The feasibility of biomonitoring of heavy metals by wooden species of urban areas

The present study aims to investigate the potential of biodegradation of cadmium, nickel, lead and zinc metals by Plane, Ash and Pine wood species in Hamedan parks. After composed sampling of the unwashed leaves and soil in the 11 parks, the samples were dried, acidified, and finally, the concentration of metals were measured by atomic absorption spectrometry. The results of concentration of lead and nickel metals were higher than those in the earth's crust and the concentration of cadmium and nickel metals more than the global mean concentration of metals in urban soils. On the other hand, the highest concentrations of cadmium, lead and zinc were found in Plane leaf and nickel element in Ash leaf. In general, the concentration of metals from unwashed leaves were more than washed ones. In this regard, there was a positive and significant correlation between the amounts of metals in the soil at the site of tree growth with their concentration in leaves. According to the results of bioconcentration factors, it can be said that the Plane species is more suitable for biodegradation of heavy metal contamination, especially cadmium. Finally, due to the results, it is necessary to pay attention to the establishment of cumulative species in urban gardens.