ASSESMENT OF HEAVY METALS IN MANIHOT ESCULENTA (CASSAVA) IN SELECTED FARMS IN LAGOS STATE, NIGERIA

Abstract

Introduction: Anthropogenic activities by man in Nigeria especially Lagos State have induced accumulation of heavy metals in soils which invariably have resulted in the disturbance of living organism’s biochemical and physiological functions. Aim: This study assessed the level of heavy metals concentration in cassava (Manihot esculenta) harvested in selected farms in Lagos state. Materials and Methods: Leaves, stems, tubers of cassava were obtained from Morogbo, Badagry area and Odogunyan, Ikorodu area; and the concentrations of heavy metals content were determined using Atomic Absorption Spectrophotometric (AAS) method. Results: The results in mg/kg showed that heavy metals concentration [Nickel (3559.67 ± 5794.16), Manganese (120.33 ± 5.51), Copper (52.10 ± 2.85 and so on] were highly bioaccumulated in leafy part of the cassava. Conversely, Sodium (11620.00 ± 820.18) and Potassium (15133.33 ± 508.46) were highly bio-accumulated in the cassava’s stem while Calcium (3996.67 + 35.12) was found in high concentration in the cassava’s tuber. Lead (0.03 ± 0.05) and Cadmium (0.08 ± 0.08) were of significant values in the soil of Ikorodu and lower in the soil of Badagry. Heavy metal (Ni, Mn, Cd, Mg and Na) bio-accumulation in the two different location were higher in Badagry than Ikorodu, while Zn, Fe and K were higher in Ikorodu than in Badagry but Cobalt was not detected in both sites. Conclusion: Copper, Lead, Zinc, Manganese, Iron, Nickel, Calcium, Sodium and Potassium were above the recommended level of W.H.O. Therefore, consumption of leafy and tuber part of the cassava in both Ikorodu and Badagry areas could pose threat to animals.