Assessment of Heavy Metal Contamination in Roadside Soils Along the Shenyang-Dalian Highway in Liaoning Province, China

Heavy metal contaminations were assessed through a detailed soil survey in roadside soils along the Shenyang-Dalian Highway of Liaoning Province, China. Pb, Cu, Cd, Ni, and Zn were analyzed using atomic absorption spectrophotometry. The average concentrations of Pb, Cu, Cd, Ni, and Zn in roadside soils were 43.8, 26.5, 0.119, 32.1, and 71.3 mg/kg, respectively, and all concentrations exceeded the background values. Different heavy metal distribution patterns were found under different land use types. In farmland, a peak metal concentration occurred 25 m from the roadside soil, while in the forest and orchard soil all heavy metals decreased with distance from the roadside, which conformed to the exponential model. Heavy metal concentrations were markedly higher than those measured in 1999 and 2007, except for Cd. Concentrations in soils along the Shenyang-Dalian Highway were medium or low in comparison with roadside soils in other cities around the world. Overall, this assessment illustrates that heavy metal pollution in these soils is generally low, and we recommend that more attention should be given to Pb contamination in roadside soils along the Shenyang-Dalian Highway.