Agronomy Department, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
Environ Technol. 2010 May;31(6):655-69. doi: 10.1080/09593331003610907.
After soil remediation with ethylenediamine tetraacetate (EDTA) leaching/washing, the residual Pb, Zn, and Cd species are left in the soil in non-labile forms. The effect of earthworms as main soil biotic factors on the residual Pb, Zn, and Cd fraction lability (mobility, bioavailability to plants, and oral-availability) was investigated. Contaminated soil from a smelter site was treated with increasing EDTA concentrations (2.5 to 4-times 40 mmol kg(-1) to gradually reduce the heavy metal content and lability. Leached soils were processed by Eiseniafetida and heavy metal lability and fractionation determined in casts and earthworm-processed soils. In general E. fetida increased heavy metal accessibility/mobility, but the induced changes diminished with the intensity of soil EDTA treatment. Fractionation results indicate the possibility of a time-dependent complexation of heavy metals to carbonates favoured by earthworms' gut processes. The transition of residual heavy metals in time (ageing) should be considered.
用乙二胺四乙酸（EDTA）浸提/洗涤进行土壤修复后，残留的 Pb、Zn 和 Cd 形态在土壤中以非活性形式存在。本研究调查了蚯蚓等主要土壤生物因素对残留 Pb、Zn 和 Cd 形态（迁移性、对植物的生物有效性和口服有效性）的影响。用逐渐增加的 EDTA 浓度（2.5 至 4 倍 40 mmol kg(-1)）处理来自冶炼厂的污染土壤，以逐渐降低重金属含量和活性。对淋洗土壤进行了赤子爱胜蚓处理，并在蚯蚓处理过的土壤和蚓粪中测定重金属的活性和形态。一般来说，赤子爱胜蚓增加了重金属的可利用性/迁移性，但随着土壤 EDTA 处理强度的增加，诱导的变化减少。形态分析结果表明，重金属与碳酸盐的络合可能与蚯蚓肠道过程有关，而且这种络合具有时间依赖性。应该考虑残留重金属在时间（老化）上的转变。
