Pollution Characteristics And Chemical Speciation Study Of Heavy Metals In Street Dust Of Typical Cities In Shenyang Economic Zone

Urban street dust is particles that accumulates on the surface of street.As an unique environment medium,it contains a variety of potentially harmful heavy metals.And urban street dust is forced the repeated cycle of rising and sinking by external forces,causing great harm to human health and environment.Therefore,it is of practical significance to study on pollution characteristics of heavy metals in street dust of typical cities in Shenyang Economic Zone.The physicochemical characteristics,total concentration and chemical forms of heavy metals in street dust of Shenyang,Fushun and Benxi are analyzed.The main conclusions of this paper are as follows:The pH of street dust in Shenyang,Fushun and Benxi both more than 7,which is alkaline.There are nearly 50 % percentage street dust grains in both Shenyang,Fushun and Benxi smaller than 100 M(0.150 mm),indicating that street dust in three typical cities belongs to fine particulate matter.The average of contents of Cu,Pb,V,Zn,Cr,Mn are 3.6,3.4,2.0,4.4,3.0,1.3 times in compared with soil background value of Shenyang.The average of contents of Cu,Pb,V,Zn,Cr,Mn are 2.5,3.9,1.3,5.8,4.1,1.6 times in compared with soil background value of Fushun.The average of contents of Cu,Pb,V,Zn,Cr,Mn are 3.6,3.5,0.9,6.0,2.0,1.0 times in compared with soil background value of Benxi.Spatial interpolation technique was applied to study the content level and the spatial distribution character of heavy metal pollution in street dust of typical cities in Shenyang Economic Zone shows that heavy metals in street dust of Shenyang might be significantly influenced by road traffic,and the heavy metals in street dust of Fushun and Benxi might be significantly influenced by industrial and mining enterprises.Assess the pollution degree by using geo~accumulation index method.It shows that the pollution levels of Zn in street dust of Shenyang,Fushun and Benxi are slight to moderate,the pollution levels of V and Mn in street dust of Shenyang are slight,the pollution levels of Cu and Pb in street dust of Shenyang and Fushun are slight,the pollution levels of Cr in street dust of Shenyang and Benxi are slight,the pollution levels of Cr in street dust of Fushun are slight to moderate.The selective sequential extraction procedures BCR was used to study chemical speciation of heavy metals in urban street dust in Shenyang,Fushun and Benxi.The results shows that Pb,V,Cr and Mn are present mainly in the residual fraction in Shenyang,Fushun and Benxi.Zn existed mainly in the residual fraction in Shenyang,in reducible fraction in Fushun,in oxidizable fraction in Benxi.Cu is present mainly in residual fraction and followed by oxidizable fraction in Shenyang and Fushun,while Cu is present mainly in oxidizable fraction and followed by reducible fraction in Benxi.The order of bioavailability of heavy metals in street dust of typical cities in Shenyang Economic Zone is as followed : Zn>Cu>Mn>Pb>Cr>V.