Mercury in human and environmental samples from two lakes in Amapa, Brazilian Amazon

Total Hg was determined in sediment, piscivorous fish and human hair from t wo similar lake areas in Amapa State, Brazilian Amazon: Duas Bocas Lake (DB L), influenced by Hg releases from gold mining; and Pracuuba Lake (PL), a p ristine site 15 km to the north. In DBL, Hg profiles in sediments clearly d ocumented the evolution of Hg pollution, and Hg was significantly higher in fish and human hair than in FL. Hg-203 methylation rates in sediments and methylmercury proportions in fish suggest a high Hg bioavailability in both lakes. Average daily fish intake is approx. 200 g, and at DBL 95% of fish samples (N = 40) exceeded the 150 ng Hg g(-1) safety limit. Hg in human hai r averaged 28 mu g g(-1) (N = 15), i.e. a level at which neurotoxic effects have been found. However, Hg was also high in the pristine FL, where 67-10 0% (N = 34) of the fish had levels that exceeded the safety limit, and 87% of hair samples (N = 15) had above 10 ng Hg g(-1). In both areas, children and pregnant women should be advised to consume nonpiscivorous and/or small fish species. Hg levels should also be investigated in other areas of the Amapa coastal plain.