The use of aqueous film-forming foam (AFFF) containing per- and polyfluoroalkyl substances (PFAS) at fire, crash, and training sites has contributed to the presence of PFAS in soil, water, and sediment. The overall objective of this effort was to develop amphibian toxicity reference values (TRVs) for four PFAS (perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), and 6:2 fluorotelomer sulfonate (6:2 FTS)). These data are needed to support cleanup and/or exposure mitigation decisions.

Studies were conducted following standard published toxicity test procedures for Northern Leopard Frogs (Lithobates pipiens), American Toads (Anaxyrus americanus), and Eastern Tiger Salamanders (Ambystoma tigrinum). Toxicity testing was conducted under steady state conditions, determined through range finding studies. Range findings studies also helped determined exposure levels for longer-form tests. Experiments were conducted using larvae and juveniles reared from egg masses collected from natural amphibian populations located in West Lafayette, Indiana. Although PFAS are expected to be very stable, multiple water and/or sediment samples were collected over time to assess potential breakdown.

The project team identified chronic No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) screening levels in water for perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulphonic acid (PFHxS), and 6:2 fluorotelomer sulfonic acid (6:2 FTS). Across the studies, the most sensitive, ecologically relevant endpoint with relatively clear dose-response relationships was decreased growth (body mass).

These screening levels can be used for site-specific risk assessments that focus on amphibian population level health. Information on bioaccumulation and biomagnification in amphibians is also presented in the Final Report, and can be used in food web modeling for evaluation of dietary risks.  (Project Completion - 2024)

Abercrombie, S.A., C. de Perre, Y.J. Choi, M. Iacchetta, R.W. Flynn, M.S. Sepúlveda, L.S. Lee, and J.T. Hoverman. 2020. Sublethal Effects of Dermal Exposure to Poly- and Perfluoroalkyl Substances on Post-Metamorphic Amphibians. Environmental Toxicology and Chemistry, 40(3):717-726. doi.org/10.1002/etc.4711.

Abercrombie, S.A., C. de Perre, Y.J. Choi, B.J. Tornabene, M.S. Sepúlveda, L.S. Lee, and J.T. Hoverman. 2019. Larval Amphibians Rapidly Bioaccumulate Poly- and Perfluoroalkyl Substances. Ecotoxicology and Environmental Safety, 178:137-145. doi.org/10.1016/j.ecoenv.2019.04.022.

Ankley, G.T., P. Cureton, R.A. Hoke, M. Houde, A. Kumar, J. Kurias, R. Lanno, C. McCarthy, J. Newsted, C.J. Salice, B.E. Sample, M.S. Sepulveda, J. Steevens, and S. Valsecchi. 2020. Assessing the Ecological Risks of Per- and Polyfluoroalkyl Substances: Current State-of-the Science and a Proposed Path Forward. Environmental Toxicology and Chemistry, 40(3):564-605. doi.org/10.1002/etc.4869.

Brown, S.R., R.W. Flynn, and J.T. Hoverman. 2020. Perfluoroalkyl Substances Increase Susceptibility of Northern Leopard Frog Tadpoles to Trematode Infection. Environmental Toxicology and Chemistry, 40:689-694. doi.org/10.1002/etc.4678.

Flynn, R.W., M.F. Chislock, M.E. Gannon, S.J. Bauer, B.J. Tornabene, J.T. Hoverman, and M.S. Sepúlveda. 2019. Acute and Chronic Effects of Perfluoroalkyl Substance Mixtures on Larval American Bullfrogs (Rana catesbeiana). Chemosphere, 236:124350. doi.org/10.1016/j.chemosphere.2019.124350.

Flynn, R.W., T.D. Hoskins, M. Iacchetta, C. Perre, L.S. Lee, J.T. Hoverman, and M.S. Sepúlveda. 2020. Dietary Exposure and Accumulation of Per- And Polyfluoroalkyl Substances Alters Growth and Reduces Body Condition of Post-Metamorphic Salamanders. Science of the Total Environment, 765:142730. doi.org/10.1016/j.scitotenv.2020.142730.

Flynn, R.W., M. Iacchetta, C. De Perre, L.S. Lee, M.S. Sepúlveda, and J.T. Hoverman. 2020. Chronic PFAS-Exposure Under Environmentally Relevant Conditions Delays Development in Northern Leopard Frog (Rana pipiens) Larvae. Environmental Toxicologyand Chemistry, 40(3):711-716. doi.org/10.1002/etc.4690.

Flynn, R.W., G. Hoover, M. Iacchetta, S. Guffey, C. de Perre, B. Huerta, W. Li, J.T. Hoverman, L. Lee, and M.S. Sepúlveda. 2022. Comparative Toxicity of Aquatic Per- and Polyfluoroalkyl Substance Exposure in Three Species of Amphibians. Environmental Toxicology and Chemistry, 41(6):1407-1415. doi.org/10.1002/etc.5319.

Foguth, R.M., R.W. Flynn, C. de Perre, M. Iacchetta, L.S. Lee, M.S. Sepúlveda, and J.R. Cannon. 2019. Developmental Exposure to Perfluorooctane Sulfononate (PFOS) And Perfluorooctanoic Acid (PFOA) Selectively Decreases Brain Dopamine Levels in Northern Leopard Frogs. Toxicology and Applied Pharmacology, 377:114623. doi.org/10.1016/j.taap.2019.114623.

Foguth, R., T.D. Hoskins, G.C. Clark, M. Nelson, R.W. Flynn, C. DePerre, J.T. Hoverman, L.S. Lee, M.S. Sepúlveda, and J. Cannon. 2020. Single and Mixture Per- And Polyfluoroalkyl Substances Accumulate in Developing Northern Leopard Frog Brains and Produce Complex Neurotransmission Alterations. Neurotoxicology and Teratology, 81:106907. doi.org/10.1016/j.ntt.2020.106907.

Foguth, R., M.S. Sepúlveda, and J. Cannon. 2020. Per- And Polyfluoroalkyl Substances (PFAS) Neurotoxicity in Sentinel and Nontraditional Laboratory Model Systems: Potential Utility in Predicting Adverse Outcomes in Human Health. Toxics, 8(2):42. doi.org/10.3390/toxics8020042.

Hoover, G.M., M.F. Chislock, B.J. Tornabene, S.C. Guffey, Y.J. Choi, C. De Perre, J.T. Hoverman, L.S. Lee, and M.S. Sepúlveda. 2017. Uptake and Depuration of Four Per/Polyfluoroalkyl Substances (PFASs) in Northern Leopard Frog Rana pipiens Tadpoles. Environmental Science and Technology Letters, 4:399-403. doi.org/10.1021/acs.estlett.7b00339.s001.

Hoover, G., S. Kar, S. Guffey, J. Leszczynski, and M.S. Sepúlveda. 2019. In Vitro and In Silico Modeling of Perfluoroalkyl Substances Mixture Toxicity in an Amphibian Fibroblast Cell Line. Chemosphere, 233:25-33. doi.org/10.1016/j.chemosphere.2019.05.065.

Hoskins, T.D., E.B. Allmon, R.W. Flynn, L.S. Lee, Y. Choi, J.T. Hoverman, and M.S. Sepúlveda. 2022. An Environmentally Relevant Mixture of Perfluorooctanesulfonic Acid and Perfluorohexanesulfonic Acid Does Not Conform to Additivity in Northern Leopard Frogs Exposed Through Metamorphosis. Environmental Toxicology and Chemistry, 41(12):3007-3016. doi.org/10.1002/etc.5486.

Lech, M.E., Y.J. Choi, L.S. Lee, M.S. Sepúlveda, and J.T. Hoverman. 2022. Effects of Per- and Polyfluoroalkyl Substance Mixtures on the Susceptibility of Larval American Bullfrogs to Parasites. Environmental Science and Technology, 56(22):15953-15959. doi.org/10.1021/acs.est.2c04574.

Pandelides, Z., J. Conder, Y. Choi, E. Allmon, T. Hoskins, L, Lee, J. Hoverman, and M. Sepúlveda. 2023. A Critical Review of Amphibian PFAS Ecotoxicity Research Studies: Identification of Screening Levels in Water and Other Useful Resources for Site‐Specific Ecological Risk Assessments. Environmental Toxicology and Chemistry, 42:2078-2090. doi.org/10.1002/etc.5695.

Tornabene, B., M. Chislock, M. Gannon, M.S. Sepúlveda, and J, Hoverman. 2021. Relative Acute Toxicity of Three Per- And Polyfluoroalkyl Substances on Nine Species of Larval Amphibians. Integrated Environmental Assessment and Management, 17(4):684-690. doi.org/10.1002/ieam.4391.

Wasel, O., K.M. Thompson, Y. Gao, A.E. Godfrey, J. Gao, C. Mahaptra, L.S. Lee, M.S. Sepúlveda, and J.L. Freeman. 2020. Comparison of Zebrafish In Vitro and In Vivo Developmental Toxicity Assessments of Perfluoroalkyl Acids (PFAAs). Journal of Toxicology and Environmental Health, Part A, 84(3):125-136. doi.org/10.1080/15287394.2020.1842272.

Theses and Dissertations

Abercrombie, S.A. 2017. The Uptake and Effects of Poly- and Perfluoroalkyl Substances on Larval and Juvenile Amphibians (Master's Thesis). Purdue University.

Hoover, G.M. 2017. Effects of Per/Polyfluoroalkyl Substance Exposure on Larval Amphibians (Ph.D. Dissertation). Purdue University.

Lech M.E. 2021. Investigating the Effects of Per-/Polyfluoroalkyl Substances (PFAS) on Host-Parasite Interactions in a Larval Amphibian-Echinostome System. (Master's Thesis). Purdue University.

Perez, E. 2021. An Environmentally Relevant Binary Mixture of PFOS and PFHxS Results in Antagonism and Reduced Body Condition in Northern Leopard Frogs. (Master's Thesis). Purdue University.

Patents

Strathmann, T. J., C. Higgins, B. Wu, and S. Hoa. 2023. Hydrothermal Technology for Decontamination and Mineralization of Perfluoro- and Polyfluoroalkyl Substances (PFAS) in Wastes, Concentrate Solutions, and Chemical Stockpiles. U.S. Patent 11577111-B2.