Analysis of Heavy Metals Found in Vegetables From Some Irrigated Gardens in Katsina, Daura and Funtua Metropolis, Katsina State, Nigeria.

Abstract

This study was conducted to determine the concentration of heavy metals cadmium (Cd)) chromium (Cr) (copper (Cu), iron (Fe) manganese (Mn) zinc (Zn), lead (Pb) and in five vegetables viz;  (Bitter-leaf),  Cabbage, Cucumber, Lettuce and Spinach and soil collected from selected farm and market sites in industrial, residential and commercial areas of Lagos state. The heavy metals present in the vegetables were analyzed using Atomic Absorption Spectrophotometer (AAS). The results reveal that all the heavy metals were detected in all the vegetables from the various sites. Most of the concentrations are below the World Health Organisation (WHO) and Food and Agriculture Organisation (FAO) safe limit of 0.1 mg/kg, 0.1 mg/kg, 40 mg/kg, 1.3 mg/kg, 1.5 mg/kg, 6.61 mg/kg, 3 mg/kg, 60 mg/kg for cadmium (Cd), cobalt (Co)   (Cu), chromium (Cr), iron (Fe), lead (Pb) and  zinc (Zn), and respectively in the vegetables. However the concentration of cobalt in spinach and lead in cabbage from Katsina are above the WHO and FAO safe limits. There is a significant differences in the concentration of Cd in the vegetables from the sampling sites (P<0.05), while there is no significant difference in the concentration of Cr, Co, Cu, Fe, Mn, Pb, Zn  in the vegetables from the sampling sites (P>0.05). If the practice of treating the soils in the irrigation gardens with contaminated waters is not controlled, it may lead to health hazard on the part of consumers of the vegetables on the long term. Therefore, there is the need to continually monitor, control and take necessary policy decisions so as to limit and ultimately prevent these avoidable problems.

Keywords: Irrigation, Vegetables, Heavy metals, Atomic Absorption Spectrophotometry (AAS), Gardens