Toxicological study and health risk assessments of heavy metal contents of some commercially sold beauty soaps in Owerri, Imo State, South East, Nigeria

It has been shown that heavy metals toxicity to humans is as a result of long term or high level exposure to pollutants common in the environment including the air, water, food and numerous consumer products such as the cosmetics and toiletries. In this study, heavy metal contents of some commercially sold beauty soaps in Owerri Imo State were determined. These items were purchased from various supermarkets at different locations within Owerri capital city. The cosmetics were analyzed for heavy metals (chromium, cadmium, lead, mercury and nickel) after digestion with concentrated acids HNO3: HClO4: H2SO4 The concentrations of the selected toxic heavy metals were determined in duplicate using an atomic absorption spectrophotometer. The samples analyzed contained a detectable amount of the metals of interest. The concentration of the heavy metals in the samples ranged from 0.056-0.092 ppm (Cr), 0.083-0.183 ppm (Ni), 0.034-0.080 ppm (Cd), 0.043-0.104 ppm (Pb) and 0.013-0.022 ppm (Hg) respectively. The results showed that toxic heavy metals were present in beauty soaps sold in Owerri, Imo State, Nigeria, and the concentrations of the toxic metals were lower than the WHO limit. The estimated chronic daily intakes where lower than the minimum tolerable daily intakes (MTDI) for the various metals. The estimated hazard quotient (HQ<1) shows the concentration of the metal may not cause immediate significant health problem. Hazard index (HI) was < 1 (Table 5) indicating that consumers are found to be safer. The cancer risk of chromium was found to be 1.13E−4 in sample C, which is lower than the negligible range, indicating no cancer risk (CR). It is obvious from the present study that the use of some beauty soap products sold in Owerri exposes users to low concentrations of toxic heavy metals which could constitute potential health risk to users since it has been known that heavy metals can accumulate in the biological system over time and are known to induce skin problems or diseases such as cancer. Further research to better understand the sources of heavy metals in beauty soap products is recommended.