Mercury in Human and Environmental Samples from Two Lakes in Amapá, Brazilian Amazon

摘要

Total Hg was determined in sediment,piscivorous fish and human hair from two similar lakeareas in Amapá State, Brazilian Amazon: Duas Bocas Lake(DBL), influenced by Hg releases from gold mining; andPracuúba Lake (PL), a pristine site 15 km to the north.In DBL, Hg profiles in sediments clearly documented theevolution of Hg pollution, and Hg was significantlyhigher in fish and human hair than in PL. 203Hg methylationrates in sediments and methylmercury proportions in fishsuggest a high Hg bioavailabiligy in both lakes. Averagedaily fish intake is approx. 200 g, and at DBL 95% offish samples (N = 40) exceeded the 150 ng Hg g-1 safetylimit. Hg in human hair averaged 28μg g-1 (N = 15), i.e.a level ant which neurotoxic effects have been found.However, Hg was also high in the pristine PL, where67-100% (N = 34) of the fish had levels that exceededthe safety limit, and 87% of hair samples (N = 15) hadabove 10 ng Hg g-1. In both areas, children and pregnantwomen should be advised to consume nonpiscivorous and/orsmall fish species. Hg levels should also beinvestigated in other areas of the Amapá coastal plain.