土法炼锌区土地复垦的重金属迁移特征

Transference Characteristics of Heavy Metals in Land Reclamation of Indigenous Zinc Smelting Areas

[目的]分析废渣及炼锌区附近污染土壤剖面的Pb、Zn、Cd的分布特征。[方法]在废弃地上和废弃地附近耕地各选择1个点进行分层采样,在每个剖面的同一深度的不同位置采集3个样品,采用客土法进行复垦,在废弃地上设计10个处理,进行废渣重金属迁移模拟试验,研究废渣中Pb、Zn、Cd迁移规律。[结果]废渣表层Pb、Zn、Cd分别为3453、5678、23 mg/kg,废渣剖面上重金属含量基本一致。冶炼区附近表层土壤Pb、Zn、Cd分别为325、523、9.6 mg/kg,污染重金属向下逐渐迁移。废渣重金属向上层土壤没有明显的迁移。Pb向下层土壤几乎没有明显迁移,Zn和Cd向下层土壤有明显的迁移,Cd的迁移性最大。[结论]隔离层能有效控制废渣重金属向下层土壤的迁移。

[Objective]The study aimed to analyze the distributions characters of Pb, Zn and Cd in pollution soil profiles around waste residue and zinc smelting areas. [Method] Each point was selected to make the stratified sampling at the waste land and the cultivated land near the waste land, 3 samples were selected at different position of the same deep of every profile, the external soil method was used to make reclamation. 10 treatments was designed in the waste land to make the simulation experiment on transference of heavy metals in waste residue and research the migration law of Pb, Zn, Cd in the waste residue. [Result] Pb, Zn, Cd in waste residue surface were 3 453,5 678, 23 mg/kg, respectively , and the heavy metals content was basically identical on the waste residue profile. The Pb, Zn, Cd in surface soil near the smelting area were 325, 523, 9.6 mg/kg and the polluted heavy metals transferred downwards gradually, the waste residue heavy metals didn＇t transfer obviously to upper soil. Pb had not obvious transference scarcely to subsoil, but Zn and Cd transferred obviously to subsoil and the transference of Cd was biggest. [Conclusion] The alkali lime isolation layer could effectively control the transference of heavy metals in waste residue to subsoil.