Iranian Journal of

Background and Objective: Contamination of roadside soils with heavy metals is a serious threat to soil ecosystems and organisms and human health. Therefore, the purpose of this study was to determine the concentration of heavy metals in the roadside soils of the Rasht-Qazvin old road.
Materials and Methods: 10 out-of-town sampling sites were selected via the field observation of the entire area. surface soil sampling with three replicates was performed around the Rasht-Qazvin old road.  Heavy metals concentrations were measured using ICP-OES following samples preparation and acid digestion. The pollution level of heavy metals was assessed using geoaccumulation index (I_geo) and potential ecological risk index (PERI).
Results: The results showed that the average concentrations of Zn, Cu, Ni and Pb in the roadside soils were 58.07, 19.96, 20.26 and 23.21 mg/kg, respectively. The findings showed that concentration of Zn and Ni were higher than background values and the amount of Zn exceeded WHO standard limit. The potential ecological risk index (PERI) with an average value of 86.24, indicated low level of pollution for all of the studied metals. The results of geoaccumulation index (I_geo) revealed moderately contamination level of Ni.
Conclusion: Old roads are generally known as one of the sources of pollution for the surrounding lands. Although the concentration of pollutants around the road is expected to be very high, we did not detect elevated levels of heavy metals. This fact can be explained by the current road repairs and widening, agricultural activities on marginal lands and wind blows in mountainous regions which leads to the dispersion of the soil pollutants.

Background and Objective: Heavy metals are regarded as serious contaminants due to their toxicity, persistence in natural conditions, and ability to enter and accumulate (bioaccumulation and biomagnification) in food chains. The aim of this study was to investigate the concentrations of the heavy metals Pb, Cd, Cu, Zn, Cr, Fe and Ni in surface agricultural soils of the Miandoab landfill area.
Materials and Methods: In this study, 57 soil samples were collected from a depth of 0-20 cm. After preparing and digesting in the laboratory, the samples were analyzed using a inductively coupled plasma spectrometer (ICP-OES). The Ecological Risk Potential Index (EPRI), Earth Accumulation Index (Igeo), Principal Components Test (PCA) Pearson's Correlation, Cluster Analysis, and One-T-test were utilized. Statistical processing was conducted using SPSS software.
Results: According to the results of the single T-test, the average concentrations of Pb, Cd, Cu, Zn, Cr, Ni did not significantly differ from their background concentration in the soil (p≥0.05). A significant difference was pbserved only for Fe (p<0.05), indicating a geological origin for this element. The EPRI was within the low-risk range, with an average value of 46.95. PCA revealed that the first factor was positively associated with Cr, Pb and Fe; the second factor with Zn and Cu; and the third factor with Cd. Cluster analysis showed that Fe was predominantly influenced by natural resources. According to the land accumulation index, all metals, except Cu, were classified non-polluted or slightly polluted at stations 2 and 4.
Conclusion: The origin of elements is related to both natural and human factors. Specifically, Cr, Pb and Cd are more likely to originate from man-made sources, while Fe primarily comes from natural sources. The decrease in the concentration of metals can be attributed to continuous and annual ploughing, inactivity of the landfill, biological absorption by crops, soil leaching and transporting to lower depths.