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1J - Bioaccumulation (WE9/2) Development of a Physiologically-Based Pharmacokinetic (PBPK) Model of Metal Bioaccumulation by Bivalves. Damiani, Darin1, Farley, Kevin1, 2, Santore, Robert3, Di Toro, Dominic1, 4, 1 HydroQual Inc., Mahwah, NY, USA2 Manhattan College, Dept. of Environmental Engineering, Bronx, NY, USA3 HydroQual Inc., Camillus, NY, USA4 University of Delaware, Newark, DE, USA ABSTRACT- A physiologically-based pharmacokinetic model is being developed for use in studying metal accumulation by bivalves and resulting effects. An important long-term goal of this effort is that the model is suitable for use in predicting effects due to metals that result from the combination of waterborne and dietary routes of exposure. This multi-compartment model considers metal uptake from both food and water. The metal is transferred from the water, to the hemolymph, via exchange across the gill and mantle, or from the food, to the hemolymph, via the digestive gland. Once in the hemolymph the metal is distributed to other organs including the kidney, gill, mantle, gonad, adductor muscle and digestive gland. Accumulation occurs via partitioning between the hemolymph and the tissues of these individual organs. Losses of metal from the organism occur via diffusion from the gill and the mantle, and via renal and fecal losses. The model can be used to simulate metal accumulation and depuration under both steady state and time variable exposure conditions. While originally developed for copper, the general framework should be adaptable for use with other metals as well. The current status of model development efforts, will be reviewed, including the model structure, formulation, and initial applications of the model in the analysis of both field and laboratory data. The future direction of model development efforts and how it is envisioned for use in relating exposure to effects will also be discussed. Key words: bioavailability, metal, PBPK model, bivalve |
