Abstract

Background: Focus on environmental heavy metals is important due to their adverse impact on human health and environment. This study aimed to determine the lead and nickel concentrations and their spatial patterns in the street dust of Zanjan city, Iran, which is enclosed with metal production (especially lead and zinc industries). Methods: Fifty urban street dust samples were collected from Zanjan and analyzed for lead and nickel after Aqua Regia digestion via flame atomic-absorption spectrophotometry. The sediment contamination degree and origin of the pollutants were assessed using the geo-accumulation index. Pollution status was assessed using the enrichment factor and potential ecological risk index (Hakanson index). Results: The mean, minimum, and maximum lead were 745, 30, and 4610 mg/kg and 72, 32, and 154 mg/kg for nickel, respectively. The mean lead concentration was higher than the local background value. The element spatial distribution showed higher lead concentration in the east, west, and southwest, main streets, and Qazvin-Tabriz high ways.  Higher potential ecological risk was observed for lead, confirming regional pollution. Conclusion: High lead concentrations could be attributed to vehicle emissions and industrial activities (lead and zinc companies in Zanjan). Traffic and frequent braking of vehicles could increase nickel concentrations.