Determination of the Levels of Selected Heavy Metals in Finger Millet (Eleusine coracana) Flour in West Gojjam Zone, Amhara Region

Abstract

Background: Finger millet is a native and indigenous food crop in Ethiopia and has been cultivated in different parts of the country for centuries. However, its heavy metal contents in other parts of Ethiopia were not well studied, especially in the study area. The study was conducted in the Mankussa and Finoteselam district of the western Gojjam zone, Amhara region Ethiopia, to determine the heavy metal (Mn, Fe, Zn, Cu and Pb) levels of finger millet by using inductively coupled plasma optical emission spectroscopy. Methods: A wet digestion procedure was developed using a mixture of HCl, HNO3 and H2O2 to decompose a mixed powdered finger millet sample. Result: Mn, Fe, Cu, Zn and Pb mean levels were 3.751, 1.699, 0.072, 0.4485 and 0.024 mg/L, respectively, in Mankussa Black finger millet samples. In Mankussa mixed finger millet, the mean metal levels were 3.573 mg/L, 2.7585 mg/L, 0.0585 mg/L, 0.799 mg/L and 0.024 mg/L for Mn, Fe, Cu, Zn and Pb, respectively and the mean metal levels of Mankussa White Finger millet were found to be 2.326, 2.289, 0.045, 0.5985 and 0.014 mg/L of Mn, Fe, Cu, Zn and Pb respectively. While the mean metal level of Finoteselam black Finger millet samples was found to be 5.651 mg/L, 2.1955 mg/L, 0.0435 mg/L, 0.744 mg/L and 0.011 mg/L for Mn, Fe, Cu, Zn and Pb respectively, in the mixed finger millet it was 3.023 mg/L, 2.155 mg/L, 0.0525 mg/L,1.259 mg/L of Mn, Fe, Cu and Zn. In white finger millet, it was found to be 2.8695 mg/L, 1.412 mg/L, 0.0525 mg/L and 1.0735 mg/L of Mn, Fe, Cu and Zn. Pb was not detected by the instrument in Finoteselam mixed and white finger millet samples. The metal levels investigated in this study were comparable with international standards.