Assessment of metals content of widely used traditional toothbrushes in Addis Ababa, Ethiopia

ABSTRACT. Traditional toothbrushes are used by the vast majority of people who cannot afford to buy the commercial toothbrush and toothpaste. The traditional toothbrushes are generally obtained from any slim woody part of a toothbrush tree. The main purpose of this study was to determine selected metals (Ca, Fe, Mg, Al, Cu, Cr, Ni, Zn, Mn, Pb, and Cd) in traditional toothbrushes obtained from three plants including Ligustrum vulgare L., Phoenix reclinata and Olea africana, which are extensively used in Addis Ababa, Ethiopia, by using microwave plasma-atomic emission spectroscopy (MP-AES) after wet digestion. Recoveries of the metals in spiked samples varied from 90.4–107%. The overall mean concentrations determined (mg/kg, dry weight) were in the ranges of Ca (4267–36514) > Fe (131–318) > Al (81.6 –224) > Mg (45.6–122) > Zn (27.2–175) > Mn (20.1–29) > Cu (6.6–20.3) > Cr (6.7–8.9) > Ni (2.6–7.9). Analysis of variance at 95% indicated significant differences in the metals’ contents of three toothbrushes. The results indicated that the selected traditional toothbrushes are good sources of essential metals and free from Pb and Cd. Therefore, the investigated Ethiopian traditional toothbrushes are found to be safe for human use.                     KEY WORDS: Metal contents, Traditional toothbrushes, Wild privet (Ligustrum vulgare), Wild date palm (Phoenix reclinata), African wild olive (Olea africana), Ethiopia   Bull. Chem. Soc. Ethiop. 2021, 35(2), 257-272. DOI: https://dx.doi.org/10.4314/bcse.v35i2.4