## 3 Results and Discussion
### Metal Source Apportionment  
The earth metals were present in significantly higher amounts in the conoctions than in water, and it was a similar case with some essential elements, including Al, Fe, and Zn (Table S2). The earth metals exist abundantly in the earth's crust, and their existence in the conoctions was probably from the plant material used in preparing the conoctions. Additionally, [PERSON] in 2013 observed that the addition of salts, including CaSO\({}_{4}\), NaCl and KMnO\({}_{4}\) to herbal conoctions is common among traditional practitioners, which could have contributed to the high concentrations observed in the conoctions compared to the tap water [33]. Traditional practitioners are reported to use KMnO\({}_{4}\) to treat some sexually transmitted infections [34]. For Al, Fe, and Zn, more research is needed to identify the true source between the steaming pots and the plants used in the preparation of the conoctions. Interestingly, Zn was not detected in tap water but existed in the conoctions albeit within the drinking water guideline limits. Currently, we suspect that these metals may have leached from the pots as most practitioners either used cheap Al pots or homemade Zn pots.  
On the other hand, the concentrations of trace metals (Ni, Cr, Co, As, Cd, and Pb) were not significantly different from those of tap water, implying that their existence in conoctions was entirely due to the tap water. Previous studies on tap water have identified leaching from water pipes as a main contributor of metals such as As, Cd, Cr, Pb, Cu, Fe, and Zn [35; 36; 37]. However, in their studies, the metals remained within the permissible limits, which is in contrast with the results of As, Cd, Co, Cr, Ni, and Pb in the current study. Concentrations within the WHO guideline limits for drinking water have also been reported in Egypt [38], Turkey [39], Kenya [40], and Iran [41]. Importantly, Pb has always been associated with service connections and plumbing in buildings and the period in which the water has been in contact with the lead-containing materials. In this regard, the WHO recognizes that Pb concentrations may be higher but not more than 0.050 mg L\({}^{-1}\) in piped water [32], which is true for most studies in the literature. However, in the current  
study, its average concentration was 0.131 mg L\({}^{-1}\). A study in Thailand also reported concentrations of Pb that were higher than guideline limits, but their reported value of 0.0250 mg L\({}^{-1}\) was still less than 0.050 mg L\({}^{-1}\)[42]. For Ni, its existence has also been blamed on the chemicals used in water purification [32]. The elevated concentrations of the trace metals in the current study, therefore, raise the issue of leaching from potentially corroded pipes, which could be a sign of ailing plumbing systems in the two important cities of South Africa. For example, the area in downtown Johannesburg where the traditional practitioners operate is characterized by old buildings, some of them in a dilapidated state. The occurrence of trace metals in the drinking water should be of serious concern since drinking water is a component of many food sources. Trace metals have been detected at elevated levels in other aqueous herbal concoctions in South Africa [43], while in solid herbal concoctions, they have been reported within limits with only a few exceptions [44].