Multipathway Assessment of Heavy Metal Exposure in Urban Dust: Linking Ecological and Human Health Risks

Heavy metal contamination in settled urban dust was investigated across industrial, traffic, and residential areas of Erbil City, Kurdistan Region, Iraq. Twenty-five composite dust samples were analyzed for Pb, Cd, Cr, Ni, As, Cu, and Zn using ICP-OES. Industrial areas exhibited the highest metal concentrations, particularly Pb and Cd, followed by traffic and residential zones. Health risk assessment revealed that ingestion was the dominant exposure pathway (> 95%), and children experienced approximately 2.5-fold higher total chronic daily intake (CDI_total) than adults. Noncarcinogenic risk analysis indicated that chromium was the dominant contributor to the hazard quotient (HQ), followed by arsenic and lead, with the highest cumulative hazard index observed for children in industrial areas (HI = 0.670). Carcinogenic risk assessment showed that the incremental lifetime cancer risk (ILCR) for children exceeded the acceptable threshold (1 × 10^-4) in industrial areas, with total cancer risk reaching 3.96 × 10^-4. These findings highlight significant dust-mediated health risks, particularly for children, and underscore the need for targeted emission control and public health interventions in rapidly urbanizing cities.