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USGS · 70015541

Correlations between stream sulphate and regional SO2 emissions

R. A. Smith·R. B. Alexander
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Abstract

The relationship between atmospheric SO 2 emissions and stream and lake acidification has been difficult to quantify, largely because of the limitations of sulphur deposition measurements. Precipitation sulphate (SO 4 ) records are mostly <5 yr in length 1 and do not account for dry sulphur deposition 2 . Moreover, a variable fraction of wet- and dry-deposited sulphur is retained in soils and vegetation and does not contribute to the acidity of aquatic systems 3,4 . We have compared annual SO 2 emissions for the eastern United States from 1967 to 1980 with stream SO 4 measurements from fifteen predominantly undeveloped watersheds (Figs 1,2). We find that the two forms of sulphur are strongly correlated on a regional basis and that streams in the southeastern United States (SE) receive a smaller fraction (on average, 16%, compared with 24% of regional sulphur emissions than do streams in the northeastern United States (NE). In addition to providing direct empirical evidence of a relationship between sulphur emissions and aquatic chemistry, these results suggest that there are significant regional differences in the fraction of deposited sulphur retained in basin soils and vegetation.

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R. A. Smith, R. B. Alexander. 1986. Correlations between stream sulphate and regional SO2 emissions. https://doi.org/10.1038/322722a0

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