Theme: 07. Per- and Polyfluorinated Alkyl Substances (PFAS)

Topic Area: 7m. PFAS Site Characterization

Formatted Title:

PFAS Airport Investigations: Lesson Learned from Subsurface Investigation of PFAS at Eighteen Commercial Airports in the U.S.

Background/Objectives:

For decades, the Federal Aviation Administration (FAA) has required airports in the United States with operating certifications issued pursuant to 40 CFR Part 139 to provide aircraft rescue and firefighting (ARFF) services using aqueous film-forming foam (AFFF) that meets military specifications (MIL-PRF-24385)(MilSpec). Up until 2023, the MilSpec required the use of AFFF containing PFAS. Consequently, for several decades, Part 139 airports have been required to test and calibrate their AFFF equipment to ensure proper operation in case of an emergency. Those Federally-required training and testing activities, as well as aircraft emergency responses, have resulted in an unknown quantity of PFAS-containing AFFF to be released at the approximately 550 airports in the United States that are subject to Part 139. To date, only a fraction of those airports has undergone investigation for legacy PFAS impacts from AFFF release. As more states enact environmental regulations around PFAS and when the Federal government promulgates PFAS regulations, new airport PFAS investigations may benefit from lessons learned at the airports that have already begun or completed their investigations.

Approach/Activities:

To better inform future airport PFAS investigations, we reviewed the successes and challenges associated with PFAS investigations conducted by us at 18 Part 139 airports between 2018 and 2023. This review included our experience identifying and differentiating source areas, investigation planning and execution, and data interpretation. We also conducted a high-level review of the data collected from those investigations, which includes several hundred groundwater, soil, and storm water samples. Those data, combined with the unique perspectives of project managers, engineers, scientists, and field personnel, provided valuable insights that will inform future PFAS investigations at U.S. airports.

Results/Lessons Learned:

The findings of our review will be grouped into three categories: 1) lessons learned for investigation planning (where to start and how to prioritize investigations across very large sites like airports, etc.); 2) lessons learned for investigation execution (quality assurance planning, lab selection, etc.) and 3) lessons learned for data interpretation (dealing with the effects of differential fate and transport, source differentiation, patterns and distribution of PFAS encountered from AFFF releases, etc.). These lessons will be described and illustrated with real-world examples and data from 18 airport PFAS investigations across the country.

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Jessica Bleha