Temporal and spatial variation on heavy metal concentrations in the oyster Ostrea equestris on the northern coast of Rio De Janeiro State, Brazil.

Heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) concentrations were determined by ICP-AES in Ostrea equestris from three beaches (Barra do Furado, Buena, and Ponta do Retiro) on the northern coast of Rio de Janeiro State. The average concentration was 0.8 +/- 0.18, 0.4 +/- 0.21, 58 +/- 25.6, 249 +/- 52.3, 11 +/- 1.31, 0.55 +/- 0.16, 0.13 +/- 0.11, and 1131 +/- 321 microg x g(-1) dry weight for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn respectively. Significant spatial variation (p < 0.05) between the samples areas occurred for Cr, Pb, and Zn with higher values in Barra do Furado; and for Cu in Ponta do Retiro. Significant temporal variations (p < 0.05) were observed for all metals except Cu. Temporal variability may be related to changes in the inputs of metals associated with suspended particles. Concentrations were similar to those found in areas under low pollution impact, except for Zn, the high concentrations of which probably reflect the physiological characteristics of these organisms.

Temporal and spatial variation on heavy metal concentrations in the oyster Ostrea equestris on the northern coast of Rio de Janeiro State, Brazil

Foram determinadas as concentrações de metais pesados (Cd, Cr, Cu, Fe, Mn, Ni, Pb e Zn) na ostra Ostrea equestris em três praias (Barra do Furado, Buena e Ponta do Retiro) da costa norte do Estado do Rio de Janeiro utilizando-se ICP-AES. As concentrações médias foram 0,8 ± 0,18; 0,4 ± 0,21; 58 ± 25,6; 249 ± 52,3; 11 ± 1,31; 0,55 ± 0,16; 0,13 ± 0,11; e 1131 ± 321 µg.g-1 de peso seco para Cd, Cr, Cu, Fe, Mn, Ni, Pb e Zn, respectivamente. Entre as áreas amostradas, houve variação espacial significativa (p < 0,05) das concentrações de Cr, Pb e Zn com maiores valores na Barra do Furado, e de Cu apenas em Ponta do Retiro. Foi observada variação temporal significativa (p < 0,05) para todos os metais, exceto Cu. Essa variabilidade provavelmente está associada a entradas de metais associados ao material particulado em suspensão. Os bivalves apresentaram concentrações similares àquelas encontradas em áreas com baixo impacto de contaminação por metais, exceto para Zn, cujo acúmulo provavelmente está associado às características fisiológicas desses organismos.

Mercury content in shark species from the South-Eastern Brazilian coast.

We present here the first results of Hg concentrations in three small shark species (Rhizoprionodon lalandei, R. porosus and Mustelus higmani) from the SE Brazilian coast. Mercury concentrations in R. lalandei ranged from 21.5 to 280.0 ng.g-1 dry weight (d.w.) (average 74.6 ng.g-1 d.w.; 17.9 ng.g-1 wet weight). In R. porosus, concentrations ranged from 7.6 to 90.5 ng.g-1 d.w. (average 42.2 ng.g-1 d.w., 9.4 ng.g-1 wet weight), whereas in M. higmani, concentrations ranged from 13.0 to 162.8 ng.g-1 d.w. (average 54.9 ng.g-1 d.w., 13.4 ng.g-1 wet weight). These concentration ranges are very low compared with values reported for other large shark species of the Southwestern Atlantic Ocean. There was a significant positive correlation between Hg concentrations and individual size, suggesting that biomagnification is occurring in these animals.