Environmental & Analytical Toxicology

Heavy Metal Concentrations in Plants and Soil along Heavy Traffic Roads in North Central Nigeria

Abstract

Ogundele DT, Adio AA and Oludele OE

Plant and soil samples were analyzed to determine the heavy metals (Cd, Zn, Cu, Cr, Pb and Ni) along major roads in Kwara State, Nigeria. Control plant and soil samples were obtained from Kwara State University (KWASU). Eight soil and plant samples were collected. One sample each of soil and plant was collected from Kwara State University as the control sample. Three plant species (Kyllinga pumila michx, Kyllinga squamulata thanm ex vahl, Cenchrus biflorus roxb) on which animals feed were collected along major roadsides. The samples were digested using wet method and heavy metals were analyzed using Atomic Absorption Spectrophotometry Technique. Lead concentration of plants from the sites was found between 24-142 mg/kg and 24-157.667 mg/kg in soil samples. Copper was found between 28.55-115.2 mg/kg and 7.70-80.13 mg/kg in plant and soil samples respectively. Zinc ranges from 13.00-120.45 mg/kg and 30.8- 219.23 mg/kg in plants and soil respectively. Cadmium was between BDL-0.400 mg/kg and BDL-0.366 mg/kg in plants and soil. Chromium was detected between BDL-53.65 mg/kg and 10.57-77.10 mg/kg in plants and soil respectively. Nickel was between 1.65-11.85 mg/kg and 1.83-14.87 mg/kg in soil and plants samples. Heavy metals (Cd, Zn, Cu, Cr, Pb and Ni) in the control samples were found to be 0.35, 40.00, 88.55, 0.65, 238 and 0.65 mg/kg for Cadmium, Zinc, Copper, Chromium, Lead and Nickel in plants respectively. The soil samples were between 0.066, 9.50, 4.83, 55.63, 33.667, 4.33 mg/kg, Zinc, Copper, Chromium, Lead and Nickel respectively. Based on this study, plant and soil along road sides were found with high concentration of heavy metals.