【摘要】 通过盆栽试验,比较研究乙二胺四乙酸二钠盐(EDTA)、味精废液、柠檬酸、乙酸、草酸和混合试剂(柠檬酸∶味精废液∶EDTA∶KC l=10∶1∶2∶3)对Zn超累积植物遏蓝菜(T h lasp i caeru lescens)和东南景天(S edum a lf red ii)吸收提取Zn的影响。结果表明:各种添加剂均提高土壤中的水提取态和NH4NO3提取态Zn的含量,其顺序为EDTA混合试剂>味精废液>有机酸。除乙酸和味精废液外,其余添加剂都显著促进遏蓝菜的生长,以混合试剂的增产效果最好;但只有EDTA和混合试剂在浓度为10mm o l/kg土时提高了东南景天的生物量。混合试剂在浓度为6~10 mm o l/kg土时促进遏蓝菜对Zn的吸收和向地上部转移;EDTA和浓度为10mm o l/kg的混合试剂能显著促进东南景天对Zn的吸收和向地上部的转移。因此东南景天配合环境风险较小、用量为10mm o l/kg土的混合试剂较适合我国南方的Zn污染土壤。更多还原

【Abstract】 Chelate-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil,which adds chelates to enhance hyperaccummulation by plants.The key of the technology is to choose suitable chelates and the combining-hyperaccummulator.Several studies have documented that chelating agents such as ethylene diamine triacetic acid（EDTA） and citric acid can be used to increase metal mobility,thereby enhancing phytoextraction,with the special emphasis on EDTA due to it’s significant enhancing effect.But EDTA is not cheap and can cause underground water contamination,so "greener" or/and cheaper enhancing chelates are to be exploited.Pot experiments were conducted to examine the effects of various organic chelates,including EDTA（ethylenediamine tetraacetic aicd）,citric acid,acetic acid,oxalic acid,monosodium glutamate waste water（MGWW） and a mixture of additives（molar ratio of citric acid,MGWW,EDTA and KCl =10∶1∶2∶3）,on Zn uptake by two Zn-hyperaccumulating plants Thlaspi caerulescens and Sedum alfredii.The soil used for the experiment was collected from a paddy field that has been contaminated by heavy metal-laden mine water from a lead/zinc mine in the northern Guangdong Province of China.The application rate was 6 mmol equivalent per kg soil except for the mixed additives,which was applied in a series of concentrations varied from 2 to 14 mmol equivalent per kg soil.The results show that addition of chelates increased waterand NH₄NO₃-extractable Zn in the soil,and the capacity of chelates to mobilize Zn was in the following decreasing order: EDTAmixed additives>MGWW>organic acids.Except for MGWW and acetic acid,all the chelates enhanced the growth of Thlaspi caerulescens,especially the mixed additives.However,only EDTA and the mixed additives at 6 mmol/kg had effects on increasing the biomass of Sedum alfredii.Addition of the mixed additives at 6～10 mmol/kg increased the Zn uptake by Thlaspi caerulescens and the accumulation of Zn in the above-ground portion of the plant,While EDTA and the mixed additives at 10 mmol/kg significantly increased Zn uptake by Sedum alfredii and the accumulation of Zn in the above-ground portion of the plant.Zn extraction efficiency of Sedum alfredii was higher than that of Thlaspi caerulescens.This work suggests that the use of mixed additives at 10 mmol/kg to treat the contaminated soils for the growth of Sedum alfredii gives the best effects on the clean-up of the investigated Zn-contaminated soil among all the treatments in this study because it reduces the environmental risk due to secondary contamination by EDTA while maximizing the removal of Zn from the contaminated soil.更多还原