Validation of biokinetic model of metals in the scallop Chlamys nobilis in complex field environments.

A transplantation experiment, using the scallop Chlamys nobilis as the model organism, was carried out to investigate variations in their bioaccumulation of Cd and Zn in different environmental conditions. The diffusive gradients in the thin films technique was employed to monitor in situ dissolved labile metal concentrations. The impact of food quality on assimilation efficiency and ingestion rate also was investigated in the laboratory. The results were combined in a biokinetic model explaining the metal concentrations accumulated in the scallops. The results confirm that scallops accumulate metals differently in different marine environments with comparable ambient metal concentrations. Food quality not only influences their assimilation of metals but also their clearance rates. The ingestion rate together with the growth rate was shown to have an effect on the bioaccumulation of metals. Bioaccumulation is dependent on both the ingestion rate (when food is the dominant metal uptake pathway) and the proportion of metal taken up from the water. Environmental conditions such as food availability and hydrology must be simultaneously considered in any attempt to study metal bioaccumulation in marine bivalves.