Potentially toxic metals in passive dust of Shiraz metropolis, Iran

Contamination, distribution, and origin of potentially toxic metals (PTMs) were investigated based on ۲۲ collected passive dust samples from the Shiraz metropolis. The average and median concentrations of major and trace elements in the settled dust of Shiraz metropolis follow the order of Ca > Al > Fe > Mg > K > Na > Ti > Mn > Zn > V > Cr > Ni > Cu > Pb > Co > Cd. This trend is in agreement with the mineralogical composition of the dust samples. The dominant minerals of the selected samples in the urban deposited dust of Shiraz were carbonate minerals (۳۴.۳%), clays (۳۳.۰%), quartz (۱۴.۳%), and plagioclase (۱۰.۰%). The PTMs were spatially distributed heterogeneously in the settled dust of Shiraz. Among PTMs, Cd, Zn, Pb, and Cu showed higher enrichment. Thehighest ecological risk of PTMs occurred in the city center which can greatly be due to the excess traffic load and high human population in this sector of the city. Based on the Positive Matrix Factorization (PMF) model, Al. Co, Cr, Cu, Mn, Ni, V, Ca, Na, Mg, Fe, K, S, Li, Ti, U, and to a lesser extent Zn mainly originated from geogenic sources and natural processes, while Pb and Cd, and to a greater extent Zn mainly come from urban anthropogenic sources.

Keywords:

Dust , source , Mineralogy , PTM , PMF