Evaluation of human exposure to metals from some commonly used bathing soaps and shower gels in Nigeria.

The concentrations of nine metals (Cd, Pb, Ni, Cr, Co, Cu, Fe, Mn and Zn) were measured in selected brands of medicated, moisturizing and skin-lightening soaps and shower gels with the aim of evaluating the human health risk associated with metal exposure from the use of these products. The concentrations of metals in these products were determined by means of atomic absorption spectrophotometry after sample digestion with a mixture of acids. The concentration ranges of the metals in the bathing soaps and shower gels were found to be: <0.06-3.4 μg g-1 for Cd, <0.09-26.5 μg g-1 for Pb, <0.12-43.0 μg g-1 for Cr, <0.06-32.5 μg g-1 for Ni, <0.06-40.5 μg g-1 for Cu, <0.12-8.0 μg g-1 for Co, 61.8-4000 μg g-1 for Fe, <0.09-29.5 μg g-1 for Mn, and 25.5-1000 μg g-1 for Zn. The systemic exposure dosage values for these metals obtained from the application of these brands of bathing soaps and shower gels were below their respective provisional tolerable daily intake/or recommended daily intake values. The margin of safety values obtained for the metals were greater than 100 which indicated that there was no significant risk to the users of these brands of bathing soaps and shower gels, except in the case of Co.