Magui, Agiza Shillah2024-09-272024-09-272024-04https://ir-library.ku.ac.ke/handle/123456789/28920A Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science in Chemistry in the School of Pure and Applied Sciences of Kenyatta University, April 2024 1. Ruth Wanjau. 2.Ram ManoharThe desire to be more attractive by many people has increased demand for cosmetic products over the last few decades around the world. Today, the use of facial cosmetics has become routine body care for millions of women around the world and in Kenya as well. Facial cosmetics are common in all classes of society from the lower class through the middle class to the upper class. The demand for these products continues to rise even though issues about their safety are yet to be properly addressed. Some of these cosmetics products have higher levels of heavy metals than the allowed level tolerable by the body. These metals include lead, cadmium, nickel, chromium, and many others. Permissible levels of lead by WHO is 10 ppm while those of Cd, Ni, and Cr are 0.3 ppm, 200 ppm, and 50 ppm respectively. Permissible levels by KEBS for Pb, Cd, Ni, and Cr are 2.0 ppm, 0.1 ppm, 200 ppm, and 50 ppm respectively. High levels of lead cause skin problems, and cancer among others. Cadmium, nickel, and chromium also have negative health effects such as causing cancer, respiratory diseases, and damage to several human organs. It is based on this background that this study was conducted to find out the presence and concentration of some of the heavy metals in facial cosmetics particularly in lipsticks and face powders. Heavy metals that were studied are cadmium, lead, nickel, and chromium. Lipsticks and face powders were obtained from supermarkets and shops within Nairobi city in three batches A, B, and C. This study adopted an experimental research design where the atomic absorption spectroscopy technique (AAS) was employed in assessing levels of lead, cadmium, chromium, and nickel in sampled brands of lipsticks and face powders in Nairobi City, Kenya. Data obtained was analyzed by one-way ANOVA at a 95% confidence level using SPSS version 23 for Windows. Significant differences were taken at p<0.05. Lead levels in lipsticks ranged between 0.0057 to 0.0082 ppm while those in face powders ranged between 0.0013 to 0.0066 ppm. The mean concentrations of lead in batches A, B, and C of lipsticks and face powder were all statistically significant. The concentration of cadmium in lipsticks was below the level of detection while in face powders the levels ranged from 0.0009 to 0.0048 ppm. The mean levels of cadmium in batches A, B, and C of face powders were not statistically significant. The concentration of chromium in lipsticks was below the level of detection. The level of chromium in face powders ranged from 0.0010 to 0.0029 ppm. These mean levels were not statistically significant. The levels of nickel in lipsticks ranged from 0.0006 to 0.0031 while in face powders, it ranged from 0.0041 to 0.0217 ppm. The mean levels of nickel in lipsticks were statistically significant. Levels of Pb, Cd, Cr, and Ni in brands A, B, and C of lipsticks were significantly different. Levels of Pb, Cd, Cr, and Ni in brands B and C of face powder were also significantly different while the levels in brand A of face powders were not statistically significant. The levels of lead, nickel, cadmium, and chromium in both lipsticks and face powders in the brands analyzed were lower than the maximum allowed level set by both WHO and KEBS, an indication that the lipsticks and face powders are potentially safe for use. However, the significant differences that were noted between some samples pose a risk of combined and continuous usage. There is therefore need to indicate levels of heavy metals on labels of lipsticks and face powders by manufacturers to enable users to make informed choices of these products.enThesis