Fractionation, source identification and risk assessment of potentially toxic elements in street dust of the most important center for petrochemical products, Asaluyeh County, Iran

Street dust samples from Asaluyeh County were collected in summer season for analysis of PTEs and mineralogy. For this purpose, 43 street dust samples were collected from industrial and urban areas. Also, three soil background samples were collected from 40cm depth. Calculated enrichment factors revealed high enrichment of Sb, Mo, Zn, Pb, Cu and Hg. Generalized estimating equations (GEE) and positive matrix factorization (PMF) models are used as a robust statistical method. GEE, PMF, Mann-Whithney, and PCA statistical analyses revealed two main sources of trace elements as road traffic and industrial emissions (Sb, Mo, Cu, Pb, Zn, Ni, Co, As and Cd) and re-suspended soil particles (Al, Cr, Ti, Sc, Mn and Fe). BCR sequential extraction results and interpolation maps indicated higher Mo, Cu, Fe, Cr, Zn, Sb, Co and Cd concentration in industrial regions and higher Mn, Ni, Cu, Pb, Hg, and As in urban areas. Measured physicochemical parameters showed that traffic load and velocity of vehicles have direct effect on the texture of street dust. Also Eh-pH diagrams revealed dominant species of Pb and Zn (S-O-H system), Cu and Sb (S-C-O-H system) in runoff as Zn2+, ZnCO3, ZnO, ZnO22-, CuO, Cu2O, Sb2O4, PbCO3, and PbO. Finally, calculated human health risk using mobile phase of elements indicated that HI for the studied elements were lower than the safe level of 1, revealing little adverse health risks from street dust exposure. Scanning electron microscope (SEM) result indicated some nanometer-size particles which can be very dangerous to human health.