Intake of Lead, Cadmium and Mercury in Kaolin-eating: A Quality Assessment

Clay-eating or kaolin-eating (geophagy or geophagia) is a global practice that exists among humans as well as numerous animal species. Geophagy has been studied by anthropologists, geologists, nutritionists and ecologists in present and traditional cultures from areas across continents, including present-day Arizona and California, Central and South America, Sweden and Sardinia, sub-Saharan Africa, Indonesia and Australia. In 2002, the European Union alerted the Cameroon Ministry of Public Health that kaolin carried from Cameroon to Europe had abnormally high amount of lead (Pb) at levels a 100 times higher than the maximum permissible level. This kaolin that is sold on the several markets is mined from different sources, some locally and others from Nigeria. To investigate this, markets of wholesale dealers in kaolin were visited in five districts selected in a manner as to represent the entire territory. Six samples of 1 kg each were then randomly selected and bought. A total of 30 kg was collected from all the districts. The sources of procurement were also visited and 24 samples of approximately 300 g each were collected from all the harvesting sites. Analytical methods for flame spectroscopy were used and statgraphic for data analysis. The results show that all kaolin is contaminated not only with Pb but Cd and Hg as well. The differences in Pb content at district levels is statistically significant p = 0.02 (p<0.05) while no significant difference exist as regards the origin of kaolin or source of procurement (p = 0.53).