CHAPTER 9
Content
CHAPTER
9:ENDANGERED
ECOSYSTEM
Name:Lim Jo Lynn
Class:4 Anggerik
Index:
Topics
1
pag
e
9.1 Human activities that endanger an
ecosystem
9.1.1 The impact of human activities on
the ecosystem
3
3-7
Air pollution
Water pollution
Eutrophication
Thermal pollution
Noise pollution
9.2 The Greenhouse Effect and the
Thinning of Ozone Layer
8-11
12-14
15-16
16-17
17-18
19-20
The Thinning of the Ozone Layer
9.3 Measure taken in the management of
Development activities
21-22
22-24
9.1 Human activities that endanger
an ecosystem
Human activities that threaten the ecosystem:
*
2
Human activities often affect the whole ecosystem.
*
The negative effects of hasty and unplanned development and
mismanagement of the ecosystem result in various environmental
problems.
*
These problems bring about negative effects that are increasingly
threatening the economic resources, health and survival of the ecosystem.
9.1.1 The impact of human
activities on the ecosystem
(1) Deforestation:
*
The rapid destruction of woodlands or removal of trees from forests is
known as deforestation.
*
Tropical rainforests play important ecological roles:
*
Oldest ecosystem on earth and house of flora n fauna
*
Contain many unique species which provide food, medicine and other
biological products.
*
Regulate the world’s climate by influencing wind, rainfall, humidity
and temperature patterns.
*
Called the ‘carbon sink’ of the Earth because they absorb vast
amount of carbon dioxide during photosynthesis and release oxygen into
the atmosphere.
*
Serve as water catchment areas
Deforestation results in :
*
Soil erosion
*
Flash flood
3
*
Landslides
*
Changes in the recycling of materials
*
Severe climatic changes
*
The loss of biodiversity
Deforestation cause soil erosion, landslides and flash flood
*
Soil erosion is the removal and thinning of the soil layer due to
physical and climatic process.
*
The absence of plant root systems makes the soil structure unstable.
*
When it rain heavily for a long period of time, the top layer of the soil
disintegrates easily and this leads to landslides on steep hillsides.
*
The eroded soil is then carried away by moving water and deposited
at the bottom of river.
*
Together with depletion of water catchment areas, cause flash
flood during rainy seasons.
*
Soil erosion causes the land to be depleted of minerals and natural
resources, making the land useless for cultivation.
Deforestation results in the loss of biodiversity
The destruction by human activities:
*
The removal of the base of numerous food webs.
*
The loss of habitats for many species of flora and fauna
*
The extinction of countless species and varieties of plants and
animals, many of which have never been catalogued scientifically.
Extinction of flora and fauna species reduces biodiversity
4
*
The destruction of storehouse of genetic diversity on Earth. The
Earth’s biodiversity is a rich source of food and priceless medicines for
mankind
Deforestation affects carbon and nitrogen cycles
*
The removal of plants in the rainforests disrupts the natural cycle of
nutrients.
*
The level of atmospheric carbon dioxide rises as less carbon dioxide
is removed by plants while the level of atmospheric oxygen drops as less
oxygen is released during photosynthesis.
*
The recycling of nitrates and other ions is slowed down.
*
Tree roots bind soil particles together, and the tree canopy reduces
the force of rain beating down on the soil and cause nutrients to be lost
through leaching and run-off.
Deforestation cause climates change
*
Deforestation disrupts normal weather patterns, creating hotter and
drier weather and causing global climatic changes.
*
Removal of trees reduces transpiration and rainfall cause the
increase in carbon dioxide level in atmosphere and prevent heat from
escaping from atmosphere.
*
This is known as greenhouse effect and lead to global warming.
(2) Burning of fossil fuels and its effects
*
Contributes about 75% of carbon dioxide
*
Cause greenhouse effect and global warming
5
(3) Intensive farming and its effect
*
Excessive use of land for intensive farming decrease the space and
resources available for other species
(4) The effect of an increase in domestic waste and industrial waste
*
A rapidly expanding human population also generates an increase in
both domestic and industrial waste.
Polution:An undesirable change in the chemical,physical or biological
characteristics of the nature
6
Air
Therm
al
Pollutio
n
Water
Noise
1.Air pollution
1. Air pollution is caused by the presence of pollutants in the air
which are harmful to life and the environment.
2. Sources of pollution are as follows:
a) Burning
Rubbish
Forest
Solid waste
7
b) Factories and industries
Burning of fossil fuels such as petroleum, diesel and gas in
factories and power stations.
Agricultural industries that use agrochemicals such as
fertilizers, pesticides, insecticides and herbicides.
c) Motor vehicles
Release harmful gases in car exhaust fumes.
3. Burning of fossil fuels produces gases such as sulphur dioxide
and nitrogen dioxide. Burning of rubbish and emission of smoke
and fumes from car exhausts and chimneys in factories produce
carbon dioxide, carbon monoxide and soot (unburnt carbon
particles).
4. Increase in carbon dioxide (a greenhouse gas) in the
atmosphere will trap the Sun’s radiation and retain it as heat in
the Earth’s atmosphere. This contributes to the greenhouse
effect.
5. This will cause an increase in the Earth’s temperature.
Source of pollution:
(a) Pollutant: Dust and soot
-Cement factories, quarries, sawmills, burning of rubbish and
motor vehicles.
(b) Pollutant: Carbon monoxide, carbon dioxide, sulphur dioxide
and nitrogen dioxide
-Burning of fossil fuels and rubbish
-Car exhaust fumes.
(c) Pollutant: Lead
-Car exhaust fumes which contain lead
(d) Pollutant: Agrochemical substances
-Activities of agricultural industry
(e) Pollutant: Radioactive radiations
-Nuclear power stations
(f) Pollutant: Chlorofluorocarbon (CFC)
-Aerosol and foam industries
Acid Rain
8
(I) Causes of acid rain:
1. The combustion of fossil fuels (cool, air and gas) in power
station, factories, domestic boilers and internal combustion
engines releases large quantities of sulphur dioxide (SO2 ) and
oxides of nitrogen (NO and NO2).
2. Both sulphur dioxide and oxides of nitrogen combine with
water vapour in the atmosphere to form sulphuric acid and nitric
acid respectively.
3. Then, they fall to earth as acid rain.
4. Rain is naturally acidic, with pH of about 5.6. This acidity is
due to the carbon dioxide in the air, which dissolve in rain to form
carbonic acid.
5. However, the pH of acid rain is less than 5.0.
(II) Effects:
(a) Agricultural:
The soil becomes very acidic and unsuitable for the cultivation of
crops.
Acid rain causes the leaching of minerals such as potassium,
calcium, and magnesium. This affects the growth of crops.
(b) Aquatic ecosystem:
Acid rain causes insoluble aluminum ions to accumulate in lakes
and rivers. The concentration of aluminum ions eventually
reaches a toxic level which can kill aquatic organisms such as fish
and invertebrates.
(c) Health:
Acidic soil releases the ions of certain heavy metals such as
cadmium, lead, mercury which may contaminate the supply of
drinking water.
Increased acidity in the aquatic ecosystems also kills
phytoplankton which changes the food chain.
9
Photosynthesis tissues are destroyed. Plant leaves turn yellow
and fall off. The roots are damaged and cannot absorb minerals.
(d) Buildings:
Metal railings and bridges corrode.
Limestone, stonework and marble monuments are eroded due to
chemical weathering.
(III) Solutions:
Acid rain can be reduced by:Cleaning up emissions from vehicle exhausts through the use of
catalytic converters. The pollutants react with one another in the
catalytic converters to produce less harmful products.
Cleaning emissions from power stations and industrial plants with
scrubbers. This process involves the spraying of water to trap
pollutants.
Air Pollution Index (API)
The Air Pollution Index (API) is used as a measure of air quality.
It normally includes the major air pollutants which could cause
potential harm to human health.
10
In Malaysia, the air pollutants included are ozone, carbon
monoxide, nitrogen dioxide, sulphur dioxide and suspended
particulate matter.
This index is calculated by using the concentrations of major air
pollutants, but it is developed in easily understood ranges of
values as shown below.
Air Pollution Index
API
0-50
Status
Good
51-100
Moderate
101-200
Unhealthy
201-300
Very unhealthy
301-500
Hazardous
Above 500
Emergency
Level of pollution
Low, no ill effects on
health
Moderate pollution,
no ill effects on health
Mild aggravation of
symptoms among
high risk groups
Significant
aggravation of
symptoms and
decreased exercise
tolerance among high
risk groups
Severe aggravation of
symptoms and a
danger to health
Severe aggravation of
symptoms and a
danger to a health
WATER POLLUTION
Sources, Components, Effects, Solution of water pollution
11
Sources
Agricultur
al
run-off
and
waste
12
Component
s
Nitrates
and
phosphates
Effects
Solutions
Lead to
eutrophicatio
n
Control the use
of fertilisers
a)
Applying
only when crops
are growing.
b)
Not
applying in
empty fields.
c)
Not
spraying when
there is a
forecast of rain.
d)
Not
disposing of
them into rivers
and ponds.
e)
Reducing
the usage of
excess nitrates
from fertilisers
and ammonia.
Herbicide
and
pesticide
residues
-Have toxic
effects on
organisms in
water and
human
-Pesticides
levels can be
magnified as
they pass
through food
chain
Accumulation
of pesticides
-Use
biodegradable
pesticides
-Use alternative
method
(biological pest
control)
-Planting
genetically
modified crops
that can resist
attacks by
insects as this
may reduce the
Untreated
sewage –
human
faeces
and
domestic
waste
13
in consumers
may kill them
or affect their
metabolism
-Lead to
lower sperm
counts,
decreased
ovulation,
inability to
conceive and
birth defects.
need to use
chemical
pesticides
Suspended
solids
Reduce light
penetration
-High demand
for oxygen
-Treat sewage
before it enters
rivers
-Prevent slurry
(liquid manure)
from farms from
entering rivers
and ponds
Nitrates
and
phosphates
Detergents
Leads to
eutrophicatio
n
-‘Hard’
detergents
create foam
which
reduces the
availability of
oxygen to
organisms
living in the
water
-‘Soft’
detergents
are
biodegradabl
e but may
-Use
biodegradable
detergents with
low phosphate
contents
Effluent
from
industries
Electronic
s and
electropla
ting
plants
-Food and
beverage
processin
g industry
-Rubber
products
processin
g industry
Undergro
und pipes
14
Microorgani
sms
(viruses,
bacteria,
and
protozoa)
Heavy
metals
(copper,
mercury,
zinc, and
chromium),
oil, grease,
and
suspended
solids,
waste
water
contains
numerous
contaminan
ts,
(including
hydroxide
sulphide).
Lead
(highly
toxic heavy
metal)
contain high
levels of
phosphates
which can
lead to
eutrophicatio
n
- Cause
cholera
-Drink properly
treated and
boiled water
-Highly toxic
accumulate in
the
organisms via
food chains
-Mercury
causes acute
nervous
disorder in
humans.
-Treat effluents
before
discharging into
water sources
-Taking legal
action against
illegal dumping
of toxic wastes
-Accumulate
in the tissues
of living
organisms
-Impair the
mental
performance
-Replace lead
pipes used in
plumbing with
copper-based
pipes.
of children
Eutrophication
Defination: Artificial nutrient enrichment of an aquatic system
with organic material or inorganic nutrients, causing an excessive
growth of aquatic plant life.
Causes by
a) Leaching of inorganic fertilisers, especially nitrates and
phosphates, from agricultural lands
b) Input of untreated sewage as well as discharge from sewage
treatment plants
c) Run-off of animal waste from pastures and farmlands into
lakes, rivers or ponds.
Process of eutrophication
1)
Run-off of excess nutrients into water encourage rapid
growth of algae, results in a population explosion known as an
algae bloom
15
2)
At night, high respiration rate of the algae results in a high
demand for oxygen.
3)
Excessive growth of algae restricts the penetration of light
into the water. The rate of photosynthesis of aquatic plants
reduced and further reduced the supply of oxygen in water.
4)
The algae grow faster than their consumers. Most of algal
population dies without being consumed.
5)
Decomposing microorganisms especially aerobic bacteria
used up the oxygen in deeper water at a fast rate.
6)
Untreated sewage or animal wastes from farm that contain
high concentration of organic matter encourage the rapid growth
of aerobic bacteria.
7)
The aerobic bacteria use up oxygen faster than it can be
replenished. An increase in biochemical oxygen demand (BOD)
results in a severe depletion of oxygen.
8)
Low level of oxygen concentration kills larger aerobic aquatic
organisms and organisms that require higher oxygen levels
(freshwater shrimps and mayfly nymphs)
9)
If the oxygen levels continues to drop and water become
completely deoxygenated, anaerobic bacteria will grow and
release toxic gases (eg. hydrogen sulphide), causing the death of
aquatic organisms.
10) During the growth of algae, certain blue green bacteria also
produce toxins.
11) At night BOD levels, organisms that are more tolerant of
lower concentration of dissolved oxygen (eg. leeches, Tubifex
worms, and sludge worms) may appears and multiply.
What is BOD?
Biochemical oxygen demand (BOD) is the amount of dissolved
oxygen required by the microoganisms to decompose the organic
matters in the water.
The measurement of BOD is an indication of the level of water
pollution.
If there is a large amount of organic waste in the water, the
population of aerobic bacteria will increase to decompose the
organic matter. The dissolved oxygen level in the water
decreases, and the value of BOD will be high.
16
A lower BOD level (or higher dissolved oxygen level)
indicates better water quality. A higher BOD level (or
lower dissolved oxygen level) indicates poor water quality.
9.1.4 Thermal Pollution
In thermal pollution, the temperature of a body of water is
unintentionally raised as a
result of human activities
1. Causes:
Hot water is discharged into nearby lake and river from
the effluent of industrial processes and cooling tower of
electrical power station, which use water as a cooling agent.
The excess heat that is released into the environment
leads to thermal pollution.
2. Effects:
Thermal pollution causes the temperature in a body of
water to rise above the normal value.
17
Water temperature can affect the level of dissolved
oxygen.
As the temperature of the water increases, oxygen
become less insoluble in water.
If the temperature increase persists over a longer period,
this may result in permanent changes in the species
composition of the aquatic ecosystem.
3. Ways to prevent:
Control the amount of hot water discharged into still or
slow - moving rivers.
Control the amount of hot water discharged from
industrial plants and power station to the surrounding lakes
and rivers.
9.1.5 Noise Pollution
1. Causes:
Noises from cars, motorcycles, aeroplanes, construction
sites, agriculture and industrial machinery.
Noise level of residential areas should not exceed 55
decibels (dB).
2. Effects:
Prolonged exposure to noise level at or above 80 decibels
can lead to deafness.
High level of noise can contribute to the development and
aggravation of stress – related problems such as high blood
pressure, coronary disease, ulcers, depression and
headache.
Loud noise can cause an arousalresponse in which a
series of reactions occurs in the body.
Adrenaline is released into the bloodstream. A person’s
heartbeat, blood pressure and
respiration rate are likely to increase.
The blood vessels constrict and the muscles become
tense.
18
Constant exposure to noise can contribute to a
deterioration in health.
9.2 The Greenhouse Effect and the Thinning of Ozone
Layer
The Greenhouse Effect has the same effect as a
greenhouse used in farming:
19
Causes:
1. Increases of the
greenhouse gases especially carbon dioxide in the atmosphere
due to:
(a) combustion of fossil fuels
(b) deforestation
(c) industrial production
2. As the concentration of greenhouse gases rises, more heat is
trapping in the atmosphere and raising the average temperature
on earth. Hence, this phenomenon brings to global warming.
Effects:
1. Occurrence of floods
·
As the average temperature rises, the polar ice caps and
glaciers melt.
·
This increases the sea level causing low-lying areas to be
flooded.
20
2. Climate changes
·
Global warming leads to changes in wind directions and
distribution of rainfall. As a result, agricultural activities are
affected.
·
Global warming causes weather patterns to change. This
affects the distribution of species which may lead to the
extinction of species in certain region.
3. Occurrence of droughts
·
Global warming increases the frequency of droughts.
·
The land becomes dry and infertile. This leads to a drop
yields.
4. Spread of diseases
·
With warmer climates, pests and vectors may spread to
new areas.
·
The warmer conditions lead to an expansion of territories
for disease-carrying vectors, resulting an increase in the outbreak
of diseases.
Solutions to global warming:
1. Reduce the burning of fossil fuels.
2. Develop alternative sources of energy such as wind, solar and
geothermal energy.
3. Reduce deforestation
4. Replant trees which have been cut down.
21
The Thinning of the Ozone Layer
Causes of ozone depletion:
The increasing levels of chlorofluorocarbons (CFCs) in the atmosphere.
In the stratosphere, CFCs molecules are broken down by ultraviolet rays, releasing chlorine
radicals which destroy ozone in a chain reaction.
Effects of ozone depletion:
Prolonged exposure to ultraviolet radiation can lead to higher risks of:
(a) skin cancer
(b) cataracts
(c) sunburns
Ultraviolet radiation weakens the immune system and the ability of the body to resist infectious
diseases.
Ultraviolet radiation reduces nutrient contents and crop yield of plants.
22
Ultraviolet rays destroy the leaf cells and chlorophyll. This lowers the rate of photosynthesis and
reduces crop yield.
Ultraviolet rays kill microorganisms and phytoplankton that are at the bottom of the marine food
chain.
Leads increases in the temperature on Earth.
High levels of ultraviolet radiation can damage the eggs of amphibians.
Ways to reduce ozone depletion:
Reduce or stop the use of CFCs.
Replace chlorofluorocarbons (CFCs) with hydrochlorofluorocarbons (HCFCs) and
hydrofluorocarbons (HFCs).
9.3 Measure taken in the management of Development activities
Implementation of laws
*control pollution
~Enviromental Quality Act,1974
(water quality management)
~Enviromental Quality Regulation,1989
(waste treatment & disposal facilities)
~Enviromental Quality Regulation,1977
(crude palm oil)
~Enviromental Quality Regulation,1979
(sewage & industrial effluents)
~Protection of Wildlife Act,1972
Use of Technology
*catalytic converters (clean up exhaust emissions & convert harmful gasses)
23
*use unleaded petrol
*treat sewage treatment plants
*treat toxic waste produced in factories
*use microorganisms to clean up the environment
*develop hydrogen-basedfuel-cell vehicles
*use technology to capture carbon dioxide emissions
*use methods to reduce & capture methane emissions,a by-product of cattle & other
livestock waste & uses better controls on nitrous oxide emissions from nitrogen
fertilizers
Education on the management of resources
*4Rs (recycle,reuse,reduce & renew)
~RECYCLING means collecting &
segregating waste materials according to their types & turning them into new products.
~REUSE means to reuse things instead of throwing them away.
~REDUCE means reducing the use of materials.
~RENEW means to renew the use of materials after they are cleaned.
Preservation & conservation of soil , water , flora & mangrove swamps
*Preservation involves efforts to protect an ecosystem so that natural resources are utilised in a
suitainable manner & the equilibrium of the ecosystem is maintain.
*Conservation involves effort to return an affected ecosystem to its natural equilibrium.
*Sustainable agricultural development is the effective use & preservation of soil to ensure
continuous agricultural production.
~good farming techniques & agricultural pratices
*Water sources & catchment areas must be preserve
24
~rivers must not be regarded as dumping sites
~the use of nitrates & phosphate in agriculture must be control
*Forests
~establishing a level of selective harvesting
~reforestation
~restoration programmes
~forest reserves
~greater productivity must be reduce
*Mangrove swamps (flood control,nutrient & toxicant retention,sediment control,coastal erosion
prevention,barrier against rising sea level)
The practice of biological control
*Biological control is the use of natural predators to control the population of pest species.
~cheap
~will not pollute the environment
The use of renewable energy
*RENEWABLE ENERGY is the energy flow that occurs naturally in the environment &
can be harnessed for the benefit of human.(inexhaustible & does not pollute the
environment)
~solar , wind , wave , flowing water , geothermal , biomass & palm oil fuel energy
The efficient use of energy
*reduce the use of coal , petroleum & other fossil fuels
*substitude natural gas for coal*improve fuel efficiency
*use cleaner fuel
*improve energy effiency
25
*use more hybrid car which combine electric & gasoline engines
26
9:ENDANGERED
ECOSYSTEM
Name:Lim Jo Lynn
Class:4 Anggerik
Index:
Topics
1
pag
e
9.1 Human activities that endanger an
ecosystem
9.1.1 The impact of human activities on
the ecosystem
3
3-7
Air pollution
Water pollution
Eutrophication
Thermal pollution
Noise pollution
9.2 The Greenhouse Effect and the
Thinning of Ozone Layer
8-11
12-14
15-16
16-17
17-18
19-20
The Thinning of the Ozone Layer
9.3 Measure taken in the management of
Development activities
21-22
22-24
9.1 Human activities that endanger
an ecosystem
Human activities that threaten the ecosystem:
*
2
Human activities often affect the whole ecosystem.
*
The negative effects of hasty and unplanned development and
mismanagement of the ecosystem result in various environmental
problems.
*
These problems bring about negative effects that are increasingly
threatening the economic resources, health and survival of the ecosystem.
9.1.1 The impact of human
activities on the ecosystem
(1) Deforestation:
*
The rapid destruction of woodlands or removal of trees from forests is
known as deforestation.
*
Tropical rainforests play important ecological roles:
*
Oldest ecosystem on earth and house of flora n fauna
*
Contain many unique species which provide food, medicine and other
biological products.
*
Regulate the world’s climate by influencing wind, rainfall, humidity
and temperature patterns.
*
Called the ‘carbon sink’ of the Earth because they absorb vast
amount of carbon dioxide during photosynthesis and release oxygen into
the atmosphere.
*
Serve as water catchment areas
Deforestation results in :
*
Soil erosion
*
Flash flood
3
*
Landslides
*
Changes in the recycling of materials
*
Severe climatic changes
*
The loss of biodiversity
Deforestation cause soil erosion, landslides and flash flood
*
Soil erosion is the removal and thinning of the soil layer due to
physical and climatic process.
*
The absence of plant root systems makes the soil structure unstable.
*
When it rain heavily for a long period of time, the top layer of the soil
disintegrates easily and this leads to landslides on steep hillsides.
*
The eroded soil is then carried away by moving water and deposited
at the bottom of river.
*
Together with depletion of water catchment areas, cause flash
flood during rainy seasons.
*
Soil erosion causes the land to be depleted of minerals and natural
resources, making the land useless for cultivation.
Deforestation results in the loss of biodiversity
The destruction by human activities:
*
The removal of the base of numerous food webs.
*
The loss of habitats for many species of flora and fauna
*
The extinction of countless species and varieties of plants and
animals, many of which have never been catalogued scientifically.
Extinction of flora and fauna species reduces biodiversity
4
*
The destruction of storehouse of genetic diversity on Earth. The
Earth’s biodiversity is a rich source of food and priceless medicines for
mankind
Deforestation affects carbon and nitrogen cycles
*
The removal of plants in the rainforests disrupts the natural cycle of
nutrients.
*
The level of atmospheric carbon dioxide rises as less carbon dioxide
is removed by plants while the level of atmospheric oxygen drops as less
oxygen is released during photosynthesis.
*
The recycling of nitrates and other ions is slowed down.
*
Tree roots bind soil particles together, and the tree canopy reduces
the force of rain beating down on the soil and cause nutrients to be lost
through leaching and run-off.
Deforestation cause climates change
*
Deforestation disrupts normal weather patterns, creating hotter and
drier weather and causing global climatic changes.
*
Removal of trees reduces transpiration and rainfall cause the
increase in carbon dioxide level in atmosphere and prevent heat from
escaping from atmosphere.
*
This is known as greenhouse effect and lead to global warming.
(2) Burning of fossil fuels and its effects
*
Contributes about 75% of carbon dioxide
*
Cause greenhouse effect and global warming
5
(3) Intensive farming and its effect
*
Excessive use of land for intensive farming decrease the space and
resources available for other species
(4) The effect of an increase in domestic waste and industrial waste
*
A rapidly expanding human population also generates an increase in
both domestic and industrial waste.
Polution:An undesirable change in the chemical,physical or biological
characteristics of the nature
6
Air
Therm
al
Pollutio
n
Water
Noise
1.Air pollution
1. Air pollution is caused by the presence of pollutants in the air
which are harmful to life and the environment.
2. Sources of pollution are as follows:
a) Burning
Rubbish
Forest
Solid waste
7
b) Factories and industries
Burning of fossil fuels such as petroleum, diesel and gas in
factories and power stations.
Agricultural industries that use agrochemicals such as
fertilizers, pesticides, insecticides and herbicides.
c) Motor vehicles
Release harmful gases in car exhaust fumes.
3. Burning of fossil fuels produces gases such as sulphur dioxide
and nitrogen dioxide. Burning of rubbish and emission of smoke
and fumes from car exhausts and chimneys in factories produce
carbon dioxide, carbon monoxide and soot (unburnt carbon
particles).
4. Increase in carbon dioxide (a greenhouse gas) in the
atmosphere will trap the Sun’s radiation and retain it as heat in
the Earth’s atmosphere. This contributes to the greenhouse
effect.
5. This will cause an increase in the Earth’s temperature.
Source of pollution:
(a) Pollutant: Dust and soot
-Cement factories, quarries, sawmills, burning of rubbish and
motor vehicles.
(b) Pollutant: Carbon monoxide, carbon dioxide, sulphur dioxide
and nitrogen dioxide
-Burning of fossil fuels and rubbish
-Car exhaust fumes.
(c) Pollutant: Lead
-Car exhaust fumes which contain lead
(d) Pollutant: Agrochemical substances
-Activities of agricultural industry
(e) Pollutant: Radioactive radiations
-Nuclear power stations
(f) Pollutant: Chlorofluorocarbon (CFC)
-Aerosol and foam industries
Acid Rain
8
(I) Causes of acid rain:
1. The combustion of fossil fuels (cool, air and gas) in power
station, factories, domestic boilers and internal combustion
engines releases large quantities of sulphur dioxide (SO2 ) and
oxides of nitrogen (NO and NO2).
2. Both sulphur dioxide and oxides of nitrogen combine with
water vapour in the atmosphere to form sulphuric acid and nitric
acid respectively.
3. Then, they fall to earth as acid rain.
4. Rain is naturally acidic, with pH of about 5.6. This acidity is
due to the carbon dioxide in the air, which dissolve in rain to form
carbonic acid.
5. However, the pH of acid rain is less than 5.0.
(II) Effects:
(a) Agricultural:
The soil becomes very acidic and unsuitable for the cultivation of
crops.
Acid rain causes the leaching of minerals such as potassium,
calcium, and magnesium. This affects the growth of crops.
(b) Aquatic ecosystem:
Acid rain causes insoluble aluminum ions to accumulate in lakes
and rivers. The concentration of aluminum ions eventually
reaches a toxic level which can kill aquatic organisms such as fish
and invertebrates.
(c) Health:
Acidic soil releases the ions of certain heavy metals such as
cadmium, lead, mercury which may contaminate the supply of
drinking water.
Increased acidity in the aquatic ecosystems also kills
phytoplankton which changes the food chain.
9
Photosynthesis tissues are destroyed. Plant leaves turn yellow
and fall off. The roots are damaged and cannot absorb minerals.
(d) Buildings:
Metal railings and bridges corrode.
Limestone, stonework and marble monuments are eroded due to
chemical weathering.
(III) Solutions:
Acid rain can be reduced by:Cleaning up emissions from vehicle exhausts through the use of
catalytic converters. The pollutants react with one another in the
catalytic converters to produce less harmful products.
Cleaning emissions from power stations and industrial plants with
scrubbers. This process involves the spraying of water to trap
pollutants.
Air Pollution Index (API)
The Air Pollution Index (API) is used as a measure of air quality.
It normally includes the major air pollutants which could cause
potential harm to human health.
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In Malaysia, the air pollutants included are ozone, carbon
monoxide, nitrogen dioxide, sulphur dioxide and suspended
particulate matter.
This index is calculated by using the concentrations of major air
pollutants, but it is developed in easily understood ranges of
values as shown below.
Air Pollution Index
API
0-50
Status
Good
51-100
Moderate
101-200
Unhealthy
201-300
Very unhealthy
301-500
Hazardous
Above 500
Emergency
Level of pollution
Low, no ill effects on
health
Moderate pollution,
no ill effects on health
Mild aggravation of
symptoms among
high risk groups
Significant
aggravation of
symptoms and
decreased exercise
tolerance among high
risk groups
Severe aggravation of
symptoms and a
danger to health
Severe aggravation of
symptoms and a
danger to a health
WATER POLLUTION
Sources, Components, Effects, Solution of water pollution
11
Sources
Agricultur
al
run-off
and
waste
12
Component
s
Nitrates
and
phosphates
Effects
Solutions
Lead to
eutrophicatio
n
Control the use
of fertilisers
a)
Applying
only when crops
are growing.
b)
Not
applying in
empty fields.
c)
Not
spraying when
there is a
forecast of rain.
d)
Not
disposing of
them into rivers
and ponds.
e)
Reducing
the usage of
excess nitrates
from fertilisers
and ammonia.
Herbicide
and
pesticide
residues
-Have toxic
effects on
organisms in
water and
human
-Pesticides
levels can be
magnified as
they pass
through food
chain
Accumulation
of pesticides
-Use
biodegradable
pesticides
-Use alternative
method
(biological pest
control)
-Planting
genetically
modified crops
that can resist
attacks by
insects as this
may reduce the
Untreated
sewage –
human
faeces
and
domestic
waste
13
in consumers
may kill them
or affect their
metabolism
-Lead to
lower sperm
counts,
decreased
ovulation,
inability to
conceive and
birth defects.
need to use
chemical
pesticides
Suspended
solids
Reduce light
penetration
-High demand
for oxygen
-Treat sewage
before it enters
rivers
-Prevent slurry
(liquid manure)
from farms from
entering rivers
and ponds
Nitrates
and
phosphates
Detergents
Leads to
eutrophicatio
n
-‘Hard’
detergents
create foam
which
reduces the
availability of
oxygen to
organisms
living in the
water
-‘Soft’
detergents
are
biodegradabl
e but may
-Use
biodegradable
detergents with
low phosphate
contents
Effluent
from
industries
Electronic
s and
electropla
ting
plants
-Food and
beverage
processin
g industry
-Rubber
products
processin
g industry
Undergro
und pipes
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Microorgani
sms
(viruses,
bacteria,
and
protozoa)
Heavy
metals
(copper,
mercury,
zinc, and
chromium),
oil, grease,
and
suspended
solids,
waste
water
contains
numerous
contaminan
ts,
(including
hydroxide
sulphide).
Lead
(highly
toxic heavy
metal)
contain high
levels of
phosphates
which can
lead to
eutrophicatio
n
- Cause
cholera
-Drink properly
treated and
boiled water
-Highly toxic
accumulate in
the
organisms via
food chains
-Mercury
causes acute
nervous
disorder in
humans.
-Treat effluents
before
discharging into
water sources
-Taking legal
action against
illegal dumping
of toxic wastes
-Accumulate
in the tissues
of living
organisms
-Impair the
mental
performance
-Replace lead
pipes used in
plumbing with
copper-based
pipes.
of children
Eutrophication
Defination: Artificial nutrient enrichment of an aquatic system
with organic material or inorganic nutrients, causing an excessive
growth of aquatic plant life.
Causes by
a) Leaching of inorganic fertilisers, especially nitrates and
phosphates, from agricultural lands
b) Input of untreated sewage as well as discharge from sewage
treatment plants
c) Run-off of animal waste from pastures and farmlands into
lakes, rivers or ponds.
Process of eutrophication
1)
Run-off of excess nutrients into water encourage rapid
growth of algae, results in a population explosion known as an
algae bloom
15
2)
At night, high respiration rate of the algae results in a high
demand for oxygen.
3)
Excessive growth of algae restricts the penetration of light
into the water. The rate of photosynthesis of aquatic plants
reduced and further reduced the supply of oxygen in water.
4)
The algae grow faster than their consumers. Most of algal
population dies without being consumed.
5)
Decomposing microorganisms especially aerobic bacteria
used up the oxygen in deeper water at a fast rate.
6)
Untreated sewage or animal wastes from farm that contain
high concentration of organic matter encourage the rapid growth
of aerobic bacteria.
7)
The aerobic bacteria use up oxygen faster than it can be
replenished. An increase in biochemical oxygen demand (BOD)
results in a severe depletion of oxygen.
8)
Low level of oxygen concentration kills larger aerobic aquatic
organisms and organisms that require higher oxygen levels
(freshwater shrimps and mayfly nymphs)
9)
If the oxygen levels continues to drop and water become
completely deoxygenated, anaerobic bacteria will grow and
release toxic gases (eg. hydrogen sulphide), causing the death of
aquatic organisms.
10) During the growth of algae, certain blue green bacteria also
produce toxins.
11) At night BOD levels, organisms that are more tolerant of
lower concentration of dissolved oxygen (eg. leeches, Tubifex
worms, and sludge worms) may appears and multiply.
What is BOD?
Biochemical oxygen demand (BOD) is the amount of dissolved
oxygen required by the microoganisms to decompose the organic
matters in the water.
The measurement of BOD is an indication of the level of water
pollution.
If there is a large amount of organic waste in the water, the
population of aerobic bacteria will increase to decompose the
organic matter. The dissolved oxygen level in the water
decreases, and the value of BOD will be high.
16
A lower BOD level (or higher dissolved oxygen level)
indicates better water quality. A higher BOD level (or
lower dissolved oxygen level) indicates poor water quality.
9.1.4 Thermal Pollution
In thermal pollution, the temperature of a body of water is
unintentionally raised as a
result of human activities
1. Causes:
Hot water is discharged into nearby lake and river from
the effluent of industrial processes and cooling tower of
electrical power station, which use water as a cooling agent.
The excess heat that is released into the environment
leads to thermal pollution.
2. Effects:
Thermal pollution causes the temperature in a body of
water to rise above the normal value.
17
Water temperature can affect the level of dissolved
oxygen.
As the temperature of the water increases, oxygen
become less insoluble in water.
If the temperature increase persists over a longer period,
this may result in permanent changes in the species
composition of the aquatic ecosystem.
3. Ways to prevent:
Control the amount of hot water discharged into still or
slow - moving rivers.
Control the amount of hot water discharged from
industrial plants and power station to the surrounding lakes
and rivers.
9.1.5 Noise Pollution
1. Causes:
Noises from cars, motorcycles, aeroplanes, construction
sites, agriculture and industrial machinery.
Noise level of residential areas should not exceed 55
decibels (dB).
2. Effects:
Prolonged exposure to noise level at or above 80 decibels
can lead to deafness.
High level of noise can contribute to the development and
aggravation of stress – related problems such as high blood
pressure, coronary disease, ulcers, depression and
headache.
Loud noise can cause an arousalresponse in which a
series of reactions occurs in the body.
Adrenaline is released into the bloodstream. A person’s
heartbeat, blood pressure and
respiration rate are likely to increase.
The blood vessels constrict and the muscles become
tense.
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Constant exposure to noise can contribute to a
deterioration in health.
9.2 The Greenhouse Effect and the Thinning of Ozone
Layer
The Greenhouse Effect has the same effect as a
greenhouse used in farming:
19
Causes:
1. Increases of the
greenhouse gases especially carbon dioxide in the atmosphere
due to:
(a) combustion of fossil fuels
(b) deforestation
(c) industrial production
2. As the concentration of greenhouse gases rises, more heat is
trapping in the atmosphere and raising the average temperature
on earth. Hence, this phenomenon brings to global warming.
Effects:
1. Occurrence of floods
·
As the average temperature rises, the polar ice caps and
glaciers melt.
·
This increases the sea level causing low-lying areas to be
flooded.
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2. Climate changes
·
Global warming leads to changes in wind directions and
distribution of rainfall. As a result, agricultural activities are
affected.
·
Global warming causes weather patterns to change. This
affects the distribution of species which may lead to the
extinction of species in certain region.
3. Occurrence of droughts
·
Global warming increases the frequency of droughts.
·
The land becomes dry and infertile. This leads to a drop
yields.
4. Spread of diseases
·
With warmer climates, pests and vectors may spread to
new areas.
·
The warmer conditions lead to an expansion of territories
for disease-carrying vectors, resulting an increase in the outbreak
of diseases.
Solutions to global warming:
1. Reduce the burning of fossil fuels.
2. Develop alternative sources of energy such as wind, solar and
geothermal energy.
3. Reduce deforestation
4. Replant trees which have been cut down.
21
The Thinning of the Ozone Layer
Causes of ozone depletion:
The increasing levels of chlorofluorocarbons (CFCs) in the atmosphere.
In the stratosphere, CFCs molecules are broken down by ultraviolet rays, releasing chlorine
radicals which destroy ozone in a chain reaction.
Effects of ozone depletion:
Prolonged exposure to ultraviolet radiation can lead to higher risks of:
(a) skin cancer
(b) cataracts
(c) sunburns
Ultraviolet radiation weakens the immune system and the ability of the body to resist infectious
diseases.
Ultraviolet radiation reduces nutrient contents and crop yield of plants.
22
Ultraviolet rays destroy the leaf cells and chlorophyll. This lowers the rate of photosynthesis and
reduces crop yield.
Ultraviolet rays kill microorganisms and phytoplankton that are at the bottom of the marine food
chain.
Leads increases in the temperature on Earth.
High levels of ultraviolet radiation can damage the eggs of amphibians.
Ways to reduce ozone depletion:
Reduce or stop the use of CFCs.
Replace chlorofluorocarbons (CFCs) with hydrochlorofluorocarbons (HCFCs) and
hydrofluorocarbons (HFCs).
9.3 Measure taken in the management of Development activities
Implementation of laws
*control pollution
~Enviromental Quality Act,1974
(water quality management)
~Enviromental Quality Regulation,1989
(waste treatment & disposal facilities)
~Enviromental Quality Regulation,1977
(crude palm oil)
~Enviromental Quality Regulation,1979
(sewage & industrial effluents)
~Protection of Wildlife Act,1972
Use of Technology
*catalytic converters (clean up exhaust emissions & convert harmful gasses)
23
*use unleaded petrol
*treat sewage treatment plants
*treat toxic waste produced in factories
*use microorganisms to clean up the environment
*develop hydrogen-basedfuel-cell vehicles
*use technology to capture carbon dioxide emissions
*use methods to reduce & capture methane emissions,a by-product of cattle & other
livestock waste & uses better controls on nitrous oxide emissions from nitrogen
fertilizers
Education on the management of resources
*4Rs (recycle,reuse,reduce & renew)
~RECYCLING means collecting &
segregating waste materials according to their types & turning them into new products.
~REUSE means to reuse things instead of throwing them away.
~REDUCE means reducing the use of materials.
~RENEW means to renew the use of materials after they are cleaned.
Preservation & conservation of soil , water , flora & mangrove swamps
*Preservation involves efforts to protect an ecosystem so that natural resources are utilised in a
suitainable manner & the equilibrium of the ecosystem is maintain.
*Conservation involves effort to return an affected ecosystem to its natural equilibrium.
*Sustainable agricultural development is the effective use & preservation of soil to ensure
continuous agricultural production.
~good farming techniques & agricultural pratices
*Water sources & catchment areas must be preserve
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~rivers must not be regarded as dumping sites
~the use of nitrates & phosphate in agriculture must be control
*Forests
~establishing a level of selective harvesting
~reforestation
~restoration programmes
~forest reserves
~greater productivity must be reduce
*Mangrove swamps (flood control,nutrient & toxicant retention,sediment control,coastal erosion
prevention,barrier against rising sea level)
The practice of biological control
*Biological control is the use of natural predators to control the population of pest species.
~cheap
~will not pollute the environment
The use of renewable energy
*RENEWABLE ENERGY is the energy flow that occurs naturally in the environment &
can be harnessed for the benefit of human.(inexhaustible & does not pollute the
environment)
~solar , wind , wave , flowing water , geothermal , biomass & palm oil fuel energy
The efficient use of energy
*reduce the use of coal , petroleum & other fossil fuels
*substitude natural gas for coal*improve fuel efficiency
*use cleaner fuel
*improve energy effiency
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*use more hybrid car which combine electric & gasoline engines
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