MERCURY POLLUTION AS A RESULT OF GOLD EXTRACTION IN NORTH-CAROLINA, USA

Water, sediment and panned concentrate from active streams, together w ith some mosses and well waters, all from the vicinity of old Au opera tions in North Carolina, were analyzed to determine the extent of poll ution from metallic Hg introduced into these areas in the 1800s and ea rly 1900s and by modern ''weekend panners''. Heavy mineral concentrate s, Au grains, sediment and moss were all found to be indicators of Hg pollution, with concentrations of up to 784,000 mug/kg in heavy minera l concentrates, 7400 mug/kg in sediments, and 4900 mug/kg in moss. Sur ficial spots on Au grains contained as much as 44.8% Hg. Analyses of f ish tissue from several of the drainage channels did not indicate Hg p ollution with all values below the North Carolina average of 210 mug/k g. Mercury concentrations in stream and well waters were all below the LLD of 0.2 mug/l. In North Carolina, heavy mineral concentrates appea r to be the best indicators of introduced metallic Hg.