Characterization and modeling of per- and polyfluoroalkyl substances (PFAS) leaching in a vadose-zone source area
Marcy Nadel1, Mark Brusseau1, Bo Guo1, Min Ma1, Christopher Pisarri2, Joseph Quinnan3, Richard H. Anderson4
1 University of Arizona, Tucson, AZ
2 BEM Systems, Inc., Anchorage, AK
3 Arcadis U.S., Inc., Novi, MI
4 Noblis, Inc., San Antonio, TX
Soil exposed to aqueous film-forming foam (AFFF) is a major, ongoing source of per- and polyfluoroalkyl substances (PFAS) at many sites. The objective of this study is to identify and quantify the primary factors and processes that mediate PFAS leaching and mass discharge to groundwater at an AFFF-impacted military installation in subarctic Alaska. The study employs soil and porewater sampling, detailed soil characterization, bench-scale experiments, and mathematical transport and fate modeling to investigate location-specific retention, attenuation, and leaching behavior. Suction lysimeters and in-situ soil moisture probes were installed at three depths in multiple source areas to quantify PFAS porewater concentrations and water saturations. Soil samples were collected from the boreholes in which the instruments were subsequently installed, and were subjected to high-resolution physical, geochemical, and hydraulic characterization. These datasets are being used to parameterize and validate a suite of tiered mathematical models that incorporate PFAS-specific retention and transport properties. The project is a partnership between the University of Arizona, BEM Systems, Inc., Arcadis, U.S, Inc., and the U.S. Air Force Civil Engineer Center. This poster will focus on the initial site-characterization efforts and preliminary results for this ongoing study.