Determination of the Concentration Level of Selected Heavy Metals in White and Red Teff from Abdeta Village, Guto Gida District, East Wollega Zone, Oromia Region, Ethiopia

Abstract

Teff (Eragrostis teff) is an annual, warm-season cereal crop that self-pollinates. It is thought to have originated in Ethiopia, but because of its high nutritional value, it has been domesticated and used as feed for livestock and humans worldwide. Consumption of heavy metal-contaminated food crops is a primary food chain route for human exposure. Heavy metal contamination is one of the world's main health issues due to its long-term cumulative effects. This study was conducted to determine the concentration level of eight heavy metals (Fe, Cu, Zn, Cd, Pb, Ni, Mn, and Cr) in white and red teff samples collected from three different sites (Tuja, Babo and Masera) of Abdeta village, Oromia regional state, Ethiopia. The concentration levels of selected heavy metals in the white and red teff grains collected from Tuja, Babo and Masera were determined by atomic absorption spectroscopy (AAS)after wet acid digestion. The range of concentration level of heavy metals in the two varieties of teff samples from the from three sites were Fe (6.26-13.51), Zn (1.49-1.70), Cu (1.43-1.86), Mn (1.09-1.42), and Cr (0.98-0.99) mg/kg, respectively. The metal concentration level revealed that, in comparison to the white teff samples, the red teff samples collected from the Tuja and Babo area had a higher level of Fe. Fe concentrations are higher in the white teff samples that were taken from Masera. Zn, Cu, Mn, and Cr concentrations found in the two types of teff samples were nearly identical in each sampling site; however, no Cd, Pb, or Ni was found in the two types of teff samples taken from the three sites. When compared to other metals, iron has the highest availability, indicating that it is the primary component of plant nutrients and the most prevalent trace metal in all other heavy metals studied in nature. This implies that whereas there were fewer tendencies for the four heavy metals Zn, Cu, Mn, and Cr to transfer from soil to teff, there was a high level of Fe metal transfer. The distribution and concentration of heavy metals in teff samples can also be affected by soil fertility, the collection of teff samples from different areas, and the application of different agrochemicals such as pesticides, fungicides, and synthetic fertilizers. The percentage recoveries of the heavy metals analyzed ranged from 83.5% to 110.5%, which is within the acceptable range (80 - 120%). In general, the current concentrations of heavy metals were found to be within the recommended permissible limits, and thus may not pose a health risk to humans.