Summerize primary information about water pollution. 

Water is essential for life. Without water there would be no life. We usually take water asgranted for its purity, but we must ensure the quality of water.

Pollution of water originates from human activities. Pollution reaches surface or ground waterthrough different paths.

Easily identified source or place of pollution is called as point source. e.g., municipal andindustrial discharge pipes.

A source of sources of pollution are those where a source of pollution cannot be easilyidentified, e.g., agricultural run off (from farm, animals and crop-lands), acid rain, storm-waterdrainage (from streets, parking lots and lawns), etc.

The major water pollutants and their sources are listed below :

Pollutant	source
Micro-organisms	Domestic sewage
Organic wastes	Domestic sewage, animal excreta and waste, decaying animals and plants, discharge from food processing factories.
Plant nutrients	Chemcial fertilizers
Toxic heavy metals	Industries and chemical  factories.
Sediments	Erosion of soil by agriculture and strip mining.
Pesticides	Chemicals used for killing insects, fungi and weeds.
Radioactive  substances	Mining of uranium containing minerals.
Heat	Water used for cooling in industries.