Hwa Chong Institution
Sec 2 Geography 2014
Types of Pollution
Handout 2: Types of Pollution (Air, Water and Land)
Name: _______________________ (
)
Date: _____________
Class: ______
Land Pollution
Waste is
 materials which are useless
 no longer wanted
Pollution occurs when
 Waste is not disposed of properly
 There is an excessive amount of waste
Classification of waste
1) By its source – domestic/industrial/agricultural
2) By its state
 Solid
o Much of the waste produced by domestic and industrial sources is solid and bulky
o Takes up space and is difficult to dispose of
 Liquid
o For example, sewage
 Gaseous
o For example, carbon monoxide from car exhaust pipes
3) By whether it can be recycled
 Recyclable waste can be processed and used again. Examples include
o aluminium
o paper
o glass
4) By whether it is harmful
 Much of industrial waste is harmful. It can cause birth defects, brain damage, cancer and
even death
Disposal of Waste
 Use of landfills
o Methane gas produced during decomposition is sometimes collected and channeled
to homes and industries for use as fuel
o Unfortunately, landfills take up too much space
o Not a long-term solution for land-scarce countries like Singapore

Incineration
o Solid waste is burnt at high temperatures
o Reduces the volume of waste by as much as 90%
o Energy produced by the waste can be converted to electricity
Incineration
 In Singapore, the lack of land forces us to incinerate more than 60% of our waste
Shortcomings
 Some types of waste cannot be incinerated
 Burning releases dust particles into air which is a form of pollution in itself
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Causes of Land Pollution
 A large amount of waste is produced every day
 Excessive amount of waste pollutes the land
 Land is also polluted when waste is not disposed of properly
 Sometimes, waste is disposed on roadsides as litter
 At other times, it is left in great heaps at public places not designated as rubbish dumps
 A lot of time and effort is required to clean up the land
 Improper disposal of waste occurs on mining sites where heaps of waste materials are left
behind after the minerals have been extracted
 Pesticides and herbicides
o Pesticides are used by farmers to kill insects and other animals that may eat their
crops or spread diseases
o Herbicides are used to kill weeds that compete with the crops for water and nutrients
in the soil
o Unfortunately, pesticides and herbicides can pollute the land when they are washed
into the soil
o Pesticides and herbicides are sprayed on crops to help improve their yield, but they
also pollute the land when used excessively
Effects of Land Pollution
 Negative effect on public health
o Waste that is carelessly thrown away can be smelly, unhygienic or even dangerous
o Attracts pests such as flies and rats

Poisoning of plants and animals
o Pesticides and herbicides are toxic
o They may be washed into the soil and consumed by earthworms
o The earthworms accumulate toxic chemicals in their bodies
o When they are eaten by bigger animals, the chemicals pass to the predators, causing
side effects

Soil contamination
o Mining leaves behind harmful substances that contaminate the soil
o Fertilisers, pesticides and herbicides can remain in the soil and affect plant growth
o When it rains, some of these chemicals are washed into rivers and streams, thus
contaminating the water
o The chemicals may also seep into groundwater and pollute it
o We have just seen that the effects of land pollution are seldom confined to land
o Groundwater, rivers and streams can also be affected
Problems Faced in Waste Disposal in Sinagpore
 Although we can reduce the volume of incinerable waste significantly by incineration, it is not
a sustainable solution to manage waste and the environment for the following reasons:
o Escalation of waste output
o Land-scarce Singapore
o Costly waste disposal facilities
o Save the environment

Land-scarce Singapore
o difficult to find land in land-scarce Singapore to construct incineration plants and
landfills.
o resorted to build the first offshore Pulau Semakau landfill. The lifespan of Pulau
Semakau is expected to last 30 years till 2030.
o Costly waste disposal facilities

It is expensive to construct, operate and maintain incineration plants and landfill.
o in 1979, it cost only $130 million to construct an incineration plant while the fourth
plant at Tuas South cost about $900 million (in 2000).
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o
o
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some $610 million was also spent to construct the landfill at Pulau Semakau.
Concern of Landfill at P Semakau
(http://www.youtube.com/watch?v=PUzEp0c_lNw)
Save the environment
o Wasteful consumption patterns also exploit and diminish the natural resources.
o The waste also poses harmful effects to the environment, polluting the air and
land.
o there is an obligation for the community to minimise waste output and to recycle
as much waste as possible.
o For instance, recycling of paper reduces air pollution by 74% and water pollution
by 35%. Each ton of paper recycled could also save 17 small trees.
Water Pollution
How Water is polluted?
 Many of our rivers and streams have become so polluted that they are not safe for human
use
 Pollutants discharged directly into rivers, lakes and seas
 Pollutants on land are blown by wind or washed by rainwater into water bodies
 One major water pollutant is waste such as sewage and litter
Water Pollution: Causes
1) Sewage
 Large amount of sewage is discharged directly into rivers and seas
 Comes from homes and factories
Contains
o Human waste
o Detergents
o Chemicals
o By-products from industries
o Bacteria and poisonous substances
o Sewage

In some countries, sewage is treated at sewage treatment plants
o To remove waste products from the water before releasing it into the sea
o Unfortunately, some of the substances in sewage such as detergents are nonbiodegradable
2) Littering and dumping
 A lot of rubbish is carelessly dumped into rivers, lakes and seas by people living near them
 Rubbish is also discharged by ships and washed ashore by tides
3) Fertilisers, pesticides and herbicides
 Washed by rainwater from fields into streams, rivers and seas
 Estimated that up to 90% of pesticides used do not reach the pests they are supposed to kill
but end up polluting the land and water
4) Seepage from landfills
 Hazardous materials deposited in landfills seep into the surrounding soil and groundwater
 Contaminated groundwater eventually reaches nearby rivers and lakes where it endangers
aquatic plants and animals
5) Oil spills
 Pollution of seas and oceans occurs when oil is spilled from tankers, refineries and oil
platforms
 Oil spills can be due to accidents and careless disposal of oil into the sea
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Water Pollution: Effects
1) Endangering species
 Water pollution endangers plants and animals living in the affected rivers, lakes and seas
 Poisonous chemicals from pesticides, herbicides and industrial by-products can destroy
entire food chains
2) Negative effects on health
 Improper disposal of waste attracts pests such as rats which are carriers of disease
 Poisons in pesticides, herbicides and industrial chemicals accumulate in the bodies of fish
and shellfish and are passed to us when we consume them
 Groundwater which is a source of freshwater for many people becomes contaminated
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
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Improper disposal of waste attracts pests such as rats which are carriers of disease
Poisons in pesticides, herbicides and industrial chemicals accumulate in the bodies of fish
and shellfish and are passed to us when we consume them
Groundwater which is a source of freshwater for many people becomes contaminated
3 ) Eutrophication
 This is the process whereby fertilisers washed into rivers, lakes and seas by surface
runoff cause the water to have an excessive amount of nutrients
 The nutrients encourage the rapid growth of algae and other water plants until they cover
the entire water surface
 The plants prevent sunlight from entering the water hence killing other plants below
 When these dead plants decay, oxygen content in the water is reduced. Fish and other
organisms living in the water are killed and the water becomes foul.
Case Study: Exxon Valdez incident
Water Pollution through Oil Spills
Causes of Oil Spills
 Accidents
o Exxon Valdez in Prince William Sound in Alaska, USA, 1989
o Hull of the oil tanker torn by sharp rocks
o More than 50 million litres of oil spread over a distance of 900 km
o Millions of fish, at least 1 000 otters and almost 35 000 birds killed
o
Water Pollution through Oil Spills
 When tankers load and unload crude oil
 Waste engine oil discharged from ships
 Tankers and cargo tanks cleaned out at sea
 Oil released from oil platforms
Effects of Oil Spills
1) Deprive fish and other marine life of oxygen
 Spreads out as a thin layer over the surface of the water
 This oil film stops oxygen from reaching the marine life below
 Fish and other marine life will die from lack of oxygen
 Sets off a chain effect
 Lack of oxygen kills off the most basic organism in the food chain - plankton
 Fish and other marine creatures that feed on these microscopic plants and animals will be
deprived of food and starve to death
 Their predators will in turn decline in number as their source of food is reduced
2) Oil sticks to feathers and furs of animals
 Removes air trapped by the feathers or fur which functions as a layer of insulation
 Without insulation, these animals will freeze to death in the cold
 Clogs feathers of birds
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Prevents them from flying or floating on water
Numerous birds die from drowning
3) Poisoning
 Sea animals poisoned when they swallow the toxic oil while cleaning themselves
 May cause disorders in body systems, birth defects or death of the animals
 Shellfish and fish that survive carry the toxins in their flesh
 Their predators may die from eating them
 People will also be affected when they consume these poisoned animals
4) Other effects:
 Threatens the fishing industry and livelihood of people who depend on fishing for a living
 Dirties the beach and discouraging tourism
 Cleaning up oil spills costs a lot of money and effort
 Ecosystem may be irrecoverably damaged
Air Pollution
Causes of Air Pollution
 Natural causes
o Erupting volcanoes
o Forest fires
 Human causes
o Toxic gases emission
o Industries
o Vehicles
o Aerosol cans/ CFCs
Effects: Haze & Smog
 Haze
o Suspension of dust and smoke particles in the air
o Affects how far or clearly we see
 Smog
o More severe than haze
o More than just dust and smoke particles
o Includes a mixture of toxic gases, example,
carbon monoxide, nitrogen oxides and sulphur dioxide
 Man-made causes
o Construction work
o Use of diesel in vehicles
o Industries and power plants
Effects of Haze & Smog
 Causes irritations to the lungs and eyes
 Covers things with layers of dust particles
 Reduces visibility
 Toxic gases in smog cause serious health problems
 Inhalation of small amount of carbon monoxide can result in death
 Sulphur dioxide and nitrogen oxides attack the respiratory system
 Long-term effect of breathing in toxic gases include the development of illnesses such as
asthma, bronchitis and cancer
 Shorter life span for people in polluted cities
Air Pollution Knows No Boundaries
 Pollutants produced in one country may affect another
 Haze in Singapore caused by widespread forest fires in Indonesia.
 Smoke particles carried by wind from Indonesia to Singapore
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