Effects of Multispecies Phytoremediation on the Fate of Phenanthrene and Pyrene in Soils

摘要

The potentials of three plant species, rape, alfalfa and white clover, separately or jointly on the degradation of polycyclic aromatic hydrocarbons (PAHs) in soils were estimated by pots experiments. Results showed that the presence of vegetation apparently enhanced the dissipation of PAHs at initial concentrations ranging from 20.05 to 322.06 mg-kg~(-1), but the efficacy enhanced varied greatly among plant species and cropping patterns. Within 70-day experiment, alfalfa and white clover showed higher efficiencies for the removal of PAHs than those of rape, and mixed cropping greatly enhanced the dissipation of PAHs as compared to single cropping. On average 74.87% of phenanthrene or 62.81% of pyrene were removed from soils with mixed cropping of rape and alfalfa, and 72.01% of phenanthren or 68.44% of pyrene removed by mixed cropping of rape and white clover. Under similar pollution level, PAHs accumulated in plant, irrespective of root and shoot, was much lower in mutli-planted treatments than in mono-planted ones. Results suggested a feasibility of the establishment of multispecies remediation for enforcing the dissipation of PAHs, which may also decrease the accumulations of PAHs in plant and thus reduce their risks to humans.