Determination of Levels of Heavy Metals in Some Selected Traditional Medicinal Plants in Southern Ethiopia

Medicinal plants have worldwide applications in the treatment of different types of human diseases. The purpose of the current study was to determine the concentration of selected essential and non-essential metals; Na, Ca, Cu, Fe, Zn, Mn, Cr, Ni, Cd, and Pb in traditional medicinal plants (Artemisia afra (ariti), Hagenia abyssinica (kosso enchet), Foeniculum vulgare (Ensilal), Echinops kebericho (qeberecho)) grown in Wolaita Zone, southern Ethiopia. A wet digestion procedure involving the use of mixtures of (69-72%) HNO3 and (70%)HclO4 at an optimum temperature and time duration were used to isolate metals from the medicinal plants by using FAAS.Based on the results, the concentration of Ca ranged from 1.75 mg/kg to 4.98 mg/kg, the concentration of Mg ranged from 1.35 mg/kg to 2.22 mg/kg, the concentration of Na raged from 1.29 mg/kg to1.80mg/kg, Mn ranged from 0.09 mg/kg to 1.21 mg/kg and that of Fe lied in range of 0.23 mg/kg to 0.78 mg/kg in the plants studied. Among the toxic heavy metals, the concentration of Pb was in the least range (0.08 mg/kg to 0.11 mg/kg) and the levels of remaining trace metals were in the ranges of 0.54-0.97 mg/kg, 0.25-0.29 mg/kg and 0.20-0.33 in Zn, Cd and Cu respectively. None of the studied samples were found to contain Cadmium, Copper and Nickel concentrations in above WHO/FAO limits for safe human consumption (25, 40 and 5 mg/kg respectively) Further studies will be continued on the screening of phytochemical activities of the plants under study.