Heavy metals pollution in cancer and wound-healing medicinal plants: A comprehensive assessment of health risk

The use of medicinal plants for treating diseases is a common practice in Ethiopia, where people have limited access to modern health care, without understanding their chemical composition or the health hazards. Thus, this study was aimed at quantifying the amount of heavy metals in medicinal plants that are found in the Simada district, Ethiopia. A 0.5 g of powdered samples was digested using a mixture of HNO₃ and HClO₄ acids. The results indicated that the mean concentration of heavy metals in C. macrostachyus, C. africana, O. europaea, C. spinarum, C. anisata, C. aurea, and M. arbutifolia ranged from 131.2 ± 4.5 to 236.2 ± 9.1, 30.6 ± 1 to 48.7 ± 0.7), 21.3 ± 2.1 to 114.2 ± 8.4, 31.7 ± 4.5 to 154.4 ± 11.2, and BDL to 6.3 ± 0.3 for Fe, Zn, Cu, Mn and Pb, respectively. Cd was below the detection limit. Except the concentration of Cu in C. spinarum (114.25 mg/kg), the concentrations of other heavy metals were below WHO values. THQ and HI levels are less than unity, demonstrating that heavy metals have no substantial non-carcinogenic effect on users. Similarly, the carcinogenic risk (CR) values were less than tolerable limits (10–6), showing that ingesting medicinal plants in the study area did not pose any carcinogenic health risk.