Evaluation of heavy metal contamination and its potential ecological risk to the soil in Taiyuan,China

In order to determine the concentration of heavy metals in the soils of Taiyuan,China,and the associated potential ecological risk,80 soil samples were obtained and analyzed for Pb,Cu,Ni,As,Cd,Cr,Hg and Zn.Two indices-the Index of Geoaccumulation and the Potential Ecological Risk Index-were used to evaluate the degree of pollution by heavy metals.The results indicated that the soils in study area are characterized by no-to-moderate pollution and pose a light potential ecological risk.The relative degree of pollution was in the order of CdHgZnPb=CuNiAsCr.Likewise,the potential ecological risk was characterized by the order of HgCdAsPb=CuCrZn,with the predominant risk factor being Hg.Comparatively speaking,the soils within the urban areas pose the greatest potential ecological risk,followed by those in rural areas.The excess of these eight elements in soils primarily results from transportation,coal combustion,fertilization,and irrigation with sewage.