Distribution characteristics of soil heavy metal pollution at both sides of the roads along Shenyang-Dalian expressway

The contents of Pb,Cd,Zn,Cr,Ni and Cu in the soil at both sides of the roads in Shenyang,Liaoyang,Anshan,Yingkou and Dalian were determined along Shenyang-Dalian expressway.The results indicate that soil Pb and Cd contents in each section are accumulated in the range of 250 m at both sides along the expressway,while the contents of Zn,Cr,Ni and Cu are lower.The maximum pollution indices for soil Pb and Cd are 3.34 and 2.42,respectively.The higher values of soil Pb and Cd contents occur within 50 m to the road shoulder,especially in the ranges from 20 m to 40 m.Most soil heavy metal contents are close to the background values at 150 m away the expressway,while soil Pb content is at 250 m.