【作者】 张维碟；

【导师】 陈英旭；

【作者基本信息】 浙江大学 ， 环境工程， 2002， 硕士

【摘要】 近年来，由于土壤重金属污染问题日益突出，有关污染土壤的植物萃取修复技术的基础理论和实际应用正成为研究热点。本文通过植物萃取的盆栽试验、离子树脂交换法、偏剔除试验以及重金属模拟形态试验，研究了施加EDTA、柠檬酸废水、味精废水、木屑真菌腐化物等诱导措施对植株富集土壤中重金属能力及其机理、土壤重金属活性及其各形态的植物可利用性等的影响，得出以下结论： 诱导措施对植株的吸收与转运重金属方面有不同程度的促进作用。EDTA对Cu，Pb的效果较明显；味精废水与木屑真菌腐化物对Zn、Cd的活化效果较好；柠檬酸废水对促进香根草吸收重金属的效果较好，而对高羊茅较弱。EDTA和味精废水对四种重金属在植物体内的运输均有较大的促进作用；柠檬酸废水对Pb在植株体内的运输起抑制作用；除Cd外，柠檬酸废水和淹水处理均使重金属的运输能力增高；真菌腐化物对香根草吸Zn有负面作用，而对其它重金属效果较好。 在外源物质影响下，富阳水稻土根际土壤化学行为异于非根际。诱导措施使富阳水稻土植物根际pH降低，产生“根际酸化”现象，其中以味精废水效果最为明显；在根系和外源物质作用下，根际土壤溶液中重金属含量均高于非根际，外源物质活化程度超过了植物吸收与根际向非根际转移速度之和，其对Cu、Zn的溶出效果顺度为：EDTA＞味精废水＞柠檬酸废水＞木屑真菌腐化物。另外，根际微生物量均高于非根际，不同诱导措施对促进根系分泌的作用不同，其中以味精废水与淹水处理的效果最为明显。根泌物与根际微生物增加提高了根际DOC浓度的增加，但淹水处理降低了根际DOC浓度。 富阳水稻土中重金属的溶解度顺序为Zn＞Pb＞Cu，在有机络合剂作用下，其顺序转变为Zn＞Cu＞Pb；青紫泥中重金属的溶解度顺序为Zn＞Cu＞#b，在有机络合剂作用下，其顺序转变为Cu＞Zn＞Pb。有机络合剂使得土壤溶液中可溶性与离子态重金属的浓度改变，反映了其活性与可利用性较对照不同。 诱导措施与植物根系对土壤重金属的存在形态产生了较大影响。诱导措施对土壤有效态重金属（CaCl₂提取态）的活化程度高于植物吸收与向非根际转移速度之和。以Cu的形态转化为例，诱导措施与根系作用对碳酸盐结合态与有机结合态的活化效果较好，且植物吸收也较强；铁锰氧化物结合态和残渣态使Cu无效化，在EDTA与味精废水作用下，它们可能向可利用性较高的形态转化。 Cu各形态的植物可利用性的顺序为水溶态、交换态、有机结合态＞碳酸盐结合态＞铁锰 氧化物结合态＞残渣态；其中有机结合态最易被植物吸收，而水溶态和交换态最易被植物所 转运。CU各形态受活化俏况oJ植物吸收俏况与有机络合剂的成分与性质有关，EDTA对CU 形态的溶出与促进植物吸收与转运CU素的效果最为明显，味精废水次之。更多还原

【Abstract】 Recently, phytoextraction theory and application has become a focus in environmental scientific area. In this paper, the plant effect and soil chemical behavior under inducement, including adding EDTA, citric acid waste water, monosodium glutamate waster water and wood fungi contagion was studied by pot experiment, heavy metal activity was evaluated with a cation exchange batch procedure, and the plant availability of heavy metal forms was evaluated with partial dissolution procedure and stimulated Cu forms.Study of the effect of inducement on absorb and transfer of heavy metals by plant showed that, the amout of Cu and Zn absorbed by plant was increased evidently by adding EDTA, as Zn and Cd were concerned, similar phenomenon presented when adding monosodium glutamated waste water or wood fungi contagion. Besides, except citric acid waste water, addition promoted the transference of heavy metals from root to shoot in plant.The chemical behavior of paddy soil was difference between with rhizosphere and non-rhizosphere under inducement. The pH value of rhizosphere was reduced by inducement, especially adding monosodium glutamate waster water. The phenomenon that heavy metal concentration in rhizosphere was higher than that of non-rhizosphere showed that, the activation rate was greater than the rate of plant absorbing and matter passing from non-rhizosphere. The most evident effect of addition on chemical behavior of Cu and Zn was EDTA, followed with monosodium glutamate waste water and citric acid waste water. In addition, microbe biomass in rhizosphere under inducement was higher than that of non-rhizospher, which resulted in increasing of DOC concentration in rhizosphere.The solubility sequence of heavy metals in Fuyan paddy soil was Zn>Pb>Cu, it was changed to Zn>Cu>Pb effected by organic complexing agent. Similarly, the solubility sequence of heavy metals in Qingzi soil was Zn> Cu>Pb, it was changed to Cu>Zn>Pb effected by organic complexing agent. The change of soluble and ionic heavy metal concentration in soil solution showed that, the activity and plant availability of heavy metals was higher than that of the check.The existing forms of heavy metal in soils were greatly changed by root and inducement. The amount of CaCI2 extractable heavy metal was increased elfected by inducement. As the transform of Cu was concerned, the Cu bounded to carbonate and organic matter bound Cu wasstrongly activated by inducement , so them were easily absorbed by plant compared with others forms. The Fe/Mn oxide bound Cu and residual Cu were poorly available, they could slightly transformed to other forms induced by EDTA and monosodium glutamate waster water.Study of availability of various Cu fractions in soil-plant system and its inducing effect showed that, the sequence of availability of Cu forms to plant is soluble plus exchangeable Cu and organic matter bound Cu > Cu bounded to carbonate > Fe/Mn oxide bound Cu > residual Cu. Effect of EDTA on dissolving of Cu from soil and absorb and transfer of plant was greater than that of monosodium glutamate waste water and citric acid waste water.更多还原