河南省典型工业区周边农田土壤重金属分布特征及风险评价

为深入探讨典型工业区周边农田土壤重金属分布的特征，以河南省新乡市凤泉区大块镇工业区周边农田土壤为研究对象，对表面和剖面方向上土壤As、Cd、Cr、Cu、Ni、Pb和Zn等7种重金属污染的空间分布和污染风险进行分析，并使用主成分分析进行污染源解析，为该类工业区周边农田重金属污染治理与防控提供理论基础.结果表明，该工业区内表层土壤Cd、Cu和As含量分别为（2.56±1.23）、（205.58±157.49）和（15.27±4.14） mg·kg^-1，点位超标率分别为100%，89.44%和3.40%.空间上，受污染源分布、地势和风向共同影响，研究区7种重金属在土壤表层方向上均呈现出南部含量高北部含量低的空间分布；在剖面方向上，Cd和Cu含量随土壤深度增加显著降低，As在碱性土壤条件下迁移能力较强，其含量随土壤深度增加含量变化较小.污染评价结果表明，Cd和Cu达到重度污染（5级），同时Cd存在极强的潜在生态风险（5级），Cu存在中等潜在生态风险（2级），其余重金属均为低潜在生态风险（1级），风险排序为Cd > Cu > Ni > As > Pb > Cr > Zn，研究区内重金属综合潜在生态危害属强生态危害.主成分分析表明，土壤As、Cd和Cu外源污染主要来自电池生产和铜（管、线）生产等活动，属工业污染源.综上所述，该研究区应重视土壤Cd和Cu污染的治理与防控，同时警惕As对土壤环境质量进一步的影响.

Spatial Distribution and Risk Assessment of Heavy Metal Pollution in Farmland Soils Surrounding a Typical Industrial Area of Henan Province

In order to fully explore the spatial distribution of soil heavy metal contaminants in farmland soil surrounding a typical industrial area in Dakuai town, Xinxiang city, Henan Province, the concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn in the surface soil and within the soil profile were determined and assessed. The principal components were also analyzed for source apportionment to provide a theoretical basis for the control and prevention of heavy metal pollution. According to the results, the soils in the study area are severely contaminated by Cd and Cu and moderated contaminated by As due to the battery manufacture and Cu (e.g., pipe and wire) processing. The concentrations of Cd, Cu, and As in soils were (2.56±1.23) mg·kg^-1, (205.58±157.49) mg·kg^-1, and (15.27±4.14) mg·kg^-1, respectively, which exceeds standards by 100%, 89.44%, and 3.40%, respectively. Accounting for the influence of pollution sources, terrain, runoff erosion, and prevailing wind direction, all heavy metal concentrations were higher in the south direction, lower in the north direction. The concentrations of Cd and Cu in soil profile samples decreased with depth, with highest concentrations at the surface, indicating the strong effect of industrial activities. Arsenic concentrations varied little with soil depth due to its strong migration ability in alkaline soil, again suggesting an industrial source. Among them, the soil of study area was severely contaminated by Cd and Cu (Level 5). Cd poses a severe potential ecological risk (Level 5) and Cu poses a medium risk (Level 2) in the study soils, while other heavy metals show low potential ecological risk (Level 1). The order of the risk identified was Cd > Cu > Ni > As > Pb > Cr > Zn. In addition, the combined potential ecological risk of heavy metals in the target area is severe. The principal component analysis showed that the high As, Cd, and Cu contents are mainly derived from industrial areas. Therefore, it is urgent to remediate Cd and Cu soil contamination in this area and implement precautions to limit As contamination.