Abstract

The nitrate/nitrite and heavy metal (Pb) concentrations of four leafy vegetables species: Corchorus olitoriu (ewedu), Telfairia occidentalis (fluted pumkin), Amaranthus viridis (green), Vernonia amygdalina (bitter leaf) are the objectives of study. The vegetables, collected from five farms after harvesting were subjected to phenoldisulfonic acid method for nitrate and Nessler’s method for nitrite before analysis using a T80 UV/VIS Spectrophotometer. Atomic absorption spectrophotometer (Perkin Elmer Analyst 200) was used for Pb determination after acid digestion. The data were analyzed with ANOVA and Pearson Correlation analysis. The result shows that the average nitrate/nitrite contents of the vegetables were less than the ADI of European Commission. The highest and lowest average nitrate content (μg/g dry weight) was found for bitter leaf (101.63) and green (62.84) respectively while their nitrite values were given as 76.47 and 33.93μg/g dry weights. Green had the highest Pb content 4.36 while ewedu had the lowest 3.84 μg/g dry weight. The Pb levels which were not significantly affected by variations in locations (P>0.05), are above the FAO and WHO/EU joint limit, may predispose the consumers to low levels Pb poisoning. We conclude that the urban activities have significant effect on the vegetables and fertilizer application is acceptable.