A MODIFIED SESOIL MODEL FOR SIMULATING PFAS TRANSPORT IN THE VADOSE ZONE

The US EPA SESOIL model was enhanced to simulate the transport and fate of per- and polyfluoroalkyl substances (PFAS) in the vadose zone. Although adsorption to the air-water interfaces plays a crucial role in the transport and fate of PFAS, most vadose zone models do not incorporate this process. Suggesting that vadose zone models developed for non-PFAS contaminants may not be appropriate for evaluating risks to groundwater quality posed by PFAS contaminants. SESOIL now simulates the effects of seasonal variability in soil moisture and soil heterogeneity on the non-linear air-water interfacial adsorption of PFAS in the vadose zone. The model results were verified by comparison with existing literature data.