The study of the traceability of lead heavy metal in the leaves of eucalyptus (Eucalyptus microtheca) and Burhan (Albizia lebbeck) trees in Shush city

Background and This study aimed to investigate Pb pollution levels in the urban area of Shush City, utilizing dominant tree species as biological tracers. Sampling was conducted over one year, targeting two tree species, Albizia lebbeck and Eucalyptus microtheca, at four locations with varying traffic levels in the urban area. Soil samples were collected from zero to 30 cm where the trees were situated, and leaves were gathered from 2 meters above the ground, covering four cardinal directions and performed in triplicate. 120 leaf and soil samples were transported to the laboratory for chemical analysis. The highest average concentration of Pb in the winter of 2018 was recorded as 1183.2±4.6 mg/kg in the soil beneath the trees at the high-traffic station and 95.1±2.4 mg/kg in the unwashed leaves of Albizia lebbeck at the low-traffic station. During the summer season of 2019, Pb concentrations were 1056±2.7±3.3 mg/kg in the soil beneath the trees at the high-traffic station and 95.3±1.4 mg/kg in the unwashed leaves of the Albizia lebbeck tree at the low-traffic station. With bioaccumulation coefficients in all samples remaining below 1, it can be concluded that neither Albizia lebbeck nor Eucalyptus microtheca species possess a significant capacity for transferring heavy metals from the soil to their aerial organs. Additionally, they do not appear to absorb the available lead within their growth environment, making them unsuitable as bio-tracer plants