Development, validation and application of a time-dependent food web bioaccumulation model for organic pesticides in aquatic ecosystems

Currently, steady-state based bioaccumulation models are used by regulators to assist environmental guideline development and to conduct legislation of pesticides. For high Kow chemicals that do not reach steady-state in environmental compartments quickly, the steady-state based models could overestimate chemical concentrations and lead to errors in environmental evaluation. A time-dependent food web bioaccumulation model was developed to improve the evaluation of the fate and effects of pesticides in aquatic environments. The performance of the model was evaluated by simulating a Bluegill bioconcentration study for metaflumizone and microcosm studies for three pesticides, metaflumizone, kresoxim-methyl and pyraclostrobin. The model predictions were compared with the empirical data to determine the accuracy of model predictions. Model predictions for these three pesticides are in good agreement with the empirical data. The model can be applied to ecological risk assessment to provide exposure concentrations, internal body burden and remediation target for the impacted aquatic ecosystems.