Investigating distribution, contamination and health risk of heavy metals in street dust of Kermanshah Metropolis

In recent years, the long period of droughts and dust storms have caused dust particles to enter the west of the country. The large population, development of industrial centers and the existence of various sources of urban pollutants may increase the pollution load of dust particles in Kermanshah Metropolis. In this study, concentration of six heavy metals (Cd, Cr, Cu, Pb, Zn, and Ni) was investigated in street dust of this city. For this purpose, 21 street dust samples were collected and analyzed by ICP-MS. The results showed high concentrations of Cd, Cu, Pb and Zn with a mean values of 0.34, 128, 98.71 and 282.24 mg/kg, respectively. Enrichment factor, pollution load index, potential ecological risk index and health hazard index were used to investigate the contamination level of dust particles. The results of these indices indicated relatively high levels of lead, zinc, copper and cadmium in most parts of the city. Also, 42.85% of the sampling sites have low ecological risk index and 52.30% of the stations show moderate risk index. The highest hazard quotient (HQ) was calculated for the ingestion pathway, particularly for Cr and Pb. However, the risk index values for all the studied heavy metals were below unity for children except for lead in three stations. Principal component analysis (PCA) showed that chromium and nickel were predominantly originated from geogenic sources and other elements were highly affected by anthropogenic sources.