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| Combined phytoremediation effect of several plants in PCBs contaminated farmland soils |
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Abstract A field microzone experiment was carried out to study the co-remediation effect of PCBs contaminated farmland soils under different planting models for using three plant species, alfalfa( Medicago sativa L), Elsholtzia splendens and Sedum plumbizincicola. The results indicated that mixed croppings of alfalfa with Elsholtzia splendens or Sedum plumbizincicola could enhance PCBs removal in soils compared to the monoculture with alfalfa. About 43.0% of PCBs were removed from the soils in mixed cropping of alfalfa and Elsholtzia splendens at the end of the 120d experiment, and 47.8% in mixed cropping of three plants. The mixed croppings of alfalfa with Elsholtzia splendens or Sedum plumbizincicola could increase the total biomass of plants, facilitate the uptake and accumulation of the PCBs in plants. Analysis of PCBs composition showed that the planted treatments could decrease the concentration of lower chlorinated PCBs in soils, and multi-species phytoremediation could improve the transformation of higher chlorinated PCBs into lower chlorinated PCBs. The mixed croppings of alfalfa with Elsholtzia splendens or Sedum plumbizincicola show a good potential in the remediation of PCBs contaminated farmland soils.
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Received: 19 January 2010
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