powerpoint presentation jiji

8/11/2019 Powerpoint Presentation Jiji

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WATER POLLUTIONWater is one of the most abundant compounds on Earth.

About 75% of the Earths surface is covered with water.The three main types of water sources are -:

Surface waterGround waterSalty waterUnfortunately, we have been constantly polluting our

rivers, seas, and other water bodies.


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WATER POLLUTION


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Causes of Water PollutionThe main causes of water pollution are -:Discharge of untreated industrial and domestic

sewage in to water bodies.Bathing animals, washing clothes, etc., in or near

lakes, rivers, etc., dirties these water bodies.Oil leaks from ferry boats and ships leave a trail of oil

on the water surface and pollute rivers and oceans.Inorganic pesticides and chemical fertilizers used by

farmers drain into water bodies by a process called

leaching. As a result, certain pesticides such as DDTcan enter the bodies of aquatic animals andeventually reach human beings by the way of foodchains.


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Causes of Water Pollution


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Effects of Water Pollution - 1 Industrial wastes discharged into the waters contain a lot of

toxic substances that make water unfit for drinking andbathing.

Untreated domestic sewage, when released into waterbodies, becomes a breeding ground for a number oforganisms that cause water-borne diseases.

Oil spills are very harmful to aquatic animals, and lead todestruction of marine life. The cleaning up process alsocauses a lot of damage to marine habitat.

Pollution of water also leads to a reduction in thenumber of aquatic plants and animals due todestruction of habitat and nesting places.


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Effects of Water Pollution


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Prevention of Water Pollution

Some steps to prevent water pollution are-:1.) Bathing and washing clothes near water bodies

such as lakes, ponds, and rivers should be avoided.

2.) Domestic and industrial sewage wastes should betreated to remove toxic substances before beingreleased into water bodies.

3.) Pollution-control rules enforced by thegovernment should be followed strictly.

4.) Use of eco-friendly fertilizers and herbicidesshould be encouraged.


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Purification of Water - 1Water supplied in our homes generally comes fromrivers and is contaminated with suspended

impurities like sand, silt, and clay; solubleimpurities like salts; and also microorganisms.Water, therefore, has to be cleaned in bigpurification plants before it reaches our homes. The

three main processes that water undergoes duringpurification are sedimentation, filtration, andchlorination .


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Various methods to purify waterFiltrationThe process of removal of insoluble impurities

by passing impure water through a filter paper is calledfiltration.

Sedimentation and decantationIn this method, impure

water is allowed to stand undisturbed in a container, whichallows insoluble impurities such as mud to settle to thebottom as sediments. This process is called sedimentation.Clean water can thereafter be transferred into a cleancontainer by the process of decantation.

DistillationIn this method, impure water is first heated to

its boiling point to convert water into steam. Theimpurities are left behind in the container. The steam isthen passed through a condenser, where it cools andchanges back into liquid water.


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powerpoint presentation jiji

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