A comparative study of metals in roadside soils and urban parks from Hamedan metropolis, Iran

A total of 25 roadside and 25 park soils have been sampled from six major streets and seven urban parks of the city of Hamedan (Iran) and analyzed for Pb and Cd. Metal pollution and spatial distribution maps were carried out using the pollution index(PI), integrated pollution index(IPI) and ordinary kriging with Geographic Information Systems. High levels of Cd and Pb were observed with average concentrations of Cd and Pb in the urban roadside soils being 1.57 ± 0.53, and 164.04 ± 50.08 mg/kg, respectively. However, the concentrations in urban park soils (1.16 ± 0.62, and 105.4 ± 46.47 mg/kg, respectively), were significantly lower. Vehicle traffic has resulted in a significant enrichment of Cd and Pb in the roadside soils with the highest concentrations found in the city center. The spatial distribution pattern of Cd and Pb in urban soils of Hamedan indicated that the concentration of metals in the central and northern parts of Hamedan is high, due to the human activities. Findings of metals in soils of major streets and urban parks indicated that metal contamination in urban roadside soils was higher than urban parks showing suitability of these soils than urban parks as indicators of metal contamination in urban areas.