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Environmental Release and Occupation Exposure Models Used in Chemical Risk Evaluation
Citation:
Barrett, William M., Ray Smith, D. Meyer, S. Takkellapati, AND Michael A. Gonzalez. Environmental Release and Occupation Exposure Models Used in Chemical Risk Evaluation. American Institute of Chemical Engineers Annual Meeting, Phoenix, AZ, November 13 - 18, 2022.
Impact/Purpose:
This product is a critical review of the Office of Pollution Prevention and Toxics' existing generic scenario library that will be used to define the scope and approach for subsequent research products in this output. Generic Exposure Scenarios are developed and used by the Office of Pollution Prevention and Toxics to address data gaps in chemical assessments performed under the Toxic Substances Control Act program. Research supporting the product evaluates the potential to model and apply generic scenarios within a high-throughput context to increase the chemicals covered by the models. Initially, the library of existing generic scenario documents will be reviewed to understand the approaches/methods, data needs, data sources, and uncertainty associated with the various scenarios. The review will focus on the identification of core elements of a generic scenario, provide an overview of methods used to model these elements, enumerate data needs and sources applied in scenarios, outline how these data can be quickly obtained by users, and assess the extent of potential uncertainties when applying the scenarios to chemical assessments. A second effort of this research will compare the potential use of high-throughput occupational exposure modeling approaches being developed in Output 2 of the Rapid Exposure Modeling and Dosimetry research area with typical approaches applied during generic scenario modeling. The comparison will consider how the new methods will impact data needs, release and transport mechanisms, and uncertainty when compared to existing models. Specifically, this product will identify potential limitations or trade-offs for the occupational component of a generic scenario if implemented within a high-throughput context.
Description:
Under the Toxic Substances Control Act (TSCA), the US Environmental Protection Agency (US EPA) is required to determine whether a chemical substance poses an unreasonable risk before the chemical is manufactured in or imported into the United States. This presentation will provide an overview of the environmental release and occupational exposure models used by the US Environmental Protection Agency (USEPA) to conduct chemical risk evaluations under the Toxic Substances Control Act (TSCA). Additionally, this presentation will provide an overview of methods used to model occupational exposures and environmental releases as part of the chemical risk evaluation process used in other jurisdictions, along with work being performed to improve these models. Finally, the alternative methods to evaluate occupational exposures and environmental releases that may be used as part of the decision-making process regarding a chemical are identified. The contribution provides a path forward for reducing the time required and improving the chemical evaluation of the unreasonable risk determination regarding the manufacture or import of a chemical.