High fluoride concentration in drinking water causes widespread health problems to many
residents in the Rift Valley region of Kenya that encompass dental and skeletal fluorosis
(Kaseva, 2006). The excessive fluoride in groundwater is a serious water quality problem. The
WHO and national standard (ES 261:2001) permit only up to 1.5 mg/L of fluoride whereas the
concentration of fluoride in groundwater in the Rift Valley Region is much higher. Use of HAP
provides a potential method of fluoride removal through adsorption. Therefore, there is need to

The study is aimed at establishing and understanding properties of Black Cotton soil that
compromise structural and serviceability limits of flexible pavements. This will be achieved
by sampling Black Cotton soil from the area of study and undertaking laboratory
investigations. Results obtained will be analysed and conclusions derived that ultimately link
the soil’s characteristics to these defects.