Immobilisation of PFAS in AFFF-Contaminated Soil: Impact on Ecological and Human Exposure
New Publication
Professor Albert Juhasz from the Future Industries Institute, University of South Australia, led this study on reducing PFAS exposure from AFFF-contaminated soil. Collaborating with a team of researchers, the study assessed the effectiveness of various soil amendments in immobilising PFAS, reducing its leachability, and minimising ecological and human exposure. The study was presented at the 2024 Batelle Chlorinated Conference in Denver, Colarado, USA.
Summary
The study evaluated RemBind®, a composite soil amendment consisting of aluminum hydroxide, activated carbon, and kaolin clay, to immobilise PFAS in AFFF-contaminated soils across several Australian sites. The research tested PFAS leachability, bioaccumulation in earthworms, and bioavailability in rats to understand the effectiveness of the soil amendment in reducing both ecological and human exposure.
Key Findings
Leachability Reduction
- PFAS leachability, especially for PFOS and PFHxS, was reduced by over 99% when treated with 5% w/w RemBind®.
Ecological Impact:
- Earthworm bioassays showed significant reductions in PFAS bioaccumulation when exposed to treated soil, with bioaccumulation factors dropping from 12 – 44 (PFOS) to 0.2−0.6 (PFOS) after treatment.
Human Health Impact:
- Using a rat bioassay, the relative bioavailability of PFOS in amended soils decreased from 45 – 107% in untreated soil to 5.1 – 24% in treated soil, indicating a reduction in potential human health risks from incidental soil ingestion.
Soil Treatment Result
Rat Bioassay Results
Conclusion
The study highlights that using RemBind® soil amendments can significantly reduce PFAS mobility, bioavailability, and accumulation in biological receptors, providing a promising strategy for reducing environmental and human exposure to PFAS from contaminated soils. This may also pave the way for remediation solutions for other secondary sources such as biosolids and compost.