Background
Eucalyptus species have been used for the remediation of mine tailings dams in Zimbabwe. However, a traditional medicinal remedy (TMR) for the treatment of mild acute respiratory infections, such as common cold and flu includes the use of Eucalyptus leaves. Objectives: The
Conclusions
Concentrations of PTEs in leaves and leaf extracts of E. grandis were very low. However, TMRs should not be prepared from medicinal plants growing on metalliferous environments, such as mine tailings dams, due to the presence of cumulative toxins such as Cd and Pb. Further studies are needed to investigate the effect of various boiling times and should include arsenic in the studied PTEs. Competing interests: The authors declare no competing interests for this study.
Methods
Mine tailings and leaves of E. grandis were randomly collected at a gold mine tailings dam between April and June 2019. They were digested for laboratory analysis using standard analytical methods. Leaves were boiled in water for 10 minutes to prepare the TMR as practiced by the local community. The concentrations of PTEs were determined spectrometrically. Significant differences between PTEs in young and mature leaves were determined by analysis of variance.
Results
Mine tailings were acidic (pH 4.52±0.62) with very low content of organic matter (0.02%) and contained PTEs in increasing concentrations of cadmium (Cd) < nickel (Ni) < lead (Pb) < chromium (Cr) < copper (Cu) < zinc (Zn) (n = 27). Mature leaves of E. grandis had higher concentrations than young leaves for Cr, Pb and Zn (p <0.05) which were lower than permissible limits in medicinal plants. Overall, boiling leaves in water for 10 minutes resulted in low extraction of PTEs (< 20%). Participant consent: Obtained. Conclusions: Concentrations of PTEs in leaves and leaf extracts of E. grandis were very low. However, TMRs should not be prepared from medicinal plants growing on metalliferous environments, such as mine tailings dams, due to the presence of cumulative toxins such as Cd and Pb. Further studies are needed to investigate the effect of various boiling times and should include arsenic in the studied PTEs. Competing interests: The authors declare no competing interests for this study.