Mercury Concentrations in Abiotic Materials and Biota

Clams collected near gold mining operations had elevated concentrations of mercury (up to 0.64 mg Hg/kg FW) in soft tissues. Laboratory studies suggest that mercury adsorbed to suspended materials in the water column is the most likely route for mercury uptake by filterfeeding bivalve mollusks. 

Fish that live near gold mining areas have elevated concentrations of mercury in their flesh and are at high risk of reproductive failure. Mercury concentrations of 

0 mg/kg FW in fish muscle are considered lethal to the fish, and 1.0-5.0 mg/kg FW sublethal predatory fishes frequently contain 2.0-6.0mg Hg/kg FW muscle. Mercury-contaminated fish pose a hazard to humans and other fish consumers, including the endangered giant otter (Pteronura brasiliensis), and the jaguar. Giant otters eat mainly fish and are at risk from mercury intoxication  

0 mg/kg FW, about 90% methylmercury). Motor difficulties were seen in some individuals with 50.0 mg total Hg/kg FW hair. In the Tucurui Reservoir area, where the main source of mercury is from gold mining activities upstream, a human male needs 0.3 mg of mercury daily to reach a hair mercury concentration of 50.0 mg/kg DW. To receive this amount of mercury from fish containing 1.0 mg total Hg/kg FW muscle, a daily ingestion of 

0 g of fish muscle is calculated, although this needs verification. 

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