Assessing multimedia/multipathway exposures of young children to multiple pollutants using a mechanistic source-to-dose modeling framework
Y.C. Yang, S.W. Wang, P.G. Georgopoulos
Environmental and Occupational Health Sciences Institute, UMDNJ - R.W. Johnson Medical School and Rutgers University
This study presents an assessment of simultaneous multimedia/multipathway exposures of children 0-6 years old to arsenic, chlorpyrifos and trichloroethylene (TCE), employing the Modeling Environment for Total Risk (MENTOR) system and field measurements: the National Human Exposure Assessment Survey (NHEXAS) [Region V and Arizona/Minnesota], and the Children’s Post Pesticide Application Exposure Study (CPPAES). Child-specific physiological attributes and exposure factors, i.e. higher inhalation rates, higher water intake rates, mouthing behavior, etc., were incorporated in this study.
MENTOR employs a mechanistically consistent framework for conducting population exposure assessments for multiple pollutants considering five exposure routes: inhalation, food intake, drinking water consumption, non-dietary ingestion, and dermal absorption. Simulations consist of: (1) Characterization of multimedia background levels of contaminants through a combination of environmental model predictions and measurement studies; (2) Characterization of multimedia levels and temporal profiles of contaminants in residential microenvironments using an extension of the SHEDS (Stochastic Human Exposure and Dose Simulation) modeling methodology; (3) Development of activity event sequences for each member of the sample population by matching attributes to entries of USEPA’s Consolidated Human Activity Database (CHAD); (4) Development of dietary, water usage profiles for each member of the sample population by matching attributes to entries of USDA’s Continuing Survey of Food Intakes by Individuals (CSFII); (5) Calculation of intake rates for the members of the sample population, reflecting/combining physiological attributes and activities pursued; (6) Combination of intake rates from multiple routes to assess exposures; (7) Estimation of target tissue doses (e.g., kidney, liver) with physiologically based toxicokinetic (PBTK) modeling.
This work had been funded in part by the US Environmental Protection Agency under Cooperative Agreement # EPAR-827033 to the Environmental and Occupational Health Sciences Institute (EOHSI). The viewpoints expressed here are the responsibility of the authors and do not necessarily reflect the views of the USEPA or its contractors.