Health risk assessment of heavy metals in the dust street of Mehran city, as a busy city in religious times, Iran.

The concentration of various potentially toxic metals (Pb, Cd, As, Ni, Zn, and Cr) in street dust samples collected from Mehran city, Iran, was analyzed. The samples were obtained during normal traffic conditions, NTT, prior to the Arbaeen ceremony, as well as after the pilgrims' return, which corresponds to high traffic time, HTT. Street dust samples were analyzed for HM content using ICP-OES, following acid digestion. The subsequent evaluation of the data involved the application of the geo-accumulation index, enrichment factor, and potential ecological risk index (PER) and health risk assessment. The findings demonstrate a notable increase in the levels of HMs during HTT compared to the NTT. The highest enrichment values for Pb and Cd were observed in Mehran Street dust during the HTT. The mean of PER for all sampling points increased to 138.24, indicating a moderate-potential ecological risk at this time. Based on the health risk assessment, it was found that the hazard index for all samples was below one. The incremental lifetime cancer risk was below 10. This indicates that the exposed population is not exposed to substantial health risks. Despite the heavy traffic caused by the Arbaeen ceremony in this area and the high enrichment of HMs, along with potential ecological risks, no significant health risks were observed for individuals exposed to street dust. However, it is important to note that the continuation of this trend, in the absence of proper traffic management, could lead to significant environmental and health problems in the future.