Evaluation of Cadmium,Copper, Lead,and Zinc Levels in Soil Samples near Locust Pods

The genus Prosopis is a tree or shrub in the leguminosae family, subfamily fabaceae (mimosaceae). Many plants of the genus Prosopis are known to have medicinal properties. Only one species of Prosopis is found in Jordan, Prosopis farcta (Banks & Sol.) J.F. Macbr. The local name is Yanbout, and the English name is locust pods.

The aim of this study was to investigate some selected heavy metals including cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in Prosopis farcta, an unexplored Jordanian species of the Prosopis genus, because no data are available about these levels in this medicinal plant. These metals were tested in different parts of Prosopis farcta including root, aerial, and fruit as ethanolic extract plant and dry plant. Moreover, these metals were investigated in soil samples collected from the same area in which Prosopis farcta was grown. Results revealed that there was a significant difference between root and fruit for all test elements (P < 0.05). Roots were found to contain high average concentrations of Pb (2.14 µg g^?1), Cu (18.56 µg g^?1), and Zn (13.74 µg g^?1). Copper and Zn concentrations in Prosopis farcta were within the permissible limits, whereas Pb concentration exceeded the permissible limit. Moreover, soil samples were analyzed for the metals. Results revealed that there was a positive correlation between the levels of Cu and Zn in medicinal plants and soils, whereas there was a negative correlation for Pb.

Two certified reference materials (tea leaves, NCSDC 73351; soil, GBW 07406) were analyzed to authenticate the accuracy of the method, and the precision was expressed by relative standard deviation.