Bioaccumulation of Dissolved Arsenic in the Oyster Crassostrea virginica: A Radiotracer Study

摘要

In the framework of a program focusing on marine resource protection and management in the Caribbean, the objective of this work was to characterize As bioaccumulation in the common edible oyster Crassostrea virginica. Dissolved As (stable As + 73As as a tracer) was taken up according to saturation kinetics for all tested exposure concentrations (2-10 g l-1), and steady-state was reached rapidly within 1 week. A slight decrease in uptake efficiency was observed for the higher concentration tested. Whole-body depuration kinetics showed that 73As was lost according to double exponential depuration kinetics that were characterized by short-lived biological half-lives (Tb1/2s) of 0.5-0.9 d and by long-lived Tb1/2l of 8-16 d. No significant difference in 73As retention was found among different initial exposure concentrations of As. Overall, our results indicate that C. virginica bioaccumulates As proportionally to the ambient dissolved As concentration, and retains it with similar efficiency regardless of the initial exposure level. Therefore C. virginica could be used as a reliable bioindicator species to monitor ambient levels of dissolved As contamination as well as to reveal short-term variations in As levels in seawater.