Acid rain can damage lakes and streams. In southern Norway and Sweden, one fifth of the lakes no longer contain any fish. Healthy aquatic environments have a pH of 6.5 or higher. Below a pH of 4.0 a lake is essentially dead. The loss of aquatic organisms in acidic lakes may be due in part to an increase in the quantity of metals, especially aluminum, leached from the soil as the pH falls.
Acid rain can damage forests and reduce the productivity of agricultural crops.
However, a direct relationship between acid rain and forest decline cannot be easily proven because acid deposition may cause trees to be more susceptible to disease, insects, drought or high winds from which they die, rather than directly from the acid deposition itself. For more information, check out the USGS .