兰坪铅锌矿区不同污染梯度下优势植物的重金属累积特征

对兰坪铅锌矿区污染程度不同的3个样地(云南松林、魁蒿群落和马桑灌丛)进行植被调查,选择其中9种共有的自然生长的优势草本植物为研究对象,测定了土壤及植物体的重金属含量.结果显示,3个样地土壤Cu、Cd、Pb和Zn等4种重金属含量均表现为马桑灌丛>魁蒿群落>云南松林;植物体内重金属积累呈现出随着土壤污染程度增加而增加的趋势;所选择的9种植物均不符合超富集植物的标准,依据不同的耐性机制将9种植物分为3类,野棉花能较强吸收土壤中重金属,并转移到地上部分,属于富集型植物;西南金丝梅、倒提壶、长籽柳叶菜、魁蒿、翻白叶和四脉金茅吸收的重金属主要积累在根部,属于根部囤积型植物;尼泊尔蓼和中华山蓼体内重金属含量较低,属于规避型植物.讨论了利用这些植物进行矿山治理.

Accumulation characteristics of heavy metals in dominant plant species growing on Lanping lead/zinc mining wasteland with different pollution gradients

Vegetation survey was conducted at 3 plots with different gradients of heavy metal pollution, including Pinus yunnanensis forest, Artemisia princeps community, and Coriaria nepalensis scrub, in Lanping Lead/Zinc Mining Area, Yunnan. Nine dominant herbaceous species common to these plots were selected and sampled for measuring heavy metals concentrations. The concentrations of heavy metals in soils from three plots were also measured. The aim of this study is to assess the potential for use of the selected plant to phyto-remediate heavy metal polluted soil. The results showed that soil heavy metals concentration at Coriaria nepalensis scrub was the highest, while Pinus yunnanensis forest is the lowest of the 3 ecosystems. Accumulation of heavy metals in plants increased with increasing heavy metal concentration in the soils. The 9 common species could be classified into three types according to metal concentrations in the plant shoots and roots. The accumulator, e.g. Anemone vitifolia, which absorb a large amount of heavy metal by the roots and transported to the shoots; the root compartment, e.g. Hypericum henryi, Epilobium pyrricholophum, Potentilla griffithii var. velutina, Eulalia quadrinervi, Artemisia princeps, Cynolgossum officinale also absorbed a large amount of heavy metal but held in the roots; and the excluder, e.g. Polygonum nepalense and Oxyria sinensis absorbed less heavy metal. In the end, the measurements how to remedy pollution areas by using these plants were discussed.