Mercury pollution as a result of gold extraction in North Carolina,U.S.A.

Water, sediment and panned concentrate from active streams, together with some mosses and well waters, all from the vicinity of old Au operations in North Carolina, were analyzed to determine the extent of pollution from metallic Hg introduced into these areas in the 1800s and early 1900s and by modern “weekend panners”.Heavy mineral concentrates, Au grains, sediment and moss were all found to be indicators of Hg pollution, with concentrations of up to 784,000 μg/kg in heavy mineral concentrates, 7400 μg/kg in sediments, and 4900 μg/kg in moss. Surficial spots on Au grains contained as much as 44.8% Hg. Analyses of fish tissue from several of the drainage channels did not indicate Hg pollution with all values below the North Carolina average of 210 μg/kg. Mercury concentrations in stream and well waters were all below the LLD of 0.2 μg/l. In North Carolina, heavy mineral concentrates appear to be the best indicators of introduced metallic Hg.