PFAS RETENTION AND LEACHING IN SOILS & THE VADOSE ZONE

Per- and polyfluoroalkyl substances (PFAS) are contaminants of critical concern due to their persistence and widespread distribution in the environment and potential human-health impacts. Recent studies have demonstrated that soils are a primary reservoir for PFAS, and serve as potential long-term sources of groundwater contamination. Understanding the transport behavior of PFAS in soil and the vadose zone is critical for accurate site characterizations and risk assessments and for the design of effective remedial actions. Our recent research has demonstrated that adsorption at air-water interfaces is a critical retention process for PFAS transport in unsaturated porous media. This is illustrated with the results of a series of miscible-displacement transport studies. The impact of PFAS molecular structure, solution chemistry, and other factors on interfacial adsorption and transport is discussed.