Development of Per and Polyfluoroalkyl Substances Ecological Risk‐Based Screening Levels

Abstract

Evaluation of chemical risks to threatened and endangered 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 threatened and endangered 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 perfluorononanoic acid, perfluorooctanesulfonic acid, perfluorooctanoic acid, perfluorohexanoic acid, perfluorobutanesulfonic acid, and pentafluorobenzoic acid. Uptake information for surrogate PFAS were considered to calculate RBSLs for PFAS with toxicity data and insufficient bioaccumulation data to develop an RBSL. Both no‐observed–adverse effect level (NOAEL)– and lowest‐observed–adverse effect level–based wildlife RBSLs were calculated to allow for a range of risk estimates appropriate to individual threatened and endangered species and populations of nonlisted 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 1600 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 to 642 mg/kg and from 1 to 50 mg/kg, respectively. Environ Toxicol Chem 2021;40:921–936. © 2020 SETAC

Strategic resources for assessing PFAS ecological risks at AFFF sites

“…In general, the lowest (most conservative RBSLs) were found for small invertivorous/insectivorous or piscivorous wildlife associated with aquatic habitats, consistent with conclusions by Conder et al (2020) and Gobas et al (2020) that these ecological receptors will particularly influence site‐specific investigations and decisions at many AFFF‐ and other PFAS‐impacted sites. These results are also published, with minor updates, in the peer‐reviewed journal Environmental Toxicology and Chemistry (Zodrow et al, 2021).…”

“…The focus of the project by Zodrow et al (2020) was to develop risk‐based screening levels (RBSLs) protective of T&E species that may be present specifically at DoD sites in the United States. A comprehensive set of RBSLs, a major emphasis that was unique to this project (Table 1), were derived based on published toxicity and bioaccumulation data and standard risk assessment approaches (US Environmental Protection Agency [USEPA], 2005, 2012): Surface water RBSLs protective of fish, invertebrate aquatic life, and aquatic plants were derived based on USEPA's Great Lakes Initiative approach (USEPA, 2012) following a comprehensive literature search for aquatic toxicity data.…”

“…The four SERDP projects were conducted by four research groups working independently over a 1‐ to 2‐year period, with periodic in‐progress updates to coordinate and collaborate. The end products of the four projects consisted primarily of four publicly available, free, and online (https://www.serdp-estcp.org/) documents: (1) “Guidance for Assessing the Ecological Risks of PFAS to Threatened and Endangered Species at Aqueous Film Forming Foam‐Impacted Sites” (Conder et al, 2020); (2) “Per‐ and Polyfluoroalkyl Substances Ecological Risk‐Based Screening Levels” (Zodrow et al, 2020); (3) “Investigating Potential Risk to Threatened and Endangered Species from Per‐ and Polyfluoroalkyl Substances (PFAS) on Department of Defense (DoD) Sites” (Suski et al, 2020); and (4) “A Framework for Assessing Bioaccumulation and Exposure Risks of Per‐ and Polyfluoroalkyl Substances in Threatened and Endangered Species on Aqueous Film Forming Foam (AFFF)‐Impacted Sites” (Gobas et al, 2020).…”

Risks posed by per‐ and polyfluoroalkyl substances (PFAS) on the African continent, emphasizing aquatic ecosystems

“…Zodrow et al (2020) determined water risk‐based screening levels (RBSLs) for aquatic wildlife based on the no‐observed‐adverse‐effect‐level (NOAEL) and lowest‐observed‐adverse‐effect‐level (LOAEL). These values were derived in laboratory tests on single species of aquatic organisms with growth, survival and/or mortality, and reproduction and/or development as endpoints.…”

“…In surface waters, the PFOS concentrations in the Lake Victoria Gulf in Kenya (Orata et al, 2009), several Nigerian rivers (Ololade, 2014; Ololade, et al 2018), and several South African rivers, that is the Plankenburg River (Fagbayigbo et al, 2018), Vaal River (Groffen et al, 2018), and Salt and Eerste rivers (Mudumbi et al, 2013), exceeded the EQS for high conservation value freshwater ecosystems (ANZECC/ARMCANZ, 2000). In addition, the PFOS concentrations in the Diep River (Mudumbi et al, 2013) and the Pra and Kakum rivers in Ghana (Essumang et al, 2017) exceeded the EQS for slightly disturbed systems (ANZECC/ARMCANZ, 2000) and the NOAEL‐based minimum wildlife RBSL (Zodrow et al, 2020). Furthermore, in all of these studies, the PFOS concentrations are higher than the EQS determined for secondary poisoning of top predators (EC, 2011).…”