Contaminação Mercurial Em Peixes Do Rio Madeira: Resultados E Recomendações Para Consumo Humano

Abstract

RESUMO -A concentração de mercúrio total foi determinada em onze espécies de peixes coletados de setembro a outubro de 1991, na área de garimpo de ouro da Cachoeira de Tcotônio e da área considerada controle em Guajará-Mirim, ambas no rio Madeira, Estado de Rondônia. Utilizou-se, para a análise, a técnica de espectrofotometria de absorção atômica com gerador de vapor frio de Hg. Quase todos os peixes predadores da área de garimpo tiveram concentrações de mercúrio acima do nível critico de 0,5 pg.g" 1 permitido para consumo humano pelo Ministério da Saúde do Brasil e Organização Mundial de Saúde, sendo bem maiores que as concentrações de mercúrio nas espécies predadoras da área controle, evidenciando a influência do garimpo de ouro na contaminação dos peixes por mercúrio. As espécies não-predadoras tiveram concentrações de mercúrio abaixo daquelas das espécies predadoras para as duas áreas, indicando o efeito da biomagnificação do mercúrio na cadeia alimentar. Procurou-se estabelecer limites para o consumo de peixes pelas populações humanas da área de garimpo estudada, calculando-se a taxa de ingestão necessária para se desenvolver os primeiros sintomas de contaminação mercurial. Concluiu-se que espécies como o pacu podem ser consumidas sem restrição, já os peixes como matrinchã, curimatã, mandi e tucunaré, deveriam ser consumidos com moderação e que a maioria dos peixes predadores (em geral Siluriformes), deveriam ser consumidos apenas esporadicamente. Discutemse alguns fatores que poderiam estar interagindo no processo de contaminação por mercúrio dos ribeirinhos dessa área de garimpo.Palavras-chaves: mercúrio, Hg, garimpo-de-ouro, Rio Madeira, Rondônia, amazônia, peixes. Mercury Concentrations in Fishes of the Madeira River: Results and Recomendations for Human ConsumptionABSTRACT -Samples of eleven fish species were collected during September and October of 1991 in the gold mining area of Cachoeira de Teotônio and in the control area Guajará-Mirim, along the Madeira River, (Rondônia, Brazil) and anaiized for total mercury by cold vapor atomic absorption spectrofotometry. Almost all fish predators from the gold mining area had mercury concentrations above the maximal level of 0.5 ug.g" 1 , permitted for human consumption by Brazilian Secretary of Health and the World Health Organization and much greater than those found in predatory fish species in the control area were all below this critical value (0.5 pg.g'X demonstrating the influence of anthropogenic contamination in the gold mining area. In both areas, non-predators fish species had lower mercury concentrations than predators fish species, indicating the effects of biomagnification of mercury in the food chain. Safety limits for fish consumption by the human populations in this gold mining area were estabilished considering the mercury levels encontred in fish and the critical intake rate associated with the signs of mercury poisoning. Pacu, could be consumed without restrictions, matrinchã, curimatã, mandi and tucunaré, could be consumed with moderation...

Mercury Hazards from Gold Mining to Humans, Plants, and Animals

“…However, only 2% of fish collected in 1988 (vs. 1% in 1991) from the Tapajos region exceeded the Brazilian standard of 0.5 mg total mercury/kg FW muscle, and all violations were from a single species of cichlid (tucunare/speckled pavon, Cichla temensis) (Lima et al 2000). In a 1991 survey of 11 species of fishes collected from a gold mining area (Cachoeira de Teotonio), it was found that almost all predatory species had >0.5 mg Hg/kg FW muscle versus <0.5 mg/kg FW in conspecifics collected from Guajara, a distant reference site (Padovani et al 1995). Limits on human food consumption were set for individual species on the basis of mercury concentrations in muscle.…”

“…Limits on human food consumption were set for individual species on the basis of mercury concentrations in muscle. Specifically, no restrictions were placed on some species, mostly herbivores and omnivores, some restrictions on some omnivores and small predators, and severe restrictions on larger predators (Padovani et al 1995).…”

Reviews of Environmental Contamination and Toxicology

“…In a 1991 survey of 11 species of fishes collected from a gold mining area (Cachoeira de Teotonio), it was found that almost all predatory species had >0.5 mg Hg/kg FW muscle versus <0.5 mg/kg FW in conspecifics collected from Guajara, a distant reference site (Padovani et al 1995). Specifically, no restrictions were placed on some species, mostly herbivores and omnivores, some restrictions on some omnivores and small predators, and severe restrictions on larger predators (Padovani et al 1995). Specifically, no restrictions were placed on some species, mostly herbivores and omnivores, some restrictions on some omnivores and small predators, and severe restrictions on larger predators (Padovani et al 1995).…”

The philometrid nematodePhilometroides acreanensis n. sp. from the stomach wall of the catfishPimelodus blochiiin north-western Brazil

“…Bloch's catfish is one of eight species of Pimelodus Lacépède occurring in the Amazon River drainage system. This is a highly appreciated and the most consumed species in the region, considered by locals to be a tasty and cheap fish (Padovani et al , 1996; Boujard et al , 1997; Ribeiro & Lucena, 2006).…”