An Integrated Approach to Mapping Per- and Polyfluoroalkyl Substances Sorption in Sediments Using Electromagnetic Induction

Understanding the fate and transport of per- and polyfluoroalkyl substances (PFAS) at contaminated sites is crucial for effective remedial and regulatory decision-making. This interdisciplinary study offers a novel approach for estimating and mapping PFAS sorption properties and their impact on PFAS fate and transport. By integrating electromagnetic induction (EMI) surveys, physical and chemical sediment characterization, mineralogical characterization, and batch sorption experiments of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), we develop a comprehensive mapping of sorption dynamics. Sediments collected from a compound bar deposit were analyzed to establish correlations between EMI signal, sediment characteristics, and PFOA and PFOS sorption distribution coefficients (K_d). Sorption behavior and EMI response of these compounds were consistent with the sediments’ physical and chemical properties where K_d and electrical conductivity was higher with finer grain size, higher organic matter content, and higher aluminum and iron contents. The study demonstrates that EMI effectively maps PFAS sorption properties spatially, providing crucial insights into the sedimentological controls that govern both EMI responses and PFAS sorption. Correlation analysis yielded Pearson correlation values of 0.71 for EMI-PFOA K_d and 0.56 for EMI-PFOS K_d, underscoring the potential of EMI in predicting the spatial distribution of PFAS sorption in complex sedimentary environments. While these Pearson correlation values indicate moderate to strong correlations, their significance is amplified by the cost-effectiveness and extensive aerial coverage of EMI, the sparsity of sediment samples typically collected for batch sorption, and their spatial distribution. These results highlight the potential of EMI to identify sorption hotspots, thereby guiding targeted remediation efforts and enhancing site management strategies, ultimately reducing both costs and environmental impacts.