For many years now the issue of excess fluoride in drinking water or groundwater has been a great problem in many countries. Consumption of such water has health effects such as dental and skeletal fluorosis. The occurrence of fluoride in water depends on the nature of the rock and the occurrence of fluoride bearing rock. Waters with high fluoride content are found mostly in calcium-deficient ground waters in many basement aquifers such as granite and gneiss, in geothermal waters and in some sedimentary basins. The WHO has set the limit for acceptable fluoride levels in water to be 1.5 mg/L. Water containing fluoride beyond this limit is harmful for consumption. In Kenya, the rift valley region is the most affected with waters with excess fluoride. Dental fluorosis is a common problem in this area due to consumption of water with excess fluoride.
Since water is necessary for survival, people living in areas experiencing excess fluoride concentrations in water have to come up with alternative methods to get water with less fluoride. One of these methods is defluoridating the water. Defluoridation can be accomplished through various defluoridation methods. These methods vary in terms of cost, materials required, efficiency and technology required. Also some of these methods can be used on at the source of water while others can be used both at the source and point of use of water. The choice of which method to use depends on various factors such as fluoride concentration of the water, efficiency of the method, how well the community can operate the machinery involved. In Kenya, there is specific set guideline on which method to use. However, the catholic diocese of Nakuru has a water quality programme which develops filters that use bone char to defluoridated water. These filters are made available to the community at affordable prices.


Lucy Wandia Kinyua.pdf1.45 MB