不同改良剂对黔西北锌冶炼区农用地土壤重金属修复效果研究

为研究不同改良剂对土壤重金属（Cd、Cu、Pb、Zn）的修复效果，以黔西北锌冶炼区农用地土壤为研究对象，分别将不同比例（1%、2%、5%）的海泡石（H）、石灰（S）和蚯蚓粪（Q）施加于锌冶炼区重金属（Cd、Cu、Pb、Zn）复合污染农用地土壤，稳定陈化75 d后，分析土壤理化性质（pH、EC、含水率）、有机质、有效态养分（N、P、K）、重金属有效态含量变化特征。结果表明，与对照相比，除低添加量的海泡石处理（H1%）略微降低土壤pH外，海泡石和石灰处理均提高了土壤pH，而添加蚯蚓粪处理则降低土壤pH。除石灰处理分别降低土壤有机质和碱解氮含量外，海泡石和蚯蚓粪均可有效提高土壤有机质、碱解氮、有效磷和速效钾含量，其中蚯蚓粪和石灰处理分别对土壤碱解氮和有效磷的增加效果最为明显，分别增加了36.53%～72.34%和67.96%～144.01%。与对照相比，添加石灰明显降低了土壤中DTPA-Cd、DTPA-Pb和DTPA-Zn含量，分别降低了16.94%～29.87%、8.26%～20.46%、27.91%～51.02%。添加蚯蚓粪则总体上增加土壤中DTPA提取态重金属（Cd、Cu、Pb、Zn）含量，而海泡石添加可增加土壤中DTPA-Cd和DTPA-Cu含量，降低DTPA-Pb和DTPA-Zn含量。石灰和海泡石处理都不同程度降低土壤中TCLP提取态重金属（Cd、Cu、Pb、Zn）含量，然而，添加蚯蚓粪处理显著地增加TCLP提取态重金属（Cd、Cu、Pb、Zn）含量。综合分析表明，石灰对于复合污染土壤中Cd、Cu、Pb、Zn的固定效果最佳，其次为海泡石，而蚯蚓粪的添加对土壤重金属具有活化作用。

Remediation Effect of Different Amendments on Heavy Metals in Agricultural Soil in Zinc Smelting Area of Northwest Guizhou

To study the remediation effect of different amendments on heavy metals (Cd, Cu, Pb, Zn) in soil, sepiolite (H), lime (S) and vermicompost (Q) with different proportions (1%, 2%, 5%) were applied to the agricultural soil of a zinc smelting area in northwest Guizhou. The results showed that both the sepiolite and lime treatment, except for the low addition of sepiolite (H1%), increased the soil pH value, while the vermicompost treatment decreased the soil pH value. Unlike the lime treatment which decrease the soil organic matter and available nitrogen, sepiolite and vermicompost can effectively increase the contents of soil organic matter, available nitrogen, available phosphorus, and available potassium. The treatments by vermicompost and lime obviously increased the soil available nitrogen and available phosphorus by 36.53%-72.34% and 67.96%-144.01%, respectively. Compared with the control, the contents of DTPA-Cd, DTPA-Pb and DTPA-Zn in soil treated with lime were significantly reduced by 16.94%-29.87%, 8.26%-20.46% and 27.91%-51.02%, respectively. The addition of vermicompost increased the content of DTPA extractable heavy metals (Cd, Cu, Pb, Zn) in soil as a whole, while the addition of sepiolite increased the content of DTPA-Cd and DTPA-Cu in soil and decreased the content of DTPA-Pb and DTPA-Zn. Treatment with lime and sepiolite reduced the leachability of Cd, Cu, Pb, Zn in soil by means of TCLP, but treatment with vermicompost significantly increased the contents of heavy metals (Cd, Cu, Pb, Zn) in the leachate with the TCLP experiment. This study indicates that lime has the best immobilization effect on the multi-heavy metal (Cd, Cu, Pb and Zn) polluted soil, followed by sepiolite, and the addition of vermicompost can activate heavy metals in the soil.