Assessing the Toxicity and Related Health Risks of Potentially Toxic Elements (Zn, Pb, Cd, and Cr) in the Roadside Soils of City of Hamedan

The road transportation has become one of the major metal contamination sources that could impact on roadside soils. Therefore, this study was conducted to evaluate the toxicity and related health implications of roadside contaminated soils with Zn, Pb, Cd, and Cr in city of Hamedan, west of Iran. In so doing, a total of 63 surface soil samples were collected along 700 m of a 9 km segment of the three major highways (i.e. Goltepeh (G), Razen (R) and Kermanshah (K)) in Hamedan Province. After acid digestion of samples, the element contents were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). The computed values of the Nemrow integrated pollution index (NIPI) showed that the pollution of all the analyzed elements in the highways with higher traffic volume (i.e. R and K) could be classified as "severe", indicating that effect of human activities, especially with the traffic origin. Also, based on the mean values of the toxic risk index (TRI) of the elements, the soil samples could be classified as 'non-toxicity'. Besides, the non-carcinogenic risk index (HI) values of the tested elements suggested that the HI could be classified as 'low risk' for both children and adults. Moreover, the carcinogenic risk (CR) of Cr was at a tolerable level for both children and adults, while Pb and Cd have been shown no significant carcinogenic risk. In conclusion, it is suggested that contaminated soil analyses be included in future studies in order to maintain environmental and human health.