Harmful Effects of Water Pollution :-
1)Human diseases:
Pathogens(viruses,bacteria,fungiprotozoa etc)are
biological pollutants of water.They cause
typhoid,cholera,dysenteryjaundice,hepatitis.
2)Removal of desirable substance from water bodies:
With increase in the amount of organic waste the
bacteria multiply rapidly and use up the available
oxygen.Lack of oxygen kills fish and other animals.
3)Effects of thermal pollution or change in
temperature:
Aquatic organisms are used to certain range of
temperature,a sudden marked change in the
temperature would be dangerous for them ie it
affects breeding of aquatic animals.
4)Destruction of useful microorganism:
When untreated industrial waste get mixed with
water in lakes and rivers,the acids,alkalies,heavy
metals present in them kill useful organism present in water bodies.