Determination Of Levels Of Selected Heavy Metals In Food Barely Varieties Collected From Local Markets Of Hambiso Town Of Degem District, North Showa Zone, Oromia Regional State, Ethiopia

Abstract

Food safety is a challenging concern worldwide, due to food crops pollution problems by organic and inorganic chemical pollutants including heavy metals. In this study, concentration levels of selected heavy metals were determined in two barley varieties widely used for food in Degem district of North Showa Zone, Oromia regional State, Ethiopia. The heavy metals quantification was made using flame atomic absorption spectroscopic technique after digesting the barley samples using standard wet method with acid reagents such as HNO3, HClO4 and H2O2.In this wet digestion method 1 g of dried and powdered barely sample were digested using the acid reagent in 2.5:1:1 volume ratio at temperature of 240 °C for 2:30 hours. The method validation result showed that good instrumental sensitivity (LOQ = 0.013 – 0.043 mg/kg-dw), and linearity (r2 = 0.9925 - 0.9999), good method precision (%RSD = 0.0 – 15.9%) and accuracy (%recovery = 81.1 – 99.8%) were achieved indicated acceptable instrumental sensitivity and extraction method. The heavy metals quantification results showed that mean concentration values that range from 0.11±0.01-0.14±0.02, 0.71±0.05-0.98±0.15, 0.51±0.01-0.62±0.09, 0.07±0.01-0.10±0.00, 0.17±0.02-0.18±0.00, 0.49±0.08-0.46±0.04, 0.37±0.01-0.40±0.06, 0.43±0.00-0.48±0.03, and 1.11±0.02-1.32±0.11 in mg/kg-dw were observed for Cu, Fe, Zn, Mn, Co, Ni, Cr, Pb and Cd, respectively. Although the concentration levels of many of the studied heavy metals are low as compared to literatures and quality threshold values, the mean values of Cd and Pb in both barley varieties exceeded the permissible limits. This indicated that the metals likely cause human health risks to consumers. Our result further indicated the potential of geogenic processes for heavy metals pollution to food crops and to the supporting agricultural soils