Levels of selected essential and non-essential metals in wheat (Triticum aestivum) flour in Ethiopia

Abstract

In the present study, the levels and probable public health risks of selected metals (Fe, Mn, Cu, Zn, Ni, Cd and Pb) in nine wheat flour samples collected from Amhara, Oromia, South region, and the Strategic Food Reserve Agency were determined using FAAS and compared with results of prior studies and critical level. The wet digestion method using 65 % HNO₃ and 72 % HClO₄ in 300°C for 3 h was used when preparing the sample. Validation of the optimised digestion method was assessed using the spiking method, and an acceptable percent recovery from all metals. The levels of Fe, Cu, Mn, Zn, Ni and Cd ranged between 8⋅5297 and 11⋅1535, 1⋅633 and 4⋅2346, 3⋅1875 and 8⋅5313, 2⋅3589 and 2⋅7719, 0⋅154 and 0⋅854, and 0⋅0411 and 0⋅216 mg/kg, respectively, for Ethiopian wheat flour, while the level of Fe, Cu, Mn, Zn, Ni, Cd and Pb were ranged between 8⋅0099 and 8⋅1089, 1⋅663 and 1⋅6691, 4⋅5625 and 4⋅6250, 2⋅3015 and 2⋅3072, 0⋅9423 and 1⋅1346, 0⋅1593 and 0⋅1606, and 0⋅13 and 0⋅1381 mg/kg, respectively, for imported wheat flour. However, Pb had a concentration of less than 0⋅043 mg/kg for Ethiopian wheat flour. Findings indicate that Ethiopian wheat is comparatively higher in Fe, Mn, Cu, Zn and Cd, but lower in Ni and Pb than imports. From the result of the study, it can be concluded that the level of heavy metals determined in this study was within the permissible limit, and no probable health risk because both the Hazard quotient (HQ) and the Hazard Index (HI) are found to be below 1⋅0 regarding study metals.

Keywords: Cd; Cu; Fe; Flame atomic absorption spectrometer; Ni; Pb.

Fig. 1.

Distribution of metals in various types of wheat flour.