Water
Water Pollution
‘Water pollution’ Central Pollution Control Board, Ministry of Environment and Forests, 2011
We have read in the last chapter that water gets polluted due to the presence of harmful substances in the water like micro-organisms, chemicals, contaminated water generated from industrial, domestic or commercial establishments etc. In fact, it is called water pollution. The physical, chemical and biological properties of water are affected due to the mixing of such harmful substances. Due to the harmful side effects of pollutants on water quality, polluted water is no longer eligible for domestic, commercial, industrial agriculture or any other common use.
In addition to drinking, household, irrigation, agricultural work, use of cattle, industrial and commercial activities etc. consumes large amounts of water and the water used is converted into contaminated water after use. As a residue in this contaminated water, during the activities carried out through them, the parts of substances or chemicals in contact with water remain. Their presence makes the water unsuitable for use. When this contaminated water is found in a clean water source, it also contaminates it. The contaminated water contains viruses, bacteria and other harmful micro-organisms along with organic and inorganic compounds and chemicals which pollute the waters according to their nature.
Pollution of water sources occurs in two ways:
- Pollution through point source
- Pollution through Wide Source
The pollutant points of different waters are also different.
1. Rivers: – Where industrial contaminated water is found in rivers through various drains, domestic water is also immersed in it through drains etc. Also, fertilizers, pesticides and soil effluents along with the flow of water are also found in the rivers.
2. Pollution of seawater: – All the rivers eventually meet in the oceans. So they are definitely polluted through them. Industrial contaminated water and sewage, pesticides, fertilizers, heavy metals, plastics, etc. are found in the sea through rivers. Apart from these, maritime pollution also occurs due to maritime activities such as sea transport, exploitation of petroleum products from the sea, etc.
Only by observing the physical condition of the watershed can they be estimated to be polluted. The increase in the number of aquatic weeds along with the color of the water, its smell, taste etc., decrease or die in the number of aquatic organisms such as fish and other animals, floating oily material on the surface, etc. are signs of water pollution. Sometimes, water may be contaminated even without these symptoms, such as acid or alkaline discharge or mixing in water bodies or meteorites from metallic pollutants. Chemical analysis of water is mandatory to detect such pollutants.
The nature of substances that pollute water is mainly of two types –
1. Biologically perishable
2. Biologically non-perishable
Primarily all organic matter pollutants are biologically perishable. These pollutants are destroyed by micro-organisms present in the water. In fact, organic materials are the food of microbes. These activities of micro organisms use a large amount of dissolved oxygen in water. This is the reason that when organic matter pollutants such as sewage or contaminated water of distillation industry are found in the watershed, there is a significant decrease in the amount of dissolved oxygen in them, sometimes it happens that aquatic animals like fish etc. lack oxygen Are killed due to
Conversely, there are many pollutants that are not destroyed under normal conditions, such pollutants contain various metallic pollutants or inorganic salts.