生物钝化修复镉污染土壤研究进展

回顾了我国含镉土壤的场地修复。综述了利用生物钝化技术修复镉污染土壤的研究现状，重点探讨了微生物的代谢产物与镉产生硫化物或磷酸盐沉淀的微生物沉淀作用、微生物的细胞壁和其分泌的胞外聚合物直接吸附镉的微生物吸附作用以及镉离子透过微生物的细胞膜而被固定在细胞内的微生物摄取作用等生物钝化机理，并对有机钝化过程和无机钝化过程进行了介绍和评价。分析了镉在土壤中的离子交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态和残渣态等赋存形态以及土壤中pH值、氧化还原电位、有机质、共存重金属和微生物等因素对镉的生物可利用度的影响。最后阐述了生物钝化技术的优点以及该技术不能将重金属从土壤中永久去除的问题，指出生物钝化技术与其他修复方法相结合是其未来的发展方向。

Research advance in the biostabilization remediation of cadmium contaminated soil

The site remediation of Cadmium contaminated soil was reviewed. The recent research in biostabilization of Cadmium in contaminated soil was summarized. The stabilization mechanisms were discussed with highlight，such as the bioprecipitation that microbial metabolites can react with Cadmium to form sulfide or phosphate precipitation，the biosorption that microbial cell walls and extracellular polymeric substances can adsorb Cadmium，and the biological uptake that Cadmium ions can pass through the cell membrane of microorganisms and be fixed in cells. Organic and inorganic stabilization were also introduced and evaluated. The state，e.g. ion-exchangeable，bound to carbonates，bound to iron and manganese oxides，bound to organic matter，and residual of Cadmium in soil，and the factors of pH， redox potential，organic matters，coexistent heavy metals and microorganisms which affect the consequential bioavailability of Cadmium were analyzed. Finally，the advantages of biostabilization technique and the fact that heavy metals cannot be removed from soil permanently by this technique were clarified，and the future direction that biostabilization technique should be combined with other techniques was pointed out.