Assessment Of Heavy Metal Pollution In The Surface Soil Along The Main Road In The Area Around The Qinghai Lake

In 2012,roadside top soil samples were collected from 4 main roads（G109, G315, Huanhudong Road, Huanhuxi Road）in the link Qinghai Lake region, and concentration of 9 kinds of common harmful heavy metal elements including As, Cd, Pb, V, Cr, Mn, Ni, Cu, Zn were analysed using ICP-MS.Results showed that the average concentration of Cd in the area was over the limit of the first class from soil environmental quality standard for 2.35 times,the average concentration of As, Pb, Cr, Ni, Cu, Zn was below the first class standard. Enrichment factors（EF） showed that Cd is the most obviously pollutant（EF=3.67）,which was judged as moderate pollution,and the pollution scope of Cd was also the most widely element（EF>1 in 88.6% of all sampling sites）, the pollution level of Cu, Cr, As, Hg, Pb, Zn was significantly lower than that of Cd（EF=1.06-1.61）,which was slightly enriched.Potential ecological risk index（RI） showed that Cd was the main pollutant（Ei r =103.02）, judged as high ecological risk, and in 68.2% sampling sites showed moderate and high ecological risk,While As, Zn, Pb, Cr, Cu, Ni, Mn, V in all samples showed low ecological risk.The potential ecological risk index（RI） value of the whole study area was 135.62, judged as low ecological risk.As to the spatial distribution of pollution, the pollution degree of four directions of the study areaevaluated by RI in order of south>west>east>north, the south part had the hightest pollution degree:Cd was the primary pollutant(EF_Avg=6.62, Significant pollution), following by Zn(EF_Avg=2.43, moderate pollution), while Mn, Ni, As, Hg, Cr, Cu, Pb showed slight pollution(EF_Avg=1.04-1.86).Cluster and PCA analysis showed that Cd, Zn, Pb was mainly released from anthropogenicactivities. Cd, Zn, Pb are three typical traffic pollution elements, and at the same time traffic activitiesis widely exists in the study area, which indicates that the main source of heavy metal pollution in the link Qinghai Lake region is traffic activities.