Modeling the toxicokinetics of multiple metals in oyster Crassostrea hongkongensis in dynamic estuarine environment.

Metal contamination is a major problem in many estuaries. Toxicokinetic models are the useful tools for predicting metal accumulation in estuarine organisms and managing the associated ecological risks. However, obtaining toxicokinetic parameter values with sufficient predictive power is challenging for the dynamic estuarine waters. In this study, we determined the toxicokinetics of multiple metals in the oyster Crassostrea hongkongensis in a dynamic estuary polluted by metals using a 48-day transplant experiment. During the experiment, metal concentrations in oysters, water and suspended particles were intensively monitored at 3 d intervals. The toxicokinetic parameters were then estimated using the Markov chain Monte Carlo (MCMC) method. The calibrated model could well simulate the time-course of metal bioaccumulation in oysters and was further validated by predicting the bioaccumulation at another site in the estuary. Furthermore, the model was used to assess the relative importance of different pathways in metal bioaccumulation. With the MCMC method, distributions instead of single values were assigned to model parameters. This method makes the model predictions probabilistic with clearly defined uncertainties, and are thus particularly useful for the risk assessments of metals in aquatic systems.