Environment - Water Pollution
The earth, from a spacecraft, looks blue, because its two third parts is covered with water. This part is called hydrosphere hydro means water and sphere means region. Water is elixir of life. Neither plants nor animals can survive without it.
These days’ rapidly increasing population and industrial units have been polluting the water. The water coming from the factories and homes contains liquid and solid wastes. This is called sewage. The river sources and sea coasts all are polluted by sewage. This polluted water contains organic compounds of mercury and lead which enter into the body of aquatic animals. Eating such fishes is harmful for the eyes and brain of the man. In Minamata bay of Japan, mercury was deposited in the body of the sea animals through industrial wastes. These animals were eaten by local people. It is horrifying to know that 10 thousand people were poisoned by mercury, and 100 people died mysteriously. In muddy polluted water sun rays cannot penetrate and light does not reach the aquatic plants. This halts the process of photosynthesis and plants die. Consequently, the fishes which are dependent on such plants also die.
Oil pollution is very harmful for the ecological balance of the oceans. The spilled oil spreads widely on the water surface and badly affects the aquatic life. About 30,000 aquatic birds can die due to the oil spill from a big tanker. Fishes do not get sufficient oxygen due to oil pollution and they start dying in large numbers. The oil spill during the gulf war has been the worst in the history of mankind.
Agricultural fertilizers and insecticides are also adding to water pollution. Heat of nuclear power plants too poses a danger to aquatic life. The river water in large quantity is used to control the nuclear reactions in nuclear power plants. The river water gets heated to very high temperature and is again fed into the river after use. This waste water increases the temperature of river water at the point where it goes in to the river. The hot water kills many aquatic plants and animals.
Every nation is striving to provide clear drinking water to its citizens. This can only be done by controlling water pollution. Presently, only 1.6% of the total water content is potable, i.e., fit for drinking. Water cycle in nature takes around 1000 years to complete itself.