By Lynn L. Bergeson and Carla N. Hutton
 
The U.S. Environmental Protection Agency (EPA) will hold a webinar on October 27, 2022, in its Computational Toxicology and Exposure Communities of Practice (CompTox Communities of Practice) series on “Analysis of High-Throughput Profiling Assays in Chemical Safety Screening.” The abstract for the webinar states that recent technological advancements have led to the development of new high-throughput profiling methods, such as transcriptomics, that can be used to screen rapidly chemicals for potential hazards. Decreasing costs have made it feasible to profile all protein-coding genes across thousands of samples, allowing for broad evaluation of many target pathways and modes of action in a single screening assay. Similarly, it is now possible to apply high-content imaging across many different chemical exposures to capture a variety of changes in cell morphology. According to the abstract, such methods have been applied to in vitro chemical screening studies, including screening studies at EPA that were recently released on the CompTox Chemicals Dashboard. These types of data can be used for both hazard prediction and potency estimation, thereby informing risk assessments and prioritizing chemicals for further testing.
 
The abstract notes that assessing the reliability and reproducibility of these screening platforms is critical to their utility in regulatory applications. While these platforms often have lower signal-to-noise ratios compared to individual targeted assays, the resulting data are also high-dimensional, allowing for the analysis of consistent trends across many molecular endpoints. The webinar will provide an overview of computational methods and best practices for reliable analysis of high-throughput profiling data in a variety of use cases and will highlight the recent data release on the CompTox Chemicals Dashboard. Registration is open.

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By Lynn L. Bergeson and Carla N. Hutton
 
On March 15-17, 2022, the U.S. Environmental Protection Agency (EPA) held a meeting of the Science Advisory Committee on Chemicals (SACC) to peer review EPA’s “Draft TSCA Screening Level Approach for Assessing Ambient Air and Water Exposures to Fenceline Communities Version 1.0” (screening methodology). As reported in our January 24, 2022, memorandum, EPA will use the screening methodology to evaluate potential chemical exposures and associated potential risks to fenceline communities in its Toxic Substances Control Act (TSCA) risk evaluations. EPA presented its screening methodology, as well as the results of applying the screening methodology to 1-brompropane (air pathway), n-methylpyrrolidone (water pathway), and methylene chloride (air and water pathway). EPA will use the scientific advice, information, and recommendations from SACC, as well as public comments, to inform the final protocol. EPA has posted the following materials:

• Biographical sketches of selected ad hoc reviewers;
• The draft screening methodology and supporting documents;
• Agenda and roster for the meeting;
• Meeting transcript;
• Recording of the March 15, 2022, meeting;
• Recording of the March 16, 2022, meeting; and
• Recording of the March 17, 2022, meeting.

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