HAZARDS OF
WATER POLLUTION
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INRODUCTION
• At present, water scarcity is a global difficulty in a world
as many freshwater bodies, oceans and seas are polluted
by humankind when contaminants are unloaded into
water bodies in a direct way or indirect way.
• If water gets polluted ,it affects living organisms in
water bodies ,on ground and natural biological
communities because all surviving things need water.
• We know that 75% of the earth is covered with water
and in that only 2% of water is fresh water which is used
for drinking and so mismanagement of water resources
causes water scarcity.
• Moreover, industries are increasing and these are major
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sources of polluting water because they discharge all the
waste into water bodies.
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TREND OF WATER QUALITY IN RIVER GANGA
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MAJOR CONTRIBUTORS OF POLLUTED WATER
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SOURCES AND TYPES OF WATER
• SOURCES :
1. SURFACE WATER:
a) LENTIC WATER: Stagnant water present in
ponds,lakes, ditches,swamps,reservoirs,etc.
b) LOTIC WATER: Flowing water found in
streams,rivers,fountains,falls,etc.
2. GROUND WATER
• TYPES :
1. HARD WATER: contains salts of chlorides, sulphates,
bicarbonates of calcium and magnesium.
a) TEMPORARY (bicarbonate salts)
b) PERMANENT (chloride and sulphate salts) 5
2. SOFT WATER
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TYPES OF WATER POLLUTANT
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SOURCES OF WATER POLLUTION
• DOMESTIC WASTE
It primarily include excreta of man and animals, paper, cloth,
soap, detergent, remnants of food and fuel. These accumulate in
water bodies and causes following changes in water quality:
1. EUTROPHICATION: luxuriant growth of algae due to
accumulation of phosphate compound(detergents).
2. BIOLOGICAL OXYGEN DEMAND(BOD): presence of
phosphate and nitrate triggers bacterial growth which oxidise
organic material ,increasing BOD and water pollution level(water
samples for 5 consecutive days in 20⁰C, 4-5 ppm of O₂ is ideal)
3.CHEMICAL OXYGEN DEMAND(COD)
4. pH acceptable range for drinking is 6.5-8.5. 7
5. PRESENCE OF MICROBES spread of water borne diseases.
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AGRICULTURAL DISCHARGE:
Fertilizers and pesticides wash off by rainwater to the water
bodies and pollute them.
1.LACK OF HUMUS: hampered growth of microbes & earthworm
2.METHEMOGLOBINEMIA: reduced O₂ carrying capacity of blood,
conversion of nitrates to nitrites by intestinal bcteria.
3.BIOLOGICAL MAGNIFICATION
4.PHYSIOLOGICAL DAMAGE: chlorinated hydrocarbon absorb
through skin into blood(1-2 g enough to die)
5.HUMAN DEATH: 40,000 people die every year due to toxic
pesticides like DDT, BHC, aldrin, endrin, chlordane, heptachlor
(WORLD DEVELOPMENT REPORT) 8
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INDUSTRIAL EFFLUENT:
• non biodegradable materials like burnt oil,greese, plastic,
phenol, acid, synthetic paints, cyanide, H₂SO₄(coal mine), heavy
metals(Pb,Hg,Cd,Cr).
• Arsenic and cadmium inhibit enzygmatic activity so
physiological disorder.
• Reduce light penetrating capacity of water and clog sewers
disturbing respiration of gill breathing animals.
THERMAL POLLUTION:
Hot water discharged by thermal power plant,etc cause rise in
temperatue which cause decrease in water solubility(O₂),death.
MINERAL OILS:
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Oil from moving ships and spillage forms a thick film which
hinders oxygen dissolution in water.
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PREVENTION AND CONTROL
• Pollutants can be collected in some place and discarded in some
other safer place, instead of water directly.
• Sewage system should be away from drinking water
source,cleaned regularly,treat domestic sewage before
discharge,increase aerobic bacteria.
• Pesticides can be controlled biologically (natural predators), by
applying their microbial pathogens to fields, or growth
regulator which would disturb their lifecycle.
• Thermal power plants should have their own cooling system 10
for the discharged hot water and reservoir to recycle the same.
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REMOVAL OF POLLUTANTS
• AMMONIA: by ion exchange method, converted to
ammonium sulphate(fertilizers)
• MERCURY: ion exchange resins.
• SODIUM COMPOUNDS: reverse osmosis
technique(effluent of rayon mill)
• PHENOLIC COMPOUND: polymeric absorbing
material(effluents of paper mill, oil refinery, tannery)
• DIFFERENT TYPES OF CHEMICALS: by sunlight and
catalyzers like titanium dioxide (pesticides, non polar
solvents like PCB , cyanides)
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WASTE WATER TREATMENT
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WATER QUALITY STANDARDS FOR DOMESTIC SUPPLY(USPH)
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WATER MANAGEMENT
Qualitative as well as quantitative maintenance of resources and
their utilisation.
FOCAL POINTS
• Industrial effluent causing heavy pollution day by day.
• Overpopulation increasing sewage amount.
• Agricultural runoff, mainly fertilizers and pesticides.
• Wetlands need to be protected as they mitigate water pollution
and maintain ecological balance.
MEASURES
SHORT TERM like pollution control at source, proper discharge of
sewage, coastal water management, treatment before discharge.
LONG TERM like monitoring source and usage by preparation of 14
water usage map, water quality map preparation by continuous
water quality monitoring.
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WATER BORNE DISEASES
FACTORS THAT HELP AN ORGANISM TO BECOME EFFICIENT WATER
BORNE INFECTIVE AGENT:
• Persistence in water supplies
• Resistance to chlorine
• Relative infective dose
• Animal reservoirs
TYPES OF PATHOGENS:
1. ORALLY TRANSMITTED: Salmonella (typhoid, gastroentritis),
Entamoeba histolytica(dysentry), rotavirus(diarrhoea).
2. OPPORTUNISTIC AND WATER ASSOCIATED: not formally
pathogens but able to infect people with impaired defence
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system like Pseudomonas, Aeromonas.
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INHALATION: Legionaire’s disease(contaminated air ducts)
SKIN PENETRATION: Schistosomiasis
3. MICRO-ORGANISMS TOXINS: hepatotoxins and neurotoxins
by blooms of cyanobacteria(blue green algae). Deactivation by
activated carbon and ozone.
4. NUISANCE ORGANISMS: no health hazards but lead to
undesirable effect due to turbidity or altered taste or odour.
• Cyanobacteria chokes filteration apparatus.
• Iron and sulphur utilising bacteria corrodes pipes.
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• Actinomytes produces objectionable taste.
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RELATED LAWS
• WATER (PREVENTION AND CONTROL OF POLLUTION)
ACT ,1974
• FACTORIES ACT AND AMENDMENT,1948
• ATOMIC ENERGY ACT,1982
• INDIAN FISHERIES ACT, 1897
• RIVER BOARD ACT, 1957
• MERCHANT SHIPPING ACT, 1970
• COASTAL REGULATION ZONE, 1991
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REFERENCES
• ENVIRONMENTAL EDUCATION BY H.M.
DANI
• ENVIRONMENTAL STUDIES BY S.P.
AGARWALA
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THANK YOU ! 19
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