浙中城市表土重金属污染的磁学响应

Magnetic Response of Heavy Metal Pollution in Urban Topsoil in Central Zhejiang

为了明确金华城区表土重金属污染空间分布状况,对主要道路附近表土进行了系统的环境磁学调查。结果表明:(1)样品的磁性特征主要由软磁性的亚铁磁性矿物主导,工业区和商业区的磁性矿物浓度呈现高值区;(2)重金属元素高值区同磁性矿物含量分布较为一致,最低值通常出现在受人类活动较少的近郊农田区域;(3)指示磁性矿物含量的磁学参数与Cu、Zn、Pb元素显著相关,Cu、Zn、Pb、Cr、Ni易富集在磁性颗粒较粗(MD、PSD)的样品中,而V主要存在于磁性颗粒较细(SP)样品中;(4)主成分分析结果表明交通及工业污染源是金华城区表土污染的主要来源。综上,基于城市表土介质进行环境磁学研究是侦测城市土壤重金属污染的新技术。

In order to clarify the spatial distribution of heavy metal pollution in topsoil in urban areas of Jinhua,a systematic environmental magnetic survey was conducted on topsoil near major roads in urban areas to analyze the magnetic response characteristics of heavy metal pollution in urban soils in central Zhejiang.The results showed that:①Ferrous magnetic minerals with low coercivity dominated the magnetic characteristics of the topsoil samples in the urban area of Jinhua.Regional differences in magnetic mineral concentrations were significant,and the high value areas were mainly distributed in areas with industrial concentration,high traffic flow,dense traffic and frequent commercial activities;②High values of heavy metal elements were usually located in places with industrial concentration and dense traffic,and the lowest values were usually found in suburban farmland areas which were less subject to human activities;③magnetic parameters indicating the content of magnetic minerals(lf,SIRM,ARM,SOFT)have a significant positive correlation with the content of Cu,Zn,and Pb elements.Cu,Zn,Pb,Cr and Ni are easily enriched in the samples with coarse magnetic particles(MD,PSD),while V mainly exists in the samples with fine magnetic particles(SP);④Three main factors were obtained using principal component analysis to show the significant representation of magnetic parameters and geochemical elements,and it was found that traffic and industrial pollution sources were the main sources constituting the topsoil pollution in the urban area of Jinhua.In conclusion,the environmental magnetics method is a new technique for detecting heavy metal contamination in urban soils.