tailieunhanh - WATER QUALITY AND WATER POLLUTION PROBLEMS ON THE INDIAN SUB-CONTINENT

Not only the aesthetically distasteful plastic litter, but also less conspicuous small plastic pellets and granules are a threat to marine biota. The latter are found in large quantities on beaches (Gregory, 1978, 1989; Shi- ber, 1979, 1982, 1987; Redford et al., 1997), and are the raw material for the manufacture of plastic products that end up in the marine environment through acci- dental spillage during transport and handling, not as litter or waste as other forms of plastics (Gregory, 1978; Shiber, 1979; Redford et al., 1997). Their sizes usually vary from 2–6 mm, though occasionally much larger ones can be found (Gregory, 1977, 1978). Plastic pellets can be found across the. | Water quality and water pollution problems on the Indian sub-continent B. K. HANDA Central Chemical Laboratory 4 Sapru Marg Luc know-226001 India. ABSTRACT The quality of water on the Indian sub-continent varies both in space and time. The studies on the chemical composition of rainwater at several locations in India have revealed that except at Calcutta and Bombay where acid rainfall has actually been recorded the pH of rainwater is normally above . Studies on rainwater at Lucknow has revealed that the trace metal contents are normally low. The quality of surface waters in major part of the year is good with salinity being low to moderate but in many cases due to discharge of untreated sewage and industrial effluents the quality of stream water has deteriorated and at times fish mortality has been reported. Many of the fresh water lakes like the Dal the Wular the Naini Tai the Kolleru etc. are in a state of decadence. Marine pollution off the coast of Bombay has been reported. The quality of ground water also varies considerably. Apart from salinity problems in some parts of India ground waters with high F or high Fc content are also encountered. Pollution of ground waters by plant nutrients through return irrigation flows occurs widely. At places due to infiltration of industrial waste effluents ground waters with high Cr and or high CN concentrations are also encountered. Introduction Water is put to numerous uses by man. These uses include inter alia domestic agricultural livestock watering industrial sports and recreation. Apart from natural factors the quality of water in an area may also be affected by contributions from anthropogenic sources. The release of waste gases and particulate matter into the atmosphere by various industries release of waste industrial effluents sewage into water courses and or on land etc. have added new dimensions to the water quality aspects. The unscientific use of synthetic fertilizers coupled with improper water management