Bio-Score Teocher's Edition 2008

9.1 HUMAN ACTIVITIES THAT ENDANGER AN ECOSYSTEM

Learning outcomes:

o Identiff human activities that threaten the ecosystem,o Explain the impact of human activities on the ecosystem,o Evaluate critically the effects of unplanned development and mismanagement of the ecosystem,o Describe types of pollution and sources of pollution,o Explain the effecL of pollution on living things and the environment,o Compare and contrast pollutants ln the air from different environments,o Sbate the sources of air pollution,o Interpret data on the level of air pollution in sorne cities,o Make an inference on the sources of air pollution in some cities,o Interpret data on the level of water pollution in some rivers,o Make an inference on the sources of water pollution in some rivers,o Predict the level of air and water pollution in a particular location within the next ten years,o Suggest strategies to solve problems related to air and water pollution in a particular location

within the next ten years.

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The impact of human activities on the ecosystemMany problems related to the environment are the result

interference in the ways ecosvstems function. The examples

the environment are deforestation, bad agricultural practices,

activities and also domestic activities.

of human activities and human

of devastating human activities on

active mining activities, industrial

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Deforestation

Deforestation is the permanent removal of trees from the

forests for infrastructural development, toqginq industries,

urbanisation and plantation.

lmportant roles of tropical rainforests;

" the oldest ecosystem on the Earth and home toalmost half of the world's flora and fauna

. contain many unique species which provide

foods, medicines and other resources for

human

. regulate the world climate

. act as a carbon sink of the Earth because they

absorb vast amount of carbon dioxide duringphotosynthesis and at the same time release

oxygen into the atmosphere

r ?s water catchments areas where rain water is

absorbed and released back as water vapour to

the atmosphere. ,

Deforestation

The imoacts on the environment.

. soil erosjon

. flash flood

. landslides

o global warming

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severe climatic changes e.g. drought

the loss of biodive,rsitv

destruction of natural habitat that leads

to ex.tinction of many animal and

species

destruction of recreational sites

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Bad Agricultural practices

Among the bad agricultural practices carrred out

by some farmers are.

1. The use of excessive inorganic fertilisers,pesticides and herbieides ihat would

pollute the water sources and affect the

fresh water ecosystems.

2. lntensive farming of crops and livestock which cause changes to the soil structure

. Continuous cultivation of the same plot of land.

o The plouqhinq of land down the slope instead of along the slope

contours.

. Overqrazinq by livestock that does not permit the grass to grow back.

l1Erosions of

topsoil by

flowing water

when it rains.' The loss of topsoil nutrients.

" The sihi{g of the bottom of rivers and lakes with earth sediment

causinq flash floods)

Active mining activities

ln Malaysia, the high water pressure used in the open tin mining activities alters the land surfacestructure.

lndustrial activities

lndustrialisation leads to:

a. lncrease demand for energy and natural resources. Thus,

o mining activities for fossil fuels and metal ores increase and the natural environment

would be destroyed.

r damS are built to generate hydroelectricity, resulting in the flooding of large areas of land.

b. Environmental pollution due to:

" the burning of fqss!! fuels such as petroleurn and coals, resulting in the enrission of gases

such as carbon dioxide, sulphur dioxide and nitrogen oxides that pollute the air and lead

to acid rain etc.

. the dumping of solid wastes in dumpsites, stinking the areas and also pollute the nearby

water sources.

. the discharge of effluent that dissolve and suspend in water to deteriorate the water

quality.

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Domestic activities

1. Rapid human population growth

contribute to pollution.

causes the development of housing areas that may aiso

lncrease in domestic wastes through:

l. Dumpinq of solid wastes

2.Discharge of sewaqe and detergents

The impact of human activities on the ecosystern

The major problems on the ecosystems that are caused by human activities include polluticn.

greenhouse effect and thinning of ozone layer.

Pollution

a. Definition of pollution:

Pollution can be defined as any undesirable changes in qhvsical, chemical and

bioloqical characteristics of the natural environment, brought about when harmful

st-tbstances or energy are released by human activities.

Types, sources and effecG of pollution:

i. Air pollutionDefinition: The condition when pollutants enter the air frorn various sources.

Sources:

' Faqlories that pump large amounts of carbon monoxide, carbon dioxide.

oxides of nitroqen and sulphur dioxide into the atrnosphere.

' Exhaust fumes from motor vehicles contains soot, lead, carbon monoxide anci

oxides of nitrogen.

' Open burnings and forest fire that release excessive smokes with suspended

solidp and pollutant gases such as carbon dioxide and carbon monoxide.

' Coal-fired power stations that release large amounts of carbon dioxide into the

atmosphere.

' Quarries, cement factories and sawmills which emit dusts into the air.

Cause

r-1Lead to

b.

1. Land pollution

2. Water pollution

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**"tion of haze and excessive smokes in air that:

- decrease liqht penetration and cause the deposition of dust and carbonparticles on the stornata of leaves. Photosynthesis would be affected andcrop production is reduced.

- reduce visibilifu and may lead to the closure of airports.

- coat the buildings and structures with layers of carbon and dirt thusincrease the maintenance costs.

cause health problems such as bronchitis, rhinitis, eye lrritation andconjunctivitis.

Acid rain

Gases such as nitroqen oxides and sulphur dioxide combine with watervapour in the atmosphere, forming nitric acid and sulphuric acid vrhich thenfall as acid rain. The adverse effects of acid rains are:- soil becomes more acidic and less suitable

for planting of crops.

- salts in the soil would be dissolved and

carried into rivers and lakes. High level ofcertain salts such as aluminium salts

may be poisonous to aquatic organisms.

- erosion of iron bridges, metal railings and also the limestone or marbie

structures.

- afiecied plants growth when chtcrophvlls and photosynthetic tissues aredestroyed.

Greenhouse effect and the thinning of ozone layer ("would be discussed underthe next sub-topic)

Water PollutionDefinition: The concition when pcllutants enter the water sourcesrivers and sea from various activities.

Sources:

" Domesiic activiiies

- the dispesaj oi solici wasies (e.g. rirbbish), deiergents and sewaq€ froil1housing areas.

such as lake.

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lndustrial activities

- untreated waste toxic chemicals (such as mercury, lead, zinc etc.)

- radioactive waste substances

Agricultural practices

- the run-off from excessive use of fertilisers, pesticides and herbicides

' shipping activities

- crude oil spills from tanker ships

Effects:

. Eutrophication

such as chernical fertiliqers

(phosphates and niirates) enter the

rivers or lakes would enrich the

water with nutrients.

Photosynthesizi ng organisms

particularly algae that grow rapidly result in population explosion known

as algal bloom.

High diversity of algae reduces water light intensitv hence lead to the

death of other photosvnthetic organisms in the water.

The decomposition of these dead organisms by bacteria cause severe

deoletlon of water dissolved oxygen, causing the death of other aerobic

organisms such as submerqed aquatic plants, fish etc.

High BOD and the spread of water bome diseases.

rnicro-qrqanisms such as algae, bacteria and prQ(ozoa. These lead to the

increase of BOD {BiologicallBiochemlcal OxyQen Demand). When

dissolved oxygen in water is reduced, the life of the living aquatic

organisms would be affected. Thus, the high BOD value indicates that the

level of water pol!*tlon is high..(Biochemical/Biological Oxygen ciemand is the amount of oxygen utilised

b,v aerobic microorganisms to decompose organic rnatter in a particular

sample of water)

lrefeetio{s- diseases such as chciera, tyrphcid, dysentery and hepaiitis A.

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Accumulation of ioxic materials.

industries are the main sources of toxic pollution in water resources.

organic chemicals toxins such as DDT, benzene etc in water woutdaccumulate in the benthic organisms and the producers, which woutd bepassed up to the higher rever of organisms via food chains.Bioaccumulation of these metal ions and toxic chemicals would causedevastating effects in humans such as the damage of body organs andgene mutation that wourd read to cancer and reukaemia.

Environment disaster

Spillage of crude oil from oiltankers into the sea can cause major environmentdisaster. The layer of oil on the surface of sea would:

photosvnthetic activities of aquatic plants are disturbed.

affect the organisms living in the water.poison certain animais when they come in contact with this oil.damaged animals fur and birds feathers when coated with oil, thus theycould neither fly nor escape themselves from predators. They could notaiso keep their bodies warrn but will die by freezinq to death.

Thermal Pollution

Definition: The condition where the temperature ofwhen excess heat is released into ihe environment.

Sources:

" Reflection of heai from glass buildings thatincreases the temperature of surrounding air.

' Factories that use water to cool downI

machinerieq release warm water into the rivers, lakes or seas.

" Nuclear reactors release hct water into the rivers, lakes or seas.Eifects:

" Many aquatic crganlsr:rs wculd die as they cannot toleiate the rise in tnesu;-iounding water temperature. The increase in water ter,nperq-turs ol as

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much as S'C above the normal water temperature would be fatal to aquatic

organisms that only survive within a cet'rain range of temperature.

lncrease in BOD value when the metabolic rate of aquatic organisms

increases.

Warm water contains less dissotved oxygen for the respiration of aquatic

organisms such as the planKons, thus the food webs are disturbed when

planktons die.

. Miqrations of organisms occur when the food chains are affected and the

ecosystem balance is disturbed.

iv. Noise Pollution

Def,nitiol: The condiiion where the unwanted human-created sound disrupts the

environment or becomes harmfulto human health and welfare.

Sources:

. trains F -t*

. aeroplanes

:m"il:';;"" w#' drilling machines and piling in construction sites

Effects:

. Decrease in hearing sensitiviiy when someone is continuously exposed to the

noise level at about 80 decibels (dB) and above, which wifl finalty lead to

deafness {since the safe noise level is < 55 dB according to WHO and the

noise at 140 dB damages the auditory organs).

' Development of health problems such as indigestion, ulcers, high blood

pressure, coronary disease, depresgion and headaches-

Facts to share:

NoiselevelidB)

Noise types Effects

40-60 Nonnal conversation Safe for the ear.80-1 00 Food blender, lawn mower,

heavy traffics, tractorsAnnoying and continuous exposureIeads temporary hearing damage. lf nottreated can cause permanent damaqe.

) 100 Piling, drilling, rcck concert Unprotected regular exposure causecermaneni hearino loss.

) 125 Jet enqine, shctgun Hirth poteniialfor hearinq loss.

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9.2 THE GREENHOUSE EFFECT AND THE THINNING OF THE OZONE LAYER.

Learning outcornes:o Erylain what greenhouse e{fect is.c Correlate the concentration of carbon dioxide in the abnosphere with

gtobalwarming.c Explain the thinning of the ozone layer.o Explain the impact of thinning of the ozone

the ecosystem.layer and global warming on

The Greenhouse Effect

1. When sunlight reaches the Earth, the Earth,s

surface absorbs the energy and reflects it back intothe atmosphere in the form of infrared radiation (lR).

Some of this infrared radiation goes back to thespace but some is absorbed by the pollutant gases

(greenhouse gases) in the atmosphere (such asmethane, water vapour, carbon monoxide andparticularly carbon dioxide) that re-emit the energy

back to the Eaiih's surface as heat, causing theEarth to heat up. This phenomenon is known asqreenhouse effect.

The greenhouse effect is actually responsib{e for keeping the Earth warm and suitablefor life but nowadays as the greenhouse gases increase, more heat energy is trappedin the atmosphere and the Earih ternperature is continuously rising. This excessiveheaiing of the Earth surface is known as globa! warrningThe world greenhouse gases rise due to:

a. motor vehicles

b, coal-fired power stations

c. industrialisation

d. forest fire

e. open burning of rubbish

f- deforgstation {cause the increase !n carbon dioxide concentration due to thedecrease in photosynihesis activity)

The effects of global warming include:

a. The meltinq of ice and icebergs in the pElar region that raises the sea levej andsubii-:ei"ges ihe c_qastai r=sidenilal ai-eas anc aciic:iiure lands.

2.

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The change of the world climate

i" High rate of evaporation causes the drying up of lakes and rivers, causes

droucht and expand deserts.

ii. Changes in wind directions and sea current cause natural disaster such as

hearry rains, flash floods, strong winds, typhoons, hunicanes etc,

Deterioration of health

i. High temperature lead to heat stroke

ii. The widespread of epidemic diseases after flood

iii. Lack of food and malnutrition caused by low productivity of crops and

C.

livestock due to drought and flood.

The Thinning of Ozone Layer1. The ozone layer is a region in the

stratosphere between 17 and 25

kilometres above the Earth surface"

2. The function is to shield the Earth from

receiving too much of ultra violet (U$.

The thinninq of ozone layer has been

recorded since the 1970s. The area with

very low ozone concentration ends up with the formation of ozone hole.

Since 1980's, a huge hole in the ozone layer has been found opening up over

Antarctica and similar thinning occurs over the Artic region. The ozone hole

increases the intensity of ultraviolet radiation [n the earth atmosphere.

The destruction of ozone layer is due to the increasing levels of chlorofluorocarbons

(CFCs) in the atmosphere.

6. CFCs are a group of chemical compounds that€one lay€t

K=F:s --contain chlorine, fluorine and carbon.

7. CFCs are widely used as coolants in air-s"- i \a^-.

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conditioners and refrigerators, as plopel.lqxls in

aerosol cans and as foarning agents in the making

of polystyrene packaging, pillow, cushions etc-

B. The chemical processes that destroy the ozone layer are as follow:

i. The CFCs in the atnrosphere are struck by UV iight fornring chlorine atoms.

CFC13 w, Cl + CFC}2{Trichlorofluorocarbcn) (Chlorine} {Dichiorofluorccarbon)

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ii. Chiorine atom then breaks the ozone molecule into chlorine monoxide and

oxYgen gas.

C1 +O3ClO+02(Chlortre) (Ozone) (Chlorine rnonoxide) (gnrygen molecule)

iii. Ghlorine monoxide then reacts wiih the free oxygen atom in the atmosohere toform chlorine atom and oxygen mofecule.

ClO+O-)C1 *Oz(Chlorine monoxide) (Oxygen atom) (Chlorine atom) (Oxygen molecule)

iv. The chlorine atoms repeat the bre+kinq of the ozone molecules causing thedepletion of the ozone layer continuously.

9. The impacts of ozone depletion on humans and the ecosystems:

i. Increase greenhouse effect.

o Earth temperature increases when more UV (ultra violet) radiation reaches theEarth surface and more IR (infrared) radiation is reflected into the atmosphere.

ii. Skin Cancer

o Long exposure to sunlight may cause skin cancer, especially to those with falrskin (less melanin to protect oneself from UV tight).

iii. Cataract

o Eye lens become opaque leading to blurred vision which can eventually end

with blindnes-s.

iv. Damaging the photosynihetic mesophyll layers of plants.

o Reduce crops productions and destrr-lction of forests.

v. Reduced human immune system.

o Human beings are exposed to various diseasesvi. Disturb the ecoiogical ba{ance by destroying aquatic organisms especially

phytoplanKons.

10- Ways to overcome the problems of the thinning of ozone layer:

i. Reduce or stop the use of CFC

tt- Substitute CFC wiih HCFC {hydrochlorofluorocarbon) that has less potential todestroy the czcne layer^

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9.3 THE IMPORTANCE OF PROPER MANAGEilIENT OF DEVELOPT$ENT

ACTIVITIES AND THE EGOSYSTEM.

Learning outcomesro justify the need of develoPmento explain the effect of increase in population on the ecosystem

o explain measure taken in the management of development adivitisand ecosystem to ensure a balance of nature is maintained

o care for the ecosYstemo participate in activities related to the managernent of the ecosystem

The needs for development

1. Development has to go on to provide the basic necessities and to improve the qualfu of life

of the increasing population.

2. More lands must be cleared for:

a. Agriculture - to increaseloog production

b. lndustries - to prepare job opportunities

c. Building infrastructures such as roads, houses, schools, hospitals, power stations etc.

3. Therefore, development activities shoutd be carried out without destrovinq the natural

resources and by taking into consideration the environrnental impacts.

Environment as resources for life

1" Source of toods, drinks, medicines etc.

Examples: Fresh water for drinking, fish for proteins, honey for food, herbs for medicine etc.

2. Place to live

3. Sources of enerEv

Examples: Renewable sources. Solar, wind, wave, fossilfuel.

Non-renewable sour€s: Petroleum, coal, natural gas.

4- All these sources must be managed properly to ensure continuous utilisation by hurnan

beings.

The effect of irnpropei'rfianagernent of developrnent

Many developmental projects implernenied would upset the balance of ecosvslgrn. These

include:

1. The destruction of habitats and eNtrnc'tlon of animal and plant species when }ands are

developed for agriculll,$ai activities, hgusinq projects etc.

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Poisoning of lands when pesticides, insecticides and chemicalfertilisers are widely used.The pollution of the environment caused by the emission of toxic substances into the water,

air and land.

Lost of soil fertilitv due to soil erosion, leaching,

drought etc.

Upset food chains - when mono-cultural farming

{planting only one type of plant in a big way)

is practiced.

lmbalance of ecosystem caused by destruction

of natural cycles carbon cycle, nitrogen cycle,

water cycle etc.

Itdeasures taken in management of development activities to ensure a batancect natureis maintained

1- Sustainable development is the continuous development activities with minimumirnpacts on the environment.

2- Our demands for resources have to be balanced with the needs in order to sustain theresources.

3. Measures taken to maintain the balance of nature are:

a- By the implementation and enforcement of environmental laws:

Examples.

i. Environmental Qualitv Act 1g74, {Revised 1985 and Amendment 1g96)

Cornposed of 6 regulations retated to air, vehicles srnokes and gases, clean air,

rubber, oll palm, sewage and industrial effluqtts.ii- National ForestryAcL 1g84

Forestry and Wld Life Departments are appointed to protect our national forestand the wild animats.

2.

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iv.

vi.L.U.

Pesticides and Herbicides Act. 1974.

Factories and Heaw Machines Act 1g67. 1983.

Environmental Qualitv {sewaqe and lndustrial Effluents) 1grg.

By making use of technology.

Exampies:

i- Use catalytic converters in cars io clean exhaust emission and special fihers onindustry chimnbys tc filter- the release of scct, teed parlicles and toxic gases inioihe airnosphere.

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ii. Treat the heavy metals and toxic components in liquid factory effluent-

iii. Use non*!ea1!gg[ petrol.

iv. Recvcle the waste products.

v. lncinerate the qarbage.

vi. Use micro-organisms in cleaning up the environment.

vii. lntroduction of solar powered or electric powered cars.

c. By educating the citizens on the managernent of resources:

i. lntegrating the formal environmental education into the formal education systern in

the efrort of producing generations who are conscious enough on the problems

related to the environment and skilfulin solvinq the related problems.

Exainples:

. lntroducing the study of environr4ent at school level as early as possible.

. Establishment of Environmental Faculty in the local universities such as in UPM

etc.

ii. Giving informal education to the pubiic in the effort:

. to raise their awareness and responsibilities towards the environment.

. to increase their responsibilities not to pollute the ecosystems but create a

cleaner and healthier living environment.

Examples.

TV, newspapers, magazines, pamphlets and pcsters"

environment by govemmental agencies and also the non{ovemmental

agencies such as SAM (Sahabat Alam Malaysia), \At1l/F (World Wildlife Fund)

etc.

d- By preserving and conserving the natural resources.

i. Restoring used mining lands for agniculture,

ii. Replanting forest trees that have been cut down to rnaintain the supply of

wood for the future and to prevent erosions.

iii. Restore polluted rivers tc ensure surfficient supply of water for the future.

iv. Conserving mangrove swamps as they are important ecosystems for the

breeding of many ani;'nals.

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e. By practicing biological control.

Biologicat control is the method of controlling the population of animal pests usinganimal predators. This method is more suitable since using pesticides would affectthe food chains.

Fxamples of biological controls are:

i. The breeding of owls to control the rat population in oil patm estate.

ii. The use of guppy fish to eliminate mosquito larvae.

iii. The use of female insects lchneumon that produce larvae which feed thecaterpillars that bore into the paddy stems.

f. By making use of renewable energy resources.

Examples:

i. The use of solar energv.

ii. The use of bio-fuels such as blodiese! {from palm oil) in replacing non-renewable

fossilfuels

iii. The use of bio-sas (e.g. catfle dung to produce methane gas)

g. By efficient use of enepgy.

i- Efficient use of non-renewable energy resources like fossil fuels and nuclear fuelsmust be planned and manaqed carefully.

ii- We have to develop uses of altemative energy resources especially renewableenergy resour€s like solar, wind, water and biomass energy. These energyresources €n be used more efficiently without much damage to ourenvironments.

iii. Some of the ways that we can use energy efficienfly include:

. Using energy-saving electrical appliances.

. Using fluorescent lamps which are more energy efficient.

. Using pressure cooker and cooking utensils made of good conductors of heat

to reduce cooking time and energy used.

" Use public transports such as buses and LRT instead of own car. Car pooling

will also help to reduce the use of energy.

. New buildinss should be designed to be more energy efficient. The buildingsshouid be well-ventilated, making use of solar energy and making maximumuse of natural light.

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Blo-Score Teccher's Edition 2008

EXERGISE:

Part I Structured questions

1. Diagram 1 shows the effect of human activities on the ecosystems.

a" Name the activity

Diagram 1

out in Diagram 1.

Deforestation (1 mark)

b- Give two purposes of carrying this activity.

*Any two of fhese (Housing development, road cnnstruction, agriculture, mining,industialdevelopment, urbanisation etc-) (2 marks)

c. Give three functions of tropical rain forests.

*Any three of fhese:. home fo almosf half of the worldb flora and fauna

. contain many unique species which provide foods, rnedrbtnes and ather resources for

human

. reguiate the woid climate

e &ct as a cadon srnk of fhe Eafth because ff:ey absorb vasf amount of catbon dioxide

during photosyntliesrs and at fhe same fime release axygen into the atmosphere

. as water catchmenfs areas {3 marks)

d. Exptain the effect of the activity to biodiversity.

Effect: Decrease in biodiversify

Explanation:o Losi of habitats and foodso The number of plants and aninals decreaseso Sorne planf and animalspecrbs become exfincf

(4 marks)

e. Name two geochernical cycles that may change due to the activity

Any two of fhese (" water cycle, carbon cycle, nifrogen cycle)(2 marla)

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Diagram 2 shows a factory discharging effluent into a lake that lead io pollution.

Diagram 2

What is the lype of poilution occurred?

Water pollution (1 mark)trU If the facory is a textile faciory that discharge dyes into the lake, narne two heavy metal

ions that couid be found in the lake water:

c. what would happen to the heavy metal ions in the lake water?

d. \tYhat is the biologicalterm used when the level of metal ions in the tissueskeep on increasing?

Biomagnification ft mark)

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It.

Yl"t would happen to the fisherman and his family if they continuously feed on thefish caught from the lake?Give reasons to support your answer in e(i).

I.

ii.They willhrie senbus illnesses srrch as cancer, [eukaemia, paralysrb efc.Reasons.'- Metalrbns are non-biodegradable but remains (bioaccumutate) in the human body

fibsses.- Long term feeding of frsh from the /ake causes biomagnificatjon of these meta! ions

in the human bady fi'ssues' High level metal ions in the bady fi.ssues coutd inhibit certain enzymatic reactions in

the body orcauses gene mutation that jead var[ous #Inesses. (4 narks)

f. Suggest three actions to be taken in order to avoid the fisherman and his family from hiringthe diseases related to the effects of heavy metal ions.

i. Bv the ima{ementation and enforcenent of environmentat laws-Govemment through legis{atian, rnust take acion ai tne companytfactorymanagement to protecf fhe desfruction of the natura[ resources.

ii. SJ makinq use af techThe factory musf freaf the heavy rnefals and toxic components in the liquid of factoryeff]uent befare drbcira4ring it inia the ltrafer sosrces.

*Any two of metalrbns fe-g iran, mercury, capper, zinc, atuminium etc) (2 marks)

undergo bioaccumulation in fhe fr'ssues of the lake aquatic organr.sms (1 ma*)

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3. Diagram 3 shows various human activities that involved the buminE of fossil fuels,

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Diagram 3

Name the gases emitted from the buming of fossil fuels.

* Any three of fhese gases ( cafian drbxrde ,carban manoxide, sulphur dioxide,nitric oxides/oxides of nrfrogen (nitrogen manoxide, nitragen diaxide) f3 marks)

b. i. What would happen when the gases dissolve in atmospheric water vapour?

ii. Explain the effects on aquatic ecosystems?

i. Acid nin will beformed-ii. The ecolagical balance af aquatic ecosysfern wi{l be disfurbed because many types of

phytoplanfton, zooplankfon, fsh and other aquatic species witl be desfroyed.{3 marksJ

Smoke, dust and soot can combine with cloud particles to form haze that darken the

air and reduce visibility.

i. What is the effect on the productivity of agriculture?

Explain your answer in c(ii

i The agiculture productivity will be reducedii. Explanation:

o Haze prevents sunlight fram reaching the earth and /owers the eaftlttemperature.

o lhe nte of photosynfhesrs of fhe pianls decreases that atrect ptantsgrovtth and crop productian, {3 marks}

d. Suggest three ways to reduce the problenrs caused by excessive smoke and haze.

* Any of these answers.'

i. Use catalytic converfe,'s rn cars fo clean exhausf eml'ssion

ii. Fx speck/ filters on industry chimneys to filter fhe release cf soof, lead parlicles and

toxlc gases info the atmosphere.

iii. lncinerate the garbage.

iv. Avoid open buming

v. Contro! forest fire

vi. Use fueis whtch rslease less s,':roke i3 mar,ks;

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EKSPERIMENTAn experiment was carried out to investigate the level of water pollution in three different

sources of water : well \+ater, pond water and river water,The following steps were carried out.Step 1 : 100 ml of each water sample was placed in a reagent bottles.Step 2 : 1 ml of 0.1olo methylene blue solution was added to the base of

each of water sample by using a syringe.Step 3 : All the reagent bottles were closed and placed inside a cupboard

and the time taken for the methylene blue solution to decolourisewas recorded.

Diagram 4 shows the apparatus set-up used in this experiment.

watersample

Diagram 4

(a) In Table 1, list all the materials and apparatus labeled in Diagram 1.

Material (M) Apparatus (A)

1. vr4<*&gtenc. bl qc Sd\rti ax

7. Walev Saunpl<

1. *yvivga

2, Q-o--a3c;n+ bof+t'

3, 9\-pp."v

Table 1

_ 250 m} reagentbottle

EE+syilnge

0-1% ofmethyienebluesolution

stopper

water sample +0.1% ofmethylene bluesolution

-a

Sample of Water Time taken for the methylene blue solution to decolourise(minutes)

Well Watert

"A,uo 15

Pond Water

River Water

Table 2

Table 2 shows the results of this experiment.b) Record the time taken for the methylene blue solution to decolourise in the

boxes provided in Table 2,

(c

(d

t

(c) (i) SE:e :,,,: ::3-e,-: :ts:-,,a:ions made from Table 2.

all,-^--\Jl--:C jr 3 -r, -l-

The time taken

tc decclo'u'rse is

rcr (0,10lo) methylene blue solution

ra ? h^i )1 u+ej

in well water sample

Cbser,'ailon 2

The .:.F=..,=i::..... for (0.1%) methylene blue solution in river water

sar'''p[e to d.+.=].=I*.. is 15 rninutes.

(ii) State ihe inference which corresponds to the observations'in 1(c)(i).

Inference 1

V/ell water has a high concentration of dissolved oxygen l/ less polluted

i/less microorganisms=

Inference 2

RiVe" woler ,har q tow co',,rt-c-rava;,; o^ o| d-f e,r o1y.e-d c5r$AR-u //

r^.r-Ovs p ottu le-d,/ uttS,r,e uu i c.,rrO Ofga n J fr4,Lgrrarra...a.ar.taraaaaaarrartr..laaaa.raaatatrattaa.aaaaaaaratrtatatttaaaaaaaaaaaaaaraaaatraaaaraaaraaarataraaaaa

(d Complete Table 3 based on this experiment.

Variable Method to handle the variable

Manipulated variable

Vvqkv 9e+vplaUse d.t.t*?.:?:..... water sample ll well water,pond water and river water

Responding variable

T.i** .t.qHs. for the methyleneblue solution to decolourise

R.e.9.qI*... the time taken for the methylene bluesolution to decolourise using .ltrF.Hsl*.?..

Constant variable

Volume/ Concentration ofmethylene blue solution// volumeof water sample

Use 1 ml /0.1olo of methylene blue solution // fill100 ml of water sample ( in the reagent bottle foreach experiment).

Table 3

(e) State the hypolhesis for this experiment.T1.r-a,l-tv*c- {qvorn frr., ls^- vt^c-*{ag\eru- !4.^o BoLrtlon rL we-{l qJq}ev +\ Pafti

clecolor.r,rte€. fS 4<-l+<- cgr1aapq'r-d ,h, rlve{ v':aF<* 4 Ttts ri Veu hJql*e-4:. 1. z.

\S \\^o&+ pol\q+-a.4 Co,.^/?ore4 hr y.relt uJqler a.rrad P.u.d !^tqfet

(f) (i) Construct a table and record all the data collected in this experiment.Your table shou/d have the followlng titles:- Water sample- Time taken for the methylene blue solution to decolourise (mrnutes)- Level of water pollution

r^r a {€vge \N^ p !€

Tl t\Ae +4tlc-r^ fav .l-taa h,4+t4U(eul-Lt rro So\q H o r,n l.o d a c-o\ o un s-e Cvur'u)

\.<vel o$uJcrl-€r po\\uhiou

\N€r\ ulq+eF 4-o leJ s p o\\ ta !e{

pornd wqle-v s-g vr,to{.e ra k

P.1'v-ev w q[e" ls Wgl-a f uzog Yo t\vFe4

(f,) (ii) Using the data in 1(f)(i), draw a bar chart to show the relationship between thetime taken for the methylene blue to decolourise and the water sample

(g) Based on the bar chart in 1(l)(ii), explain the relationship between the timetaken for the methylene blue to decolourise and the level of water pollution.

the s,b,:1fl.... tf'e time taken to decolourise the methylene blue solution, thehigh*y.. the level of water pollution of water sample. The numQer of bacteria in watersample is h.\g"h.... More oxygen is used to decompose oIa?.?.t? substances in watersample.// vice versa

(h) This experiment is repeated on a water sample nearby poultry farm. Predict thetime taken for the methylene blue to decolourised,Explain your prediction,

t<,<tl._than 15 minutes because of the lower concentration of dissolved olfr,*P.. in

water sample and contain more pfe!!!ltf$* I faeces// the level of water pollutionis higher.

(i) Based on the result from this experiment, what can be deduced about the waterpollution?Water potlution is the tJI+*..H!*fl... to d9.9.o-1:.ll?.'0.1% methylene blue solutionand is affected by different se,YL*{.,?lw.*fl'.,'

Ansl

1. a

t

,a

Part2 EssaY question

1. a. i. Define Poituiicn

ii. Discuss the effecis of sound pollution on human health and welfare.

b. Over the last 40 years, the Earth average temperature has been on a

rising trend that lead to global warming. what is global warming and

discuss its effects.

Answer:

1. a. i.

il.

b.

(2 marks)

(6 marks)

later/ater

1.. in

vater

(12 marks)

pollution can be defined as any undg{.?.9.?13............. changes in physical, chemical and

biological characteristics of the natural ellY!PIII3J.,..., brought about when

h.?.195}1. ... substances or energy are r*lf1=a'.. by human activities.

Noise could affect humans physiologically and psychologically'

Physiologically, the person will develop h.?3.1i11 ...'..' problems such as poor

body defence mechanism, in4i.?+t':91.r...r!r.!., ulcers, high b1.9.9d........... pressure,

h.€*Tf,............diseases, depression and H1*.-.. lf the person is

c.p.lfn*l*y... exposed to the noise level at about BO d'ggh:l*...'.."'..(dB) and

above, he will finally end with d.g4t*3# since the safe noise level is < 55 dB

according to WHO and the noise at 140 dB damages the a'Y*.tr$" """' organs'

psychologically, noise could disturb a person's sleep. This will have negative effect

on his mental stn$.9.P.. that could affect his thinking, concentration and mode of

communication.

Global warming is the rise in Earth temperature due to the r.9}ft5:1"..".'. of heat

in Earth atmosphere by the g!:94f'b:.Y'-.... gases'

Globalwarming changes the world c.S.f1r3.*. ..... The heat melts the ice caps

and the i.q+.hf.Pi..........in the polar-regions, raises the sea tPJ3. and

submerges the c.C.?.Yn}............ residential areas and agriculture lands'

High rate of eY*P.?FI9.?........... lead to the drying up of many inland lakes and

rivers, causing d.f.q.S,9.f1...........in several regions and also expand the d.9*?S"""

areas.

Wind directions and sea c.!*Y.I3!!..... change drastically that cause natural

d.{.tf.:ff...... such as heavy rains, flash floods, strong winds, typhoons, hurricanes'

E

As the effect of these climatic changes, human h.ffi*. is deteriorated.

Those who are exposed to high t.9.3ff.9nf*....... would suffer heat stroke.

The tropical pests and vectors are likely to s.?.Y.*.4. to new areas, resulting

in more outbreaks of tropical d.i:.f?:.::. such as malaria and dengue fever.

E.tr.d.f.gi? diseases would also spread widely especially after natural

catastrophes such as flood, typhoon, etc.

Low productivity of c.[ePS.. ... and livestock due to drought and flood

cause the lack of food that lead to h.VW( and malnutrition. Humans are

more likely to be exposed to various diseases due to poor body d.?.f.f*:mechanism.

Suggested projects:1. Conduct activities to care for the following ecosystems in school or home:

a. Fish pondsb. Gardens

2. Plan and conduct a programme related to the management of ecosystem.Example: "Environment Day"