Investigation of Heavy Metals Contamination in Atmospheric Deposition of Zahedan City by Using Pollution Indices

Urban environmental pollution by heavy metals causes undesirable changes in the physical, chemical, and biological properties of life's main sources including water, air, and soil. This study has been carried out to map the spatial distribution concentration of heavy metals copper, zinc, lead, and cadmium and to evaluate the ecological and environmental hazards of these pollutants, by pollution indices mCd, Igeo, RI, and Cf indices in Zahedan city. In this research, 90 samples of deposited dust were collected by using a systematic random sampling method, and the concentrations of these metals were measured. To the model of the spatial distribution of heavy metals, the kriging method was used in Arc GIS. The results of heavy metals concentration measurements showed that the highest mean concentration was obtained for Pb 270.51 (mg. kg-1) and the lowest mean concentration was obtained for Cd 20.74 (mg. kg-1). Also, average concentrations of lead and cadmium were higher than the standard level in the soil. Also, the results of the Pearson correlation coefficient showed that there is a significant correlation between zinc and cadmium. Based on the results of the contamination factor and the potential environmental risk index, the copper and zinc showed low pollution range, lead high pollution range, and cadmium very high pollution range. Geoaccumulation index showed moderate pollution class for cadmium and high pollution class for copper, lead, and zinc. According to the spatial distribution maps, the highest concentrations of metals were observed in the city center and main roads which showed the role of human activities in the distribution of these elements.