Possible active fault traces on or near the Castle Mountain fault between Houston and the Hatcher Pass Road: A section in RGeologic studies in Alaska by the U.S. Geological Survey, 1993

Abstract

Potential mercury contamination was evaluated downstream from an abandoned mercury mine and a site downstream from placer mines in the Kuskokwim River region of southwestern Alaska. Mercury and other heavymetal concentrations were measured in liver, muscle, and whole fish samples of Arctic grayling, as well as in stream-sediment, heavy-mineral-concentrate, and streamwater samples. Results indicate that mercury is most concentrated in samples collected below the mercury mine, where stream-sediment samples contain in excess of 36 ppm and samples of muscle and whole fish from Arctic grayling range from 0.24 to 0.55 ppm wet weight. Mercury concentrations in whole fish and muscle samples of grayling collected downstream from placer mines range from 0.067 to 0.30 ppm wet weight. Although mercury concentrations in fish are elevated with respect to those in fish from a control site, the mercury concentrations in fish samples do not exceed the Food and Drug Administration (FDA) action level of 1 ppm wet weight for edible fish. Results for other heavy-metals in samples collected in this study are not in concentrations high enough to be of concern. c=s BR1F03M muscle 108 .