Risk assessment of elemental contamination in road dust and roadside soil in residential areas adjoining major industrial areas of Delhi

This study analyzed the < 63 μm fraction of road dust (RD) and roadside soil (RDS) collected from residential areas adjoining industrial zones in Delhi. Elemental concentrations in RD exhibited greater variability than in RDS, indicating heterogeneous sources. The RDS samples were contaminated mainly with Ni, Cu, Pb, Co, and Cr. Contamination patterns followed the order Fe > Mn > Cr > Zn > Ni > Pb > Cu > Co for RD and Fe > Mn > Cr > Ni > Zn > Cu > Pb > Co for RDS. Lead (Pb) displayed a distinct source signature, likely originating from historical deposition. Health risk assessment revealed that both carcinogenic and non-carcinogenic risks were higher for children compared to adults. Cr(VI) in RD (RI = 5.73E-03) and RDS (RI = 1.80E-03) posed notable carcinogenic risk, whereas Mn levels in RD (HI = 1.08E + 00) indicated non-carcinogenic risk among adults. For children, Ni (RD: RI = 3.43E-03; RDS: RI = 2.77E-03) and Cr(VI) (RD: RI = 7.66E-01; RDS: RI = 2.13E-01) contributed to carcinogenic risk. Cr in RD and Pb in both RD and RDS also exhibited non-carcinogenic risk. Additionally, elevated non-carcinogenic health risks were observed for Pb in RD (HI = 1.15E + 00) and Cr(VI) in RD (HI = 6.09E + 00) and RDS (HI = 1.91E + 00). Overall, Cr, Mn, Ni, and Pb in RD and RDS of residential areas adjoining industrial locations in Delhi were identified as the major contributors to risk, with ingestion being the dominant exposure pathway for both children and adults.