An Assessment of Trace Elements in Selected Leafy Vegetables from Lagos State, Nigeria

Trace elements have been identified as one of the major contaminants of leafy vegetables that can accumulate in human organs with potential health risks. Thus, this study assessed the levels of cadmium (Cd), chromium (Cr), lead (Pb), copper (Cu), zinc (Zn), and iron (Fe) in 5 commonly consumed leafy vegetables’ samples of Telfairia occidentalis, Celosia argentea, Corchorus olitorius, Talinum triangulare, and Vernonia amygdalina from two markets in Lagos State. The Atomic Absorption Spectrophotometer (AAS) was used in metal determination and the data were analyzed using ANOVA and tested with the Tukey test (p<0.05). Cd levels were below the detectable limit, but Pd and Cr were observed in T. Occidentalis (20.82 mg kg-1) and C. olitorius (7.89 mg kg-1) from Oyingbo and Mile 12, respectively. Fe levels were the highest in all the vegetables, with a range of 392.66 – 2,072.97 mg kg-1 and 573.13 – 1,255.38 mg kg-1 in Mile 12 and Oyingbo, respectively. Zn concentration was significantly different among the vegetables in both markets, with the highest concentration in C. argentea (308.33 mg kg-1) and T. triangulare (303.96 mg kg-1), and lowest concentration in C. olitorius (97.1 mg kg-1) and V. amygdalina (102.33 mg kg-1) in Mile 12 and Oyingbo, respectively. Cu had the lowest concentration ranging between 4.55 – 33.34 mg kg-1 and 0.17 – 7.34 mg kg-1. The Pb, Cr, Zn, and Fe levels were above allowable limits by FAO/WHO (1996). Thus, there are potential risks of toxicity from these vegetables and it’s a major concern for public health and safety.