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8/14/2019 Ppt E2ch01 e
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The Tai Hu () isthe third largest lake
in China.
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Algal bloom appearedthere occasionally.
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In 2007, the algalbloom was so serious
that the water became
smelly and unsuitable
for use. Many fish die.
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Some people claimedthat the algal bloom
was caused by global
warming and
insufficient rain.
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Others suggested thatit was caused by
pollutants.
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What is an algal
bloom1
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Why do many fish
die when algal blooms
occur
2
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Why may
global warming and
insufficient rain leadto algal blooms
3
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What types of
pollutants may cause
algal blooms
4
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1.1 Human population growth
The pattern of humanpopulation growth
How has the world
human populationchanged?
1 1 Human population growth
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1.1Human population growth
0 400 800 1200 1600 2000
12
3
45
6
78
9
billionofp
eople
year
population
increased slowly
1 1 Human population growth
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1.1Human population growth
0 400 800 1200 1600 2000
12
3
45
6
78
9
billionofp
eople
year
Industrial
Revolution
economic growth
living standard improved
1 1 Human population growth
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1.1Human population growth
0 400 800 1200 1600 2000
12
3
45
6
78
9
bi
llionofp
eople
year
Industrial
Revolution
better nutrition, medical care and
sanitation
great decrease in
death rate
1 1 Human population growth
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1.1Human population growth
0 400 800 1200 1600 2000
12
3
45
6
78
9
bi
llionofp
eople
year
Industrial
Revolution
birth rate remains high
population increased
exponentially
1 1 Human population growth
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1.1Human population growth
Human population is
increasing at a rate ofone billion people every
13 years.
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1 1 Human population growth
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1.1Human population growth
Why is population control
necessary? the earth has limited resources
carrying capacity():the maximum size of population whichthe available resources can support
1 1 Human population growth
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1.1Human population growth
increased exhaustion of naturalresources
rapid growth of human population
1 1 Human population growth
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1.1Human population growth
environmental degradation
rapid growth of human population
1 1 Human population growth
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1.1 p p g
e.g. through birth control methods
and other measures
population controlhelps solve
the problems
1.1 Human population growth
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and improved
1Since the Industrial Revolution, thelarge scale use of fossil fuel-
powered machinery has led to greateconomic growth
1.1 p p g
living standard. The death rate
decreases significantly and the birthrate remains high. Thus, the human
population rapidly.increases
1.1 Human population growth
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2The rapid growth in humanpopulation will increase the
exhaustion ofnatural resources
and .
can help
environmental degradation
1.1 p p g
Population control
ensure a continuous supply of naturalresources for our current needs and
for the future generations.
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1.2 Use of natural resources
What natural resources dowe have?
renewable
resources
()non-renewable
resources
()
1.2 Use of natural resources
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1 Renewable resources
1.2
can be replaced after use
timber fish
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1.2Use of natural resources
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1.2
overexploitation
some non-renewable resources will
soon become depleted even some renewable resources
have become limited
1.2Use of natural resources
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What are the environmental
impacts of malpractices infisheries?
- heavy demand for fish
as food
- destructive fishing
methods
causes:
1.2Use of natural resources
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1 Depletion of fish stock
overfishing
humphead wrasse
3/4 of marine fisheries are exploited
up to or beyond the rate that the fish
stock can recover
I may become
extinct!
1.2Use of natural resources
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2 Killing of non-target species
cyanide fishing
used to stun fish
1.2Use of natural resources
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2 Killing of non-target species
cyanide fishingkills large numbers of non-target fish
and invertebrates such as coral
1.2Use of natural resources
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2 Killing of non-target species
drift net fishing
1.2Use of natural resources
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2 Killing of non-target species
drift net fishingbycatch: dolphins, sea turtles,
seabirds,juvenile fish
1.2Use of natural resources
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3 Destruction of marine habitats
dynamite fishing and bottom trawling
damage coral reefs()
1.2Use of natural resources
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4 Disturbance of ecological
balance large decrease in the number of fish
threatens predatorsalters the structure and functioning
of the ecosystems
1.2Use of natural resources
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What are the environmental
impacts of malpractices inforestry?
- heavy demand for land
and timber
- deforestation
causes:
1.2Use of natural resources
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1 Destruction of natural habitats
forests are clearedreduces biodiversity
1.2Use of natural resources
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2 Soil erosion
trees are removedtop soilbecomes easily washed away
by rainwater or blown away by wind
1.2Use of natural resources
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3 Global warming
forests are burnt for land clearingCO2level in the atmosphere increases
greenhouse effect
() is enhancedglobal warming
()
1.2Use of natural resources
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Greenhouse effect
Solar radiation passes through theatmosphere.
Animation
atmospheresun
earth
1.2Use of natural resources
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The earths surface absorbs mostradiation and becomes warm.
Greenhouse effect
1.2Use of natural resources
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Some solar radiation is reflected intospace by the earth and the atmosphere.
Greenhouse effect
1.2Use of natural resources
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Infrared radiation is emitted fromthe earths surface.
Greenhouse effect
1.2Use of natural resources
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Some of the infrared radiation is trappedand re-emitted by the greenhouse gases
in the atmosphere.
Greenhouse effect
water vapour
carbon dioxide
methanenitrous oxide
ozone
CFCs
1.2Use of natural resources
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Greenhouse effect
The earths surface gain more heat.
1.2Use of natural resources
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Greenhouse effect
a naturalprocess important in maintaining a relatively
stable temperature
however
1.2Use of natural resources
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Greenhouse effect
There has been an
increasing level ofgreenhouse gases in
the atmosphere.
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1.2Use of natural resources
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Greenhouse effect
the greenhouse effect is enhanced atmospheric temperaturegradually
increases
global warming
1.2Use of natural resources
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3 Global warming
increases melting of icebergs
loss of habitats
shortage of food
1.2Use of natural resources
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3 Global warming
rise in sea level
flooding of
low-lying areas
increases melting of icebergs
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1.2Use of natural resources
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3 Global warming
some species may move to higherlatitudes or altitudes
some species may become extinct
1.2Use of natural resources
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3 Global warming
spread of infectious diseases tonew regions
e.g. malaria and dengue fever
1.2Use of natural resources
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What are the environmental
impacts of malpractices inagriculture?
- clearing large areas of land for
agriculture
- overgrazing
()
causes:
1.2Use of natural resources
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What are the environmental
impacts of malpractices inagriculture?
- extensive use of pesticides
and chemical fertilizers
- use of chemicals in rearing livestock
causes:
- monoculture ()
1.2Use of natural resources
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1 Destruction of natural habitats
forests are clearedreduces biodiversity
1.2Use of natural resources
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2 Soil erosion
reasons:i) Clearing forests
ii) Use of chemical fertilizers
iii) Overgrazing
loss of humus
grass is consumed faster
than it can recovery
may lead to desertification 1.2Use of natural resources
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i) Effects of pesticides toxic
3 Chemical pollution
- harm the beneficial insects, aquatic
organisms or humans
1.2Use of natural resources
DDT
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stable
3 Chemical pollution
- the concentration
of the chemicals
accumulated in
organisms increasesup the food chain
DDT
i) Effects of pesticides
1.2Use of natural resources
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ii) Effects of chemical fertilizers
3 Chemical pollution
eutrophication()leaching()
algal bloom()
1.2Use of natural resources
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ii) Effects of chemical fertilizers
3 Chemical pollution
algal bloom
- algae uses up the
oxygenat night
suffocation
1.2Use of natural resources
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ii) Effects of chemical fertilizers
3 Chemical pollution
algal bloom
- algae prevents
penetration of light
no photosynthesis
1.2Use of natural resources
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ii) Effects of chemical fertilizers
3 Chemical pollution
algal bloom
- decomposition
of dead algae by
bacteriafurther
consumes oxygen- bacteria produce
toxic substances
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1.2Use of natural resources
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growth hormones or drugs
3 Chemical pollution
- to promote growth
iii) Effects of chemicals used in rearinglivestock
- leakage may cause
unpredictable healthrisk
1.2Use of natural resources
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antibiotics
3 Chemical pollution
- to protect against diseases
iii) Effects of chemicals used in rearinglivestock
- indiscriminate use may speed up
the development of resistancein pathogens
1.2Use of natural resources
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4 Impact of monoculture
growing the same crop on the same pieceof land for many years
wheat 1.2Use of natural resources
4 f
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i) Increased soil erosion
4 Impact of monoculture
when a crop is harvested, soil is
left bare
1.2Use of natural resources
4 I f l
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ii) Depletion of certain minerals fromthe soil
4 Impact of monoculture
soil becomes infertile
extensive use of chemical fertilizers
can lead to soil erosionand chemical
pollution
1.2Use of natural resources
4 I f l
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iii) Increased pest population
4 Impact of monoculture
when the same type of crop is growth
continuously, the peststhat feed on
the crop are readily provided withfood and they grow quickly
removal becomesmore difficult
1.2Use of natural resources
4 I f l
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iii) Increased pest population
4 Impact of monoculture
extensive use of pesticides
chemical pollution
development of resistancein pests
1.2Use of natural resources
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They come from organisms andcan be replaced after use.
a resources1Natural resources:
Renewable
1.2Use of natural resources
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They cannot be replaced afteruse. They have a limited supply.
b resources1Natural resources:
Non-renewable
1.2Use of natural resources
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- Heavy demand for fish as
Causes:
2aEnvironmental impact ofmalpractices in fisheries:
food
- fishing methodsDestructive
1.2Use of natural resources
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- Depletion of
Impact:
2aEnvironmental impact ofmalpractices in fisheries:
fish stock
- Killing of organismsnon-target
- Destruction of marine habitats
- Disturbance of
ecological balance 1.2Use of natural resources
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- Heavy demand for land and
timber leads to
Cause:
2bEnvironmental impact ofmalpractices in forestry:
deforestation
1.2Use of natural resources
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Impact:
- Destruction of natural
and reduced
habitats
- Soil and increasedrisk of
erosion
2bEnvironmental impact ofmalpractices in forestry:
biodiversity
flooding
- Global warming 1.2Use of natural resources
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- Clearing of large areas of land
for agriculture
Causes:
2cEnvironmental impact ofmalpractices in agriculture:
pesticides
- Overgrazing
- Extensive use of and
chemical fertilizers 1.2Use of natural resources
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- Use of in rearing
livestock
Causes:
2cEnvironmental impact ofmalpractices in agriculture:
- Monoculture
chemicals
1.2Use of natural resources
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Impact:
- Destruction of natural habitats
and reduced biodiversity
- Soil erosion and increased riskof flooding
-
2cEnvironmental impact ofmalpractices in agriculture:
Desertification 1.2Use of natural resources
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Impact:
- in pesticides
harm other non-target organisms
2cEnvironmental impact ofmalpractices in agriculture:
Toxic chemicals
1.2Use of natural resources
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Impact:
- Concentration of toxic chemicals
along , causing
harm to consumers attrophic levels
2cEnvironmental impact ofmalpractices in agriculture:
food chains
higher
1.2Use of natural resources
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Impact:
- Leaching of chemical fertilizers
causes
2cEnvironmental impact ofmalpractices in agriculture:
algal blooms
1.2Use of natural resources
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Impact:
- The use of
and drugs in rearing livestock
may cause health risks to wildorganisms and humans
2cEnvironmental impact ofmalpractices in agriculture:
growth hormones
1.2Use of natural resources
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Impact:
- The indiscriminate use of
antibiotics may speed up the
development of inpathogens
2cEnvironmental impact ofmalpractices in agriculture:
resistance
1.2Use of natural resources
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Impact:
- Increased soil erosion,
of certain minerals from the soil
and increased pest populationdue to
2cEnvironmental impact ofmalpractices in agriculture:
depletion
monoculture
1 3 Environmental effects of
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0
2
4
8
6
1950 1970 1990 2010 2030
1.3 Environmental effects of
urbanization and industrialization
popu
lation(b
illion)
year
world urban
population
world ruralpopulation
1.3Environmental effects of urbanization and industrialization
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urbanization and industrialization
require large areas of land
land obtained by land clearance orreclamation
damage the habitats
1.3Environmental effects of urbanization and industrialization
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pollution
urbanization and industrialization
Impact of land clearance1.3Environmental effects of urbanization and industrialization
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Impact of land clearance
and reclamation destructionand loss of habitats
decrease in population of wildlife
Chek Lap Kok Island
was cleared for the
construction of theairport
Impact of land clearance1.3Environmental effects of urbanization and industrialization
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Impact of land clearance
and reclamation
decrease in population of wildlife
I lost my
breeding
ground.
destructionand loss of habitats
Impact of land clearance1.3Environmental effects of urbanization and industrialization
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Impact of land clearance
and reclamation soil erosionand flooding
Impact of land clearance1.3Environmental effects of urbanization and industrialization
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Impact of land clearance
and reclamationreclaimed land
Impact of land clearance1.3Environmental effects of urbanization and industrialization
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Impact of land clearance
and reclamation coastal habitatsare
destroyed
dredging()disturbs seabed
habitats and upsetsmarine ecosystems
Impact of land clearance1.3Environmental effects of urbanization and industrialization
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suspended mud
particles may clog
the gillsof fish andblock sunlight
dredged materialmay contain toxic
chemicals
Impact of land clearance
and reclamation
Air pollution1.3
Environmental effects of urbanization and industrialization
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Air pollution
major sources:
exhaust fumesand dust
from burning of fossil fuels
Air pollution1.3
Environmental effects of urbanization and industrialization
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Air pollution
major sources:
exhaust fumesand dust
containair pollutantssuch ascarbon particles, lead particles,
carbon dioxide, carbon monoxide,
sulphur dioxide and nitrogen oxides
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Air pollution1.3
Environmental effects of urbanization and industrialization
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Air pollution
1 Health problems caused by air
pollutants
lead particles
damage thenervous system
and the kidneys
Air pollution1.3
Environmental effects of urbanization and industrialization
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Air pollution
1 Health problems caused by air
pollutants
carbon monoxide
reduces oxygen-carrying capacity
of the blooddizziness and
headaches
Air pollution1.3
Environmental effects of urbanization and industrialization
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Air pollution
1 Health problems caused by air
pollutants
sulphur dioxide and
nitrogen oxidesirritation to the
breathing system,heart and eyes
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1.3Environmental effects of urbanization and industrialization
Normal condition
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sunlightcool air
warm air
Warm air rises, carrying smoke upwards.
1.3Environmental effects of urbanization and industrialization
Normal condition
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sunlightcool air
warm air
Wind quickly blows smoke away.
1.3Environmental effects of urbanization and industrialization
Smog formation in windless condition
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sunlightwarm air
cool air
Cool air at ground level forms fog.
1.3Environmental effects of urbanization and industrialization
Smog formation in windless condition
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sunlightwarm air
cool air
Smoke and pollutants mix with fog
to form smog.
Air pollution1.3
Environmental effects of urbanization and industrialization
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Air pollution
2 Global warming
carbon dioxide,nitrogen oxidesand
chlorofluorocarbons(CFCs)are greenhouse gases
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Air pollution1.3
Environmental effects of urbanization and industrialization
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p
3 Ozone depletion
ozone layerscreens the earths surface
from the suns harmful ultraviolet light
destroyed by CFCs
110 220 330 440 550
total ozone
(Dobson Units)
Air pollution1.3
Environmental effects of urbanization and industrialization
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p
3 Ozone depletion
ozone layerscreens the earths surface
from the suns harmful ultraviolet light
destroyed by CFCs
skin cancer in humans
reduces crop yield
Air pollution1.3
Environmental effects of urbanization and industrialization
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p
4 Acid rain () sulphur dioxideand nitrogen oxides
dissolve in rain water to form acid rain
lowers pH of surface water and soil
corrodes man-made material
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1.1
1.3Environmental effects of urbanization and industrialization
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1.1
Design and perform an investigation to
study the relationship between the level of
air pollution and the lichen distribution in
different locations.
1.2
1.3Environmental effects of urbanization and industrialization
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1.2
Investigation of the air quality indifferent locations
Choose five locations with different levels
of air pollution.
Video
1.2
1.3Environmental effects of urbanization and industrialization
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A
Investigating the amount of particulatesin different locations
1 Place a microscope slide in a Petri dish.
2 Use a clean brush to smear the upper surfaceof the slide with a thin layer of vaseline.
3 Repeat steps 1and 2to prepare 14 more
set-ups.
1.2
1.2
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4 Put three set-ups in each of the locations.Collect all the set-ups after 24 hours.
5 Cover the microscope slide with a
transparent grid.6 Observe the slide under a microscope.
Count and record the number of
particulates for a total area of 100 mm2
.
7 Repeat steps 5and 6with other set-ups.
1.2
1.3Environmental effects of urbanization and industrialization
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B
Investigating the acidity of air indifferent locations
1 Use three plastic bags to collect three air
samples in location A.2 Tie the open end of the plastic bags.
3 Repeat steps 1and 2to collect air
samples in locations B to E.
1.2
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4 Rinse the probe of the pH meter withdistilled water.
5 Calibrate the pH meter.
6 Add 50 cm3
of distilled water into a beaker.7 Insert one end of a length of rubber tubing
into the plastic bag. Put the other end into
the beaker with distilled water.
1.2
1.3Environmental effects of urbanization and industrialization
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8 Squeeze the bag slowly so that the air in
the plastic bag bubbles through the distilled
water.
9 Rinse the probe of the pH meter withdistilled water.
10 Put he probe into the distilled water bubbled
with air sample. Record the reading.
11 Repeat steps 6 to 10 with other air samples.
Water pollution1.3
Environmental effects of urbanization and industrialization
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p
main pollutants:
sewage(), solid wasteand oil
1.3Environmental effects of urbanization and industrialization
Water pollution
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1 Health problems caused by sewage
discharge
domestic sewagecontains faeces,
urine and dirty water that holdmany bacteria and viruses
p
e.g. acute conjunctivitis ()cholera, dysentery, gastroenteritis
infection and diseases
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1 Health problems caused by sewage
discharge
hot water
p
reduces solubilityof oxygen
suffocation
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1 Health problems caused by sewage
discharge
hot water
the dead bodies ofmarine organisms
decay and spread
diseases
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1 Health problems caused by sewage
discharge
chemical poisoning
- concentrations of cyanidesand heavymetal ionscan increase along the food
chains
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2 Algal bloom
industrial sewageand detergents contain
phosphatesand nitrates
nutrients for algae
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3 Solid waste at sea
harms the habitats and marine organisms
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4 Oil spill
poisonous oil sticks to feathers of
waterbirds
damages the insulation andwaterproofing capability
die of freezing,drowning and
poisoning
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4 Oil spill
oil prevents atmospheric
oxygen from dissolving
into the sea watersuffocation
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Comparison of the oxygen content
of clean and polluted water using a
data logger
Part 1:Computer set-up
1 Connect the data logger interface to the
computer. Turn on the interface and the
computer.2 Connect the dissolved oxygen sensor
to the interface.
Video
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3 Run the software and open the
pre-configured file.
Part 2:Equipment set-up
1 Use the software to calibrate the dissolved
oxygen sensor.
2 Rinse the dissolved oxygen probe withdistilled water.
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Part 3:Data recording
1 Put the tip of the dissolved oxygen probe
into the clean water sample.
2 Start recording data by clicking the STARTor REC button on the computer screen.
3 Stir the sample gently with the probe.
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4 Record data for 1 minute and then stop.
5 Rinse the probe with distilled water.
Repeat steps 1 to 4 using the polluted
water sample.
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Part 4:Data analysis
1 Use the graph display function to display
the data.
2 Calculate the minimum, maximum andmean dissolved oxygen concentration for
each sample using the built-in functions of
the software.
1.4
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Design an investigation to study the
types, sources and effects of
pollutants in a freshwater stream or a
shore habitat
1.4
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There is a lot
of rubbish.
Its too bad!The stream is
polluted.
1.4
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Design and perform an investigation to find
out the types, sources and effects of pollutants
in a freshwater stream or a shore habitat.
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Destruction and loss of
2Impact of land clearance on theenvironment:
natural habitats
Soil and floodingerosion
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Destruction and loss of naturalhabitats
3Impact of reclamation on theenvironment:
suffocate
The suspended mud particles
may marine
organisms and block fromlight
penetrating into the water 1.3Environmental effects of urbanization and industrialization
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The toxic chemicals releasedfrom the dredged material may
3Impact of reclamation on theenvironment:
poison marine organisms
4Urbanization and industrialization
produce many .pollutants
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released from the
burning of fossil fuels in vehicles,
power plants and factories
aSources of pollutants
5Air pollution:
Exhaust fumes
Dust produced in constructionsites
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caused by
air particulates such as carbon
particles
5Air pollution:
Respiratory illnesses
kidneys Damage to nervous system and
by lead particles
bEffects on human health
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Irritation of the system,
heart and eyes by sulphur dioxide,nitrogen oxides and
Dizziness and headaches due to
5Air pollution:
carbon monoxide
breathing
bEffects on human health
smog
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formation due to the
release of sulphur dioxide and
nitrogen oxides
5Air pollution:
Acid rain
cEffects on the global environment
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sewage containing
inorganic nutrients, bacteria,
viruses and organic waste
aSources of pollutants
6Water pollution:
Domestic
sewage containingtoxic chemicals and hot waterIndustrial
Oil spill
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by bacteria and viruses
bEffects on human health
6Water pollution:
Infection
Hot water causes marine organisms
to ; the dead bodies
decay and spread
suffocate
diseases
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Chemical poisoning, accumulation
of mercury ions in body tissues
through feeding
bEffects on human health
6Water pollution:
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What is an algal bloom?1Algal bloom is the rapid growth of
algae resulting from an increase innutr ient supply in water.
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Why do many fish die when algal
blooms occur?2The f ish die of suffocation as the algae
use up the oxygen in the water at night.
When the algae die, their
decomposition further consumes the
oxygen in the water.
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Why may global warming and
insufficient rain lead to algal blooms?3The growth of the algae may be
promoted by an increase in
temperature, together with high
concentrations of nutr ients in the lake
due to insuff icient rain.
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What types of pollutants may cause
algal blooms?4Sewage from homes, farms andfactories contain many nutr ients for
the growth of algae.
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are mainly caused by
Human impact on the environment
urbanizationand
industrialization
rapid humanpopulation
growth
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rapid human population growth
leads to
overexploitation of resources
types of natural resources include
non-renewable
resources
renewable resources
depletion
overexploitation
will soon lead to
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may be exploited due
to malpractices in
renewable resources
agriculturefisheries
lead to
forestry
environmental degradation
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urbanization and industrialization
obtain land from
land clearance and reclamation
lead to
environmental degradation
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such as
environmental degradation
disturbanceof ecological
balance
soilerosion
pollution
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including
pollution
water pollutionair pollutionmay result in
global warming
and acid rain
may result in
algal bloom