State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China.
J Hazard Mater. 2010 Sep 15;181(1-3):673-8. doi: 10.1016/j.jhazmat.2010.05.065. Epub 2010 Jun 15.
In order to explore a practical approach to the remediation of the cadmium (Cd)-contaminated soil in the lower reaches of the Yangtze River, we evaluated the effects of a local willow (Salix x aureo-pendula CL 'J1011') of absorbing, accumulating, and translocating Cd; and assessed the potential of chelator ethylenediaminetetraacetic acid (EDTA) in combination with ethyl lactate for enhancing the efficiency of the willow in removing Cd in two water-culture growth chamber trials and a field one. The willow showed a high tolerance to Cd in growth chamber trial 1 where the Cd concentration in the medium reached up to 25 mg L(-1) medium, and the bioaccumulation factors (BAFs) of the shoots for Cd rose from 3.8 to 7.4 as the Cd concentration in the medium was elevated from 5 to 25 mg L(-1) medium. In growth chamber trial 2, the average Cd removal rates in two treatments with EDTA and ethyl lactate (molar ratios of EDTA to ethyl lactate=68/39 and 53.5/53.5, respectively) reached 0.71 mg d(-1) pot(-1) for the duration of Day 5-8 and 0.59 mg d(-1) pot(-1) for that of Day 8-11, which were 5- and 4-fold of their counterparts in the control, respectively. In the field trial, for the remediational duration of 45 days, three treatments-willow alone, willow combined with EDTA, and willow combined with EDTA and ethyl lactate-led to decreases in the Cd concentration in soil by 5%, 20%, and 29%, respectively; increases in that in the leaves by 14.6%, 56.7%, and 146.5%, respectively; and increases in that in the stems by 15.6%, 41.2%, and 87.4%, respectively, compared to their counterparts on Day 0. These results indicate that EDTA combined with ethyl lactate significantly enhanced the efficiency of willow in removing Cd from the soil. Therefore, a phytoextration system consisting of the autochthonous willow, EDTA, and ethyl lactate has high potential for the remediation of the Cd-polluted soil in the lower reaches of the Yangtze River.
为了探索一种修复长江下游地区镉污染土壤的实用方法，我们评估了本地柳树（Salix x aureo-pendula CL 'J1011'）对镉的吸收、积累和转运能力，并评估了螯合剂乙二胺四乙酸（EDTA）与乳酸乙酯结合在两种水培生长室试验和田间试验中提高柳树去除镉效率的潜力。在生长室试验 1 中，柳树对镉有很强的耐受性，其中培养基中的镉浓度高达 25mg/L，当培养基中的镉浓度从 5mg/L 升高到 25mg/L 时，柳树茎部的生物积累因子（BAFs）从 3.8 升高到 7.4。在生长室试验 2 中，EDTA 和乳酸乙酯处理的平均镉去除率在第 5-8 天分别达到 0.71mg/d·盆-1和 0.59mg/d·盆-1，第 8-11 天分别达到 0.59mg/d·盆-1和 0.59mg/d·盆-1，分别是对照的 5 倍和 4 倍。在田间试验中，对于 45 天的修复期，柳树单独处理、柳树与 EDTA 联合处理和柳树与 EDTA 和乳酸乙酯联合处理分别导致土壤中镉浓度降低 5%、20%和 29%，叶片中镉浓度增加 14.6%、56.7%和 146.5%，茎中镉浓度增加 15.6%、41.2%和 87.4%，与试验开始时的对照相比。这些结果表明，EDTA 与乳酸乙酯联合使用显著提高了柳树从土壤中去除镉的效率。因此，由本地柳树、EDTA 和乳酸乙酯组成的植物提取系统对修复长江下游地区镉污染土壤具有很大的潜力。
