重金属复合污染土壤稳定化研究及效果评价

Stabilization study and evaluation on heavy metals combined contaminated soil

用自制稳定化试剂CTS-AC01试剂对广西河池某砒霜厂遗址As、Cd、Pb、Zn复合污染土壤进行稳定化研究并进行效果评价。结果表明:(1)CTS-AC01试剂可以降低土壤中重金属的毒性特征浸出程序(TCLP)浸出液浓度,使As、Cd、Pb、Zn的稳定效率分别达到87.7%、93.7%、90.9%、99.5%;(2)经过20次模拟淋溶,淋溶液中As、Cd、Pb、Zn的质量浓度分别为0.199、0、0、0.017mg/L,除As浓度超过《地表水环境质量标准》(GB 3838—2002)的Ⅴ类水质标准外,其他3种重金属均已达标;(3)通过土壤中重金属形态分析发现,稳定化主要是将可交换态和氧化结合态向残渣态转化,但20次模拟淋溶对土壤中重金属形态的影响不大,更长期的淋溶作用有待进一步研究。

Stabilization study and evaluation were conducted with self-made stabilization agent CTS-AC01 reagent on As,Cd,Pb and Zn combined contaminated soil sample from the arsenic factory site in Hechi,Guangxi.Results showed that CTS-AC01 reagent could lower the concentrations of heavy metals by toxicity characteristic leaching procedure(TCLP).Stablization efficiencies of As,Cd,Pb and Zn were 87.7%,93.7%,90.9% and 99.5%,respectively.After 20 times of leaching,the mass concentrations of As,Cd,Pb and Zn in leachate were 0.199,0,0,0.017mg/L,respectively.Pb,Cd and Zn all met class Ⅴ standard of 'Surface water environmental quality standard'(GB 3838-2002),except As.Speciation analysis of the heavy metals in soil showed that exchangeable form and oxides-bounded form changed to residual form in the stabilization process.20 times of leaching had little influence on heavy metal speciation,but the influence of more long-term leaching should not be ingnored.