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Title: Biomarcadores para avaliação de risco ecológico de mercúrio em peixes: Sistema costeiro do Estado do Rio de Janeiro e bioensaios
Keywords: Baía da Ribeira;  Baía de Guanabara;  Bioacumulação;  Distribuição interna do mercúrio;  Saúde animal;  Avaliação de risco;  Contaminação por mercúrio;  Gestão ambiental;  Produção intelectual;  Biomarcadores;  Peixe;  Ribeira Bay;  Guanabara Bay;  Bioaccumulation;  Internal distribution of mercury;  Animal health
Issue Date: 25-Mar-2010
Abstract: In aquatic ecosystems, mercury is involved in multiple reactions, among them mutilation seems to be the most important, producing methylmercury, capable to accumulate throughout food web, reaching fish species and other top predators. This study aimed to evaluate potential biomarkers for ecological risk assessment related to mercury exposure for fish from two coastal aquatic systems Guanabara Bay (contaminated area) and Ribeira Bay (Reference area), as well as to assess the dose-response relationship by using bioassays investigating if all the effects found in field work would be found in laboratory experiments. At Ribeira Bay, 211 specimens of 3 species were collected: 120 specimens of Genidens genidens, 38 specimens of Aspistor luniscutis and 53 specimens of Haemulon steindachneri. At Guanabara Bay, a total of 132 specimens were collected being 65 specimens of Genidens genidens and 67 specimens of Haemulon sp.. Mercury levels in muscles in both areas were bellow of the limit for human consumption (500ng/g), being the highest values found for catfishes from Ribeira Bay. At Guanabara Bay, Gradim and Praia da Bica stations showed the highest concentrations of mercury in fish. At Ribeira Bay, the station with highest levels was Enseada do Bracuí. Mercury levels depended on species and trophic level (assessed using stable isotopes), and each species had oscillations on mercury levels according to seasons, sex and age (length). Mercury accumulation throughout exposure time is faster than the accumulation reported previously for catfishes from both areas. Methylmercury percentage showed that fishes have similar exposure to this organic form of mercury, but this percentage in muscles demonstrated that are different behavior in its absorption and possible excretion depending on species. Hematological and biochemical effects frequencies in the collected specimens were similar among areas. During the laboratory experiments, it was observed that methylmercury can cause hematological alterations, especially in corpuscular volume and in hemoglobin concentrations, can activate leukocytes production, can possibly inhibit acetylcholinesterase and glutathione activities, as well as increase genotoxic effects frequencies and damage on liver and gonad tissues.
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