Source apportionment and human exposure pathways of potentially toxic elements in road dust from an industrial...

This present study aims to evaluate the concentration, spatial distribution, source apportionment, and health risks of potentially toxic elements (PTEs) in roadside dust from the Durgapur Industrial Area (DIA), an intensively industrialized, urbanized, and mineral-rich belt located in eastern India. The study investigated pollutant exposure pathways and identified health risks associated with vulnerable population groups like children. Dust samples (n = 42) were collected using the coning and quartering method and analyzed for PTEs (Fe, Mn, Zn, Cu, Pb, Ni, Co, As, Cd, Cr). The mean concentrations of PTEs were observed in the following order: Fe > Mn > Cr > Zn > Cu > Pb > Ni > Co > As > Cd. The dominant PTEs were Fe (11,246 mg/kg), Mn (1,145 mg/kg), Zn (425 mg/kg), and Cr (191 mg/kg). Geo-accumulation index (Igeo) and enrichment factor (EF) analyses revealed significant enrichment of Cd, Cr, and As. Contamination and pollution indices (Contamination Factor, Pollution Load Index, Nemerow Pollution Index) confirmed a substantial overall pollution load, primarily influenced by Cd, Cr, As, Mn, Zn, and Pb. Morphological analysis under Scanning Electron Microscopy showed that the dust particles exhibited diverse shapes and structures, such as oval, nutshell-like, and small crystalline forms, as examined. Statistical analyses, including Pearson correlation, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis, were employed to identify potential sources. Pearson correlation showed strong associations among PTE pairs-As-Zn-Pb, Pb-Zn, Cr-Fe, and Ni-Cu-(p ≤ 0.05), indicating common anthropogenic sources including traffic emissions, coal combustion, and industrial processes. PCA identified industrial emissions and vehicular sources as dominant contributors. Health risk analysis showed ingestion as the main exposure route, with hazard indices (HI) for children reaching 1.52 (Cr) and 1.12 (Mn), exceeding the safe limit (HI > 1). Total carcinogenic risk (TCR) for children ranged from 2.47 × 10⁻⁸ to 1.87 × 10⁻⁴, with As and Pb as major contributors.