Assessment of Zn, Cu and Pb Contamination in Soils and Vegetables from Some Farmlands in Lagos Metropolis, Lagos, Nigeria

Abstract: The contamination of leafy vegetables with heavy metals poses a serious threat to humans but little attention has been given to such studies in Nigeria. Investigated in this study are the levels of concentration of three heavy metals;  Zn, Cu and Pb in some leafy vegetables viz., cockscomb (Celosia argentea), african spinach  (Amarathus viridis), , jute plant (Corchorus olitorus) and lettuce (Lactuca capensis) from four  farmlands designated as Idi - araba, Isolo, Owode - Onirin and Badore in Lagos Metropolis. The concentrations of Cu, Zn and Pb in the leaves, stems and roots of cockscomb, african spinach,  jute plant and lettuce were found to be 1.542 "“ 0.125, 88.417 "“ 17.700, 7.568 "“ 0.028; 1.633 "“ 0.125, 82.417 "“ 18.250, 16.334 "“ 0.083; 1.583 "“ 0.028, 17.542 "“ 8.243, 10.833 "“ 0.167; 0.046 "“ 0.235, 0.00, 0.456 "“ 0.342 mg kg^-1 respectively. The concentrations of Pb of the leaves of vegetables at Isolo,  Corchorus olitorus at Idi "“ araba, Celosia argentea and Lactuca capensis at Badore were above the recommended maximum acceptable limits by WHO Expert Committee on Food Additives. The Zn and Cu contents of leaves of all vegetables are below the recommended limits in the four farmlands. The estimated daily intake of Cu, Zn and Pb through the consumption of Celosia argentea, Amarathus viridis and Corchorus olitorus are below the provisional tolerable daily intake of heavy metals established by FAO/WHO. This study shows that the vegetables obtained directly from the study sites may not constitute a health hazard for consumers.