广西某铅锌矿区农田土壤重金属形态分布特征

目的]研究广西某铅锌矿区农田土壤中重金属的形态分布特征。方法]采用Tessier连续萃取法研究广西某铅锌矿区农田土壤中Cd、Pb、Zn、Hg的存在形态分布,分析各存在形态的相关性与重金属的生物可利用性。结果]研究区土壤Cd主要以可交换态为主,Pb以碳酸盐态和铁锰氧化态为主,Zn以残渣态、有机结合态和铁锰氧化态为主,Hg以残渣态和有机结合态为主。重金属Cd、Pb、Zn的可交换态均与相应的总量呈极显著或显著相关,而Hg的可交换态与其总量不相关;Cd的可交换态与碳酸盐态存在极显著相关,Pb的可交换态、铁锰氧化态和残渣态之间相关性较好,Zn的铁锰氧化态、有机结合态和残渣态之间显著相关;Hg的各存在形态之间的相关性较差。研究区土壤中重金属的生物有效性大小依次为Cd、Pb、Zn、Hg。结论]该研究为今后开展矿区土壤修复工作提供理论支持。

Distribution Characteristics of Heavy Metal Forms in Farmland Soil in a Lead-Zinc Mining Area in Guangxi

Objective] To research the form distribution characteristics of heavy metal in farmland soil in a lead-zinc mining area in Guangxi. Method] An experiment was conducted to study the form distribution of heavy metals (Cd, Pb, Zn, Hg) in farmland soil in a lead-zinc min-ing area in Guangxi by using Tessier sequential extraction procedure, and regression analysis was made between the heavy metals fraction in bioavailability.Result] Cd was dominated by exchangeable form, Pb was mostly in the carbonate and Fe-Mn oxides forms, Zn existed mainly in residual, organic and Fe-Mn oxides forms, while the residual and organic forms was most for Hg .According to the results of regression anal-ysis, there was an extremely significant or significant correlation between the exchangable form of Cd, Pb, Zn and its total amount, which was not performed in Hg.It was extremely significant between exchangeable and carbonate form for Cd, and also among exchangeable Fe-Mn ox-ides and residual forms for Pb and Fe-Mn oxides, organic and residual forms for Zn.While it had poor correlation between each forms of Hg . The bioavailability size of heavy metals in the soil was for Cd, Pb, Zn, Hg in turn in the study area.Conclusion] This research provides the-oretical foundation for the soil remediation in mining area .