Some of the sources, effects, causes and controlling measures of water pollution are listed below:
(a) Microbial growth: Sewage from big cities is usually drained into rivers. This sewage promotes the growth of microscopic bacterial life. This excessive growth depletes the oxygen of water and causes the death of these bacteria and other aquatic organisms.
(b) Oil: Oil-spills and washing of automobiles can pollute rivers.
(c) Effluents: Industrial wastes include a variety of poisonous chemicals, which are drained into nearby waters. The chemicals include acids, alkalis and a variety of salts.
(d) Fertilisers and Pesticides: Due to the good solvent property of water, it dissolves the fertilisers and pesticides, that we use in our farms. So, some percentage of these substances are washed away in the water-bodies,
(e) High Temperature: Hot water released from factories and power generators cause thermal pollution of water. The temperature of water in rivers is also affected when water is released from dams. The water inside the deep reservoir would be colder than the water at the surface, which gets heated by the sun. Water pollution can be controlled by avoiding the addition of pollutants in various water-bodies.
Some of the control measures of water pollution are as follows:
(i) Effluent Treatment: All effluents from factories should be cleaned off, before releasing into rivers or other water bodies.
(ii) Sewage Treatment: Sewage should be fully treated before releasing into the rivers or fields. Biogas produced in sewage treating tanks is a valuable kitchen gas and the left-over solid is rich manure.
(iii) The use of fertilisers and pesticides should be avoided.
(iv) No garbage should be thrown in the nearby water bodies.
