Explain Surface Water Pollution.
Water present in rivers, streams and lakes constitute the surface water. It is present to the extent of only 0.0091 per cent of the total global water (see Table 2.8). All segments of our society (urban, rural, industrial, agricultural) are responsible for surface water pollution. Various materials and processes may pollute fresh water bodies.
Some of these sources are given in Fig:1 below
The chemical composition of surface water (river water) is given in Fig:1. The maximum permissible limits of effluents discharged in surface water is given in Fig: 2 below.
The harmful effects of surface water pollution are similar to that of ground water pollution. ff course, the effects depend on the extent of pollution. Attempts should be made so that the surface water is free from the following contaminats.
- Compounds imparting colour, odour, taste and turbidity, e.g. oils, grease, phenols, toxic materials.
- Substances which float on the surface as oil, scums, etc.
- Toxic radionuclides.
- Materials which are harmful to acquatic flora and fauna.
- Thermal effluents which should not be discharged in the surface water.
- Chlorinated compounds.
Water, as we know is the only natural resource available in plenty and is essential for survival of all living organisms. Fresh potable water is available only to the extent of about one per cent in rivers, lakes and as ground water. However, clean (or potable) water has become a precious commodity since its quality is degraded by various sources of pollution. Some of the important sources are
- Sewage and domestic wastes
- Industrial effluents
- Agricultural discharge/run off
- Soap and detergents