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

Abstract

.. Introduction Methods CONTENTS

National water summary 1983: Hydrologic events and issues

“…In contrast, stations in the northeastern quarter of the Nation have tended to show either no trend or declines in sulfate con- centrations. These changes in sulfate levels tend to coincide with the historical pattern of trends in atmospheric sulfur dioxide emissions in the United States from 1965 through 1980 and lend support to the hypothesis that stream sulfate concentrations in surface water tend to follow regional trends in deposition rates of acidic precipitation (Smith and Alexander, 1983). When acidic precipitation falls on the land surface in areas of alkaline terrane, the acidity generally is neutralized by reaction with alkaline constituents of the soil, rock, and vegetation; thus, in areas of alkaline terrane, the acidity of the precipitation has little effect on surface or ground water.…”

“…Recently, data were analyzed for the 8-year period 1974 through 1981 to detect trends in selected waterquality constituents and properties in the major rivers in the United States (Smith and Alexander, 1983). Some preliminary results for selected constituents are shown in table 4.…”

Assessment of the theory and hypotheses of the acidification of watersheds

“…Geological Sumey data shows that all four of the llundisturbedll Northeast headwater streams examined have pH values that are becoming increasimrlv more acidic (Smith and Alexander, 1983 Figure 1; 2 ) . wlt most of the salmon i n llaffectedll rivers w e r e l o s t between 1910 and 1920 ( Figure 5) w i t h massive fishkills occurring a f t e r heavy r a i n s and snawmelts as early as 1911 w i t h autopsy results indicating mortality due t o sytptm diagnostic of highly acidic waters (Braekke, 1976) .…”

Areal and temporal variability of selected water-quality characteristics in two hydrologic-benchmark basins in the northeastern United States

“…S. Geological Survey, written commun., 1984), and Smith and Alexander (1983a). Both groups used the Seasonal Kendall test, a distribution-free test that adjusts the data for seasonality.…”

“…Data from the Esopus Creek station were analyzed for temporal trends in the acidity of surface waters of New York (Peters and others, 1982). Data from both stations were analyzed for (1) acid-precipitation-induced trends in stream chemistry (Smith and Alexander, 1983a) and (2) trends in comprehensive stream chemistry (Smith and Alexander, 1983b).…”