What is the effect of acid rain

Acid rain has been shown to have adverse impacts on forests, freshwaters and soils, killing off insect and aquatic lifeforms as well as causing damage to buildings and having possible impacts on human health.


Surface waters and aquatic animals
Both the lower pH and higher aluminum concentrations in surface water that occur as a result of acid rain can cause damage to fish and other aquatic animals. At pHs lower than 5 most fish eggs will not hatch and lower pHs can kill adult fish. As lakes become more acidic biodiversity is reduced. Acid rain has eliminated insect life and some fish species, including the brook trout in some Appalachian streams and creeks.However, there has been some debate on the extent to which acid rain contributes to lake acidity (i.e., that many acid lakes may result primarily from characteristics of the surrounding watershed, and not the rain itself).[10] The EPA's website states: "Of the lakes and streams surveyed, acid rain caused acidity in 75 percent of the acidic lakes and about 50 percent of the acidic streams".


Soils
Soil biology can be seriously damaged by acid rain. Some tropical microbes can quickly consume acidsbut other microbes are unable to tolerate low pHs and are killed. The enzymes of these microbes are denatured (changed in shape so they no longer function) by the acid. The hydronium ions of acid rain also mobilize toxins and leach away essential nutrients and minerals

nH+ (aq)+ Mn2+ (clay)⇌ nH+ (clay)+ Mn2+(aq)

Forests and other vegetation
Acid rain can slow the growth of vulnerable forests and cause leaves and needles to turn brown and fall off. Adverse effects may be indirectly related to acid rain, like the acid's effects on soil or high concentration of gaseous precursors to acid rain. High altitude forests are especially vulnerable as they are often surrounded by clouds and fog which are more acidic than rain.

Other plants can also be damaged by acid rain but the effect on food crops is minimized by the application of fertilizers to replace lost nutrients. In cultivated areas, limestone may also be added to increase the ability of the soil to keep the pH stable, but this tactic is largely unusable in the case of wilderness lands. Acid Rain depletes minerals from the soil and then it stunts the growth of the plant.


Human health
Some scientists have suggested direct links to human health, but none have been proven. However, fine particles, a large fraction of which are formed from the same gases as acid rain (sulphur dioxide and nitrogen dioxide), have been shown to cause illness and premature deaths such as cancer and other deadly diseases

Other adverse effects
Acid rain can also cause damage to certain building materials and historical monuments. This is because the sulfuric acid in the rain chemically reacts with the calcium compounds in the stones (limestone, sandstone, marble and granite) to create gypsum, which then flakes off.

CaCO3 (s) + H2SO4 (aq) = CaSO4 (aq) + CO2 (g) + H2O (l)
This is also commonly seen on old gravestones where the acid rain can cause the inscription to become completely illegible. Acid rain also causes an increased rate of oxidation for iron.Visibility is also reduced by sulfate and nitrate in the atmosphere.