Evaluation of PFAS migration from soil to groundwater using a diagnostic method for PFAS residues in soil

Abstract

As PFAS contamination becomes a global concern, there is a need for methods to accurately assess PFAS migration from soil to groundwater in Japan. To overcome the limitations of conventional leaching test methods, the “Diagnostic method for PFAS residues in soil” (NARO Method) was developed and validated. The NARO method uses 5 g of soil, adds a surrogate at the start to track the entire process, sequentially performs water extraction and solvent extraction, and quantitatively evaluates PFAS migrated from soil to the aqueous phase and residual PFAS in the soil. In Andosol (Kuroboku soil), PFOS tends to remain in the residual, while PFOA and HFPO-DA readily migrate to the aqueous phase. This enables quantitative estimation of groundwater migration potential, significantly reducing work time and effort while ensuring traceability. These findings have the potential to contribute to rapid risk assessment and the formulation of administrative policies.