Sequestration and degradation of per- and polyfluoroalkyl substances in soil: Opportunities and challenges

Per- and polyfluoroalkyl substances (PFAS) are increasingly detected in soils, posing potential risks to human health via their accumulation in food crops and other exposure pathways. Unfortunately, options for effective remediation of PFAS-contaminated soils are limited. This review provides a comprehensive analysis of recent advancements in soil remediation technologies aiming to lower PFAS bioavailability by focusing on either sequestration or in situ degradation. Specifically, highly effective soil amendments such as clay minerals and activated carbon are often used for PFAS immobilization. However, despite their initial effectiveness, the long-term stability of sequestered PFAS may be compromised as a result of sorbent aging and other soil condition changes, leading to the potential remobilization of the sorbed PFAS. In situ chemical degradation including advanced oxidation and advanced reduction processes could achieve long-term PFAS removal, especially by combining with other downstream treatment technologies. However, detailed studies are still lacking. This review highlighted several urgent research needs to advance PFAS remediation in soil and proposed new approaches such as an integrated approach that combines sequestration with chemical degradation to achieve more sustainable long-term stabilization and removal of PFAS from contaminated soils. • PFAS soil remediation via sequestration and in situ degradation was thoroughly reviewed. • Clay, activated carbon, and biochar are potential adsorbents for PFAS immobilization in soil. • Biochar modification substantially enhances its effectiveness for PFAS sequestration. • In situ chemical oxidation or reduction of PFAS requires additional studies. • An integrated sequestration–degradation approach is proposed for sustainable PFAS remediation.