Analyses of water collected at 32 sites on headwater streams in Pennsylvania during low-flow conditions in 1970-80 were compared to pre-1971 data to evaluate whether acid rain had changed the chemistry of the streams in the previous decade. Most pH, alkalinity, and sulfate values of the samples collected in 1970-80 fell within the ranges of values for samples collected before 1971. The limited data indicate, however, that pH may have increased and alkalinity and sulfate may have decreased with time.
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USGS Numbered Series
An evaluation of the effects of acid rain on low conductivity headwater streams in Pennsylvania