Soil amendments reduce PFAS bioaccumulation in Eisenia fetida following exposure to AFFF-impacted soil.

The efficacy of RemBind® 300 to immobilize per- and polyfluoroalkyl substances (PFAS) in aqueous film forming foam (AFFF)-impacted soil (∑ PFAS 1280-8130 ng g; n = 8) was assessed using leachability (ASLP) and bioaccumulation (Eisenia fetida) endpoints as the measure of efficacy. In unamended soil, ∑ PFAS leachability ranged from 26.0 to 235 μg l, however, following the addition of 5% w/w RemBind® 300, ∑ PFAS leachability was reduced by > 99%. Following exposure of E. fetida to unamended soil, ∑ PFAS bioaccumulation ranged from 18,660-241,910 ng g DW with PFOS accumulating to the greatest extent (15,150-212,120 ng g DW). Biota soil accumulation factors (BSAF) were significantly (p < 0.05) higher for perfluoroalkyl sulfonic acids (PFSA; 13.2-50.9) compared to perfluoroalkyl carboxylic acids (PFCA; 1.2-12.7) while for individual PFSA, mean BSAF increased for C to C compounds (PFBS: 42.6; PFPeS: 52.7; PFHxS: 62.4). In contrast, when E. fetida were exposed to soil amended with 5% w/w RemBind® 300, significantly lower PFAS bioaccumulation occurred (∑ PFAS: 339-3397 ng g DW) with PFOS accumulation 23-246 fold lower compared to unamended soil. These results highlight the potential of soil amendments for reducing PFAS mobility and bioavailability, offering an immobilization-based risk management approach for AFFF-impacted soil.