As part of a project for the U.S. Department of Defense's Strategic Environmental Research and Development Program (SERDP), Geosyntec staff developed a guidance document that presents a current state-of-the-practice overview of available methods, best practices, and key data gaps in assessing the potential for risks to threatened and endangered species from exposure to per- and polyfluoroalkyl substances (PFAS) at sites impacted by aqueous film forming foam (AFFF).
PFAS are a family of thousands of man-made compounds that are emerging as potential hazards to human and ecological health, some of which are a key ingredient in AFFF. AFFF was used not only to put out actual fires but also in training activities at airports and military training facilities.
The guidance document Geosyntec staff prepared includes a critical review of bioaccumulation metrics and uptake factors, aquatic toxicity data, and mammalian and avian toxicity reference values for many PFAS compounds commonly encountered at AFFF sites. The document also provides the framework for evaluating direct effects to plant and invertebrate communities exposed to PFAS, evaluating risks to aquatic life from exposure to two types of PFAS compounds, and developing a model to estimate exposure to PFAS in the food chain and evaluate risks to wildlife. We also provided a discussion of uncertainties, data gaps, and critical additional research that are still needed.
Intended to provide clear guidance to quantitatively evaluate ecological risks to PFAS, the guidance enables site managers to make defensible, risk-based management decisions using the best available information and approaches. While developed with the level of conservatism needed to assess risks to threatened and endangered species specifically, the guidance provides flexibility for application at PFAS-impacted sites where such species are not considered receptors of concern."Guidance for Assessing the Ecological Risks of PFAS to Threatened and Endangered Species at Aqueous Film Forming Foam-Impacted Sites" is available for download at the SERDP project website.