ATOMIC ABSORPTION SPECTROSCOPIC ANALYSIS OF HEAVY METAL CONTENTS OF MALT BEVERAGES CONSUMED IN ETHIOPIA

Abstract

This study was designed to detect the levels of some heavy metals such as, nickel, cobalt, chromium, lead, and copper in five different brands of malt beverages commonly consumed in Ethiopia (Sinq, Sofi, Nigus, Malta Guinness and Bertat), using flame atomic absorption spectrometry (FAAS). The heavy metal contents obtained using FAAS shows slight differences among the five malt beverages. Generally in all brands of malt beverages, the concentration of Cu is the highest and Ni has the lowest concentrations. The order of abundance of these heavy metals is: Cu > Co > Cr > Ni. The levels of Ni and Cr show very small variations among the different brands of malt beverages. On the other hand, concentrations determined for Cu, Co shows slightly higher variations among the different brands. The level of Cobalt (Co) concentrations are in the range between 0.048 mg/L and 0.073 mg/L, which is above the maximum limit that has set by WHO (0.01 mg/L) in five malt beverages. The Ni level obtained in the beverages range between 0.015 mg/L and 0.029 mg/L, which is above the maximum limit set by WHO (0.02 mg/L) except the Bertat that has concentration range 0.015mg/L. The concentration of Cu is in the range from 0.4 mg/L to 0.68 mg/L, while the maximum allowed value set by WHO has 2.0. Therefore the levels of Cu in all the samples are within the acceptable limit. The level of Cr in the samples range between 0.032 and 0.047 which is again below the maximum allowed limit set by WHO (0.05 mg/L). In all samples, the level of Pb is below the detection limit of the instrument. In general, few malt drinks, the level of some heavy metals are slightly above the maximum limit set by the national and international organizations. Therefore, I suggested that malt beverage producing companies should pay attention to continuous monitoring of the sources of these heavy metals in malt beverages. The experimental results are validated in terms of accuracy, precession, linearity and method of detection limit. The accuracy was determined by spiking experiment and an accepted percentage recovery was obtained in the range of 97%-98%.