20E011 - Tools for Evaluating the Ecological Risks of Per- and Polyfluoroalkyl Substances at AFFF Sites
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Background/Objectives: Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) have been widely used in numerous applications since the 1950s, including aqueous film forming foams (AFFFs) used for fire suppression at airports, firefighting training facilities, and other industrial locations.

Many AFFF sites host ecological habitat, or, due to the offsite transport potential for PFAS, PFAS-impacted AFFF sites may affect nearby and downgradient habitats. Ecological Risk Assessments (ERAs) may be needed at these sites to facilitate decision making; however, the required supporting information and strategic guidance have historically been unavailable.

Approach/Activities: As part of a United States Department of Defense Strategic Environmental Research and Development Program (SERDP) project, a guidance document was developed to provide a current state-of-the-practice overview of methods, practices, and key data gaps for assessing the potential for risks from exposure to PFAS for threatened and endangered (T&E) species at AFFF-impacted sites. The guidance is intended to provide the technical support to quantitatively evaluate ecological risks and enable site managers to make defensible, risk-based management decisions using the best available information and approaches. As an added effort to this guidance, which has been available since 2019, we have developed two Microsoft Excel based food web modeling tools based on the detail technical reviews included in the guidance. These Excel models allow a user to input concentrations of PFAS in abiotic media (i.e., soil, sediment, and water) and/or biotic media (i.e., tissue samples) to predict concentrations of PFOS in biota of aquatic and terrestrial food webs, concentrations of PFAS in the diets of vertebrate wildlife, and daily exposure estimates for vertebrate wildlife.

Results/Lessons: Learned This presentation will provide information on how the user can access and download the free aquatic and terrestrial Excel modeling tools. In addition, we will provide a demonstration of the tools, including how they can be modified for evaluating the risks to Australasian wildlife. Based on model performance with real world data and additional experiences with ecological risk assessments conducted in Australasia and North America, it is apparent that at many sites, PFOS is commonly a key driver of risk-based concerns for ecological receptors. Along with highlighting these new tools for PFAS-focused ERAs, and current general lessons learned from their application, ongoing data gaps and research needs for PFAS ecological risk assessments will be discussed.

Publication Summary

  • Geosyntec Authors: Jason Conder, Jennifer Arblaster
  • All Authors: Jason Conder, Jennifer Arblaster
  • Title: EcoForum 2020 eConference
  • Event or Publication: Event
  • Practice Areas: Per- and Polyfluoroalkyl Substances (PFAS)
  • Citation: Geosyntec will deliver five presentations and one keynote at EcoForum 2020 eConference on September 14-18, 2020.
  • Date: September 14-18, 2020
  • Location: eConference
  • Publication Type: Platform Presentation