Determination of the Level of Heavy Metals in Some Selected Vegetables from an Irrigated Farmland of Kudenda in Kaduna Metropolis, Nigeria

Abstract

Heavy metal contamination of soil resulting from wastewater irrigation is a cause of serious concern due to the potential health risk of consuming contaminated produce. The use of wastewater for irrigation increases the contamination of heavy metals (Cd, Cu, Pb, Mn, Ni, Zn etc) in the plants. In this study, an assessment is made on the impacts of wastewater irrigation on heavy metals (Cd, Cu, Pb, Mn, Ni and Zn) contamination on vegetables cultivated in an irrigated farmland of Kudenda in Kaduna Metropolis, Nigeria. Samples of water, soil and some selected vegetables were collected and analysed for Cd, Cu, Pb, Mn, Ni and Zn using Buck scientific VGP 210 Atomic Absorption Spectroscopy (AAS). The wastewater used for irrigation had the following concentration 0.006±0.003 µg/mL Cd, 0.002±0.001 µg/mL Cu, 0.002±0.001 µg/mL Mn, 0.002±0.001 µg/mL Zn, while Pb and Ni were below detectable limit (BDL). The level of heavy metals in the vegetables under study differs with vegetables species. Cd level in tomato, cabbage and garden egg is the same 0.01±0.00 μg/g, and the level in one of the soil sampling site is found to be 0.03±0.01. The level of heavy metal was higher in soil than in vegetables studied. Accumulation of heavy metals varied from vegetable to vegetable. The mean concentrations of all the heavy metals studied were below the internationally permissible limits set by FAO/WHO and USEPA.