Distribution and pollution assessment of heavy metals in roadside soil of Guiyang City, China.

The concentration and spatial distribution of heavy metals in roadside soil of Guiyang and its affecting factors were studied.Taking the baseline values as references,the method of indexing geo-accumulation was applied to assess heavy metal pollution in the roadside soil of Guiyang City.The results showed that the concentrations of heavy metals(Hg,Cd,As,Pb,Cr,Cu,Ni and Zn) varied significantly,and their concentrations were much higher than the environmental background value of Chinese surface soil and the baseline values of heavy metals in surface soils of Guiyang,with the exception of Pb and Cr.So,we could conclude that the soil has not been polluted by Pb and Cr,and the pollution of the roadside soil mainly resulted from Hg,Cd and Zn,which have caused medium or serious pollution.Moreover,the soil has been polluted by other heavy metals(As,Cu,Ni) to some extent,but not seriously.According to the investigation,the concentration and dispersion patterns of heavy metals are mainly affected by coal burning,transportation,terrain and road conditions,meteorological factors,construction of urban districts,and so on.