The objective of this Statement of Need was to develop an improved understanding of the ecological toxicity and risk associated with per- and polyfluoroalkyl substances (PFAS) in avian species. The work should lead to a better understanding of actual avian exposures via field measurements of PFAS in biological samples at or near aqueous film forming foam (AFFF)-impacted sites. The following sub-objectives were of interest:

• Develop an improved understanding of the uptake and excretion rates of PFAS by avian species to include assessment of correlation between effects reported in the scientific literature in laboratory exposures and observed population effects in the field. For any identified discrepancies between predicted and observed effects, determine potential causes of this discrepancy.
• Develop and/or validate modeling tools that can define exposures in comparison to established avian toxicity reference values.
• Assess PFAS bioaccumulation and biomagnification throughout a food web with avian species as the receptor. Questions that could be addressed include:
  • Are PFAS accumulating in biota within avian food webs in areas of known AFFF use?
  • Which PFAS biomagnify? Does the relative distribution of PFAS change with each subsequent trophic transfer? What is the relative role of perfluoroalkyl acids precursors in determining total body burdens?
  • Do the collective data show direct pathways from soils/sediments/surface water to higher trophic levels?
• Determine whether observed PFAS mixtures in avian tissue, serum or eggs are correlated with any adverse population level effects. Such an assessment must primarily identify such mixtures from the literature or conduct small efforts to address data gaps.

Proposals should have addressed one or more of the sub-objectives listed above. Exposures should have been correlated with relevant ecological effect measurements including, but not limited to, mortality, fecundity, clutch size, fledge success, or other indicators of population health. Preference was given to proposals that adopted a holistic food web approach with emphasis on biomagnification through various prey/food items.

Proposers were asked to provide the rationale and justification for the parameters of the study, including specific PFAS, biological endpoints, and environmental media. Additionally, proposers should have provided a brief summary of their proposed analytical plan for measuring PFAS concentrations in biological media.

Substantial work has been conducted on understanding the ecotoxicity and ecological risk of specific PFAS. Investigators were encouraged to view past research and demonstrate how the proposed effort builds on previous efforts. A summary of SERDP-funded efforts in these areas can be found at the following web pages:

• Ecotoxicity of Perfluorinated Compounds
• Defining Knowledge Gaps in the Understanding of Per- and Polyfluoroalkyl Substances in the Subsurface
• Ecological Risk Characterization of Per- and Polyfluoroalkyl Substances in the Subsurface: Bioavailability, Bioaccumulation and Biomagnification
   

The following projects were funded. Project overviews will appear below as they are posted to the website.

• Food-Web Exposure and Consequent Effects of PFAS on Birds
  • Principal Investigator: Matthew Etterson U.S. Environmental Protection Agency
• Validation of Food Web Models Incorporating the Toxicity and Bioaccumulation of PFAS in Avian Species
  • Principal Investigator: Jean Zodrow Geosyntec Consultants, Inc.