紫花苜蓿对钒钛磁铁尾矿重金属铜和镉的吸收、转运特性

    Absorption and Transport of Heavy Metals Copper and Cadmium in Alfalfa from Vanadium-titanium Magnetite Tailings

    • 摘要: 对矿山废弃地进行生态修复时会广泛应用植物修复,植物吸收尾矿重金属的能力不容小觑。为探究紫花苜蓿对钒钛磁铁尾矿重金属Cu和Cd的吸收特性,通过外源添加Cu和Cd到钒钛磁铁尾矿中模拟不同污染程度,并分析三个月后钒钛磁铁尾矿中Cu和Cd的赋存形态、紫花苜蓿长势及其体内对Cu和Cd吸收、转运情况,研究Cu和Cd胁迫下紫花苜蓿重金属的吸收、转运特性。结果表明,三个月后,Cu主要以酸溶态形式存在,Cd主要以可氧化态形式存在,生态风险都比较高。Cu的加入会抑制紫花苜蓿出苗及地上部生长,但紫花苜蓿对Cu的吸收量会显著增加,紫花苜蓿地上部地下部对Cu吸收量分别增加了1.78%~109.62%和48.46%~463.11%,地上部是Cu主要富集部位。Cd主要累积在紫花苜蓿根部,随着Cd胁迫浓度的增加紫花苜蓿从根部向地上部转移Cd能力会增强。研究结果可为矿区植物修复研究提供理论基础。

       

      Abstract: Phytoremediation technology is widely used in ecological restoration process of abandoned mines, and the ability of plants to absorb heavy metals should be taken into account. In order to explore the absorption characteristics of Cu and Cd in the tailings of vanadium-titanium magnetite by the restoration plant alfalfa, Cu and Cd were added externally to the tailings to simulate different pollution levels. After three months, the occurrence forms of Cu and Cd in vanadium-titanium magnetite tailings, the growth of alfalfa and the absorption and transport of Cu and Cd in alfalfa were analyzed to study the absorption and transport characteristics of alfalfa under Cu and Cd stress. The results showed that after three months, Cu mainly existed in acid-soluble form and Cd mainly existed in oxidizable form, the ecological risk was relatively high. The addition of Cu could inhibit the emergence and shoot growth of alfalfa, but the uptake of Cu by alfalfa increased significantly. The uptake of Cu by the shoot and the ground increased by 1.78%~109.62% and 48.46%~463.11%, respectively. The shoot was the main enrichment site of Cu. Cd was mainly accumulated in the roots of alfalfa. With the increase of Cd stress concentration, the ability of alfalfa to transfer Cd from root to shoot increased. The results can provide a theoretical basis for the study of phytoremediation technology in mining areas.

       

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