ارزیابی مقادیر فلزات سنگین در ذرات گرد و غبار باریده بر شهرهای سنندج، خرم آباد و اندیمشک در غرب ایران1392-1391

Background & Objectives: Dust storms happening frequently in arid and semiarid regions of the world carry huge amount of particulate matters hence, these are recognized as one of the most important environmental issues at regional and international scales. This study aimed to evaluate heavy metals laden dustfall particles in Sanandaj, Khoramabad, and Andimeshk cities, West Iran. Materials & Methods: Sampling of dustfall particles was conducted once every 10 days from June 20, 2012 for one year at three stations of Sanandaj, Khorramabad, and Andimeshk simultaneously using Deposit Gauge Method. The concentration of Fe and Mn were measured using Flame Atomic Absorption Spectroscopy and Furnace Atomic Absorption Spectroscopy was used for analyzing Ni, Cr, Ag, As, Cu, and Zn. Then, pollution levels for the heavy metals were evaluated using Geo-Accumulation Index (Igeo) and Integrated Pollution Index (IPI). Mineralogy and morphology of the dustfall particles were inspected using X-ray diffraction and scanning electron microscopy. Results: Igeo index indicated that levels of pollution for Ag and Cu were higher than As and Zn among the dustfall particles of the three stations whereas the concentrations of the other heavy metals were not evaluated as contaminant. Moreover, means of IPI values calculated for stations of Sanandaj, Khorramabad, and Andimeshk were 2.86, 1.55 and 1.40 respectively. X-ray diffraction revealed abundance of silicate (quartz) and carbonate (calcite) minerals in dustfall particles. Additionally, scanning electron microscopy emphasized on similarity of shape of dustfall particles in the three stations. Conclusion: Although mean of dustfall particles on area unit in Sanandaj station was less than Khorramabad and Andimeshk, heavy metals concentration was relatively higher among the sampled dustfall particles.