湘南某铅锌矿区重金属赋存形态分析

Analysis of Chemical Speciation of Heavy Metals in a Lead-zinc Mine Located in Southern Hunan

以湘南某铅锌矿区土壤、尾矿库尾砂及附近不同植物根部土壤为研究对象,采用Tessier五步连续萃取法分析了Pb、Cd、Zn、Cu 4种重金属的化学赋存形态分布特征。结果表明:矿区和尾矿库土壤样品中4种重金属主要以残渣态形式存在,其中Cu的有机结合态也较高,Pb、Zn、Cu的可交换态很低,但是Cd的可交换态很高,所占的百分比达20%;Pb、Zn、Cu在土壤中迁移能力较弱,短期内对环境影响不大,而Cd虽然总量不大,但其可交换态所占的比例较高,易释放到周围环境中,其对环境的影响不容忽视,应引起重视;对比两个采样区重金属的赋存形态,发现尾矿库土壤中的重金属潜在迁移能力要大于矿区土壤;各个采样点的重金属赋存形态分布特征存在很大的差异,主要与土壤的性质有关。

Taking the soils and tailings in and around a lead-zinc mine located in southern Hunan as study objects,this paper adopts Tessier five-step sequential extraction method to analyze the chemical speciation of four kinds of heavy metals in the samples. The results show that these heavy metals mainly exist in the form of residual fraction, the organic substance form of Cu is great, and the exchangeable form of Cd is the greatest within the four heavy metals,reaching 20. The speciation characteristics indicate that Pb,Zn and Cu have slight impact on the environment in short time, while the impact of Cd on the environment cannot be ignored. Comparing the two sampling zones shows that the motility of heavy metals in tailing dam is stronger than that in mining area. There are many differences between the samples in chemical speciation characteristics due to the physical properties of soils.