An evaluation of the effects of acid rain on low conductivity headwater streams in Pennsylvania

Abstract

ILLUSTRATIONS Figures 1-4.-Maps showing: 1.-pH of precipitation in the eastern United States,

Evidence for acid-precipitation-induced trends in stream chemistry at hydrologic bench-mark stations

“…Based on previous literature, it is difficult to construct a comparable nationwide picture of trends in stream and precipitation sulfate concentrations due to the limited number and uneven distribution of sampling sites with adequate record lengths (Bubenick and others, 1983). For the Northeast, however, there are other recent reports of declining stream and precipitation sulfate concentrations from scattered locations (National Research Council, 1983;Peters and others, 1982;Ritter and Brown, 1981;Likens and others, 1980).…”

An evaluation of trends in the acidity of precipitation and the related acidification of surface water in North America

“…Two reports are available on the chemistry of streams in Pennsylvania (Arnold and others, 1980;Ritter and Brown, 1981). The former report has been extensively criticized (U.S. Environmental Protection Agency, 1983b); deficiencies reported were primarily a failure to discuss sites at which pH and alkalinity showed no trends or increasing trends, and the inclusion of very short-term changes (for example, 1 year) in the comparisons.…”

“…The second report on trends in the chemistry of Pennsylvania streams (Ritter and Brown, 1981) compared samples collected during low-flow conditions in 1979-80 with samples collected prior to 1971. After selection of historical samples representing similar flow and specific conductance, most sample comparisons indicate a decrease in sulfate and alkalinity and possibly an increase in pH.…”

Atmospheric deposition of selected chemicals and their effect on nonpoint-source pollution in the Twin Cities Metropolitan Area, Minnesota

“…This input of contaminants to both terrestrial and aquatic ecosystems can be detrimental (Driscoll, 1980;Johnson, 1979;Swank and Henderson, 1976). Deposition of airborne contaminants is considered to be nonpoint-source pollution, which contributes to the nonpointsource pollution problem throughout the United States and the world (Lewis and Grant, 1980;Ritter and Brown, 1981).…”