Effects of Tween 80 on Degradation of Benzo[f]pyrene in Soils Growing Sudan Grass

Abstract

Abstract. Phytoremediation is becoming a cost-effective technology for the in-situ clean up of sites polluted with hydrophobic organic contaminants (HOCs). The major factors limiting phytoremediation are the mass transfer, rate of plant uptake, and microbial biodegradation of HOCs. To evaluate the potential of surfactants to enhance phytoremediation for HOC-contaminated sites, the efficacy of Sudan grass, at the absence or presence of polyoxyethylene sorbitan monooleate (Tween 80), on the degradation of benzo[â ]pyrene (BaP) in soils were investigated, and mechanisms of surfactant-enhanced phytoremediation (SEPR) were discussed. Results showed that the presence of Tween 80 enhanced dissipation of BaP at initial contents ranging from 20.24 to 321.42 mg/kg. During the 70-d SEPR-experiments, about 731.84~469.99‰ of BaP was removed from planted soils, only 242.28~122.79‰ degradation of BaP occurred in unplanted ones. With the presence of Tween 80, the dissipation ratios of BaP in planted ones were increased up to 863.94~609.63‰, which was 139.64~ 190.16‰ higher than those in corresponding soils without surfactant. Among all possible pathways, contribution of plant-microbial interactions on dissipation of BaP was the most significant, either at the presence (456.73‰) or absence (515.58‰) of Tween 80, were the primary means of contaminant degradation. Results suggested SEPR may be a feasible way for reinforcing removal of HOCs in contaminated sites.