多氯联苯复合污染农田土壤的植物协同修复效应

采用田间微域试验,初步研究了紫花苜蓿与海州香薷、伴矿景天在不同栽培模式下对多氯联苯(PCBs)复合污染农田土壤的协同修复作用.结果表明,紫花苜蓿与海州香薷、伴矿景天混作对PCBs复合污染土壤的修复效果明显高于紫花苜蓿单作,其中紫花苜蓿-海州香薷混作、紫花苜蓿-海州香薷-伴矿景天混作种植120d后,土壤中PCBs含量比紫花苜蓿单作时分别降低43.0%和47.8%,强化效果显著.与紫花苜蓿单作相比,紫花苜蓿与海州香薷、伴矿景天混作可有效提高植株总生物量,增强植物对土壤中PCBs的吸收富集能力.土壤PCBs同系物分析结果表明,种植植物可有效降低土壤中低氯代PCBs含量,植物混作栽培模式可以促进高氯代PCBs组分向低氯代PCBs组分的转变.可见,紫花苜蓿与海州香薷、伴矿景天混作对多氯联苯复合污染农田土壤具有较好的协同修复作用.

Combined phytoremediation effect of several plants in PCBs contaminated farmland soils

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.