基于PMF模型的吉木萨尔县土壤重金属空间分布特征与来源解析

Distribution Characteristics and Source Analysis of Soil Heavy Metal Pollution in Jimusar County Based on PMF Model

土壤重金属污染对区域土壤环境和人类健康构成严重威胁,因此土壤重金属污染评价和预警在土壤资源保护和区域可持续发展中至关重要.共采集了48个土壤样本,并测定了其中六种重金属含量,运用潜在生态风险指数法、地累积指数法和克里金插值分别对该区域土壤中Zn、Cu、Cr、Pb、Hg和As六种重金属元素的污染状况和空间分布特征进行了分析,并利用PMF模型对土壤重金属来源进行解析.1)研究区土壤Cu、Pb和As含量均超出中国新疆土壤背景值和全国土壤背景值,Zn和Cr的含量未超过这两种标准.2)污染评价结果显示:土壤未受到Zn、Cu和Cr的污染,Hg处于轻-中污染,Pb和As处于中等和中-强污染.结合潜在生态风险指数分析可知,Zn、Cu、Cr和Pb为低风险状态,Hg和As为中风险状态.3)从重金属元素空间分布来看,Zn元素的空间分布呈中心区域低、四周高的格局;Cu和Hg元素的分布规律存在一定的相似性,均为从西北向东南递减的变化趋势;Cr元素的空间分布呈现从西向东递减的趋势;Pb元素在研究区的分布较均匀.4)PMF模型结果显示:煤炭开采、煤化工和一系列煤电等人类活动容易引起土壤中Hg和As的积累;Cr和Pb主要来自汽车排放;Zn和Cu主要与土壤母质等自然因素密切相关;煤矿开采和工业活动对土壤重金属的贡献最高.吉木萨尔县土壤受到Hg、Pb和As不同程度污染,且该区域污染来源主要为工业生产和汽车尾气.

Heavy metal contaminated soil poses a serious threat to regional soil environment and human health,so soil heavy metal pollution assessment and early warning are very important in soil resource protection and regional sustainable development.A total of 48 soil samples were collected to determine the content of six heavy metals.The pollution status and spatial distribution characteristics of Zn,Cu,Cr,Pb,Hg and As in soil were analyzed by potential ecological risk index method,geo-accumulation index method and Kriging interpolation method,and the sources of soil heavy metals were analyzed by PMF model.1)The contents of Cu,Pb and As in soil in this study area exceeded the soil background values of Xinjiang of China and the national soil background values,while the contents of Zn and Cr were lower than these two standards.2)The pollution evaluation results showed that Zn,Cu and Cr were not polluted,Hg was lightly-moderately polluted,Pb and As were moderately and moderately-strongly polluted.According to the analysis of potential ecological risk index,the ecological risk of Zn,Cu,Cr and Pb is low,and the ecological risk of Hg and As is medium.3)From the perspective of spatial distribution of heavy metal elements,the spatial distribution of Zn elements is low in the central area and high in the surrounding area.The distribution of Cu and Hg elements is similar,showing a decreasing trend from northwest to southeast.The spatial distribution of Cr decreases from west to east.Pb element is evenly distributed in the study area.4)The results of PMF model show that the accumulation of Hg and As in soil is caused by human activities such as coal mining,coal chemical industry and coal power.Cr and Pb mainly come from automobile emission;Zn and Cu are closely related to natural factors such as soil parent material.Coal mining and industrial activities have the highest contribution to soil heavy metals.The soil in Jimusar County was polluted by Hg,Pb and As to different degrees,the main sources of pollution in the region are industrial production and vehicle exhaust.