Distribution of eight perfluoroalkyl acids in plant-soil-water systems and their effect on the soil microbial community

Phytoremediation of per- and polyfluoroalkyl substances (PFAS) appears to be a green remediation technique. To understand distribution of PFAS in plant-soil-water systems, eight perfluoroalkyl acids (PFAAs) at three different concentrations were spiked to Juncus effusus grown in a greenhouse for 21 days. Results from this study demonstrated that mass-based plant uptake of PFAAs correlated positively with concentrations and time. On the basis of removal percentages, the higher the initial PFAA concentrations, the less removal by plant was observed. With the low level of PFAA spike, J. effusus roots and shoots accumulated 30-40% of PFAAs (C4 to C8) except PFOS with a lower uptake of approximately 20%. Together with soil sorption, >82.8% of PFAAs were removed from the aqueous solution in 21 days. Uptake of PFAAs also depended on their carbon chain length and plant compartments (roots or shoots). This dependence resulted in different bioaccumulation factors and translocation factors for different PFAAs. Besides physical and chemical distribution, PFAAs, especially those added at the high level led to significant change of soil bacterial communities in terms of composition and structure. Potential impact to the community's functions warrants further investigations.