BIOACCUMULATION OF HEAVY METALS IN SOILS AND Telfairia occidentalis LEAF GROWN AROUND TEMBOGA RIVER BANK

ABSTRACT

Heavy metal levels may result to heavy metal entry into the food chain, the studiy aimed at accessing the concentration of heavy metals (Ni, Pb, Co, Cr, Se and Cd) in soil and Telfairia occidentalis leafgrown along Temboga river bank. Surface soil and Telfairia occidentalis leaf samples were collected from Temboga river bank, 50 m and 100 m away from the river bank in 3 replicates, making a total of 9 soil and 9 Telfairia occidentalis samples. The soil samples were analyzed for physical, chemical and heavy metal properties using standard laboratory methods while the Telfairia occidentalis were only analyzed for heavy metal contents using the di-acid (HNO₃ and HClO₄) digestion method. Result showed that soil heavy metals content in river bank soils decreased with increased distance from the river bank except Cadmium which increase with increased distance from the river bank, the river bank soil contained 0.005 mg Cd kg^-1 and 100 m away from river bank was 0.009 mg Cd kg^-1 and Nickel which also increase with increased distance from the river bank, the river bank soil was 1.364 mg Ni kg^-1 and 100 m away from river bank was 1.371 mg Ni kg^-1. The Telfairia occidentalis heavy metal content varied with decreased in the soil away from the river. Cadmium and Nickel content were found to be toxic in the Telfairia occidentalis leaf with content of Ni as 2.563 mgkg^-1 at river bank and 1.287 mgkg^-1 100 m away from the river bank and Cd content as 0.457 mgkg^-1,0.697 mgkg^-1 and 1.507 mgkg^-1 at river bank, 50 m and 100 m away from river bank. It concluded that heavy metals concentrations in the soil is low and are not completely absorbed by the crop. The concentration of heavy metals in the crop are not harmful to human health.