Concentration, sources, potential ecological and human health risks assessment of trace elements in roadside soil in Hamedan metropolitan, west of Iran

The road shipping has become one of the major metal contamination sources that could impact on roadside soils. Therefore, this study was conducted to determination, possible source identification and potential ecological and human health risks assessment of trace elements (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) in roadside surface soil samples in Hamedan, west of Iran in 2018. In so doing, a total of 63 roadside soil specimens from three main highways, including Goltapeh (G), Razan (R), and Kermanshah (K), were collected. Then, the contents of elements in roadside soils were determined using ICP-OES. Based on the results obtained, the highways with heavy traffic have the highest accumulation of all the metals, suggesting the effect of traffic density on metals concentrations. Computed values of pollution indices with mean of 0.970 for I-geo and 2.16 for PI pointed out that the soils collected from R and K roads primarily contaminated by Zn. The results of potential ecological risk assessment (RI) indicated that the surface soNo potential conflict of interest was reported by the author(s).ils at all the sites with RI < 150 have low ecological risk. Also, based on the results of human health risk assessment there was no substantial non-carcinogenic risk found to both children and adults through exposure to studied metals in roadside soil. The carcinogenic risk of Cr for both target populations was at the tolerable or acceptable level, while the other metals have no considerable carcinogenic risk. Hazard quotient (HQ) values demonstrated that ingestion was the main path of road soil metal exposure to man beings. Multivariate statistical analyses represented that Mn in the roadside soils derived from both soil minerals erosion and exhaust sources. Other metals also derived from non-exhaust sources (e.g. wear and tear of brakes, tires, engines, and lubricating oil). Our findings could be provided a theoretic basis and data support for pollution monitoring and control, soil remediation treatment and the implementation of public prevention in roadside areas of Hamedan.