铜川市土壤重金属形态迁移及抗坏血酸淋溶特性

Mobility of Heavy Metals and the Leaching Characteristics with Ascorbic Acid from Urban Soil in Tongchuan City

在野外调查的基础上,以铜川市土壤为研究对象,采用BCR法研究重金属Pb、Cu、Cr、Zn的形态分布与迁移转化差异;利用一次平衡法(振荡24 h)探讨抗坏血酸对4种重金属的淋溶动力学特征。实验结果表明:土壤中元素含量差异比较明显,重金属Pb、Cu的含量较高,污染程度较重;但从形态分布迁移特征来看,4种重金属主要以残余态形式存在,元素Zn和Cu易于迁移;表层土壤重金属总体污染程度严重,潜在生态风险程度较强,Pb是主要的潜在生态危害元素;但重金属Cr在抗坏血酸存在下,更容易解析溶出,能被生物利用的潜在可能性更大,应引起重视。

In this paper, the mobility of heavy metals Pb, Cu, Cr and Zn in urban soil in Tongchuan City and the leaching characteristics with ascorbic acid were investigated with once balance method. The pollution degree was assessed with the ecological risks index. The results showed that the contents of heavy metals Pb, Cu, Cr and Zn in urban topsoil were significantly different, and the contents of Pb and Cu were high. The holistic pollution degree of heavy metals was serious. The speciations of these 4 heavy metals were dominated by the residual forms, and Zn and Cu was mobile in soil environment. However, Pb was not mobile due to its existence forms of hydroxide, car-bonate or phosphatic in the environment. The total potential ecological risk degree was high. It was found that Pb was a main element of potential ecological risk, Cr, however, was easy to be leached and transferred in soil organ-ism, which could be paid more attention to in the future.