Evaluation of Carcinogenic and Non-Carcinogenic Risks of Heavy Metals in Selected Medicinal Plants

The concentrations of essential and non-essential metals were determined in four medicinal plants (Acacia abyssinica, Carissa spinarum, Dodonaea angustifolia and Euclea acemose) grown in Tara Gedam forest. The concentrations (in mg kg-1) of metals in D. angustifolia were 11.7 for Cu, 106 for Fe, 29.2 for Mn, 23.8 for Zn, 4.01 for Ni, 0.171 for Cd, and 3.11 for Pb; C. spinarum were 8.87 for Cu, 107 for Fe, 41.1 for Mn, 12.3 for Zn, 8.02 for Ni, 0.202 for Cd, and 8.53 for Pb; E. racemosa were 24.6 for Cu, 55.9 for Fe, 64.9 for Mn, 11.5 for Zn, 3.84 for Ni, 0.292 for Cd, and 0.771 for Pb; and A. abyssinica were 25.3 for Cu, 58.1 for Fe, 28.3 for Mn, 17.6 for Zn, 4.42 for Ni, 0.402 for Cd, and 4.04 for Pb. The percentage recoveries were ranged from 81.1% to 102.6%. The values of hazard index (HI) were greater than unity, thus there was non-carcinogenic adverse health risk for users. Since the carcinogenic risk (CR) due to Cd and Pb intake was lower than the recommended values (10-6), the use of these plants do not pose carcinogenic health risks.