石家庄市冬季道路积尘PM_(2.5)中金属元素污染特征及来源

Pollution Characteristics and Source Analysis of Metal Elements in PM_(2.5) of Paved Road Dust in Shijiazhuang City during Winter

为研究石家庄市冬季道路积尘PM_(2.5)中金属元素污染特征及来源,利用移动式采样法收集石家庄市不同类型铺装道路积尘,使用ICP-MS和ICP-OES分析测定PM_(2.5)中Cr、Zn、Mn、Cu、Pb、Ni、Sn、As、Sb、Co、Mo、Cd、Al、Mg、Ca、Fe共16种元素的质量分数.结果表明:石家庄市冬季道路积尘PM_(2.5)中金属元素质量分数之和依次为支路>快速路>主干道>次干道,与车流量、车辆类型、道路类型等影响因素有关,w(Mg)、w(Ca)、w(Cr)、w(Cu)、w(Ni)、w(Zn)、w(Pb)、w(Sn)、w(Sb)、w(Mo)、w(Cd)的平均值均高于当地土壤背景值,是背景值的1.2~40.5倍,其中Cr、Zn、Cu、Pb、Sn、Sb、Mo、Cd等元素中,除Pb的富集因子(9.38)接近10外,其他均高于10,来源于人为污染.Igeo(地累积指数)评价结果显示,Cr、Sn(Igeo为4~5)达到强-极强污染水平;Cd、Cu(Igeo为3~4)达到强污染水平;Sb、Mo、Zn(Igeo为2~3)为中-强污染水平,Pb(Igeo为1~2)为中污染水平.多元统计分析结果表明,石家庄市冬季道路积尘中金属元素来源可分为四大类:As、Mo、Zn、Cd、Ni、Pb主要来自机动车和大气中的燃煤沉降;Mn、Co、Sb来自于自然来源、机动车尾气的排放和焊接材料及轴承的磨损;Cr、Cu、Sn主要来自于工业排放的沉降和机动车刹车片磨损;Al、Ca、Mg、Fe主要来自绿化带或机动车携带的土壤尘.研究显示,石家庄市冬季道路积尘PM_(2.5)中金属元素污染严重,主要来源于交通排放.

In order to study the pollution characteristics and sources of metal elements in PM2.5 of road dust in Shijiazhuang City in winter,dust samples were collected from different types of paved roads by mobile sampling method. We measured the contents of 16 metal elements in PM2.5 including Al,Mg,Ca,Fe,Cr,Zn,Mn,Cu,Pb,Ni,Sn,As,Sb,Co,Mo and Cd by using ICP-MS and ICP-OES instruments. The results revealed that the sequence of the sum of mass fraction in PM2.5 from different types of roads is branch way expressway main road the secondary trunk road. This indicated that the contents of metal elements in PM2.5 are mainly influenced by traffic flow,vehicle type,road type and other factors. The average contents of Mg,Ca,Cr,Cu,Ni,Zn,Pb,Sn,Sb,Mo and Cd are higher than those of local soil background value with being 1. 2-40. 5 times of the background values. The abundant degree of Zn,Cu,Pb,Sn,Sb,Mo,Cr and Cd are more serious than that of other elements. Except for the enrichment factor of Pb is 9. 38,all others are higher than 10,which is caused by man-made pollution. The Geo-accumulation indices analysis showed that Cr,Sn（Igeo：4-5） reached an extremely high pollution level; Cd and Cu（Igeo：3-4） achieved a high pollution level; Sb,Mo,Zn（Igeo：2-3） achieved a medium-strongpollution level; Pb（Igeo：1-2） reached a moderate pollution level. Multivariate statistical analysis results showed that the source of these elements could be stemmed from four categories： As,Mo,Zn,Cd,Ni and Pb mainly came from vehicle emission and deposition of airborne dust with coal combustion; Mn,Co,Sb were mainly from natural sources,vehicle exhaust emissions,wear of welding materials and bearings; Cr,Cu and Sn sourced from deposition of industrial emissions and wear of vehicle brake pads; Al,Ca,Mg,and Fe were mainly from nature soil at road sides and discarding and littering from vehicles. In conclusion,metal elements pollution in PM2.5 is mainly caused by traffic emissions in Shijiazhuang City.