Multivariate statistical analysis of heavy metals contamination in atmospheric dust of Kermanshah province, western Iran, during the spring and summer 2013

Atmospheric dust is known to contain heavy metals in different levels that can cause environmental pollution. In west of Iran, despite of the large number of dusty days per year, heavy metals content of the atmospheric dust has not been previously investigated. A total of 98 samples of atmospheric dust were collected during the spring (T1) and summer (T2) of 2013 from urban and suburban locations in Kermanshah province, and analyzed for Zn, Cu, Ni, Cr, Mn, and Fe total concentrations. Correlation, principal component and cluster analyses suggested probable natural and anthropogenic sources of the metals in the dust. The contamination levels of heavy metals were assessed on the basis of enrichment factor (EF), geo-accumulation index (Igeo), and ecological risk (RI). Comparing with the background values of world soils, elevated metal concentrations were found in dust samples, except for Mn and Fe. Manganese and Fe were mainly of natural origin with traces of anthropogenic influences; while Zn and Cu were mainly from traffic sources and probably were partly from industrial sources; Ni and Cr mainly resulted from industrial activities and probably in part from traffic sources. The analysis of EF revealed moderate enrichments for Mn and Cr, and significant enrichments for Zn, Cu, and Ni in T1 and T2, and similarly in urban and suburban areas. Based on Igeo index, the levels of Mn and Fe were classified as uncontaminated, while Zn, Cu, Ni, and Cr levels were evaluated to have moderate contamination in T1 and T2, and similarly in urban and suburban areas. The values of RI showed a low level of heavy metals pollution.