Abstract: The heavy metal (Pb, Zn, Cr, Cu, Cd, and Hg) concentrations in paddy soils, collected from the Pb-Zn mining and smelting area of Shuikoushan in Hunan, China, were investigated. Enrichment factor and potential ecological risk index were used to evaluate the pollution level and ecological risk of heavy metals in soil. Compared with the soils in surrounding area, the soils in central area (the mining and smelting area) exhibited elevated heavy metal concentrations. The maximum heavy metal contents of Pb, Zn, Cr, Cu, Cd, and Hg in paddy soils were up to 4330.63, 4451.25, 153.75, 315.69, 34.94, and 2.379 mg/kg, respectively. The contamination degree for different heavy metals were in the order of Cd > Pb > Zn> Cu > Cr = Hg, while the monomial potential ecological risk factor for different heavy metals followed the order of Cd > Hg > Pb > Cu > Zn > Cr. The potential ecological risk index demonstrated that about 50%, 22%, 17%, and 11% of the total sampling sites in the central area were low risk, moderate risk, considerable risk, and very high risk, while the corresponding percentages were 75%, 18%, 5%, and 2% in the surrounding area, respectively. The heavy metal contamination inhibited the dehydrogenase activity significantly, and the soil pH was relatively lower for soil samples with higher metal concentrations.

Key words: heavy metal, paddy soil, enrichment factor, potential ecological risk index, Pb-Zn mining and smelting area

摘要： 以我国典型的铅锌矿区??湖南水口山铅锌矿区及其周围地区为研究对象, 分析水稻土样品中不同重金属(Pb, Zn, Cr, Cu, Cd和Hg)的污染特征, 用富集因子和潜在生态危害指数法分区域评价了土壤中重金属的污染程度及生态危害, 用主成分分析的方法探讨了土壤性质与重金属污染的关系。结果表明, 受铅锌选矿和冶炼活动的影响, 矿区范围内中心区域水稻土中重金属含量明显高于周围区域, 土壤中Pb, Zn, Cr, Cu, Cd和Hg含量分别高达4330.63, 4451.25, 153.75, 315.69, 34.94和2.379 mg/kg。土壤中不同重金属污染程度大小顺序为Cd > Pb > Zn > Cu > Cr = Hg, 而其潜在生态危害大小顺序为Cd > Hg > Pb > Cu > Zn > Cr。多重金属综合潜在生态危害指数评价结果表明, 中心区域属于轻微、中等、强和很强生态危害的采样点比例分别为50%, 22%, 17%和11%, 而周围区域相应的采样点比例为75%, 18%, 5%和2%。主成分分析表明, 土壤重金属污染明显抑制脱氢酶活性, 且污染严重的采样点土壤pH也较低。

关键词: 重金属, 水稻土, 富集因子, 潜在生态危害指数, 铅锌矿区