Water Pollution Causes - Practice Questions & MCQ

Water is the important constituent of life-support systems. Water is the most important natural resource. 80% of the earth's area is occupied by water. However, hardly 2.5% makes up the total world's supply of freshwater including the frozen water in the polar ice caps and glaciers. Water is needed for irrigation, industry, domestic needs, shipping and for sanitation and disposal of waste. The conservation and keeping up a good supply of water is this very essential. Man has, however, polluted much of this limited supply of water by industrial wastes, sewage and a number of synthetic chemicals. Many rivers of the world receive heavy flux of sewage, domestic waste, industrial effluents, agricultural wastes, etc, which contain substances varying from simple nutrients to highly toxic materials. Polluted water is the water which has more negative qualities than it has positive ones, i.e, it is no longer fir for any use. 

Water pollution is the presence of any foreign substance (organic, inorganic, radioactive or biological) in water which tends to degrade the quality so as to constitute a hazard or impair the usefulness of water.

The common water pollutants are:

• Oxygen-demanding wastes
• Disease-causing agents
• Plant nutrients
• Inorganic chemicals and minerals
• Suspended solids
• Radioactive substances
• Thermal discharges
• Oil