||Botanical Aspects of Acidic Precipitation.
Evans, L. S. ;
||Brookhaven National Lab., Upton, NY.;Corvallis Environmental Research Lab., OR.;Department of Energy, Washington, DC.
Soil microbiology ;
Air pollution ;
Acid deposition ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
Acidic precipitation can be characterized as wet or frozen atmospheric deposition with a hydrogen ion concentration greater than 2.5 microequivalents liter-1. Acidic precipitation is perceived as a significant air pollution problem derived chiefly from combustion of fossil fuels, smelting of sulfide metals, and other industrial processes. Precipitation data from the northeastern U.S. show a mean pH of between 4.0 and 4.2 with a range of from 3.0 to 6.0 among individual events. Although visible injury to plant foliage has been documented in a variety of studies only one case of visible foliar injury from the acidity in ambient rainfalls has been documented. Acidic precipitation can contribute nutrients to vegetation and could also influence nutrient leaching rates from vegetation. Although these processes occur, there are no data that show changes in nutrient levels in foliage that relate to crop or natural ecosystem productivity. Although no consistent patterns are presently known, acidic precipitation may affect host-plant pathogen interactions. (Copyright (c) 1984 The New York Botanical Garden.)