146-5 NUMERICAL MODELING OF SHORT-CHAIN PFAS SORPTION AND TRANSPORT THROUGH SOIL VADOSE ZONE

Session: Contaminants Near Groundwater-Surface Water Interfaces (Posters)

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Perfluoroalkyl and polyfluoroalkyl substances (PFAS), also known as "forever chemicals," have caused great concerns from their widespread detections in soil and water in the environment. Literatures show that PFBS, a short-chain PFAS, can migrate deeper through vadose zone soils and get into groundwater. This study aims to utilize HYDRUS-1D/2D model packet to evaluate PFBS retention and transport through a 100 cm soil profile under different saturation conditions. Effects of variation in soil–solute partitioning on leachate dynamics were examined. Simulations indicate that soils with higher organic carbon content (OC) significantly increased sorption and restricted PFBS transport within upper soil layers. After 180 days of simulation, the model PFBS of 0.2 mg/L concentration reached the bottom of the soil profile with low OC content. In contrast, the concentration was reduced to 50% in the soil profile with medium OC, and nearly 0 mg/L in the soil with high OC content. Results demonstrate pronounced sorption patterns and have a significant impact on transport outcomes. The findings are expected to provide a better understanding of physicochemical mechanisms for PFAS mobility and retention, offering valuable insights for field applications and engineering designs for remediation.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9819

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