Eutrophication calculates the destructive effects of ammonia, nitrates, nitrogen oxides and phosphorus (emitted in air and waters) on freshwater systems. In inland waters, it is one of the major factors that determine the ecological quality of an aquatic environment.
This process of pollution occurs when a lake or stream becomes over-rich in plant nutrient – as a consequence, phytoplankton increases, and the water becomes overgrown in algae and other aquatic plants. The plants die and decompose, robbing the water of oxygen so that ultimately the lake, river, or stream becomes lifeless.
While eutrophication occurs naturally in freshwater systems, man-made eutrophication occurs over millions of years and is caused by organic pollutants from man’s activities, like effluents from industries and homes.