Water Pollution

water po the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). Water pollution occurs whenpollutants are discharged directly or indirectly into water bodieswithout adequate treatment to remove harmful compounds.

Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels (international downto individual aquifers and wells). It has been suggested that it is the leading worldwide cause of deaths and diseases,[1][2] and that it accounts for the deaths of more than 14,000 peopledaily.[2] An estimated 700 million Indians have no access to a proper toilet, and 1,000 Indian children die of diarrheal sickness every day.[3] Some 90% of China's cities suffer from some degree of waterpollution,[4] and nearly 500 million people lack access to safe drinking water.[5] In addition to the acute problems of water pollution in developing countries, developed countries continue to struggle withpollution problems as well. In the most recent national report on water quality in the United States, 45 percent of assessed stream miles, 47 percent of assessed lake acres, and 32 percent ofassessed bay and estuarine square miles were classified as polluted.[6]
Water is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use,such asdrinking water, and/or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, andearthquakes also cause major changes in water quality and the ecological status of water.

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Causes
The specific contaminants leading to pollution in waterinclude a wide spectrum of chemicals, pathogens, and physical or sensory changes such as elevated temperature and discoloration. While many of the chemicals and substances that are regulated may...