Determination of Selected Heavy Metals in the Leaf of Vernonia Amygdalina Collected from Gurage Zone Sodo Woreda Using Atomic Absorption Spectroscopy Technique
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Date
2024-09
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Addis Ababa University
Abstract
This study aimed to determine the concentration of heavy metals (Cd, Ni, Cr, Cu, and Pb) in leaf of vernonia amygdalina in Amharic 'Grawa' using flame atomic absorption spectrometry. An optimized digestion procedure was selected based up on less reagent consumption, digestion time and temperature. 0.5 gram of oven dried sample was digested by mixing 3 ml of 69% HNO3 and 1 ml of 70% HClO4 at a temperature of 270℃ for 2:30 hour due to minimum time, temperature and reagent conception. The leaf of heavy metals (Cr, Cd Cu, Pb, and Ni) in vernonia amygdalina was determined and the obtained concentrations of these metals were compared with the limit values set by WHO. The mean concentrations of the selected heavy metals were determined from triplicate samples of vernonia amygdalina, which were grown in different areas of Sodo Buee. In this study the mean concentrations of heavy metals obtained in vernonia amygdalina samples in mg/Kg were; Pb (0.3944±0.0096), Cu (0.18867±0.00236), Ni (0.0429±0.023), Cd (0.0191±0.028), and Cr (0.0150±0.00086). The mean concentration of heavy metals in vernonia amygdalina were in the order of Pb > Cu > Ni Cd >Cr. The concentration of all analyzed metal in vernonia amygdalina sample was below the maximum allowable concentration for V.amygdalina leaf given by WHO except lead which is comparable to WHO permissible limit this was due to different value in different year. These suggest to they were safe in terms of health risk perspective for used as medicine plant. Low RSD values, as seen in for Pb and Cu, suggest that the FAAS method was effective for these metals. The concentrations metals in this specific area are comparable to values for plants reported in other parts of the world. However, higher RSD values, for Ni, indicate potential challenges in measurement precision, possibly due to low concentrations or other experimental factors. The validity of the optimized procedure was evaluated by the analysis of spiked samples whose recoveries were in the range 92-98%.
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Vernonia Amygdalina, Heavy Metals, FAAS