宿州市街尘重金属的粒径分布特征及污染评价

Particle Size Distribution Characteristics and Pollution Assessment of Heavy Metals in Street Dust of Suzhou City

在宿州市不同功能区采集23个街尘样品,利用X-Ray荧光光谱法测定了样品中重金属Cu、Zn、Pb、Mn、Cr、V的含量,分析了街尘重金属的粒径分布特征,并利用地累积指数法对其污染状况进行了评价。结果表明:(1)宿州市街尘中细颗粒质量比重较高,在<75μm、75～150μm、150～250μm、250～500μm四个粒径段的街尘质量比例分别为39.73%、27.52%、22.57%和10.18%;(2)街尘中各重金属元素的含量最大值均出现在<75μm和75～150μm粒径范围内,说明重金属易在细颗粒中富集;(3)各重金属元素在<75μm粒径范围内的赋存比例均高于其他3个粒径级别,达40%左右;(4)随着街尘粒径的由粗到细,其重金属污染程度从无污染到轻度污染,各重金属元素的污染程度依次为:Zn>Pb>Cr>Cu>V>Mn。

By X-ray fluorescence spectrometry and geoaccumulation index method,an investigation of 23 samples which were collected from different functional areas was conducted to study the particle size distribution characteristics and pollution conditions of Cu,Zn,Pb,Mn,Cr,V in street dust of Suzhou City.The results showed that：（1） The quality proportion of fine grain size particles is higher in street dust,and there were 39.73%,27.52%,22.57% and 10.18% of street dusts which are 75 μm,75～150 μm,150～250 μm and 250～500 μm in diameter;（2） The concentrations of heavy metals in the particles which are 75 μm,75～150 μm in diameter are relatively high,indicating that the heavy metals were enriched in fine grain sized fraction.（3） The enrichment ratio of heavy metals which are 75 μm in diameter is about 40%,higher than that in other fractions;and（3） From coarse to thin,the dust particles show a transition from non-pollution to light pollution,and the pollution extent follows the order of Zn Pb Cr Cu V Mn.