Determination of some heavy metals in vegetable garden soil and waste dumpsite soil in Mubi North, Adamawa State, Nigeria

Abstract

Abstract. A research conducted on soil samples using different depths were carried out on the determination of heavy metals (Pb, Cu, Zn, Ni, Cd and As) in Wuro-Gude vegetable garden soil and waste dumpsite soil, Mubi Metropolis Adamawa State, Nigeria. The soil samples were collected on different depths and were transported to the department of animal production laboratory for digestion. The mixtures were digested with tri-acid mixture (HNO3: HCO4: H2SO4) and determination of the heavy metals was done using a Buck Scientific 200A Model, Atomic Absorption Spectrophotometer (AAS). It was found that the heavy metals concentration in both types of soils at the depth of 5, 15 and 25cm was as follows: a) Vegetable garden soil: Ni – 7.33mg/g, 5.06mg/g and 3.04mg/g; Zn – 16.31mg/g, 13.08mg/g and 8.37mg/g; Cu – 6.94mg/g, 4.77mg/g and 3.28mg/g; Pb – 1.07mg/g, 0.57mg/g and 0.42mg/g and Cd – 0.35mg/g, 0.31mg/g and 0.29mg/g, respectively; As was not detected in all the depths; b) Waste dumpsite soil: Ni – 6.75mg/g, 4.33mg/g and 1.95mg/g; Zn – 14.67mg/g, 12.55mg/g and 9.04mg/g; Cu – 8.34mg/g, 5.72mg/g and 3.82mg/g; Pb – 2.15mg/g, 1.06mg/g and 0.67mg/g and Cd – 0.68mg/g, 0.57mg/g and 0.84mg/g, respectively; As was not detected in all the samples. All measured heavy metals concentrations were within the permissible limit set by the World Health Organization, except Cd which was above the permissible limit in waste dumpsite soil. Therefore, waste dumpsite soil should not be used for farming and effort should be made to educate the public on the health effect of these metals when ingested, to avoid bioaccumulation and biomagnification in the food chain.