宝景天-小麦轮作修复重金属污染土壤的工程案例

Case project of phytoremediation of heavy metal contaminated soil by rotation Sedum spectabile with Triticum aestivum

河北省邢台市某重金属锌、镉污染农田,通过现场采样调查,确定其污染面积约39.09 hm^2,Zn、Cd最大污染浓度为404 mg/kg、2.91 mg/kg。本项目采用八宝景天-小麦轮作的植物修复模式,配合施加重金属活化剂、钝化剂、复合肥等措施提升八宝景天的生物量和对Zn、Cd的吸收量。经过三轮修复,土壤中Zn、Cd平均浓度分别为292.09 mg/kg(修复目标值为300 mg/kg)、0.38 mg/kg(修复目标值为0.6 mg/kg),去除率分别为14.65%和48.7%;小麦籽粒中Zn、Cd平均浓度分别为43.263 mg/kg(标准限值50 mg/kg)、0.059 mg/kg(标准限值0.1 mg/kg),去除率分别为44.05%和42.7%,均达到修复目标要求。

It was determined that,through on-site sampling survey,the polluted area of a farmland,in the city of Xingtai(Hebei Province),was about 39.09 hm^2,and the main pollutants were zinc(Zn)and cadmium(Cd),of which the maximum pollution concentrations of zinc and cadmium were 404 mg/kg and 2.91 mg/kg respectively.The phytoremediation model of Sedum spectabile and Triticum aestivum rotation was used in the field.At the same time,measures such as heavy metal activator,passivator and compound fertilizer were applied to increase the biomass of Sedum spectabile,thereby increasing the absorption of zinc and cadmium.The result of this project reached the remediation target,after three rounds of remediation.The average concentration of zinc and cadmium in the soil decreased to 292.09 mg/kg(remediation target value is 300 mg/kg),and 0.38 mg/kg(remediation target value is 0.6 mg/kg),respectively.And,the removal rates for zinc and cadmium were 14.65%and 48.7%,respectively.The average concentration of zinc and cadmium in Triticum aestivum decreased to 43.263 mg/kg(standard limit 50 mg/kg),and 0.059 mg/kg(standard limit 0.1 mg/kg),respectively.And,the removal rates for zinc and cadmium were 44.05%and 42.70%.