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Modeling Human Exposures and Dose Using a 2-Dimensional Monte-Carlo Model (Sheds)

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Abstract: Since 1998, US EPA's National Exposure Research Laboratory (NERL) has been developing the Stochastic Human Exposure and Dose Simulation (SHEDS) model for various classes of pollutants. SHEDS is a physically-based probabilistic model intended for improving estimates of human exposure and dose to multimedia, multipathway pollutants and incorporates a two-dimensional Monte-Carlo simulation methodology implemented using SAS software. The two dimensional Monte-Carlo feature of the model is used to characterize population distributions of exposure and dose by explicitly quantifying the variability and the uncertainty in model inputs, parameters, and outputs. In particular, SHEDS-Pesticides combines human activity data (from national time/activity diary surveys and videography studies) with pesticide residue and concentration measurements in media contacted, exposure factors, and pharmacokinetic rate constants. Incurred exposure and dose are predicted for user-specified cohorts via eating contaminated foods or drinking water, inhaling contaminated air, touching contaminated surface residues, and ingesting residues from hand- or object-to-mouth activities. SHEDS-PM (i.e., particulate matter and its associated constituents) and SHEDS-ATOX (i.e., air toxics) use the same modeling approach as the SHEDS-Pesticides model, however the primary focus is on inhalation exposure and dose. The SHEDS model is designed to investigate the intensity, duration, frequency, route, and timing of exposures; to identify critical exposure factors and how to effectively reduce exposures; and to verify estimates with available biomarkers.

This work has been wholly funded by the United States Environmental Protection. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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Citation:Ozkaynak, A. H., J. Xue, V. Zartarian, J. M. Burke, and S. E. Graham. Modeling Human Exposures and Dose Using a 2-Dimensional Monte-Carlo Model (Sheds). Presented at Society for Risk Analysis, Baltimore, MD, December 7-10, 2003.
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Contact: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov
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Division: Human Exposure & Atmospheric Sciences Division
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Branch: Immediate Office
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Product Type: Abstrct/Oral
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Presented: 12/08/2003
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Related Entries:
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Bullet Item Next Generation Multimedia/Multipathway Exposure Modeling
spacer Relationship Reason:   A Project of the Product
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