The toxicity data landscape for environmental chemicals.

Area of Science:

• Environmental Science
• Toxicology
• Computational Chemistry

Background:

• Thousands of chemicals lack sufficient toxicological evaluation, necessitating prioritization for testing.
• The U.S. Environmental Protection Agency (EPA) is developing programs for chemical screening and prioritization.
• Cataloging existing toxicology information is crucial for these efforts.

Purpose of the Study:

• To define a list of environmental chemicals for the U.S. EPA screening and prioritization process.
• To catalog the available toxicology information for these prioritized chemicals.

Main Methods:

• Development of the Aggregated Computational Toxicology Resource (ACToR) database.
• ACToR integrates data from over 200 public sources, including government agencies and academic institutions.
• Data includes chemical structures, properties, in vitro and in vivo assay results, and toxicology summaries.

Main Results:

• Analysis focused on 9,912 environmental chemicals identified for the U.S. EPA ToxCast program.
• These chemicals include high/medium production volume chemicals, pesticides, and drinking water contaminants.
• Toxicity data landscape assessment was performed using ACToR.

Conclusions:

• Approximately two-thirds of the analyzed chemicals have some form of toxicity summary available.
• About one-quarter have been evaluated in highly curated databases like the U.S. EPA's IRIS and the National Toxicology Program.
• This highlights the need for further toxicological evaluation and data integration.