Aqueous film-forming foam (AFFF) was developed to rapidly extinguish and suppress hydrocarbon fuel fires. Perfluorochemicals (PFCs) were used to manufacture AFFFs through 2001. However, the characteristics that make PFCs effective petroleum fire extinguishers and suppressors also make them extremely stable in the environment where they can be found contaminating soil, sediments, water, and biota. The two most abundant PFCs in the environment and biota are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) (Pan et al., 2014; Route et al., 2014). The objective of this work is to provide focused toxicity information for PFOA and PFOS, and upon recommendation from the Scientific Advisory Board, similar toxicity information for two other PFCs: perfluorobutane sulfonate (PFBS) and perfluorohexane sulfonate (PFHxS), which also are often associated with AFFFs. This information will a) allow for more accurate benchmark derivation consistent with existing regulatory guidance and frameworks and b) allow for optimal operational flexibility at ranges while ensuring environmental health. Information from this project will be used to generate defensible wildlife toxicity reference values (TRVs) for use in ecological risk assessment programs. This information will be transferred to environmental risk assessors and regulators through publications of Wildlife Toxicity Assessments (WTAs; publicly available via the web, Army reports, and text books) and peer-reviewed journal articles and presentations made at Department of Defense (DoD) meetings and international conferences.

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Controlled toxicity tests designed to fill class-specific data gaps for the two PFCs found most often found in sediment, water, and biota – PFOA and PFOS – and two other PFCs often associated with AFFFs – PFBS and PFHxS – will be used to generate defensible wildlife TRVs. Mammalian studies will use a wild rodent species, the white-footed mouse (Peromyscus leucopus) to help eliminate possible discrepancies from data collected in laboratory rodents as has been demonstrated elsewhere (reviewed in Lau et al., 2007). The data from these toxicity tests will be used to derive TRVs by employing the hierarchy described in the Technical Guide 254 (USACHPPM, 2000) with every effort to develop benchmark dose derivations, as this method allows risk assessors to more accurately and quantitatively determine thresholds of response.

Results from these studies will provide benchmarks to develop defensible TRVs for mammalian wildlife. The strong body of toxicology data derived from the studies will help reduce the use and magnitude of uncertainty factors used to develop environmental remediation criteria. TRVs are critical components of environmental risk assessments that help determine if the risk of exposure is acceptable. These values will directly assist in sustaining range and cleanup operations and lend support to Army Health System capabilities. The TRVs, along with the data collected from these studies, will be documented in substance-specific WTAs which are used by the Defense Environmental Restoration Program and the Army and published on the Army Public Health Center (PHC) website and in peer reviewed journals and text book chapters used by DoD contractors. (Anticipated Project Completion - 2020)

Narizzano, A. M., M. E. Bohannon, A. G. East, C. McDonough, S. Choyke, C. P. Higgins, and M. J. Quinn. 2021. Patterns in Serum Toxicokinetics in Peromyscus Exposed to Per- and Polyfluoroalkyl Substances. Environmental Toxicology and Chemistry, 40(10):2886-2898.