Heavy Metals in Soil and Accumulation in Medicinal Plants at an Industrial Area in Enyimba city, Abia State, Nigeria

Abstract

The study assessed heavy metals in the soil and subsequent accumulation in plants at an industrial site at Enyimba city, Abia State, Nigeria. Soil and medicinal plant samples were analyzed for zinc (Zn), lead (Pb) and cadmium (Cd). The highest concentration of Zn (142.06 ± 2.91 mg/kg), Pb (18.06 ± 1.30 mg/kg) and Cd (27.055 ± 2.468 mg/kg) were obtained at the sampling points of 2, 7 and 5, respectively. The highest concentrations of Zn (27.09 ± 1.44 mg/kg) and Cd (2.000 ± 0.156 mg/kg) were accumulated by Azadiractha indica while the highest concentration of Pb (4.58 ± 0.51 mg/kg) was accumulated by Mangifera indica. The levels of Zn and Cd in soil were 13.77 ± 1.35 to 142.06 ± 2.91 and 0.695 ± 0.106 to 27.055 ± 2.468, and their concentrations in Azadiractha indica were 5.06 ± 0.35 to 27.09 ± 1.44 and 0.002 ± 0.001 to 2.000 ± 0.156 mg/kg, respectively. The concentrations of Zn and Cd in soil and Cd in Azadiractha indica reflected a state of pollution relative to Dutch criteria for soil and the FAO/WHO Codex Alimentarius Commission for soil and herbal plants.