Mercury hazards from gold mining to humans, plants, and animals.

摘要: Mercury contamination of the environment from historical and ongoing mining practices that rely on mercury amalgamation for gold extraction is widespread. Contamination was particularly severe in immediate vicinity refining operations; however, mercury, especially form water-soluble methylmercury, may be transported to pristine areas by rainwater, water currents, deforestation, volatilization, other vectors. Examples mining-associated pollution have been shown Canada, U.S., Africa, China, Philippines, Siberia, South America. In parts Brazil, example, concentrations all abiotic materials, plants, animals, including endangered species mammals reptiles, collected near sites were far excess allowable levels promulgated regulatory agencies protection human health natural resources. Although authorities Brazil are unable detect conclusive evidence intoxication, potential exists absence mitigation epidemic poisoning population environs. environmental mostly practices, portions Nevada remain sufficiently contaminated pose a hazard reproduction carnivorous fishes fish-eating birds. Concentrations total lethal sensitive representative resources range 0.1 2.0 microg/L medium aquatic organisms; 2,200 31,000 microg/kg BW (acute oral) 4,000 40,000 (dietary) birds; 100 500 (daily dose) 1,000 5,000 diet mammals. Significant adverse sublethal effects observed among selected at 0.03-0.1 microg Hg/L. For some birds, effects, mainly reproduction, associated with (microg/kg FW) feathers, 900 eggs, 50-100 diet, daily intakes 640 BW. Sensitive nonhuman showed significant when 250 BW, dietary 1,100 microg/kg, or tissue exceeded microg/kg. Proposed criteria life 0.012 freshwater 0.025 marine life; less than FW; small mammals, FW diet. All these proposed provide, best, minimal protection.