Guidance for Assessing the Ecological Risks of PFASs to Threatened and Endangered Species at Aqueous Film Forming Foam-Impacted Sites
Dr. Jason Conder | Geosyntec Consultants
This project will develope an approach that aids the Department of Defense (DoD) in assessing ecological risks from Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) to threatened and endangered (T&E) species at Aqueous Film Forming Foam (AFFF) impacted sites. Evaluation of exposure pathways for T&E species has been identified as a critical research need for DoD, as the current lack of guidance on how to quantitatively evaluate such risks prevents defensible, risk-based decision making at the hundreds of AFFF-impacted sites currently under assessment. The lack of clear and concrete guidance leaves site management strategies with only excessive and costly remediation options based on unnecessarily conservative assumptions. The objective of this project is to produce a white paper guidance document that will provide DoD project managers with: 1) a strategic overview of state-of-the-practice for the ecological risk assessment at DoD AFFF sites; and 2) specific guidance on state-of-the-science approaches to quantitatively assess and manage PFAS risks. It is expected that site managers and technical specialists will directly apply the guidance to enable scientifically sound risk-based management to proceed at specific AFFF sites.
This project will develop a guidance with two primary objectives. The first objective will be to provide a brief strategic overview of the state-of-the-practice for the ecological risk assessment at DoD AFFF sites. The second objective of the guidance, targeted primarily for ecological risk practitioners, will identify the key species likely to drive risk-based approaches at AFFF sites and provide a state-of-the-science compendium on key recommended quantitative ecological risk modeling tools and parameters for assessing T&E PFAS risks and formulating risk management approaches. This objective, the primary effort of the project, will present recommendations for key approaches and quantitative information for assessing PFAS risks to T&E species and consist principally of the following elements: 1) identification of key representative wildlife T&E receptor types likely to drive risks at most AFFF sites; 2) sources and examples of exposure factor information for these species; 3) PFAS exposure modeling parameters (bioaccumulation, biomagnification, etc.); 4) a detailed examination of wildlife PFAS No Observed Adverse Effect Level (NOAEL) and Lowest Observed Adverse Effect Level (LOAEL) Toxicity Reference Values (TRVs) currently available and under development; and 5) available approaches and quantitative effect benchmark levels in water for evaluating risk to T&E aquatic life such as benthic invertebrates, fish, and amphibians. As toxicity information for wildlife and aquatic life is limited to only a few PFASs, specific guidance regarding the assessment and uncertainty of other commonly encountered PFASs at AFFF sites, as well as PFAS precursors, will also be provided from the perspectives of the available technical information and the various evolving DoD branch policies. The guidance will conclude with recommendations for site-specific sampling needs for AFFF sites and also general research needs for improving assessment and investigation approaches. Once the guidance is finalized, the document will be transitioned to key end-users (site remedial project managers and technical support) via a presentation that highlights the features and benefits of the guidance document (to be given during 2-3 webinars).
The primary expected benefit of this project is to enable DoD site managers to assess and manage ecological risks to T&E species from PFASs so that site-specific, risk-based management can proceed at the hundreds of AFFF sites currently under or preparing for evaluation. In addition to providing a state-of-the-science review on available technical information and approaches to support DoD-specific goals, the guidance will highlight key research needs that will further improve the assessment and management of PFASs. (Anticipated Completion - September 2019)