丛毛羊胡子草修复尾矿坝铅镉污染的初步研究

采集广西南丹长坡尾矿坝自然定居植物优势种丛毛羊胡子草及其根际土,利用原子吸收光谱法测定样品中的铅和镉含量,以完全没有植被覆盖的尾矿裸地作为对照,对铅、镉转运系数、富集系数及修复系数进行比较,分析丛毛羊胡子草对重金属元素铅和镉的吸收特性,探讨利用丛毛羊胡子草修复土壤铅镉污染的可能性,为南丹长坡尾矿坝等重金属异常区的植物修复提供理论依据。结果表明,丛毛羊胡子草具有较强的重金属耐性,其地上部分铅和镉平均含量分别为205.77 mg/kg和7.57 mg/kg,地下部分铅和镉的平均含量分别为643.66 mg/kg和21.30 mg/kg,铅和镉的转运系数均<1,富集系数镉>铅,修复系数镉>铅,说明丛毛羊胡子草清除镉污染的效果比铅好。丛毛羊胡子草虽不是铅和镉的超富集植物,但其耐性强,对铅和镉的吸收量较大,所以,可以作为尾矿坝等重金属复合污染区植物修复的先锋物种使用。

Phytoremediation with Eriophorum comosum for Lead and Cadmium Contaminated Soil in Changpo Mine Tailing Dam

The dominant species of the natural recovery vegetation,Eriophorum comosum and its rhizo-soil in Changpo mine tailing dam,Nandan county,Guangxi province were collected.Lead and cadmium contents of the specimens were detected by FAAS respectively.The control plots were set up with bare land in the mine tailing dam.Through comparative analysis of the bio-transfer coefficient,accumulation coefficient and remediation efficiency for lead and cadmium,to reveal the absorption characteristic of E.comosum for heavy metal lead and cadmium,and to search the possibility of phytoremediation with E.comosum for lead and cadmium contaminated soil,so as to provide theoretical basis for the phytoremediation of heavy metal abnormal districts,such as Changpo mine tailing dam,Nandan county,Guangxi province,etc.The results showed that E.comosum has strong heavy metal tolerance,but it is not a hyperaccumulator for lead and cadmium.The content of lead and cadmium absorbed by E.comosum above ground is 205.77 mg/kg and 7.57 mg/kg respectively,otherwise,the content of lead and cadmium absorbed by E.comosum under ground is 643.66 mg/kg and 21.30 mg/kg respectively.The bio-transfer coefficient of Pb and Cd are all less than 1.It was also indicated that the accumulation coefficient was Cd>Pb,and the effect of remediation for Cd was better than that of Pb.It was proposed that E.comosum should be used as a pioneer species of phytoremediation for heavy metal complex pollution areas in mine tailing dam.