Collaborative Research: In Situ Laboratory Imaging and Modeling of PFAS Transport and Fate in Variably Saturated Heterogeneous Porous Media

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Leaching of per- and polyfluoroalkyl substances (PFAS) currently retained in the shallow subsurface above the water table is a persistent source of groundwater contamination. This retention process is very complex because the timing and extent of PFAS mobility in the shallow subsurface are controlled by soil properties, climate, and weather events, and site-specific hydrogeologic conditions. Despite significant advances in understanding the migration and retention behavior of PFAS, there remains a critical knowledge gap on how spatial variation in geologic properties—which have a strong impact on groundwater flow processes—impact how, when, and where PFAS contamination migrates in the subsurface. This research advances the ability to measure and model PFAS migration and retention under more realistic geologic conditions. Training is provided to student researchers of diverse backgrounds, and outreach is conducted to engage with water professionals dealing with PFAS pollution problems. Improved understanding of PFAS migration in the subsurface will enable future progress in PFAS remediation strategy development.This project uses medical imaging technology and recent advances in numerical models to quantify dynamic, spatially variable PFAS adsorption in heterogeneous unsaturated geologic porous media. The specific aims are to measure in situ adsorption of two representative PFAS in saturated and partially saturated heterogeneous columns. These time-lapse imaging measurements are used, in turn, to provide direct validation to advanced spatially-resolved numerical models and enable the development of upscaled models of PFAS transport under heterogeneous subsurface conditions. This work offers unprecedented in situ transport and adsorption measurements, upscaling approaches, and parameterization of a numerical model used to describe and predict PFAS leaching through soils to groundwater aquifers.This project is jointly funded by the GEO/EAR Hydrologic Sciences (1579) Program and the ENG/CBET Environmental Engineering (1440) program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.