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Exposure Modeling Tools and Databases for Consideration for Relevance to the Amended TSCA (ISES)
Citation:
Isaacs, K., J. Wambaugh, P. Price, J. Bare, K. Dionisio, K. Phillips, Woodrow Setzer, Craig Barber, B. Wetmore, R. Tornero-Velez, J. Orme-Zavaleta, R. Thomas, E. Wong, AND C. Fehrenbacher. Exposure Modeling Tools and Databases for Consideration for Relevance to the Amended TSCA (ISES). 2017 International Society of Exposure Science, RTP, NC, October 15 - 19, 2017.
Impact/Purpose:
This talk describes current and emerging ORD exposure modeling tools and databases that may be useful in supporting the amended TSCA. This abstract is submitted as part of the OPPT Symposium "Challenges and Opportunities: Assessing Exposures to Chemical Substances under Amended TSCA- Methods, Models, and Data."
Description:
The Agency’s Office of Research and Development (ORD) has a number of ongoing exposure modeling tools and databases. These efforts are anticipated to be useful in supporting ongoing implementation of the amended Toxic Substances Control Act (TSCA). Under ORD’s Chemical Safety for Sustainability Research Program, new databases of how chemicals are used in commerce (e.g., in products or industrial processes) have been collated from dozens of public resources. These use data have enabled the development and application of high-throughput (HT) pathway-specific exposure models (e.g. the HT Stochastic Human Exposure and Dose model) and calibrated consensus exposure predictions for thousands of chemicals evaluated with biomonitoring data. These tools allow identification of the potential route of chemical exposure for certain conditions of use. A newer effort, the Human Exposure Model, incorporates new information on population variability (e.g., demographics, product use, geography, housing) that impacts exposures, and thus may be applicable to the identification of potentially exposed or susceptible subpopulations. To provide context to these predictions, new HT methods are being developed for converting external exposures to internal tissue doses, including methods that incorporate physiologic and lifestage variability. Finally, human-oriented exposure models also provide chemical release input to new ecological exposure models, which are being evaluated with public water monitoring data. While the amended TSCA provides an opportunity for ORD exposure modeling tools and databases to support amended TSCA, prior to any implementation the fitness-for-purpose of these projects (e.g., for prioritization, scoping, or risk evaluation) must be evaluated in the context of TSCA requirements. The views expressed here are those of the authors and do not necessarily reflect the views or policies of the U. S. EPA.
