A Chemical Category-Based Prioritization Approach for Selecting 75 Per- and Polyfluoroalkyl Substances (PFAS) for Tiered Toxicity and Toxicokinetic Testing

Grace Patlewicz, Ann M. Richard, Antony J. Williams, Christopher M. Grulke, Reeder Sams, Jason Lambert, Pamela D. Noyes, Michael J. DeVito, Ronald N. Hines, Mark Strynar, Annette Guiseppi-Elie, Russell S. Thomas
  • Environmental Health Perspectives, January 2019, Environmental Health Perspectives
  • DOI: 10.1289/ehp4555

Construction of a per- and polyfluoroalkyl substances (PFAS) screening library

What is it about?

Per- and polyfluoroalkyl substances (PFASs) are a group of fluorinated substances of interest to researchers, regulators, and the public due to their widespread presence in the environment. A few PFASs have comparatively extensive amounts of human epidemiological, exposure, and experimental animal toxicity data (e.g., perfluorooctanoic acid), whereas little toxicity and exposure information exists for much of the broader set of PFASs. Given that traditional approaches to generate toxicity information are resource intensive, new approach methods, including in vitro high-throughput toxicity (HTT) testing, are being employed to inform PFAS hazard characterization and further (in vivo) testing. The U.S. Environmental Protection Agency (EPA) and the National Toxicology Program (NTP) are collaborating to develop a risk-based approach for conducting PFAS toxicity testing to facilitate PFAS human health assessments. This article describes the construction of a PFAS screening library and the process by which a targeted subset of 75 PFASs were selected. Multiple factors were considered, including interest to the U.S. EPA, compounds within targeted categories, structural diversity, exposure considerations, procurability and testability, and availability of existing toxicity data.

Why is it important?

The article describes the construction of a PFAS screening library that will be used for high-throughput screening assay measurements to generate bioactivity data. It explains the process by which a targeted subset of 75 PFASs were selected from the large collection of PFAS chemicals registered on the CompTox Chemicals Dashboard at https://comptox.epa.gov/dashboard.


Dr Antony John Williams
United States Environmental Protection Agency

The article demonstrates the benefits and outcomes of doing the hard work of assembling curated lists of chemicals onto the CompTox Chemicals Dashboard and how the availability of data can greatly help the selection process of chemicals that can be screened in high-throughput screening bioactivity assays.

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The following have contributed to this page: Dr Antony John Williams and Ronald N. Hines