Abstract |
Atmospheric sulphur deposition and its impacts on surface-water chemistry and biota have been extensively studied in several areas of the United States and elsewhere during the past two decades. In the absence of regionally based statistical (probability) sampling, however, it has not been possible to extrapolate the results from intensive small-scale studies to a regional population. The authors present data from the first regional probability sampling of lakes in the United States, indicating that median lake sulphate concentrations correlate highly with estimated wet sulphate deposition at lake sites. The data further suggest that acid deposition has depleted acid-neutralizing capacity (ANC) in low-base-cation lakes, and that some high-base-cation lakes receive substantial sulphate from internal watershed sources. |