A Review of Immobilisation-Based Remediation of Per- and Poly-Fluoroalkyl Substances (PFAS) in Soils

This review provides an overview of the latest developments in immobilisation of per- and poly-fluoroalkyl substances (PFAS) for soil remediation. It examines the efficacy of a range of amendments, including those with binding agents, along with a discussion of immobilisation mechanisms and post-immobilisation assessment needs. Researchers have recently applied a variety of soil amendments to soil for PFAS immobilisation. Efficacy of these has varied widely, both between amendment and soil types and for individual PFAS molecules present in contaminated soils. Activated carbon based amendments, including composite amendments exhibit the highest efficacies of the examined studies. Immobilisation of PFAS is complex, with efficacy of immobilisation varying with soil properties including pH, clay and organic matter content, amendment properties, and molecular properties of the individual PFAS. Optimal remediation strategies need to be adjusted accordingly to site specific soil properties and contamination profiles. Additionally, bioavailability testing needs to supplement standard leaching approaches to determine effectiveness of PFAS soil immobilisation strategies.