Heavy metal concentration in soil and woody plants in a quarry.

This study determined the concentration of three heavy metals zinc (Zn), lead (Pb), and cadmium (Cd) in soil and in a woody plant species, Milicia excelsa, at Ishiagu quarry, Nigeria. The highest soil concentrations of Zn, Pb, and Cd in soil were obtained at 1 m from the quarry site. In M. excelsa, the highest concentrations of Zn, Pb, and Cd were 3.12-9.1, 3.9-6.01, and 0.51-1.12 mg kg-1, respectively. There were significant positive correlations between Cd and Zn (r = 0.963) and Cd and Pb (r = 0.974) in plants as well as between Cd and Pb (r = 9.84) in soil. The level of Cd in soil reflected significant pollution compared to average global concentrations in soils. [ABSTRACT FROM AUTHOR]