Advancing Exposure Models to Capture a Broad Continuum of Exposure Scenarios

Deborah H. Bennett1, Thomas E. McKone2, Xiangmei (May) Wu1, Hyeong-Moo Shin11University of California at Davis, 2University of California at Berkeley.

The overall objective of this project is to develop and evaluate a modeling framework capable of calculating exposures over a continuum of spatial/temporal scales resulting from a broad range of emission types and product uses. To achieve this we are producing a model that is comprehensive, transparent, and can be run quickly for thousands of chemicals. We will integrate the Bennett Indoor Fugacity Model with a nested CalTOX model, allowing users to determine exposures and intake fractions resulting from emissions at different levels of organization (indoor, urban, regional, global). We will allocate annual production levels to the various modes of entry, specifically, direct product use, indoor emissions and inventories, and ambient emissions at different spatial scales. In the first year we are
1) modifying the Indoor Fugacity Model to include human exposures to fully address SVOCs,
2) developing a nested version of CalTOX to include urban, regional, and global scales, and
3) integrating the two models into a common framework. 

In the second year, further developments will include the ability to 1) have emissions from a variety of indoor scenarios, 2) allow for tracking of secondary reaction products resulting from indoor chemistry, 3) allow for use of molecular structures to predict model inputs using quantitative structure-activity relationship (QSAR) principles, 4) include direct exposures from consumer products, 5) include an extended range of indoor environments, and 6) advance the framework to be fully dynamic at all scales. Case studies will compare model results with a variety of available measured exposure data to refine the model. 

Implications 

The new molecular biology technologies are in wide use for rapid screening of chemical toxicity as well as for prioritization of those compounds that will require additional toxicity testing. The objective of a parallel effort, the US EPA ExpoCastTM program, is to ensure that the relevant exposure science, data, and tools are available to integrate information about the potential for exposures into chemical prioritization initiatives. The current project is designed to develop a modeling framework that can quickly provide exposure information across a broad range of exposure scenarios, both indoors and outdoors, and for consumer product uses. This model framework will provide a fully dynamic tool for rapid exposure evaluation and prioritization.

Keywords

exposure, environmental health, exposure modeling, exposure screening tools

Project Start and End Dates

2010 - 2012

Project ID

MTH1001-02

Peer-reviewed Publication(s)

None to date.

Other Publication(s)

None to date.

Abstract Creation Date

July 2011

*This abstract was prepared by the principal investigator for the project.

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