珲春盆地农田重金属分布特征及源解析

为分析珲春盆地农田重金属污染状况及其来源,采集土壤样品分析其砷(As)、汞(Hg)、铜(Cu)、铅(Pb)、锌(Zn)、铬(Cr)、镍(Ni)和镉(Cd)含量,开展相关分析、主成分分析等多元统计分析和富集指数分析。结果表明,珲春盆地农田中As、Hg、Cu、Pb、Zn、Cr、Ni、Cd的平均含量分别为9.09、0.06、20.17、23.34、68.25、65.02、22.91、0.12 mg·kg~(-1)。按照中国土壤环境质量标准(GB 15618—1995),珲春盆地土壤重金属污染不明显,所有数值都小于Ⅱ级质量标准。按照吉林省土壤背景值评价,除Pb和Zn外,其余重金属的平均值都超过当地背景值,其中Hg较为严重,区域平均值为背景值的1.56倍。按富集指数评价,超过20%的样品Hg元素为重度污染,其他元素重度污染样品数都小于10%。研究表明:Hg具有明显的人为源特征,主要来源于电厂、居民煤炭燃烧、煤炭开采运输扬尘、农药化肥等。其他元素在区域上为自然源属性,Cu、Zn、Cd高富集区可能受工农业生产以及交通运输的影响,As受污水灌溉和农药化肥影响,Pb受交通运输车辆尾气等的影响,Cr受煤矿开采与运输以及煤炭燃烧等的影响。

Distribution and sources of heavy metals in the farmland soil of the Hunchun basin of Jilin Province, China

In order to understand the characteristics of the pollutants and the sources of heavy metals in the Hunchun basin farmland soil, soil samples were collected and the contents of As, Hg, Cu, Pb, Zn, Cr, Ni, and Cd were measured. The enrichment factor (EF) was calculated. Multiple statistical analyses including correlation analysis and principal component analysis was executed. The results showed that the mean contents of As, Hg, Cu, Pb, Zn, Cr, Ni, and Cd were 9.09, 0.06, 20.17, 23.34, 68.25, 65.02, 22.91 mg·kg^-1, and 0.12 mg·kg^-1 respectively in the Hunchun basin. The values of the mean content were not above the criterion by the China Soil Environmental Quality Standard (GB15618-1995, CSEQS). The contents of all the heavy metals were lower than the limit by CSEQS. The contents of Pb and Zn were lower than the background values of Jilin Province. However, the contents of the other heavy metals exceeded the background values, particularly for Hg. More than 20% of the samples were significantly polluted by Hg, according to the EF, and less than 10% by other elements. The main sources of Hg in the Hunchun basin were artificial activity such as the lighting of coal fires by power stations and loose residents, dusts arising from coal transport, pesticides, and fertilizers. The other heavy metals reach along with the parent material in the whole area. However, in the high enrichment area, the sources of Cu, Zn, and Cd were farming, communications, and transportation; the sources of As were sewage irrigation, pesticides, and fertilizers; the sources of Pb were communication and transportation; the sources of Cr were dusts from the mining, transport, and burning of coal.