Acid rain is one of the most widely publicized environmental problems of today. It has been known for many years that the chemical content of precipitation can vary as a result of scavenging of atmospheric gases and particles. The consequences of widespread acid precipitation are adverse and beneficial. This text analyses major effects of acid rain namely the impacts on aquatic ecosystems, impacts on terrestrial ecosystems and on animal-human health.
             Most of the data available on impacts of acidic precipitation are derived from studies on the effects of increased acidity on aquatic organisms. The chemical composition of lakes is determined largely by the composition of influents from precipitation and watershed drainage.
             Acid rain causes a decrease in pH level. Acid rain has also effect on fish. In acidified lakes, the fish mortality increases. A sudden short change in pH can kill fishes. It often occurs in early spring when snow melt releases acidic constituents accumulated during the winter. A gradual decrease in pH with time is a second mechanism of the increase of fish mortality. Field observations and laboratory experiments have showed that prolonged acidity interferes with fish reproduction. That is to say, there is a decrease in fish population density and a modification of the size and age of fishes (become older and larger).Elimination or reduction of fishes is the most obvious biological impact associated with acidification of lakes, but the effects on other aquatic organisms are really important too. Each organism can be affected. Changes in pH cause a decrease in phytoplankton and an increase in alga. Therefore, there is a reduction of nutriments and so it limits the number of organisms that can exist.
             Enumerate all the impacts of acid rain on terrestrial ecosystems is extremely difficult. In fact, at present, it is not possible to observe changes in natural terrestrial ecosystems that are only caused by acidic pr...