Efficiency of Some Plants Grown on Roadsides of Baqubah City in the Phytoremediation of Lead and Cadmium

Abstract

The study aims to test the ability of some plants grown on roadsides (Nerium oleander, Eucalyptus camaldulensis, Albizia lebbeck, Ficus nitida and Callistemon viminalis) to remove lead and cadmium from the soil and air in the Baqubah city. Species were collected from three different sites in Baqubah city (Diyala Electrical Industries, a commercial area represented by Khurasan Street and a residential area represented by Al-Tahrir area). In the current study, leaves and soil samples were collected from each plant species used in the study during the months of September to December 2023 to evaluate metal accumulation. The recorded data showed that the concentration trend of heavy metals in soil and leaves was lead > cadmium except soil of C. viminalis in Al-Tahrir area. Moreover, the results of the accumulation index of heavy metals in the study areas according to Muller’s classification showed that the soil of the studied areas in Baqubah city is divided into two categories: unpolluted to moderately polluted areas and areas containing a moderate amount of pollutants. All areas were uncontaminated to moderately contaminated with lead and fell into Class I. As for cadmium, Diyala Company for Electric Industries area (A1) and Khurasan street (A2) were moderately polluted and fell within class II, while Al-Tahrir area (A3) appeared to contain unpolluted and fell in class I. These results suggest the idea that soil and tree leaves can be used as a good in phytoremediation of cadmium and lead. In the case of lead and cadmium, a highly statistically significant relationship (P < 0.05) was found between lead and cadmium concentration in soil and plant leaves. The bioaccumulation factor for lead in all plants used in this study was E. Camaldulensis > C. viminalis > A. lebbeck > F. nitida > N. oleander, and for cadmium it was E. Camaldulensis > C. viminalis > F. nitida > A. lebbeck. >N. oleander respectively which has proven to be a bioindicator and bioaccumulator of heavy metals, so planting these trees in industrial, commercial and residential areas containing such atmospheric pollutants would be beneficial.