豫西成矿带潭头盆地金矿区农田土壤重金属污染及来源解析

Pollution and source apportionment of heavy metals in the farmland soils of the gold mining area in Tantou Basin, western Henan metallogenic belt

为查明豫西成矿带潭头盆地金矿区农田土壤重金属污染特征及污染来源,在该盆地农田中系统采集土壤样品,分析土壤中的重金属含量,采用聚类分析和主成分分析/绝对主成分分数(PCA/APCS)受体模型对污染源进行解析并计算污染源贡献率。结果显示:研究区农田土壤重金属Hg、As、Cr、Ni、Cu、Pb、Zn、Cd含量平均值均低于农用地土壤污染风险筛选值,整体土壤污染风险较低,仅部分样品Hg、As、Cu、Pb、Zn、Cd含量超过风险筛选值;Pb、Zn和Cd主要呈区域性污染,其他重金属元素主要呈孤立点状污染。Hg、Cd、Pb变异系数达到强变异水平,表明潭头盆地农田土壤中Hg、Cd、Pb元素受人类活动干扰比较强烈。综合聚类分析、主成分分析及空间分布特征,8种重金属主要来源于4类污染源:Cu、Pb、Zn和Cd污染来源于交通源(PC1);Cr和Ni污染来源于自然源(PC2);As污染来源于与金矿开采和尾矿堆存相关的矿业源(PC3);Hg污染来源于与小作坊汞溶解炼金相关的矿业源(PC4)。

Heavy metals contents of soil samples from the gold mining areas in Tantou Basin of the western Henan metallogenic belt were analyzed to determine the pollution characteristics and sources. The authors used the Cluster analysis and Principal Component Analysis/Absolute Principal Component Scores(PCA/APCS) receptor model to identify the pollution source and its contribution rate. The results showed that the average contents of Hg, As, Cr, Ni, Cu, Pb, Zn, and Cd of the farmland soil in the study area are lower than risk control standard for soil contamination of agricultural land, indicating lower risk of soil pollution in the gold mining area of the Tantou Basin. However, some samples showed excess contents of Hg, As, Cu, Pb, Zn and Cd elements with regional pollution in Pb, Zn, and Cd and point pollution in other heavy metal elements. The variable coefficients of Hg, Cd, and Pb are at a strong variation level, indicating that they were strongly influenced by anthropogenic activities. Combining the results of cluster analysis, principal component analysis and the spatial distribution characteristics, the eight heavy metals mainly come from four types of pollution sources: Cu, Pb, Zn, and Cd pollutions origin from traffic source(PC1);Cr and Ni pollutions come from the natural source(PC2);both As and Hg pollutions are derived from mining source but the former is related to gold mining and tailings stockpiling(PC3) and the latter is related to small workshop mercury dissolution smelting(PC4).