DETERMINATION OF SELECTED MAJOR AND TRACE METALS IN ONION (ALLIUM CEPA L.) CULTIVATED AROUND FOGERA WOREDA USING INDUCTIVLY COUPLED PLASMA OPTICAL EMISSIOM SPECTROSCOPY (ICP-OES)

ABSTRACT In this study, the level of major (Mg and Ca), trace (Mn, Cr and Cu) and toxic (Pb) metals in onion (Allium cepa L) bulbs were determined by using inductively coupled plasma optical emission spectroscopy (ICP OES). Wet digestion procedure was evaluated using standard addition (spiking) method and an acceptable percentage recovery was obtained in the range of (104.97-110.3). 0.5 g of oven dried samples was digested using a total volume of 12mL HNO3 (69%),6mL HClO4 (70%) and 3mL H2O2(50%) mixture in a flask fitted with reflux condenser on magnetic stirrer hotplate at180℃ for 3hours. The levels of major metals were Mg (203.1and 97.1), Ca ( 70.37 and 13.8 ), Mn (2.31 and 1.66) Cr( 4.46 and 3.86 ) Cu(2.03 and 0.73) Pb( 8.8 and 1.43) in onion cultivated with in Riza and Gumara irrigation sites respectively. The level of essential Major and trace metals are below the WHO/FAO permissible limit of mineral daily recommended intake values for human nutrition. Pb in onions grown from Riza exceeded the WHO/FAO limit of maximum recommended daily intake.