Plant uptake and soil fractionation of five ether-PFAS in plant-soil systems

Considering the grave concerns caused by conventional per- and polyfluorinated substances (PFAS), production and use of fluoroalkylether compounds (ether-PFAS) have been on the rise. These ether-PFAS are deemed as PFAS replacement chemicals. To understand distribution of ether-PFAS in plant-soil systems, we investigated plant uptake of five selected ether-PFAS (i.e., PFMOPrA, PFMOBA, GenX, ADONA, Fsingle bond53B) by Carex comosa (longhair sedge) and the fractionation of these compounds in soil. Our results demonstrated that all five ether-PFAS in this study were taken up by C. comosa and translocated to plant shoots to different extents. Exposure concentration and time both positively affected plant uptake of ether-PFAS. Unlike the other four ether-PFAS, Fsingle bond53B with the longest carbon chain length and a sulfonic functional group was largely accumulated in C. comosa roots with limited translocation to plant shoots. Results from sequential extractions revealed that the five ether-PFAS had different distributions in soil with regard to extractable by water, basic methanol, acidic methanol and non-extractable. Concentration of ether-PFAS in water-soluble fraction increased with decreasing carbon chain length and logKow values and had a positive linear relationship with the mass of ether-PFAS in plant shoots (R-2 = 0.64) and in whole plants (R-2 = 0.94). Our results also indicated that the aging process could facilitate ether-PFAS to become non-extractable, hence reducing their mobility in soil and bioavailability to plants. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Our study found that Carex comosa plants absorbed and translocated five selected ether-PFAS to plant shoots, with exposure concentration and time positively affecting plant uptake. The five ether-PFAS had different distributions in soil, with water-soluble fraction increasing with decreasing carbon chain length and logKow values.