Understanding Fate and Transport of PFAS to Develop Good Conceptual Site Models of AFFF Impacted Facilities

Background/Objectives. Poly- and Perfluoroalkyl substances (PFAS) are used in a wide range of industrial applications and commercial products due to their unique surface tension and levelling properties.. PFAS are also major components of firefighting foams known as Aqueous Film Forming Foam (AFFF). The PFAS group of compounds consists of both perfluorinated compounds, where all carbons are saturated with F atoms, and polyfluorinated compounds, where both fluorine saturated carbons and carbons with hydrogen bonds are present. The understanding of the fate and transport of these compounds in the environment is complex and challenging and will be discussed.

Results/Lessons Learned. The concepts of “biological funneling” and “dark matter” show that PFAS behave significantly differently to other contaminants and existing conceptual site models (CSM) need to be adapted to adequately understand the fate and transport of these contaminants. Examples of CSMs from AFFF impacted sites will be presented.