华南地区典型燃煤电厂周边土壤重金属分布、风险评估及来源分析

为了解华南地区典型燃煤电厂周边表层土壤重金属空间分布特征,对韶关市燃煤电厂周边20处农田表层土壤中7种重金属(镍(Ni)、铜(Cu)、锌(Zn)、镉(Cd)、铅(Pb)、铬(Cr)及砷(As))的总量进行检测,并分析了其相应的空间分布规律,同时评估了周边土壤重金属的生态风险并分析其来源。结果表明:该燃煤电厂周边土壤中重金属Ni、Cu、Zn、Cd、Pb、Cr及As的平均含量分别是17.79、19.59、159.08、3.14、111.01、96.61 mg/kg和21.48 mg/kg,Cd、Pb污染情况突出,重金属Zn、Cd、Pb、Cr的分布与盛行风向密切相关。综合污染指数法表明,Cd、Pb及Zn处于重污染状态;潜在生态风险指数法表明,Cd处于严重潜在生态风险状态;地累积指数法表明,Ni、Cu整体处于无污染状态,Cd整体处于高污染状态。多种统计方法表明,Zn、Cd、Pb及Cr受燃煤电厂影响明显,Cu、As的来源不仅受燃煤电厂等工业的影响,还与该地区农业灌溉用水密切相关,Ni的分布最为均匀,受自然因素影响明显。

Heavy metal distribution, risk assessment and source analysis of soil around a typical coal-fired power plant in South China

For exploring the spatial distribution characteristics of heavy metals in the surface soil around a coal-fired power plant in Shaoguan City, South China, the total amount of seven heavy metals (Ni, Cu, Zn, Cd, Pb, Cr and As) in the surface soil of 20 farmlands surrounding the power plant was measured. The spatial distribution was analyzed. The ecological risk of heavy metals in the surrounding soil was evaluated and its sources were identified. The results showed that the average contents of heavy metals Ni, Cu, Zn, Cd, Pb, Cr and As in the soil around the coal-fired power plant were 17.79, 19.59, 159.08, 3.14, 111.01, 96.61 mg/kg and 21.48 mg/kg, respectively. Pollution of Cd and Pb were serious. The distribution of Zn, Cd, Pb and Cr was closely related to the prevailing wind direction. The comprehensive pollution index showed that Cd, Pb and Zn were in heavy pollution. The potential ecological risk index indicated Cd was in a high potential ecological risk level. The ground accumulation index implied that Ni and Cu were in a non-pollution state, and Cd was in high pollution. Multivariate statistical analysis represented Zn, Cd, Pb and Cr were obviously affected by the coal-fired power plant. The sources of Cu and As were not only affected by the coal-fired power plant, but also closely related to agricultural irrigation water in the region. The distribution of Ni was uniform. It was obviously affected by the natural source.