Development of Per and Polyfluoroalkyl Substances (PFAS) Ecological Risk Based Screening Levels (RBSLs)

By Jeanmarie M Zodrow, Meredith Frenchmeyer, Kaitlyn Dally, Erin Osborn, Paul Anderson, and Craig Divine
Environ Toxicol Chem
January 5, 2021
DOI: 10.1002/etc.4975

Evaluation of chemical risks to threatened and endangered (T&E) species is a requirement for Superfund ecological risk assessments; however, screening levels to evaluate the potential for toxicity associated with ecological receptor exposure to per- and polyfluoroalkyl substances (PFAS) are lacking. Therefore, PFAS risk-based screening levels (RBSLs) were developed. Wildlife RBSLs were developed using surrogate receptors selected to be representative of T&E species with different habitat types, feeding guilds, and trophic levels. Published uptake and toxicity data were combined with receptor exposure factors to derive RBSLs for terrestrial and aquatic wildlife for several PFAS, including PFNA, PFOS, PFOA, PFHxA, PFBS and PFBA. Uptake information for surrogate PFAS were considered to calculate RBSLs for PFAS with toxicity data and insufficient bioaccumulation data to develop a RBSL. Both no observed adverse effect level (NOAEL)- and lowest observed adverse effect level (LOAEL)-based wildlife RBSLs were calculated to allow for a range of risk estimates appropriate to individual T&E species and populations of non-listed wildlife receptors, respectively. Recommended Water Quality RBSLs protective of aquatic life were developed for 23 PFAS based on published literature reviews and peer-reviewed aquatic toxicity studies and Great Lakes Initiative methodology. For wildlife receptors, NOAEL RBSLs ranged from to 0.013 to 340 mg/kg for soil, 0.0014 to 370 mg/kg for sediment, and 0.000075 to 1,600 mg/L for surface water. For aquatic life, chronic RBSLs ranged from 0.00022 to 3.4 mg/L. For terrestrial plants and soil invertebrates, the no observed effect concentration screening levels range from 0.084 mg/kg to 642 mg/kg and 1 mg/kg to 50 mg/kg, respectively. This article is protected by copyright. All rights reserved.

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