鄱阳湖南矶山湿地土壤重金属含量及其形态分布规律

Contents and Distribution of Heavy Metals in Soil of Nanjishan Wetland in Poyang Lake

本文利用BCR四步提取法,对鄱阳湖南矶山三种典型湿地植被类型土壤样品重金属Cu、Pb和Zn的形态和总量进行测定分析。结果表明,除Pb含量较少对土壤几乎不构成潜在生态风险外,Cu和Zn两种重金属基本呈现表层>中层>底层的特征。残渣态和铁锰氧化物结合态为鄱阳湖湿地土壤Cu、Zn和Pb的主要赋存形态,尤其是Zn大部分以残渣态为主,其他两种生物有效性态含量较少,表明鄱阳湖湿地土壤重金属生态危害较小。

In this paper, the BCR four step extraction method was used to analyze the speciation and total amount of heavy metals （Cu, Pb and Zn） in the soil samples of the typical wetland vegetation of Nanjishan （Poyang Lake）. In this study, the heavy metals （Cu, Pb and Zn） in the wetland soil in Poyang Lake are fractionaled to exchangeable and weakly acidic dissolved, Fe- Mn oxide bound, organic sulfide-bound matter and residual bound by a four- stage sequential extraction procedure. The results show that the content of Pb in the soil can almost be negligible which does not constitute a potential ecological risk to the soil, the other two kinds of heavy metals （Cu and Zn） rank in the fi^llowing order： surface 〉 middle〉 bottom; The major speciation of Cu, Pb and Zn is Fe-Mn oxide fraction and residue fraction, especially for Zn mainly existed as the form of residue, while the other two biological availability forms are comparatively rare. It shows that ecological hazard of heavy metals in the wetland of Poyang Lake is small.