The Impact of PFAS on Soil Surface Wettability

Per- and polyfluoroalkyl substances (PFAS) are a group of anthropogenically manufactured chemicals widely detected in the environment. Characterizing their transport and fate in soil is important for assessing the potential of their human exposure and health impact. However, to date, few studies have been conducted to investigate the influence of PFAS on soil physical properties. This study investigates the impact of PFAS exposure on the surface wettability of soil via contact angle (θ) measurements. Contact angle was measured based on the fluid uptake rate in the Washburn capillary rise (WCR) method. Contact angles were measurably affected by the presence of 0.5 µg/g PFAS, with an increase of 4.5–6.8% for the exposed Accusand 40/50 and a decrease of 3.6–16% for the exposed Eustis soil, after 7 days of contact. The changes were attributed to the modification of the surface properties caused by the adsorbed PFAS. These results demonstrate that PFAS can potentially alter the surface properties of soils, which could subsequently impact soil hydraulic properties as well as affect geochemical interactions.