBJECT: BIOLOGY                                                             PERIOD (S): 3

DURATION: 45 MINUTES

TOPIC: POLLUTION

SUBTOPIC 1: TYPES OF POLLUTION

SUBTOPIC 2: SOURCES, CAUSES AND EFFECTS OF POLLUTION

SUBTOPIC 3: CONTROL OF POLLUTION

PREVIOUS KNOWLEDGE: Students are familiar with the topic.

OBJECTIVES: At the end of the period(s) students should be able to:

PERIOD 1:

  1. State the types of pollution

PERIOD 2:

  1. Mention the sources of air, noise, land, water and other types of pollution on plants and animals, the ecosystem in general.

PERIOD 3: Describe measures that need to be put in place to conrol the different types of pollution

REFERENCES: Essential Biology for senior secondary schools 1-3, by M.C> Micahels pg 336 -340

Modern biology for senior secondary schools 1-3 by 148 – 156

 

CONTENT:

Pollution is defined as the release into the environment of chemicals or substances or energy (toxic or harmful) through man’s activities in such quantities and for such duration that may cause harm (Biological damage) to man or his environment or resources.

 

Pollutants are the harmful substances and energy that causes pollution.

TYPES OF POLLUTION

  1. Air pollution: This can also be referred to as the atmospheric pollution. It is caused mainly by substances produced when fossil fuels (coal, oil, natural gas) are chlorofluorocarbons(gases used in refrigerators and air conditioners as coolants propellants in aerosol cans and plastic (foams) and radiation. Below in the table are major air pollutants, their sources, effects and control.

 

 

Air pollutants

Sources

Effects

1

Carbon monoxide

Burning of fuel in cars (exhaust fumes) other combustion engines and some industrial process

Co combines readily with haemoglobin thereby causing suffocating and reduced ability to carry oxygen there by resulting in deaths if inhaled for long period.

2

Carbon dioxide

Burning of fuel and other carbon compounds in plenty of air

High concentrations of carbon dioxide leads to green house effect

3.

Nitrogen oxide

Burning of fuel (coal) exhaust fumes, electrical discharge is air and industrial processes

Forms nutric acid with water (rain water) in airto form acid rain which corrode buildings and metals structures. Damage forms petrochemical smog.

4.

Hydrogen sulphide

Industrial processes involved with coal mining and crude oil refining

Irritates the skin and the respiratory system

5.

Sulphur oxide

Burning from vehicle exhaust, coal mining and cement factory, electrical power station

Reduction in licken growth, irritation and damage of the eyes and respiratory systems. Formation of  acid rain. Lung diseases, cancer and health attacks.

6.

Smoke and soot (solid particles)

Burning of substances, motors industrial plants, electric power stations and incinerators

Damage lungs and cause discomfort. Soot covers plants leaves reducing photosynthesis. Smoke reduces visibility and blackens paints on buildings

7

Lead dust and mercury

Burning of leaded petrol and burning of coal and garbage (mercury)

Lead dust can cause anaemia on brain damage in children. Nervous injury in adults as well as lead poisoning and mercury poisoning.

8.

Dust particles

Mining, quarries, machines and industrial processes

Irritates respiratory system, cause cough and catarrh. Reduce visibility; pollen grains conaining dust can cause asthma

9.

Chlorofluorocarbons

Burning of coolants, aerosol cans and plastic foams

Depletion of the ozone layer, skin cancer, cataract, severe burns, tendency of skin to age and wrinkle, lowered resistance to infectious diseases. kill useful microorganisms affecting phytoplankton microorganisms affect phytoplankton growth and interfere with photosynthesis.

10.

 Radioactive rays

Electric plants that sue radioactive substances. Nuclear plants and readioactive fallout from testing radioactive weapons, lasers, x – rays, colour TV microwave

Impair health, alter or destroy gemrs, cancer. Fallout (Tiny radioactive particles/dust that fall to earth after nuclear explosion) can get into vegetation and become concentrated in final consumer.

 

Rain pH 5.0- 5.6

Acid rain: around 4

Smog – combination of smoke, chemical pollutants and water droplets.  Petrochemical smog- sunlight causes oxides of nitrogen and unburn hydrocarbons.

 

CONTROL OF AIR POLLUTION

  1. Conditions must be created to complete combustion of fuel in internal combustion engines.
  2. Fume chambers should be used to discharge chemical waste.
  3. Fitting chimeys with filters to remove or reduce pollutants.
  4. Using unleaded or low lead petrol
  5. Removing sulphur compounds from coal and low grade fruits oils before use.
  6. Building industries far away from residential areas.
  7. Fitting motor exhaust systems with catalytic converters to remove oxides of nitrogen, carbon monoxide and unburnt carbon.
  8. Using substitutes for ozone destroying chemicals that do not affect the ozone layer.
  9. Legislation should be made against indiscriminate burning that may bring about smoke.
  10. More nuclear test bans should be set up to further reduce radiation.

 

  1. Soil pollution – It can also be referred to as land pollution. It damages the thin layer of fertile topsoil which is essential for plants growth. The major land pollutants, their sources, harmful effects and their control are listed below.

 

 

Land pollutants

Sources

Effects

1

Sewage

Homes and offices

Results in offensive odour and provides breeding ground for disease causing organisms

2.

Metal scraps

Abandoned vehicles and machines

Occupies land space and prevents proper land use

3.

Pesticides and fertilizers

Pesticides sprayed on crops and fertilizers used in soils

Destruction of useful soil organisms death of aquatic organisms. Excess fertilizers can cause soil acidity

4

Crude oil (Oil Spillage)

Oiil drilling, loading or unloading of soil tankers

Destroys the ecosystem (soils, plants and animals)

5.

Chemicals (toxic wastes)

Chemical waste from industries

These are poisonous to plants and animals

6.

Refuse

Homes, office, market, industries.

Causes offensive odour and cause respiratory disorder

7.

Glass particles

Manufacturing industries producing or using bottles

Causes injury to the body and it occupies land space since it is non biodegradable

 

CONTROL OF LAND POLLUTION

  1. Urban wastes should be properly burnt or buried
  2. Illegal dumping of harmful or toxic wastes should be punishable by law.
  3. Required dosages of pesticides and fertilizers should be used
  4. Refuse should be burnt in incinerators
  5. Proper treatment of sewage should be done before disposal
  6. Metal scraps, bottles, (glass and plastic) tincans, motor vehicle parts should be recylced
  7. Oil pipelines should be maintained and checked regularly to prevent oil spillage

 

  1. Noise pollution : Sound that is unpleasant and irritating is called Noise. It is common in urban areas (busy towns and cities) mining and industrial centres and airfields. The loudness of sound is measured in decibels (dB). The sources of noise pollution include:
  2. Aeroplane or aviation noise
  3. Factory/industrial and mining noise

iii.      Car horns and sirens

  1. generator noise
  2. Noise from heavy guns and canon shots
  3. Thunder noise

vii.     Railway engines

viii.    High pitched musical found from  loud speakers or drumming.

 

The effect of noise pollution are as follows:

  1. Constant exposure loud noises e.g. above 85dB can cause permanent loss of hearing. Sudden explosive noises over 150dB may cause deafness.
  2. Noise can be linked to high blood pressure and coronary heart disease

iii.      Noise cause headache and inability to sleep properly. It can also lead to illness, especially mental illness over long periods.

  1. It can cause lack of concentration and general irritation.

 

CONTROL OF NOISE POLLUTION

  1. Use of ear muffs in quarries, airports and factories where noise levels cannot be reduced
  2. Use of loud speakers in public places should be prohibited by law.
  3. Installation of soundproof in industries and generators.
  4. Ban on the use of heavy guns and cannons must be placed.
  5. Railways, airports and industries should be sited far away from residential areas.

 

 

  1. Water Pollution: Freshwater that is clean is used for drinking and cleaning. Water pollution affects aquatic life in water bodies. The main cause of pollution include indiscriminate dumping of waste into water bodies as well as pollutants in air, vegetation and soil are also drained into water bodies via rainfall. Refuse (household waste) and sewage (human excreta) through biodegradable by decomposers (mainly bacteria) cause an increase in the bacterial population if present in large amounts and brings about oxygen reduction in water causing aquatic organisms with a narrow tolerance range for oxygen (mainly fish) to die.

 

 

Water Pollutants

Sources

Effects

1

Sewage

City sewage system

i. Support pathogen growth that cause infectious diseases e.g. cholera

ii. Produces unpleasant odours

iii. Can kill aquatic organisms

iv. makes water unfit for consumption

2

Chemical wastes

Industries and ships at harbours

i. Kill aquatic organisms

ii. Makes water unfit for consumption

iii. can accumulate in human body and become toxic water e.g. mercury and lead

3.

Crude oil (Oil Spillage)

Oil Drilling, loading and unloading of oil tankers

i. Destroys aquatic plants and animals

ii. Affects the food chain

iii. Makes water unfit for consumption

iv. Leads to migration of animals

4.

Pesticides and fertilizers

Washed by rain and erosion from farms to rivers, streams or ponds

i. Makes water unfit for consumption

ii. Leads to rapid vegetative growth of water plants e.g. algae bloom) which makes fishing and movement impossible

iii. Can destroy aquatic organisms

5.

Excreta or faeces

Humans and animals

i. Produces unpleasant odours

ii. serves as a medium for the breeding of pathogens

 

Eutrophication occurs when nitrates (from agricultural wastes and phosphates (from sewage and industrial wastes) get into water bodies and aquatic plant growth especially algal growth is greatly increased. Eutrophication upsets the balance of the aquatic ecosystem.

 

CONTROL OF WATER POLLUTION

  1. Treatment of sewage platns before emptying the effluent into rivers and seas
  2. Treating industrial wastes before emptying them into water bodies
  3. Building nuclear wastes silos so that the ground water does not become contaminated with radioactive material

4       Ensuring organic manure is used instead of inorganic fertilizers.

  1. Ensure that maximum precautions are taken to prevent oil spillage
  2. There should be public enlightenment on waste disposal.
  3. Industries should be sited far away from residential areas
  4. Dumping of refuse or petrochemical byproducts into water bodies should be avoided.
  5. Government should strictly monitor all industrial wastes

 

 

INSTRUCTIONAL MATERIALS: Pictures of polluted areas

TEACHING METHODS PROCEDURES

Step 1: Teacher introduces the new topic after revising the last topic with the students.

Step II: Teacher lists the types of pollution

Step III: Teacher explains the different types of pollutants, their sources and their effects

Step IV: Teacher explains in details how to control pollution

Step V: Teacher allows students to ask questions and write students’ notes on the board

 

CLASSROOM (ACTIVITIES)

PERIOD 1: Students discuss the types and sources of pollution

PERIOD 2: Students discuss the causes, effects and control of the different types of pollutants

 

EVALUATION

Period 1:

  1. What is Pollution?
  2. Name the major causes of atmospheric pollution

 

Periods 2: What are sources of water pollution?

Summary / conclusion: Teacher summarizes the topic, marks the students notes and make corrections where necessary.

 

ASSIGNMENT(S)

Period 1: What are the effects of the following  pollutants on humans?

  1. Dust ii) Smoke    iii) Refuse   iv) Sewage

 

Period 2: Describe the effects of four pollutants of water on aquatic organisms.