Abstract:
Food chain contamination by heavy metals has become a burning issue in recent years because of their
potential accumulation in bio systems through contaminated spices. Knowing the levels of heavy metals
in air, water, plant and foods was necessary to prevent human being from several diseases caused by these
metals. Rhizome of ginger samples were randomly collected from six selected market areas
in central gondar zone, Amhara region. After proper sampling and pretreatment, volume of reagents (4 ml
HNO3 and 3 ml of HClO4), digestion temperature (2000C) and digestion time (2 h) used were optimized
and using the optimized conditions the levels of metals were determined by flame atomic absorption
spectrometry. The accuracy and precision of the optimized procedure was evaluated by analyzing the
digest of the spiked samples and the percentage recoveries obtained varied from 89.73% to 99.94%. The
levels of metals determined were in the range of 77.71-81.12 mg/kg for Fe, 2.17-4.44 mg/kg for Cu, 16.74-
19.31 mg/kg for Zn, 6.49-7.58 mg/kg for Ni, 52.52-65.14 mg/kg for Cr, 4.63-5.43 mg/kg for Cd and Pb
was found below detection limit (<0.39 mg/kg). Among the investigated metals, Fe and Cu were found to
be the highest and the least concentration from all sampling sites, respectively. Significant differences (p
< 0.05) were observed in the mean concentration of Cu among the three woredas, Zn between East Dembia
and West Dembia, Cd between East Dembia and West Dembia as well as East Dembia and Gondar zuria
Woreda. However, no significant difference occurs in the levels of Fe, Ni and Cr in all the samples (pvalue > 0.05). Results of Pearson’s correlation revealed that there is positive correlation observed Ni with
Fe and Cr and Cd with Fe, Cu, Zn and Ni. However, the other metals showed negative correlation. The contents
of metals are beyond permitted limits set by WHO and FAO
