Study of Heavy Metals Accumulation in Leafy Vegetables of Ethiopia

Abstract

Energy dispersive X-ray Fluorescence (EDXRF) technique was applied for determination of heavy metals present in some selected varieties of leafy vegetables, mostly consumed in Ethiopia such as Ethiopian kale (Brassica carinata), Lettuce (Lactuca Sativa var.capitata), chard (Beta vulgaris), cauliflower (brassica oleracea.var.botrytis), Cabbage, Collard green (brassica oleracea), Siberian kale (Brassica napus var.pabularia) and Russian kale collected from Akaki, Kera and Debre Berhan. The concentration of 9 heavy metals (Zn, Cu, Ni, Co, Fe, Mn, Cr, As and Pb) were analyzed in the selected leafy vegetables. The foodstuffs examined for metal constituents are the basis of human nutrition in the study area except Siberian kale and Russian kale. The highest level of heavy metals were found in vegetables which are grown in Akaki and Kera, compared to samples of Debre Berhan , because Debre Berhan city is the place with no specific type of pollution. Metal levels observed in different sources were compared with WHO/FAO, and established permissible levels reported by different authors. Accumulation of most of the heavy metals in vegetables studied was higher than the recommended maximum tolerable levels proposed by the Joint FAO/WHO Expert Committee on Food Additives (1999), with the exception of copper, iron, cobalt and nickel, which exhibited lowlying content. Among all selected leafy vegetables, Swiss chard accumulate much higher concentrations of metals and toxic metals like As and Pb was not detected in Abyssinia kale collected from Debre Berhan.