土壤重金属复合污染及其化学钝化修复技术研究进展

Combined pollution of multiple heavy metals and their chemical immobilization in contaminated soils: A review

土壤重金属污染往往是2种或2种以上的多种重金属并存的复合污染。与单一污染相比,重金属复合污染中元素或化合物之间存在相互作用以及对生态效应的综合影响,对其污染土壤的修复具有挑战性。目前,土壤重金属污染的修复主要集中在单一元素上,而对土壤多种重金属并存的复合污染的同时修复研究较少。化学钝化修复是基于向土壤中添加稳定化剂,通过吸附、沉淀、络合、离子交换和氧化还原等一系列反应,以降低污染物的生物有效性和可迁移性,从而达到修复目的的方法。这种方法因投入低、效率高、修复快速、操作简单等优越性,对于大面积污染土壤的修复具有较好的应用前景。系统地综述了国内外土壤多重金属污染的复合作用、生态效应及其定量表征的研究进展,并重点指出土壤重金属复合污染的化学钝化修复技术的稳定化剂类型、作用效果、分子机制、影响因素和现场实例等方面的研究现状、存在问题及发展方向。

Soil contamination by multiple heavy metals is a widespread environmental concern.Compared with the single metal,multiple heavy metals in soils behave interactively and show combined ecological effects,making the soil remediation challengeable.Most of the previous studies on the remediation of metal-contaminated soils have been focused on one single metal;however,little work was reported on the remediation of multiple metals.Chemical immobilization relies on addition of the soil amendments to help retain contaminants in the stable solid phase,by sorption,precipitation,complexation,ion exchange or redox process,thereby decreasing mobility and bioavailability of contaminants.The method is most prospective for remediation of contaminated soil at a large scale,with cost-effective and easy operation.In this paper,a review was presented on the impacts of multiple heavy metals on soil ecological environment and the quantitative characterization of the combined pollution as well as the development in chemical immobilization in multi-metal contaminated soils with more attentions paid to the amendment types,treatment effectiveness,molecular mechanism,impact factors,and field demonstration.