Evaluation of the Impact of Traffic Volume on Pollution and Potential Ecological Risk of Zn, Pb, and Ni in Suburban Roadside Soils in Hamedan, Iran

Traffic emissions are one of the largest sources of heavy metal pollution, leading to ecological imbalances in roadside soils. This study was conducted to determine the content and assess the pollution and potential ecological hazard of Zn, Pb, and Ni in some suburban roadside soils of Hamadan, in 2019. In so doing, 63 surface soil samples were collected along 700 m from a 9.0 km section of Goltepeh, Razan, and Kermanshah roads. After samples preparation, content of the elements was determined by induced coupled plasma optical spectroscopy (ICP-OES). Also, pollution factor (CF), geo-accumulation index (Igeo), and cumulative potential ecological risk (RI) were calculated. Statistical analysis was performed using SPSS software. The maximum mean content of Zn, Pb and Ni in the soil samples was 122 ± 3.24, 26.4 ± 0.730, and 22.2 ± 0.360 mg/kg for, respectively, Razan, Kermanshah, and Razan and indicated the effect of traffic intensity. The positive and significant correlation between Zn and Pb (p <0.05) and Zn and Ni (p < 0.01) in the soil samples point to the common sources of these elements. The results of calculating CF, Igeo and RI indices showed acceptable soil quality in the studied stations and fell in the category of no ecological hazard. Moreover, the average values ​​of the calculated monomial potential ecological risk factor (Er) for the studied elements had a decreasing trend in the following order Pb > Ni > Zn. From the results of the current study, it may be concluded that regular monitoring of concentrations and assessment of ecological hazards of metal pollutions is necessary in order to manage and protect the soil quality.