Having, 70.8 per cent of its surface under water earth is essentially a water planet. This water, which was ‘created about three billion years ago’ (Block J.L. 1968, p. 95) is the source of life on this planet and forms a closed system. Apart from being vital for the maintenance of life on the earth, water has multi uses in power generation, navigation, disposal of sewage and cycling of nutrients in the biosphere.

Out of 1,500 kms of water present in hydrosphere, only 1 per cent is available for human needs which are obtained from groundwater, rivers, lakes, soil profile, atmosphere and biological sys­tem. Of the available total 99 per cent comes from groundwater (Dooge, 1973) which largely depends upon the amount of rainfall. In India, the total annual surface and groundwater resources are reported to be 167 million hectare meters. The country is en­dowed with 14 main, 49 medium and 55 minor rivers which account for 35 per cent of the total surface flow (Singh and Singh, 1988, p. 180).

Earth’s reserve of water is finite and same water is continually being reused since millions of years. Though water as other natural substances has self purifying capacity during recycling processes, but growing agricultural and industrial activities of man during recent years have created twin problems \ of water shortage and pollution.

Water pollution, a purely man-made phenomenon, is caused due to heavy influx of household wastes and factory efflu­ents beyond the self purifying limit of a water chan­nel (Tiwari and Yadav, 1983, p. 64). In a wider perspective, water pollution may be defined as ‘the alteration in physical, chemical and biological char­acteristics of water which may cause harmful effects on human and aquatic life’ (Report, 1965).


The substances which degrade the quality of water are called water pollutants. The U.S. Depart­ment of Health. Education and Welfare (HEW) has classified these water pollutants into eight major categories: (i) sewage and waste, (ii) infectious agents, (iii) plant nutrients, (iv) particulates, (v) radioactive substances, (vi) mineral and chemical substances, (vii) heat, and (viii) organic chemical exotics (Franke and Franke, 1975, p. 311). Water pollution may be divided on the basis of sources and storages of water into: (i) Surface water pollution, (ii) Lake Water pollution, (iii) Ground-water pollu­tion, and (iv) Sea water pollution.