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Total Hg was determined in sediment, piscivorous fish and human hair from two similar lake areas in Amapa State, Brazilian Amazon: Duas Bocas Lake (DBL), influenced by Hg releases from gold mining; and Pracuuba Lake (PL), a pristine site 15 km to the north. In DBL, Hg profiles in sediments clearly documented the evolution of Hg pollution, and Hg was significantly higher in fish and human hair than in PL. {sup 203} Hg 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{sup -1} safety limit. Hg in human hair averaged 28 {mu}g g{sup -1} (N = 15), i.e. a level at which neurotoxic effects have been found. However, Hg was also high in the pristine PL, where 67-100% (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{sup -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 30 refs, 5 figs, 1 tab