Levels of Selected Heavy Metals in Aloe Vera Branded Skin Cosmetics
Moraa, Onyambu Zipporah
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Over years, it has been reported that long term exposure of heavy metals such as mercury(Hg), lead (Pb) and cadmium (Cd) would result into numerous dangers among these; being carcinogenic, sterility and behavioural abnormalities. While there are various sources of heavy metals, both herbal (those made from Aloe vera, neem and olive oil among others) and synthetic cosmetics and toiletries are equally feared as, would be sources especially if levels are above those set by the World Health Organisation (WHO). In China for example, 60 percent of cosmetics and other product were recalled because of the presence of heavy metals in levels toxic to human in the products. In particular, fears arise when labels on these products fail to indicate either the presence or the levels of heavy metals despite certification by bodies such as the Kenya Bureau of Standards (KEBS) in Kenya. While the use of heavy metals as deliberate cosmetics ingredients may have been given attention, heavy metals could still be found as impurities. As such dermal contact with some water-soluble toxic elements and/or their compounds would cause absorption through a moist skin and hence be toxic. The aim of this study therefore was to determine the concentration of Hg, Pb, Cd, Zn, Mn and Cr in skin cosmetics; lotions, creams and soaps made from Aloe vera. Cosmetics were purposively sampled from major supermarkets in Nairobi County. All the heavy metals under study were quantified using atomic absorption spectroscopy (AAS) except for Hg where cold vapour atomic absorption spectroscopy (CV-AAS) was employed. The mean levels (ppm) of heavy metals were found to fall in the following ranges:-In lotions, Hg (0.01±0.01-0.03±0.01), Pb (0.06±0.02-0.63±0.19), Zn (0.02±0.01-0.04±0.01), and Mn (0.01±0.01-0.06±0.01). In creams Hg (0.04±0.01-0.11±0.01), Pb (0.03±0.01-0.68±0.14), Cd (0.02±0.01-0.06±0.01), Zn (0.11±0.01-1.99±0.01), Mn (0.02±0.01-0.10±0.01), and Cr (0.03±0.01-0.08±0.01). In soaps, Hg (0.09±0.01-0.21±0.01), Pb (0.14±0.07-0.83±0.01), Cd (0.01±0.01-0.15±0.01), Zn (0.02±0.01-0.07±0.01), Mn (0.01±0.01-0.06±0.01) and Cr (0.03±0.01-0.05±0.01). While their presence in the cosmetics can be as an impurity, these levels were below the maximum permissible limits set by WHO and KEBS, an indication that the aloe vera branded cosmetics are potentially safe for use. However, significant differences (p<0.05) of the levels of heavy metals were found between the lotions, creams and soaps posing risks of combined and continual usage of these products. There is need therefore to indicate the levels of heavy metals on the labels of these cosmetics in order to create awareness to the users. This would as well provide insight to the fears of the dangers that may result due to the combined or long term usage of these products.