Characterization andmetals fractionation of street dust samples fromTehran, Iran

Document Type: Original Research Paper

Authors

1 Graduate Student, School of Civil Engineering, Iran University of Science and Technology, Iran

2 School of Civil Engineering, Iran University of Science and Technology, Iran. Department of Civil Engineering, TheUniversity of British Columbia, Canada

3 Department of Civil Engineering, TheUniversity of British Columbia, Canada 4Faculty of Environment, University of Tehran, Iran

4 Faculty of Environment, University of Tehran, Iran

Abstract

Fifty street dust samples were collected from Southern and Eastern parts of Tehran, the capital
of Iran. Samples were collected during summer under dry and stable weather conditions. Total concentrations
of copper (Cu), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), zinc (Zn), iron (Fe), manganese (Mn)
and lithium (Li) were determined. Ten samples were then selected for characterization, metals fractionation
and single stage extraction studies. X-ray diffraction (XRD) and X-ray fluorescence (XRF) were utilized to
study the crystalline forms of metals and chemical compositions. In addition, sequential and single extraction
procedures were used to determine the concentrations of six heavy metals (i.e. Cu, Cd, Pb, Cr, Ni and Zn), and
also the mobility and bioavailability of elements. The risk assessment code (RAC) and IPOLLwere employed for
the risk assessment and pollution intensity of metals, respectively. Results showed that the single extraction
procedure could be used to estimate the total concentrations of most metals as an appropriate alternative for
total digestion. The mobility and potential availability of metals in Tehran street dust followed the order of Cd
> Zn > Pb > Cu > Ni > Cr. The risk assessment code results showed high risk for Pb, Cd and Zn and lowmedium
risk for Ni, Cr and Cu, and correlated positively with IPOLL result.

Keywords