Assessing the influence of different road traffic on heavy metal accumulation in rural roadside surface soils of the Eastern Ordos Plateau Grassland in China

摘要

A total of 52 roadside surface soil samples from five busy roads in the Eastern Ordos Plateau Grassland (EOPG) were investigated for accumulation of three metals (Pb, Cu, and Cr). Roadside soils were selected at various distances (1, 5, 10, 20, 40, 80 and 160 m) perpendicular to the road edges. The spatial distribution and contamination of the three metals in five roadside surface soils were studied. The mean concentrations of the three metals in the five roadside soils were as follows: Pb (14.09 ppm), Cu (11.32 ppm), and Cr (28.83 ppm). The concentrations of Cu in roadside soils decreased as distance from the road was increased. The concentrations of Cu in roadside soils were positively correlated with the contents of soil organic carbon, soluble salt, silt, and clay, and they were negatively correlated with the contents of sand. The geo-accumulation indices for the three metals in the five roadside soils were as follows: Pb (0.79) > Cu (0.35) > Cr (0.17). The roadside surface soils along the five roads were classified as being uncontaminated to moderately contaminated with Pb, Cu, and Cr. The findings presented in this study are meaningful for road planning in rural areas and addressing the environmental problems of traffic-related metal pollution.