Adsorption of Per- and Polyfluoroalkyl Substances (PFAS) by Aquifer Materials: the Important Role of Dolomite

The widespread detection of per- and polyfluoroalkyl substances (PFAS) within the groundwater system, which represents a major drinking water source, poses serious public health risks. Because of the recalcitrant nature of many PFAS such as perfluoroalkyl acids (PFAAs), their transport and fate within groundwater aquifers are determined by their interactions with the aquifer materials. The focus of this study is to quantify the adsorption of PFAAs by aquifer materials under environmentally relevant conditions. Our results showed that the adsorption of PFAAs by the aquifer materials was primarily correlated with (1) PFAA chemical structures including fluoroalkyl chain lengths and end functional groups and (2) dolomite fractions of the aquifer materials. An empirical relationship was developed based on multiple variable linear regression analysis to estimate the aquifer material-water partition coefficient (K-d) of PFAAs from the dolomite fraction of aquifer materials and the octanol-water distribution coefficient (D-ow) of PFAAs. Our findings demonstrated the critical but overlooked role of dolomite in PFAA adsorption and may facilitate the modeling of PFAA transport within a groundwater system.