Pollution status, spatiotemporal variations, and source identification of potentially toxic elements (PTEs) in street dust, the case of Hamedan metropolis, west of Iran

Abstract

ABSTRACT In the current study, a total of 162 street dust specimens were collected from 18 sites of Hamedan Megacity in 2023 and the contents of tested potentially toxic elements (PTEs) were determined by ICP-OES. The average contents of As, Cd, Cr, Cu, Ni, Pb, and Zn with 3.91, 0.609, 53.9, 70.1, 94.1, 82.4, and 308 mg kg-1, respectively, were found to be greater than those in the background samples reported for Iran, implying the anthropogenic sources of these elements. The greatest concentrations of the analyzed PTEs were observed in the commercial or industrial areas and their highest amount were related the samples obtained in fall, indicating the impact of human entries and seasonal variations of emission sources. The cumulative mean EF, I-geo, and PI values for the analyzed PTEs decreased in the order of Zn > Cd > Cr> Cu > Pb > Ni > As. Computed cumulative values of EF, I-geo, and PI ranged from 13.8 to 53.9, 0.382 to 2.35, and 1.95 to 7.66, respectively, indicating ‘severe to very severe’, ‘unpolluted to moderately polluted’ to ‘moderately to heavily polluted’, and ‘moderate to very high pollution’ contamination levels, respectively. The PLI with accumulative mean value of 2.77 reflected high pollution levels in the entire study area. Additionally, the cumulative mean values of RI with 146, demonstrated considerable ecological risks across the investigated area. The results of PCC, PCA and HCA showed that, traffic, fossil fuel combustion and industrial activities could be considered as the most important anthropogenic factors having a significant impact on the content of PTEs in the street dust. In conclusion, an accurate investigation of probability of the environmental risks due to the dust pollution by other PTEs and persistent organic pollutants (POPs) was recommended for future works.