Spatial Distribution, Ecological Risk, and Human Health Implications of Heavy Metals in Urban Road Dust from...

This study investigates the distribution, contamination status, possible sources, and health risks of heavy metals in urban road dust from Vadodara, a rapidly developing industrial city in western India. Vadodara was selected due to its increasing traffic density, mixed land-use pattern, and growing industrial activities, which may contribute to metal accumulation in roadside environments. Road dust samples were analyzed for chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn), cadmium (Cd), cobalt (Co), and copper (Cu) using microwave-assisted digestion followed by atomic absorption spectrophotometry. The mean concentrations of metals followed the order: Cr (32.87 mg/kg) > Mn (28.64 mg/kg) > Zn (7.78 mg/kg) > Ni (4.90 mg/kg) > Cu (3.85 mg/kg) > Pb (3.30 mg/kg) > Co (2.68 mg/kg) > Cd (0.40 mg/kg). Overall, metal levels were lower than those reported for highly industrialized cities, indicating moderate contamination in the study area. Contamination indices (CF, Igeo, and PLI) suggested generally low pollution, although Cd showed localized enrichment at specific high-traffic sites. Ecological risk assessment indicated low to moderate risk, mainly due to Cd. Human health risk assessment showed that ingestion is the main exposure pathway. Non-carcinogenic risk values (HI < 1) indicated no significant risk for both adults and children. However, carcinogenic risk values for children ranged from 1.59 × 10^-4 to 5.63 × 10^-4 at some locations, approaching or slightly exceeding recommended limits, mainly due to chromium and nickel. Source analysis indicated that traffic-related activities and resuspension of soil particles are the major contributors to metal accumulation. The findings highlight that, although overall contamination levels in Vadodara are not severe, localized hotspots and potential risks for children require attention. These results provide useful baseline data for urban environmental management and can support future monitoring and pollution control strategies in similar developing cities.