Pollution is undesirable changes in the physical, chemical or biological characteristics of air water and soils that may harmfully affects the life and create health hazards of any living organism. Pollution is thus direct or indirect change in any component of the biosphere that is harmful to the living components and undesirable for man.
The harm full alternation of characteristics and standard of water is called water pollution. To United States Public Health Service “Pollution means the presence of any toxic substance in water and that degrades the quality to constitute a hazard”.
To South Wiek, “alteration in physical, chemical and biological characteristics of water brought about mainly by human activities, and natural resources is called water pollution”.
Pollutants of Water Pollution:
The pollutants of water pollution includes: (i) Organic pollutants, (ii) Inorganic pollutants, (iii) Sediments, (iv) Thermal pollutants, (v) Radioactive materials etc.
(i) Organic Pollutants:
The organic pollutants include domestic sewage, pesticides plants, from agricultural run-off, oil; wastes from food processing etc. these reduce dissolved oxygen which is essential for aquatic organisms.
(ii) Inorganic Pollutants:
These organic pollutants include inorganic salts, metals, mineral acids and detergents etc.
Soil erosion, the natural process, is one of the important mechanisms for generating sediments in aquatic bodies are important reservoirs of organic and inorganic matters particularly metal like copper, nickel and magnesium.
(iv) Thermal Pollutants:
The thermal water plants coil fired nuclear fired are the main sources of thermal pollution. The hot water from these plants is dumped as waste into the reservoirs and as a result the temperature of these reservoirs increased and as a result the temperature of these reservoirs increased and acts as the major harm to the aquatic animals and plants.
(v) Radioactive materials:
Radioactive pollution is caused by the radioactive isotopes in medical, industrial and research institute and nuclear tests. Mining and processing of radioactive waste water resources is likely to create problem in future.