Publication Date


Document Type


First Advisor

Perry, Eugene C., 1933-

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Geology


Water--Pollution--Minnesota; Boundary Waters Canoe Area (Minn.)


Samples of surface water, groundwater, leachate water, sewage treatment plant discharge, and snow were collected within the Boundary Waters Canoe Area Wilderness (BWCAW) and environs during the interval from August 1981 to August 1982, and analyzed for pH, SO₄²⁻, δ¹⁸O[sub H₂O], and δ¹⁸O[sub SO₄]-δ³⁴S[sub SO₄] of dissolved sulfate. From the results obtained, it is concluded that an appreciable amount of oxidized, acid-producing sulfate in this region is contributed by non- atmospheric sources. Stable isotope data suggest that sulfate from the surface oxidation of sulfide minerals is an important non-atmospheric sulfate source. Isotopic evidence also suggests that sulfate within certain waters is not as conservative a species as widely regarded, but undergoes bacterial reduction. Regular observations of δ¹⁸O[sub SO₄] and δ³⁴S[sub SO₄] for sulfate in surface waters of the BWCAW and environs can be used to define anthropogenic pollution sources and the extent of their effect. Specifically, the δ¹⁸O[sub SO₄] signature of sulfate produced from the surface oxidation of sulfide minerals could serve as a method of tracing sulfate contributions to groundwaters, rivers, and lakes from tailing piles and stockpiles used in mining operations. The oxygen isotope geochemistry for the oxidation of sulfide minerals is found to differ from previous studies of this process (Lloyd, 1968; Mizutani and Rafter, 1973) and is explained by using equations proposed by Stumn and Morgan (1970).


Bibliography: pages 83-88.


vii, 88 pages




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