This proof-of-concept project aims to develop an improved understanding of biological compartments that most strongly accumulate per- and polyfluoroalkyl substances (PFAS). The project team will sequentially develop fundamental models that better estimate distributions between environmental and fresh and saltwater organism (fish tissue) phases of PFAS found in legacy and modern fluorotelomer-based aqueous film-forming foam (AFFF).  

In this project, a comprehensive dataset of PFAS partition coefficients (K_d) will be generated and a portfolio of stable and tunable cyclodextrin-functionalized collagen nanofibers and foams for the sorption of a broad range of PFAS will be developed. To this end, a solid-phase microextraction method will be employed to: 

• identify key proteins and lipids driving PFAS accumulation in fish tissues of fresh and saltwater fish,
• serve as parameters for an equilibrium distribution model (EDM), and
• assess the performance of EDM based on Kd to isolated biomolecules.  

In parallel, the project team will develop and test tunable material, combining cross-linked collagen nanofibers and foams, and advanced cyclodextrins for mimicking fish tissues. These materials will be characterized by kinetic and equilibrium sorption tests and will undergo laboratory experiments under various environmental conditions. This will enhance the understanding of PFAS distributions between model and organism phases under varying environmental conditions. 

The main objectives of this project are to: 

1. Identify the most abundant proteins and lipids in model fish species (fathead minnows and Atlantic killifish), and measure partition coefficients of PFAS with a broad range of physicochemical properties for these reference biomolecules and fish tissues that have been assessed for their protein and lipid composition.
2. Develop and evaluate the EDM and quantitative structure-activity relationships using the data generated in Objective 1.
3. Develop unique cross-linked collagen nanofibers and foams and advanced cyclodextrin-functionalized collagen nanofibers and foams.
4. Characterize the absorption behavior of various PFAS chemistries to novel materials from Objective 2 under various environmental conditions. 

The project objectives will be met by performing the following tasks: 

• Task 1: Laboratory experiments to measure PFAS binding to a) biomolecules and b) selected fish tissues and bioliquids.
• Task 2: Laboratory experiments to develop collagen- and cyclodextrin-functionalized nanofibers and foams tunable for PFAS sorption.
• Task 3: Laboratory experiments to characterize sorption of a broad range of PFAS on promising materials (developed under Task 2) under various environmental conditions. 

Understanding how PFAS accumulate in fish is essential for informed remediation efforts. This project will improve understanding of the fish compartments strongly accumulating PFAS at AFFF-impacted sites. Results will inform the development of a chemometer that mimics PFAS uptake in fish at these locations; and improve insights into PFAS distribution between water and fish across various environmental conditions. The resulting chemometer offers site managers reliable, on-site measurements of bioavailable PFAS, directly applicable to understanding PFAS uptake and accumulation in aquatic biota. The successful execution of this research will provide a new technology for ongoing impacted site cleanup efforts, ultimately protecting the warfighter and installation communities. (Anticipated Project Completion - 2027)