Assessing the Ecological Risks of Per‐ and Polyfluoroalkyl Substances: Current State‐of‐the Science and a Proposed Path Forward

Abstract

Per-and poly-fluoroalkyl substances (PFAS) encompass a large, heterogenous group of chemicals of potential concern to human health and the environment. Based on information for a few relatively well understood PFAS such as perfluorooctane sulfonate and perfluorooctanoate, there is ample basis to suspect that at least a subset can be considered persistent, bioaccumulative, and/or toxic. However, data suitable for determining risks in either prospective or retrospective assessments are lacking for the majority of PFAS. In August 2019, the Society of Environmental Toxicology and Chemistry sponsored a workshop that focused on the state-of-the-science supporting risk assessment of PFAS. This paper summarizes discussions concerning ecotoxicology and ecological risks of PFAS. First, we summarize currently available information relevant to problem formulation/prioritization, exposure, and hazard/effects of PFAS in the context of regulatory and ecological risk assessment activities from around the world. We then describe critical gaps and uncertainties relative to ecological risk assessments for PFAS and propose approaches to address these needs. Recommendations include the development of more comprehensive monitoring programs to support exposure assessment, an emphasis on research to support the formulation of predictive models for bioaccumulation, and the development of in silico, in vitro, and in vivo methods to efficiently assess biological effects for potentially sensitive species/endpoints. Addressing needs associated with assessing the ecological risk of PFAS will require cross-disciplinary approaches that employ both conventional and new methods in an integrated, resource-effective manner.

Evaluation of Published Bioconcentration Factor (BCF) and Bioaccumulation Factor (BAF) Data for Per‐ and Polyfluoroalkyl Substances Across Aquatic Species

“…Cause(s) of the decrease in BCFs with higher concentrations are unknown. However, PFAS residues are known to be controlled by a combination of passive diffusion and active transport processes (Ng and Hungerbühler 2014; Ankley et al 2020). Passive diffusion processes are generally not concentration dependent, which suggests there might be some type of capacity limitation in the active transport processes.…”

Sensitivity and Accumulation of Perfluorooctanesulfonate and Perfluorohexanesulfonic Acid in Fathead Minnows (Pimephales promelas) Exposed over Critical Life Stages of Reproduction and Development

“…There is widespread and growing concern regarding the potential health and environmental effects of per‐ and polyfluoroalkyl substances (PFAS; Ankley et al 2020, this issue). The Department of Defense (DoD) has many sites that are impacted by PFAS as a result of historical use of aqueous film–forming foams (AFFFs) for fire suppression and/or training activities (Anderson 2016).…”

Environmental Risk Assessment Resulting from Sediment Contamination with Perfluoroalkyl Substances

“…The established thresholds for the effects of PFASs are available only for selected compounds in the elements of the environment. Parameters are mainly estimated for direct effects of PFOS in freshwater aquatic species [ 42 ]. In the European Union (EU), several thresholds of PFOS are available.…”

“…The EU established that insufficient data are available to confirm the need for a sediment quality standard or to derive a threshold, thus electing not to set a value. Norwegian sediment thresholds (e.g., no-effect threshold = 220 μg/kg d.w.) were proposed for PFOS in marine sediments, and they may also provide some basis for screening-level risk decisions for freshwater sediments (all estimated values were lower than threshold) [ 42 , 44 , 45 , 46 ].…”