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首页> 外文OA文献 >Phytoremédiation par Jardins Filtrants d'un sol pollué par des métaux lourds : Approche de la phytoremédiation dans des casiers végétalisés par des plantes de milieux humides et étude des mécanismes de remobilisation/immobilisation du zinc et du cuivre
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Phytoremédiation par Jardins Filtrants d'un sol pollué par des métaux lourds : Approche de la phytoremédiation dans des casiers végétalisés par des plantes de milieux humides et étude des mécanismes de remobilisation/immobilisation du zinc et du cuivre

机译：通过重金属污染的土壤过滤花园进行植物修复：湿地植物重新种植的盆栽中的植物修复方法以及锌/铜的迁移/固定机制的研究

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Numerous studies in phytoremediation have tried to increase the uptake of metals by plants for soil cleanup. This work is about a new phytoremediation approach named Filtering Gardens using common wetland plants (Phragmites australis, Iris pseudacorus and Salix viminalis) in the vegetated cells irrigated so as to impose periodic flooding-drying conditions for enhancing the solubility of metals in the soil and their removal through leaching. In a pilot-scale sixteen-month experiment, this approach was applied for phytoremediation of Zn, Cu and Pb from an agricultural soil highly contaminated by sewage disposal. Metal mass balances for soil-plant systems showed that only a non-significant amount of metals was accumulated in plant tissues. An important amount of metals was removed from the soil via phytoleaching resulting from the interaction of plant roots with irrigation. An additional chemical treatment with citrate can enhance metal leaching. Mechanisms of Zn and Cu transformations involved in this phytoremediation were highlighted by combining synchrotron-based X-ray analytical tools at micro- (µXRF, µXRD, µEXAFS) and macro-scale (EXAFS) coupled with chemical analyses, allowing to determine the nature and amount of metal forms in the soil. In the initial soil, zinc was occurred mainly as secondary minerals (Zn-ferrihydrite, Zn-phosphate and Zn-kerolite-like-phyllosilicate) and copper was essentially bound to organic matter. The activity of plant roots under flooding-drying conditions clearly modified the original speciation of metals. In the phytoremediated soil, Zn-ferrihydrite, one of the initially major forms of Zn, was entirely dissolved. The reductive dissolution of this iron oxyhydroxide favored by flooding conditions was the major process inducing Zn leaching. One part of solubilized Zn coprecipitated with Fe into another less soluble iron oxyhydroxide, Zn-substituted goethite, under oxidizing conditions and with assistance by plant roots likely in defense against toxic dissolved metals, as evidenced by the formation of goethite plaques on and near roots. Moreover, the newly occurred particles of metallic Zn and ZnO were discovered in the rhizosphere, in small amount. The oxidation of organic matter likely enhanced by root oxygen release caused an excess of toxic cationic Cu. In response to oxidative stress, this Cu was biotransformed into metallic Cu nanoparticles, in important amount, by plant roots with evidence of assistance by endomycorrhizal fungi. This newly identified mode of metal biomineralization by plant roots may be typical of common wetland plants. This new way of making phytoremedation involves mainly phytoleaching inducing the solubilization of metals in the soil and their leaching and phytotransformation, due in part to phytodetoxication, driving the conversion of toxic metals into weakly soluble forms.
机译：植物修复方面的许多研究试图增加植物对土壤的金属吸收。这项工作是关于一种新的植物修复方法，该方法称为“过滤花园”，该方法在灌溉的植被细胞中使用普通湿地植物（芦苇，鸢尾鸢尾和柳柳）来施加周期性的驱干条件，以提高金属在土壤及其土壤中的溶解度。通过淋洗去除。在一个为期16个月的中试规模的实验中，该方法用于对污水处理高度污染的农业土壤中的Zn，Cu和Pb进行植物修复。土壤-植物系统的金属质量平衡表明，植物组织中仅积累了少量金属。植物根与灌溉的相互作用通过植物浸出从土壤中去除了大量的金属。柠檬酸盐的另一种化学处理可以增强金属的浸出。通过将基于同步加速器的X射线分析工具在微观（µXRF，µXRD，µEXAFS）和宏观（EXAFS）结合化学分析，突出了参与该植物修复的Zn和Cu转化机制，从而确定了化合物的性质和土壤中金属的数量。在最初的土壤中，锌主要作为次生矿物（锌亚铁酸盐，锌磷酸盐和锌硅藻土状页硅酸盐）而存在，而铜基本上与有机物结合。水淹干燥条件下植物根系的活性明显改变了金属的原始形态。在经过植物修复的土壤中，锌的水铁矿（锌的最初主要形式之一）被完全溶解。淹水条件促进的这种羟基氧化铁的还原溶解是诱导锌浸出的主要过程。一部分溶解的Zn与Fe共沉淀为另一种溶解度较低的羟基氧化铁，Zn取代的针铁矿，在氧化条件下并在植物根的协助下可能防御有毒的溶解金属，这由在根上和附近形成针铁矿斑块所证明。此外，在根际中发现了少量新出现的金属Zn和ZnO颗粒。根氧释放可能会增强有机物的氧化，导致过量的有毒阳离子Cu。响应于氧化胁迫，该铜被植物根部生物转化为重要数量的金属铜纳米颗粒，并有内生菌根真菌的辅助作用。这种新发现的通过植物根部进行金属生物矿化的模式可能是普通湿地植物的典型特征。这种进行植物除草的新方法主要涉及植物浸出，诱导土壤中金属的溶解以及它们的浸出和植物转化，这部分归因于植物的解毒作用，促使有毒金属转化为难溶形式。

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    Kirpichtchikova Tatiana;

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  • 年度 2009
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