Session 3: Exposure Modeling Overview

Exposure Space: Integrating Exposure Data and Modeling with Toxicity Information

Daniel A. Vallero


U.S. Environmental Protection Agency


Recent advances have been made in high-throughput (HTP) toxicity testing, e.g. from ToxCast, which will ultimately be combined with HTP predictions of exposure potential to support next-generation chemical safety assessment.

Rapid exposure methods are essential in selecting chemicals for

1) targeted toxicity testing,
2) higher-tier exposure assessments, and
3) biomonitoring studies.

Unfortunately, for the majority of chemicals in Phase II of ToxCast and beyond (i.e., non-pesticide environmental compounds) there are no available estimates of exposure.

Therefore, the U.S. EPA is developing scientifically-defensible HTP methods for developing quantitative or semi-quantitative exposure predictions, analogous to HTP toxicity methods.

This session will discuss advances in exposure modeling and informatics, including SHEDS-HT, ExPriori (dose ranking), computational exposure sciences (including chemical and exposure space principal components), and new product-use data sources.