Document Type : CASE STUDY
Department of arid and desert regions management, College of Natural Resources and Desert Studies, Yazd University, Yazd, Iran
Heavy metal pollutionis one of the largest problems in the Environment and human being. In industrial and urban areas trees can give better quantifications for pollutant concentrations and atmospheric deposition than non-biological samples. In order to know ability of Fraxinus excelsior (Ash tree) to reduce the concentrations of heavy metals and compared with the concentration of these pollutants in falling dust urban green belt. The results showed that the concentration of Iron, Manganese, Zinc, Lead, and Cadmium in falling dust respectively were the highest to the lowest. The distance from the highway in the concentration of pollutants in leaves and bark of the Ash tree showed significant results. Also, the effect of pollutant in the leaf of this plant was higher than that of bark, except for Cobalt. Concentrations of Zinc, Cobalt, and Nickel, increased with increasing distance from the road due to multi-directional winds and the presence of other contaminants. The Pearson correlation analysis between heavy metals found in the falling dust and Ash tree showed that the input and controlling factors of these elements in the Ash tree are probably the same as the dust. The results showed that the Fraxinus excelsior leaf with the amount of accumulation index of 1607 mg/kg has more ability to simultaneously absorb different metals. As a result, since this green belt surrounds Yazd urban area, it is hoped that a significant amount of heavy metals will be absorbed by these trees.
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