重金属污染土壤原位化学固定修复研究进展

Advances in research on in situ chemo-immobilization of heavy metals in contaminated soils

重金属污染土壤原位化学固定修复是通过添加不同外源物质固定土壤中重金属元素,达到降低重金属迁移性和生物有效性的一种重要方法.由于操作方便和效果快速,使其在污染土壤治理过程中有着不可代替的作用,尤其对于耕作土壤中的面源污染.许多具有俘获土壤中重金属离子能力的自然物质和工业副产品如磷矿石、泥炭土、石灰和有机肥等都可用在实地的固定修复中.采用实验室评价和实地应用评价,一方面可以评估这些固定物质在土壤中对重金属离子的固定效率;另一方面可以评估重金属的溶出、释放和生物毒性等生态风险.本文对原位修复过程中采用的不同固定物质的来源和分类进行了概述,对化学固定过程的机理进行了探讨,同时阐述了重金属污染土壤化学固定修复应用过程中的实验室评价和实地应用评价方法,分析了化学固定修复的局限性并提出了今后的发展方向.

In situ immobilization of heavy metals is a main method for decreasing the mobility and bioavailability of heavy metal ions through their immobilization by adding various amendments. Due to its easy operation and rapid efficiency, this method is becoming non-replaceable, especially for the remediation of non-point polluted arable soils. Natural materials and industrial by-products with high capacity of entrapping and fastening heavy metals, e. g., phosphorite, peat, lime, and organic fertilizers, can be obtained and employed, and the immobilization efficiency of these amendments as well as the environmental risk of the ionic leaching, releasing, and biological toxicity of heavy metals could be evaluated in laboratory and field. In this paper, the resources and types of the amendments were classified, and the possible immobilization mechanisms for the remediation of heavy metals- contaminated soils were discussed. The assessment methods of this remediation in laboratory and field were formulized, its limitation was analyzed, and further development directions were put forward.