Tracing source, distribution and health risk of potentially harmful elements (PHEs) in street dust of Durgapur, India.

Street dust samples from Durgapur, the steel city of eastern India, were collected from five different land use patterns, i.e., national highways, urban residential area, sensitive area, industrial area and busy traffic zone during summer, monsoon, and winter to analyze the pollution characteristics, chemical fractionation, source apportionment and health risk of heavy metals (HMs). The samples were fractionated into ≤ 53 µm and analyzed for potentially harmful elements (PHEs) viz. Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Summer season indicated higher concentrations of PHEs when compared to the other two seasons. Mean enrichment factor (EF), geo-accumulation index (Igeo), and contamination factor (CF) were high for Cd followed by Pb during all the three season in Durgapur. Chemical fractionation was executed in order to obtain distribution patterns of PHEs and to evaluate their bioavailable fractions in street dust samples. Mn was found to be highly bioavailable and bioavailability of the PHEs were in the order of Mn > Zn > Pb > Ni > Cd > Cu > Fe > Cr. Principal Component Analysis (PCA), cluster analysis, correlation analysis indicated the main sources of PHEs could be industrial, especially coal powered thermal plant, iron and steel industries and cement industries and vehicular. Multivariate analysis of variance (MANOVA) indicated that sites, seasons and their interaction were significantly affected by different PHEs as a whole. The health risk was calculated with total metal as well as mobile fraction of PHEs, which indicated that the actual non-carcinogenic risk due to bioavailable PHEs was less (HI < 1) when compared to total concentrations of PHEs. Carcinogenic risk was observed for total Cr in street dust (Child: 4.6E-06; Adult: 3.6E-06).