Physicochemical and mineralogical characteristics of dust particles deposited in Ahvaz city

More than two third of the total areas in Iran has been covered by an arid and semi-arid climate. Although dust storm is an important environmental issue in these regions especially in western and southwestern provinces, limited information is available about characteristics and sources of such phenomena. This study was carried out to identify deposition rate, particle size distribution analysis, heavy metals (Zn, Pb, and Cd) concentrations, and mineralogical composition of dust particles collected using marble dust collector (MDCO) from 15 sampling points in Ahvaz city during a 6 months period in 2011. Results indicated that that the average amount of deposited particles in the periods with dust storms was considerably more than the periods without dust storms. The results illustrated that due to local factors such as the presence of bare lands around the city, and abandoned constructional projects dust deposition rate in such parts was quite more than other localities. Results also indicated that the mineralogical composition of the dust particles is mainly composed of calcite, quartz, and feldspars. Results obtained from particle size distribution analysis showed that the dust particles are mainly silt-sized. However, with occurrence of dust storms the size of particles became smaller. The highest concentration of heavy metals including Pb, Cd and Zn was found in downtown and in neighborhood of industrial regions. In addition, the greatest concentration of heavy metals was observed in December when compared with other months of the period studied.