Removal, distribution and plant uptake of perfluorooctane sulfonate (PFOS) in a simulated constructed wetland system

A vertical-flow constructed wetland (VFCW) was used to treat simulated domestic sewage containing perfluorooctane sulfonate (PFOS). The removal rate of PFOS in the domestic sewage was 93%-98%, through soil adsorption and plant uptake, suggesting that VFCWs can remove PFOS efficiently from wastewater. The removal of PFOS in the VFCW was dependent on soil adsorption and plant uptake; moreover, the percentage of soil adsorption was 61%-89%, and was higher than that of the plants uptake (5%-31%). The absorption capacity ofEichhornia crassipes(E. crassipes) (1186.71 mg/kg) was higher than that ofCyperus alternifolius (C. alternifolius)(162.77 mg/kg) under 10 mg/L PFOS, and the transfer factor of PFOS inE. crassipesandC. alternifoliuswas 0.04 and 0.58, respectively, indicating thatPFOS is noteasilytranslocatedto leaves fromroots of wetland plants; moreover, uptake of PFOS byE. crassipeswas more than that ofC. alternifoliusbecause the biomass ofE. crassipeswas more than that ofC. alternifoliusand the roots ofE. crassipescan take up PFOS directly from wastewater whileC. alternifoliusneeds to do so via its roots in the soil. The concentration of 10 mg/L PFOS had an obvious inhibitory effect on the removal rate of total nitrogen, total phosphorus, chemical oxygen demand, and ammonia nitrogen in the VFCW, which decreased by 15%,10%,10% and 12%, respectively. Dosing with PFOS in the wastewater reduced the bacterial richness but increased the diversity in soil because PFOS stimulated the growth of PFOS-tolerant strains. (c) Higher Education Press 2020

Automated summary

The vertical-flow constructed wetland effectively removed PFOS from simulated domestic sewage through soil adsorption and plant uptake. Soil adsorption played a key role in PFOS removal, with a higher percentage compared to plant uptake.