Physiologically based pharmacokinetic (PBPK) tool kit for environmental pollutants--metals

The Agency for Toxic Substances and Disease Registry (ATSDR) is mandated by the US Congress to identify significant human exposure levels, develop methods to determine such exposures, and design strategies to mitigate them. Physiologically based pharmacokinetic (PBPK) models are increasingly being used to evaluate toxicity of environmental pollutants through multiple exposure pathways. As part of its translational research project, ATSDR is developing a human 'PBPK model tool kit' that consists of a series of published models re-coded in a common simulation language. The tool kit currently consists of models, at various stages of development, for priority environmental contaminants including solvents and persistent organic pollutants. Presented here are results of translational activities of re-coding models for cadmium, mercury, and arsenic. As part of this work, following re-coding each new model was evaluated for fidelity followed by sensitivity analysis. Good agreement was generally obtained for all three models when predictions of original and re-coded model simulations were compared. Also presented is an application of the cadmium toxicokinetic model to interpret biomonitoring data from the National Health and Nutrition Examination Survey (NHANES). The PBPK tool kit will enable ATSDR scientists to perform simulations of exposures from contaminated environmental media at sites of concern and to better interpret site-specific biomonitoring data.