Bioconcentration of Cd and Pb by the river crab Trichodactylus fluviatilis (crustacea: decapoda)

Abstract

Foi avaliada a bioconcentração de cádmio e chumbo pelo caranguejo fluvial Trichodactylus fluviatilis. Trinta animais foram expostos a 200 mg L -1 de cádmio e chumbo por 7, 14 e 21 dias. Após dissecação e digestão nitro-perclórica, os metais foram determinados nas brânquias, hepatopâncreas e músculo por espectrometria de emissão óptica com plasma acoplado indutivamente. O chumbo foi detectado apenas nas brânquias, sem diferenças significativas entre diferentes períodos de exposição. O cádmio foi encontrado em todos os tecidos após exposição. Diferenças significativas entre as concentrações de cádmio em animais expostos por diferentes períodos sugerem um processo de acumulação, com concentração estabilizada após 14 dias. Usando um procedimento de extração em fase sólida com Saccharomyces cerevisae e com o objetivo de avaliar a transferência e estocagem de cádmio nos tecidos, foi realizado o fracionamento de cádmio na forma livre (ou lábil) e cádmio-proteína (possivelmente metalotioneína) (Cd-P) em animais expostos a 200 mg L -1 de cádmio por 21 dias. A determinação de cádmio livre e Cd-P nos tecidos mostrou que nas brânquias o metal foi encontrado principalmente na forma livre, enquanto que no hepatopâncreas o metal foi encontrado principalmente ligado à proteína. Pode-se inferir que, absorvido através das brânquias, o cádmio foi transferido e estocado no hepatopâncreas dos animais.The bioconcentration of cadmium and lead by the freshwater crab Trichodactylus fluviatilis was evaluated. Thirty animals were exposed to 200 mg L -1 of cadmium and lead for 7, 14 and 21 days. Both metals were determined in gills, hepatopancreas and muscle after dissection and digestion by inductively coupled plasma optical emission spectrometry. Lead was detected only in gills, but without significant difference among different exposure periods. Cadmium was found in all tissues after exposure. Significant differences among cadmium concentrations in animals exposed for different periods suggest an accumulation process, with concentration stabilized after 14 days. Fractionation of free (or labile) cadmium and cadmium protein (possibly metallothionein) (Cd-P) in gills and hepatopancreas were carried out to assess the cadmium transference and storage in the tissues using a solid phase extraction procedure with Saccharomyces cerevisae. Fractionation of free (or labile) cadmium and cadmium protein (possibly metallothionein) (Cd-P) in animals exposed to 200 mg L -1 for 21 days in gills and hepatopancreas were carried to assess the cadmium transference and storage in the tissues using a solid phase extraction procedure with Saccharomyces cerevisae. In gills, cadmium was found mainly in the free form, while in hepatopancreas the metal was found mainly bound to the protein (Cd-P). It may be inferred that, absorbed through gills, cadmium was transferred and stored in the hepatopancreas.

Interactions between metals accumulated in the narrow-clawed crayfishAstacus leptodactylus(Eschscholtz, 1823) in Dikilitaş Lake, Turkey

“…Franchi et al, for example, reported that Cd occurs in free form in the gills and is sequestered (likely with metallothioneins) in the hepatopancreas, suggesting that the free Cd in the gills is later deposited in other tissues. [10] Likewise, Bjerregaard has demonstrated that Cd present in the hepatopancreas is transported there by haemolymph from the gills. result of their direct exposure to the surrounding environment, the gills of crustaceans also tend to accumulate high concentrations of certain metals, such as Cd [12] and Pb.…”