Contamination of Great Smoky Mountains Trout Streams by Exposed Anakeesta Formations
1979
Bacon, J. R. | Maas, R. P.
Anakeesta formations, prevalent geologic deposits in the Great Smoky Mountains National Park (GSMNP), when exposed to air and water release an acid and heavy metal containing leachate into several GSMNP streams, rendering them virtually lifeless. Anakeesta pyrite affecting Beech Flats Creek was exposed during the construction of U.S. Highway 441, while exposures affecting Alum Cave Creek and Walker Prong are naturally occurring. The road cut on U.S. 441 at Beech Flats Creek acts as point source of various contaminants. The acidity increases 100-fold (pH 6.7 to 4.7) in the several hundred meters where the stream flows through a road cut fill area. Manganese and zinc were the main metallic ions introduced at the road cut. The zinc increased from 6 to nearly 200 ppb and the manganese increased from an undetectable level to over 250 ppb. Seasonal variations below the road show a high concentration near 500 ppb in the summer to a low concentration near 100 ppb in the winter for both manganese and zinc. Both manganese and zinc showed the dilution effect expected going downstream away from the road cut. Alum Cave Creek and Walker Prong showed much lower levels of manganese and zinc and no point source could be located. The results of the present study should prove useful to National Park personnel in making management decisions. This is especially important in view of several proposed new roads in the Great Smoky Mountains National Park.
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