Per- and polyfluoroalkyl substances (PFAS) are a large group of anthropogenic chemicals that include the well-known C8 species, perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and thousands of other structurally diverse fluorinated species. The universe of environmentally relevant PFAS, including parent chemicals, metabolites, and abiotic degradants, includes more than 12,000 substances.²

PFAS have strong, stable carbon-fluorine (C-F) bonds, making them resistant to hydrolysis, photolysis, microbial degradation, and metabolism (Ahrens, 2011; Buck et al., 2011; Beach et al., 2006). The chemical structures of PFAS make them repel water and oil, remain chemically and thermally stable, and exhibit surfactant properties. These properties make PFAS useful for commercial and industrial applications and purposes but also make some PFAS persistent in the human body and the environment (Calafat et al., 2019; Calafat et al., 2007). Due to their widespread use, physicochemical properties, persistence, mobility, and bioaccumulation potential, many PFAS occur in exposure media (e.g., air, water, ice, sediment) and in tissues and blood of aquatic and terrestrial organisms and humans.

Humans are widely exposed to PFAS (Sunderland et al., 2019), and PFAS have been shown to pose ecological and human health hazards (Fenton et al., 2021; U.S. EPA, 2021c, d; DeWitt, 2015; Hekster et al., 2003). The available toxicity data, however, are limited to relatively few, well-studied PFAS (e.g., PFOA, PFOS, GenX chemicals, PFBS and others). Most of the PFAS structures listed in EPA’s CompTox Chemicals Dashboard¹ are data poor, having little to no toxicity data that might inform potential hazards to human health. One of these PFAS, PFPrA (CASRN 422-64-0), has been detected in surface and ground waters in or around manufacturing facilities. PFPrA, and its related salts, are all members of the overall PFAS class. This assessment applies to the desalted acid form of PFPrA as well as salts (including non-metal or alkali metal salts) of PFPrA that would be expected to fully dissociate in aqueous solutions of pH ranging from 4-9 (e.g., in the human body). The synthesis of evidence and toxicity value derivation presented in this assessment focuses on the forms of PFPrA with currently available toxicity data. PFPrA is a short-chain, three-carbon perfluoroalkyl carboxylic acid and is a clear and colorless liquid. The molecular formula and experimental or predicted physicochemical properties of PFPrA are presented in Table 1.

Table 1

Physical and Chemical Properties of PFPrA.

Footnotes

2

https://comptox​.epa.gov​/dashboard/chemical_lists/PFASMASTER.