title: The exposure data landscape for manufactured chemicals.
abstract: The U.S. Environmental Protection Agency is developing chemical screening and prioritization programs to evaluate environmental chemicals for potential risk to human health in a rapid and efficient manner. As part of these efforts, it is important to catalog available information on chemical toxicity and exposure from widely dispersed sources. The main objective of this analysis is to define important aspects of the exposure space and to catalog the available exposure information for chemicals being considered for analysis as part of the U.S. EPA ToxCast™ screening and prioritization program. Publicly available exposure data have been extracted into ACToR (Aggregated Computational Toxicology Resource), which combines information for hundreds of thousands of chemicals from >600 public sources. We use data from ACToR to assess the exposure data landscape for environmental chemicals. Of the roughly 100,000 chemicals that have at least limited toxicity information available, less than one-fifth also have exposure information - and for most of these the information is of limited utility (e.g., production volume). Readily accessible data on concentrations in exposure-related media are only available for a much smaller fraction. Among these, the largest number of chemicals is measured in water with over 1150 unique compounds, followed by 788 substances measured in soil, and 670 in air. These small numbers clearly reflect a focus of resources on those substances previously identified as possibly posing a hazard to human health. Exposure to a much broader number of chemicals will need to be measured in order to fully realize the envisioned goal of using exposure information to guide toxicity testing.
authors: National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States. egeghy.peter@epa.gov
authors: Peter P
authors: PP
authors: Egeghy
authors: Richard
authors: R
authors: Judson
authors: Sumit
authors: S
authors: Gangwal
authors: Shad
authors: S
authors: Mosher
authors: Doris
authors: D
authors: Smith
authors: James
authors: J
authors: Vail
authors: Elaine A
authors: EA
authors: Cohen Hubal
mesh_terms: D016208:Databases, Factual; D004781:Environmental Exposure / Q000032:analysis*; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D015386:Hazardous Substances / Q000032:analysis / Q000633:toxicity*; D006801:Humans; D007256:Information Systems; D016014:Linear Models; D012044:Regression Analysis; D018570:Risk Assessment / Q000379:methods*; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D004785:Environmental Pollutants; D015386:Hazardous Substances