Since the impacts of acid rain are complex and develop slowly, the extent of the impacts in these categories is difficult to quantify. The adverse effects of acid rain are most apparent in aquatic systems. The most common impact appears to be on reproductive cycles. When exposed to acidic water, female fish and amphibians may fail to produce eggs or produce eggs that do not develop normally. Low pH levels also impair the health of fully developed organisms.
Acid rain plays a role in the mobilization of toxic metals.
These metals remain inert in the soil until acid rain moves through the ground. Transported by acid rain, these toxic metals can then accumulate in lakes and streams, where they threaten aquatic organisms. The extent of damage acid rain causes depends on the total acidity deposited and the sensitivity of the area receiving it. An ecosystem's ability to resist change in pH is called its buffering capacity. The concentration of dissolved carbonates determines the alkalinity of the soil.