ABSTRACT

Heavy metals are those metals that have high density (weights). Even at low metal ion concentrations the presence of heavy metals can still pose a huge risk to humans and this makes it imperative to investigate the levels of these metals in foods, as they have a huge health impact when ingested by humans. While vernonia amygdalina plant is a popular plant consumed by humans and animals because of its nutritional and medicinal properties, it is important to investigate the heavy metal levels as various environmental and anthropogenic factors can give rise to their presence. In this study, the proximate composition as well as the heavy metal levels such as Pb, Mn, Fe, and Cd of V. amygdalina were studied. The leaf was found to contain (0.19 ± 0.02) mg/kg Pb, (0.01 ± 0.01) mg/kg Cd, (4.20 ± 0.22) mg/kg Mn, and (20.98 ± 0.27) mg/kg Fe. While the stem was found to contain (0.71 ± 0.03) mg/kg Pb, (0.00 ± 0.00) mg/kg Cd, (1.41 ± 0.05) mg/kg Mn, and (22.18 ± 0.54) mg/kg Fe. The heavy levels of the root showed (0.14 ± 0.01) mg/kg Pb, (0.00 ± 0.00) mg/kg Cd, (1.01 ± 0.06) mg/kg Mn, and (19.90 ± 0.89) mg/kg Fe. All of these values obtained are below the permissible limits set by WHO. However, the trace levels of these metals still pose a health risk to humans due to their tendency of accumulation in the plant. Also, it was observed that V. amygdalina plant has a low moisture content which indicates a high shelf-life of the plant. Moreover, the ash content is significantly high and this indicates a huge presence of mineral composition. These qualities imply that the V. amygdalina plant is nutritionally rich.