The major objective of this project is the evaluation of the bioaccumulation of a wide range of per- and polyfluoroalkyl substances (PFAS) and total extractable organofluorine (EOF) in estuarine food webs supporting coastal birds foraging and breeding within aqueous film-forming foam (AFFF)-influenced Charleston Harbor, South Carolina. Specifically, the project team will measure PFAS and EOF in water, sediment, plankton, marsh vegetation, and prey along spatial gradients moving away from known AFFF sources, as well as in coastal birds relying on related food webs and environments to understand how avian trophic strategies and habitat use influence the bioaccumulation of PFAS in coastal birds. This project will evaluate whether PFAS are accumulating in biota within avian food webs in areas of known AFFF use.

Further, by measuring PFAS in the representative food web and environment supporting these coastal birds, the project team will evaluate which PFAS biomagnify, if relative distribution of PFAS changes with each subsequent trophic transfer, and if the collective data show direct pathways from soils/sediments/surface water to higher trophic levels. Lastly, the project team will measure abiotic and biotic matrices for both specific PFAS and EOF content. The main objectives of this project are as follows:

• Objective 1: Describe the bioaccumulation and biomagnification of a wide range of target PFAS in food webs supporting multiple species of coastal birds.
• Objective 2: Assess how AFFF precursors may be contributing to bioaccumulation of terminal PFAS in food web bioaccumulation assessments.
• Objective 3: Evaluate how use of AFFF-impacted riverine and estuarine systems influence adult PFAS body burdens and chick uptake of PFAS.

The project objectives will be met by performing four specific tasks. Task 1 involves the collection of spatially-explicit environmental and biological samples and measurement of PFAS, EOF, and stable isotope ratios in these samples. Task 2 involves the use of satellite tags to collect data describing the movements and behavior of Brown Pelicans and American Oystercatchers, two species of coastal birds. Task 3 will pair geospatial data and PFAS measurements to constrain high-use foraging areas that may be driving PFAS accumulation in coastal birds. Task 4 entails quantitative assessment of bioaccumulation and biomagnification of PFAS and precursors.

This work will derive an unparalleled understanding on how avian habitat use influences PFAS levels by incorporating biologging technologies in tandem with egg, serum, feather, prey, and abiotic sample collections. Second, the project team will assess the importance of the unaccounted-for organofluorine fraction in abiotic and biological matrices, which will help define the role of precursors in bioaccumulation and inform analytical approaches for future work investigating bioaccumulation adjacent to AFFF sites. This sample set will provide novel, integrated information about PFAS impact in the Ashley River and Charleston, South Carolina, region, known to have elevated perfluorooctanesulfonic acid (PFOS) concentrations based on snapshot studies of multiple, individual matrices. (Anticipated Project Completion - 2026)