Trace metal bioaccumulation in oysters (Crassostrea gigas) from Liaodong Bay (Bohai Sea, China)

Cd, Cr, Cu, Pb, and Zn concentrations were measured in oysters (C. gigas), plankton, and seawater during spring, summer, and autumn in Liaodong Bay (Bohai Sea, China) to elucidate the effects of season, region, and oyster size on metal bioaccumulation in oysters. Metal concentrations were quantified via atomic absorption spectrophotometry. Our study determined that metal concentrations in oysters, plankton, and seawater were the highest in summer, whereas the lowest levels occurred in autumn. Regarding oyster sizes, the highest Pb levels occurred in C3-sized oysters (> 5-cm length), whereas the highest Cd, Cr, Cu, and Zn levels occurred in C2 (3-5-cm length) oysters. In contrast, the lowest Cu and Pb levels occurred in C1 (< 3-cm length) oysters, whereas the lowest mean Cd, Cr, and Zn concentrations were observed in C3 oysters. Significant differences in trace metal concentrations in the three sample types were observed in all sampling sites.