Accumulation of heavy metals (lead and nickel) by the soil and leaves of Albizia lebbeck and Conocarpus erectus from the city of Ahwaz

In this study, the accumulation of heavy metals included lead and nickel in Albizia lebbeck ((L.) Benth) tree, and Conocarpus erectus (L.) shrubin urban green spacewere investigated. To this, two areas with low and high traffic intensity with three replications were selected in Ahwaz, and random samples were collected from tree leaves (from 2 to 3 meters height above the ground level) and soil at the bottom of the species (depth 0 to 10 cm). The results showed that in the low traffic area, the concentrations of both heavy metals in two species were significantly different, in the case of lead, the concentration of this metal in the leaf of C. erectus was significantly higher than that of A. lebbeck, but the concentration of nickel in the leaf of A. lebbeck was significantly higher than that of C. erectus. Concentrations of lead and nickel in the soil of both species in the high traffic areas were significantly higher than the low traffic areas. The bioconcentration factor for the lead metal in both species was less than 1; But, for nickel metal, the mean of bioconcentration factor for both species is greater than 1; indicating that the two species are able to extract nickel from the soil. In summary, it can be stated that according to the findings of this study, C. erectus is more capable of absorbing nickel than Albizia lebbeck and can be used in phytoremediation projects in similar areas.