先锋植物对铅锌尾矿库重金属污染的修复作用

Pioneer Species on Remediation of Heavy Metal Contamination in Lead/Zinc Mine Tailings Pond

通过野外调查发现湖南湘西花垣铅锌尾矿库定居成功五节芒、辣蓼和截叶铁扫帚3种先锋植物。研究先锋植物对其根际土壤理化性质的改良,先锋植物对重金属Pb、Zn、Cd的吸收积累及其生长对根际土壤重金属化学形态的影响。结果表明,先锋植物的定居提高了其根际土壤有机质、全氮含量和土壤含水率,而pH值均有所降低;3种先锋植物均表现为对Zn具有较强的富集能力,而对Pb、Cd的富集能力很差;先锋植物的生长通过促进残留态Pb、Zn、Cd向弱结合态转化,改变了Pb、Zn、Cd的形态分布,影响土壤中Pb、Zn、Cd的生物有效性。先锋植物五节芒、辣蓼和截叶铁扫帚的自然定居,有利于铅锌尾矿库重金属污染的修复。

Through field investigation, three pioneer species, Miscanthus floridulus, Polygonum flaccidum Meissn. and Lespedeza cuneata, lived in lead/zinc mine tailings pond of Huayuan in Xiangxi were found. The physical and chemical properties of the soil, the uptake and translocation of Pb, Zn and Cd in pioneer species and heavy metal forms change and properties in rhizosphere soils were studied. The results showed that the inhabitation of the three pioneer species could improve the content of organic matter, total nitrogen and the water bound to soil, and reduce pH of the rhizosphere soils. The three pioneer species had strong ac- cumulate ability on Zn, and had bad accumulation ability on Pb, Cd. By promoting the transformation process from residuals fractions to weakly bound fractions, the growth of the three pioneer species could alter the distribution of Pb, Zn and Cd to change into availability of Pb, Zn and Cd in rhizosphere soils. The natu- ral inhabitation by the Miscanthus floridulus, Polygonum flaccidum Meissn. and Lespedeza cuneata, did great benefits to the remediation of heavy-metal contamination in lead/zinc mine tailings pond.