Acidified soils caused toxic aluminum in 66 percent of 565
assessed streams. Diatoms and aquatic macroinvertebrates were
moderately to severely affected. These effects have not improved
in areas surveyed in the early 1980s Document on the federally
supported interagency National Acid Precipitation Assessment
Program (NAPAP) covering research on causes and effects of acid
precipitation with the USGS as the lead agency for monitoring
wet acid deposition. Access to map of data collection sites of
the National Atmospheric Deposition Program/National Trends
Network (NADP/NTN) with links to other maps and reports on wet
atmospheric deposition (chemicals deposited via rain, sleet and
snow). Sulfate deposition to high-elevation areas has decreased
here as a result of reductions in SO2 emissions. Nitrate
deposition did not change, whereas ammonium deposition
increased, particularly at sites near urban and agricultural
areas. Fact sheet on the formation of acid rain, its effects,
investigations, and the program of a na