Phytoextraction of per- and polyfluoroalkyl substances (PFAS) by weeds: Effect of PFAS physicochemical properties and plant physiological traits

Phytoextraction is a promising technology that uses plants to remediate contaminated soil. However, its feasibility for per-and polyfluoroalkyl substances (PFAS) and the impact of PFAS properties and plant traits on phytoex-traction efficacy remains unknown. In this study, we conducted greenhouse experiment and evaluated the potential of weeds for phytoextraction of PFAS from soil and assessed the effects of PFAS properties and plant traits on PFAS uptake via systematic correlation analyses and electron probe microanalyzer with energy dispersive spectroscopy (FE-EPMA-EDS) imaging. The results showed that 1) phytoextraction can remove 0.04%-41.4%wt of PFAS from soil, with extracted PFAS primarily stored in plant shoots; 2) Weeds preferentially extracted short-chain PFAS over long-chain homologues from soil. 3) PFAS molecular size and hydrophilicity determined plant uptake behavior, while plant morphological traits, particularly root protein and lipid content, influenced PFAS accumulation and translocation. Although plants with thin roots and small leaf areas exhibited greater PFAS uptake and storage ability, the impact of PFAS physicochemical properties was more significant. 4) Finally, short-chain PFAS were transported quickly upwards in the plant, while uptake of long-chain PFOS was restricted.

Automated summary

Phytoextraction is a promising technology for remediation of contaminated soil, but its potential and the influence of PFAS properties and plant traits on efficacy are still unclear. This study evaluated the potential of weeds for phytoextraction of PFAS and investigated the effects of PFAS properties and plant traits on uptake using correlation analyses and imaging techniques. The findings suggest that phytoextraction can remove PFAS from soil, with short-chain PFAS being preferentially extracted by weeds. PFAS molecular size and hydrophilicity determine plant uptake, while plant morphological traits, especially root protein and lipid content, influence accumulation and translocation. Furthermore, short-chain PFAS are transported quickly upwards in the plant, while uptake of long-chain PFOS is restricted.