Determination of Essential and Non-essential Metals Concentration in Garlic ( Allium sativum L.) Bulb and Leaf Cultivated in Ambo Woreda, Ethiopia

In this study, the levels of twelve essential metals (Na, K, Ca, Mg, Fe, Zn, Mn, Cu, Mo, Co, Cr and Ni) and two non-essential metals (Pb and Cd) were determined in the bulb and leafs of garlic ( Allium sativum L.) cultivated in Ambo Woreda, Ethiopia. Wet digestion method using a mixture of 5 ml of concentrated HNO3:HClO4 (4:1 v/v) was used for digestion of the samples. The determination processes were done by flame photometer for Na and K, EDTA titration method for Ca and Mg, and ICP-OES for the rest of the metals. The results obtained revealed that the concentrations of metals in the garlic bulb samples in mg/kg dry weight were in the range of: Na (217–366.7), K (9080–12060), Ca (1018–1286), Mg (802–992.6), Fe (63.44–91.24), Zn (31.17–35.39), Mn (5.27–7.51), Cu (4.21–7.16), Mo (1.06–2.08), Co (0.61–1.49), Ni (1.45–3.78), Cr (0.47–1.31), Pb (1.07–2.51) and Cd (0.10–0.16). The concentrations of metals in the garlic leaf samples in mg/kg dry weight were in the range of: Na (463–730), K (11370–12860), Ca (1209–1302), Mg (871–994), Fe (72.3–108), Zn (49.1–71.39), Mn (26.74–72.36), Cu (5.41–8.44), Mo (1.01–2.30), Co (1.17–4.96), Ni (2.17–3.54), Cr (1.20–2.17), Pb (1.87–2.84) and Cd (0.12–0.18). In addition, the results show that the levels of elements were higher in the leaves than the bulbs. In general, the levels of metals in the analyzed garlic bulb and leaf samples were found below the FAO/WHO maximum permissible limit; hence they are safe for human consumption and can be considered as a good source of essential nutrients.