Effects of cadmium and copper contamination on calcium content of the bivalve Ruditapes decussatus

Heavy metals, such as Cu, Cd and Hg are known to disturb Ca homeostasis in marine invertebrates. Accumulation of Cu and Cd was studied in the clam Ruditapes decussatus. Animals were exposed to Cu (30 and 150 μg/ litre) or Cd (200 and 500 μg/litre). Metal concentrations were measured in the gills, visceral masses and remainders. Exposure to Cd increased Cd concentrations in all organs studied. In Cu experiments, a significant increase in Cu and Ca concentrations was noted in the organs studied. This increase in Ca may be induced by the action of copper. Such an increase was not observed in Cd-treated animals. Following a detoxication period of 8 days, the body content of Cu decreased strongly (ca 50% after 3 days), whereas that of Cd remained unchanged, suggesting that Cd is more firmly bound than Cu in R. decussatus.