Evaluation of Some Heavy Metals and the Associated Human Health Risks in Traditional Herbal Medicines in Addis Ababa, Ethiopia

Abstract

Traditional herbal medication drugs have been substantially prepared from plant origins. Heavy metal impurity of these plants could be a health threat to human health at concentration above the admissible threshold value. This study was designed to evaluate eight heavy metals (Fe, Zn, Cu, Pb, Cr, Cd, Mn and Ni) and the associated human health risk in traditional herbal medication in Addis Ababa, Ethiopia. Nine traditional herbal medication drug samples were collected from herbal shops of Addis Ababa city. The samples were prepared for analysis by wet digestion method using nitric acid, per chloric acid and hydrogen peroxide treatment. The levels of the heavy metals were measured using Flame Atomic Absorption Spectroscopy (FAAS). The accuracy of the method was analyzed by the spike recovery test. The percentage recoveries were ranged from 88.72–117.78%. The result showed that the concentration of metals were in the range of 0.254 ± 0.006–2.44 ± 0.02, 0.268 ± 0.01–1.12 ± 0.04, 0.0081 ± 0.003–0.033 ± 0.001, 0.635 ± 0.02–2.59 ± 0.04, 0.051 ± 0.03–0.106 ± 0.03 and 0.035 ± 0.001–0.128 ± 0.001 mg/kg for Zn, Mn, Ni, Fe, Pb and Cu, respectively. The concentrations of Cr, Pb and Cd were below the limit of detection in all analyzed samples except Pb in samples (E1) and (E2). This study showed that the level of all metals in the nine analyzed samples were within the WHO maximum permissible value. Chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), and Incremental lifetime cancer risk assessment (ILCR) were employed to assess the health risk. The HQ and HI value indices for heavy metals in various sampling sites were less than one, which showed no possible risk of non-cariogenic toxic effect for both adults and children. Since the incremental lifetime carcinogenic risk (ILCR) due to Ni intake was ranging from 2.37 × 10–6 to 3.15 × 10–5 and 2.57 × 10–6 to 3.41 × 10–5 in adults and children, respectively so, lower than the recommended values (10−6) there for, the use of these herbal medicines do not pose carcinogenic health risks and Pb, Cr and Cd were below the limit of detection value in all analyzedsamples