黄河山东段沿岸县市表层土壤重金属污染特征及源解析

Pollution Characteristics and Source Apportionment of Heavy Metals in Topsoil of Counties Along the Shandong Section of the Yellow River

黄河干流山东段流经的25县市区是山东省推动黄河流域生态保护和高质量发展的核心区,研究该区域表层土壤重金属污染现状、来源及潜在风险具有重要的意义.以黄河干流流经山东的25县市区为研究区,采集并测定了103个表层土壤样品中8种(As、Cu、Pb、Cr、Zn、Ni、Cd和Hg)重金属的含量,采用地累积指数法与潜在生态风险指数法对重金属污染特征进行分析和评价,利用相关性分析和正定矩阵因子分解(PMF)模型对土壤重金属进行来源解析.结果表明,Cu和Cr含量平均值低于山东省土壤背景值,As、Pb、Zn、Ni、Cd和Hg含量平均值分别是背景值的1.16、1.42、1.05、1.14、2.29和1.85倍,8种重金属元素含量平均值均远低于农用地土壤污染风险筛选值;从不同重金属变异情况看,As、Pb、Cr、Zn、Ni和Hg为中度变异,Cd和Cu为高度变异;研究区Cd和Hg呈轻度污染,其余6种元素无污染;Cd和Hg属于中等潜在生态风险水平,其余重金属处于低风险;联合受体模型表明研究区表层土壤重金属来源受农业活动、自然来源、工业排放和大气降尘等4种因素影响,综合贡献率分别为32.4%、34.9%、16.5%和16.2%.

The 25 counties along the Shandong section of the Yellow River are the core areas for promoting the ecological protection and high-quality development of the Yellow River in Shandong Province.Moreover,it is of great significance to study the current situation,sources,and potential risks of heavy metal pollution in the topsoil in this region.In this study,103 soil samples were collected from the 25 counties along the Shandong section of the Yellow River,and the contents of eight heavy metals(As,Cu,Pb,Cr,Zn,Ni,Cd,and Hg)were determined.The pollution characteristics of heavy metals were analyzed and evaluated using the geological accumulation index and potential ecological risk index.Correlation analysis and the positive matrix factorization(PMF)model were used to analyze the sources of heavy metals.The results showed that the average contents of Cu and Cr were lower than that of the background values of soils,whereas the average contents of As,Pb,Zn,Ni,Cd,and Hg were 1.16,1.42,1.05,1.14,2.29,and 1.85 times higher than that of the background values,respectively,and the average contents of all eight elements were lower than the screening value of soil pollution risk in agricultural land.In terms of different heavy metal variations,the coefficient of variation(CV)of Cu and Cd was higher than 0.500,indicating high variations,whereas As,Pb,Cr,Zn,Ni,and Hg showed moderate variation.Cd and Hg were slightly polluted,whereas the other six elements were not polluted.Cd and Hg had a moderate potential ecological risk level,whereas the other six elements were at a low level.Correlation analysis and PMF model showed that the sources of heavy metals in the study area were influenced by four factors,i.e.,agricultural activities,natural sources,industrial emissions,and atmospheric dust from coal combustion and vehicle exhaust emissions,and the relative contribution rates were 32.4%,34.9%,16.5%,and 16.2%,respectively.