DESCRIBE CAUSES AND METHODS OF CONTROLLING WATER POLLUTION. (20 MKS)

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Describe causes and methods of controlling water pollution. (20 mks)

It is the addition of substance or forms of energy into the water that may cause harm to organisms and are destructive to the ecosystem.
Causes of water pollution are:

 Industrial effluents.
- Industrial effluents that may be toxic chemicals which kill the aquatic organisms; this can be controlled by treating the effluents before discharging them;
- Hot water reduces the concentration of oxygen, killing the animals; it is controlled by replacing hot water with cold water;
- Oil spillage from oil tankers that reduces ability of oxygen to dissolve in water, reduce penetration of light and clog feathers of marine birds; it can be controlled by regular servicing of oil tankers to prevent spillage;

Domestic effluents;
- Untreated sewage that causes water borne diseases; it can be controlled by treating sewage before being discharged;
-Detergents that cause eutrophication causing reduced oxygen concentration and increasing biochemical oxygen demand; it is controlled by banning phosphate based detergents;

Agricultural effluents;
-Pesticides and herbicides that have heavy metal that they may accumulate along the food chain killing the higher animals; it is controlled by use of biological control pests;
-Inorganic fertilizers that have nitrates and sulphates that causes eutrophication; is controlled by use of organic fertilizers;
-Silting due to soil erosion reduces penetration of light to the plants and clog respiratory surfaces of animals; it is controlled by proper farming methods;

[20MKS]

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