The main source of water pollution are as follows:
1. Domestic Waste : Discharge of untreated domestic waste, sewage into rivers and lakes contains the chemicals present in soaps, detergents and other cleaning agents, decayed food particles. Sewage carries many kinds of disease causing germs . It also contains many kinds of worms such as tape worms, hook worms etc.
2. Industrial Waste : The discharge of toxic industrial wastes contains toxic chemicals such as cyanide, cadmium mercury lead, arsenic chromium which are highly poisonous. They make river water unfit for the use of man and aquatic plants and animals.
3. The waste water from hospitals could contain harmful chemicals and different types of disease-causing microorganisms.
4. Agricultural Waste : Fertilisers, pesticides and other chemicals are used for increasing agricultural productivity all over the world. These are washed away by rainwater into water sources like river. Pesticides can poison fish as well as the animals (including human) that eat them.
To produce more food for growing human population some fungicides and insecticides are used to kill fungi and insects, etc., for example DDT. But the increasing use is dangerous because it is non-biodegradable. Along with rain water it goes into the water.
5. Deforestation : We are polluting water also by cutting trees and by removing vegetation. The rain water goes to small drains then to big drains, to streams and ultimately to rivers. When top soil is covered with trees and other vegetation much of the rain water is retained by the soil and the extra water which flows into the water bodies does not contain much dirt and filth in it. But, when top soil is not covered with vegetation the rain washes away the top fertile soil which pollutes the various water bodies.
6. Thermal Pollution : Some factories and power generators are located near the lakes and rivers. Larger quantities of heated water is discharged in ponds, lakes and rivers. The hot water is also a kind of pollution. Many aquatic organisms cannot tolerate the rapid change in the temperature and therefore they may die. Only the organisms which can survive in warm temperature may live.
Which of the following statements is incorrect? | |||
Right Option : D | |||
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To produce more food for growing human population some fungicides and insecticides are used to kill _____________________. | |||
Right Option : A | |||
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Which among the following is not a common source of water pollution? | |||
Right Option : D | |||
View Explanation |
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