Distribution and pollution assessment of heavy metals in soils on railway side of Shangzhi section of Harbin-Suifenhe railway in northeastern China

Abstract

Heavy metals (Cu, Zn, Pb and Cd) concentrations using atomic absorption spectrometry were investigated in roadside surface (0–20 cm) and sub-surface (20–40 cm) arable soils along Shangzhi section of Harbin-Suifenhe railway, Heilongjiang province, northeastern China. The soil contamination was assessed on the basis of enrichment factor (EF) and geoaccumulation index (I geo ). The results showed heavy metals in soils 50-meter distance from railway were higher than that of 10- and 100-meter distance. Except for Zn, concentrations of Cu, Pb and Cd in surface soil (0–20cm) were higher than that of subsurface soil (20–40cm). Concentrations of Cu (17.9∼22.4 mg kg−1), Zn (106∼293 mg kg−1), Pb (18.2∼24.6 mg kg−1) and Cd (0.064∼0.386 mg kg−1) were lower than the values in China National Standards Grade II. Most of EFs of the 4 heavy metals were higher than 1.0. The highest EFs of Cu, Zn, Pb and Cd are 1.23, 5.30, 1.20 and 4.70, respectively. I geo indicated that Contamination level of Cd was Class 2, Moderately contaminated. There were no obvious pollution of Cu and Pb in the studied area.