Application of soil amendments for reducing PFAS leachability and bioavailability

In this study, changes in PFAS leachability and bioavailability were determined following the application of RemBind®100 (R100) and RemBind®300 (R300; 1-10% w/w) to PFAS-contaminated soil (Ʃ₂₈ PFAS 3.093-32.78 mg kg^-1). Small differences were observed in PFAS immobilization efficacy when soil was amended with RemBind® products although adding 5% w/w of either product resulted in a >98% reduction in ASLP PFAS leachability. Variability in immobilization efficacy was attributed to differences in activated carbon composition which influenced physicochemical properties of RemBind® formulations and PFAS sorption. PFOS, PFHxS and PFOA relative bioavailability was also assessed in unamended and amended soil (5% w/w) using an in vivo mouse model. In unamended soil, PFAS relative bioavailability was >60% with differences attributed to physicochemical properties of soil which influenced electrostatic and hydrophobic interactions. However, when PFAS relative bioavailability was assessed in soil amended with 5% w/w R100, individual PFAS relative bioavailability was reduced to 16.1 ± 0.8% to 26.1 ± 0.9% with similar results observed when R300 (5% w/w) was utilised (14.4 ± 1.6% to 24.3 ± 0.8%). Results from this study highlight that soil amendments have the potential to reduce both PFAS leachability and relative bioavailability thereby decreasing mobility and potential exposure to soil-borne contaminants.