Enhanced Phytoremediation on PAHs in Soils by Combined Plants Cultivation

Phytoremediation of PAHs in soils at initial contents ranging from 20.05 to 322.06 mg·kg-1 was investigated under different planting patterns, and enhancement mechanisms were analyzed. Results showed that the dissipation of PAHs in soils growing white clover and alfalfa significantly exceeded those vegetating single species. During 70-day experiment, about 75.06% of Phe and 68.22% of Pyr was removed from the soils under mixed cropping; while only 31.8% and 64.03% of Phe and 27.84% and 51.93 of Pyr were removed under single white clover and alfalfa cropping, respectively. Of all pathways enforcing PAHs removal, the plant-microbial interactions is the most predominant. These results suggested a feasibility of the establishment of multi-species phytoremediation for improvement of the remediation efficiencies of PAHs, which may decrease accumulations of PAHs in crops and thus reduce their ecological risks.