Determination of Heavy Metals in Hibiscus cannabinus and Moringa oleifera Cultivated at Zango Abattoir, Tudun Wada, Kaduna Metropolis

Abstract

This study was carried out to determine and evaluate the concentration of ten heavy metals (As, Cd, Co, Cr, Cu, Fe, Pb, Mn, Ni and Zn) in Hibiscus cannabinus and Moringa oleifera grown at Zango Abattoir, Tudun Wada, Kaduna Metropolis Nigeria, using Atomic Absorption Spectrophotometer. The concentration of the metals obtained ranged from 0.628±0.0006 to 3.469±0.0006 mg/kg for manganese, 8.362±0.0006 to 29.293±0.0026 mg/kg for iron, 0.700±0.0002 to 10.774±0.0026 mg/kg for zinc, 0.071±0.0002 to 0.223±0.0005 mg/kg for copper, 0.020±0.0006 to 0.044±0.0002 mg/kg for nickel, 0.017±0.0001 to 0.039±0.0001 mg/kg for cadmium, ND to 0.184±0.0004 mg/kg for chromium, 1.092±0.0003 to 1.167±0.0006 mg/kg for lead and 0.115±0.0010 to 0.201±0.0016 mg/kg for cobalt. Arsenic was however not detected in all the samples analysed. The concentrations of heavy metals in the selected samples were statistically significant at (P˂0.05). This study highlights that people consuming the vegetables grown within the abattoir consume substantial amount of metals like iron, zinc and lead. However, the values of these metals were below the recommended maximum tolerable guidelines level proposed by the WHO/FAO and NAFDAC.