Water is said to be polluted when it is contaminated with i. dissolved gases like h2s, c02, nh3 and n2.
1. Sources of pollution
Water may be polluted by:
1. sewage containing organic matter and pathogenic agents.
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2. Industrial and trade waste (containing chemicals)
3. Agricultural pollutants (containing fertilizers and pesticides).
4. Physical pollutants (like heat and radioactive materials)
2. Hazards of pollution
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1. Chemical hazards due to direct effect on humans or indirectly due to contamination of aquatic life used as food (e.g. fish).
2. Biological water borne diseases like bacterial, viral and protozoa diseases.
3. Prevention of pollution
1. Education and legislation to prevent the release of pollutants into water sources.
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2. Conventional and special water treatment or purification.
4. Water pollution law
Water Prevention and Control of pollution Act was passed in 1974. The act is a comprehensive piece of legislation. It provides legal deterrent action against water pollution. It permits the constitution of 1. Central water board 2. State water boards 3. Joint water board. These boards have powers to control water pollution.