The phenomenon of deposition of inorganic phosphate and nitrate in water bodies is called eutrophication, due to that the growth of algae population is increased suddenly and mainly blue green algae, eg. Microcystis, spread on the surface of the water bodies. Phytotoxin is generated by these algae which is harmful for organisms of waterbodies and for animals and human by food chain. 

The phenomenon by which pollutants from man’s activities like effluents from the industries and homes are radically accelerated the aging process is called accelerated eutrophication. Lakes in many parts of the earth have been severely eutrophied by sewage and agricultural and industrial wastes. The prime contaminants are nitrates and phosphates, which act as plant nutrients. They overstimulate the growth of algae, causing unsightly scum and unpleasant odors, and robbing the water of dissolved oxygen vital to other aquatic life. At the same time, other pollutants flowing into a lake may poison whole populations of fish, whose decomposing remains furhter deplete the water’s dissolved oxygen content. In such fashion, a lake can literally choke to death.

Two consequences of phenomenon are as follows– 

1. Eutrophication leads to lowering of dissolved oxygen in water body leading to death of aquatic life. 

2. Nitrates from fertilizers and detergents contaminate drinking water leading to decrese in oxygen carrying capacity of haemoglobin in human beings.