Fluoride Contamination in Drinking Water in the Rift Valley, Kenya and Evaluation of the Efficiency of a Locally Manufactured Defluoridation Filter

A survey of the amount of Fluoride in ground, potable water in Njoro division, Nakuru district and some parts outside the division was conducted to determine the concentration of Fluoride the residents are consuming through water. This area is situated in the Great Rift Valley of East Africa, which is known to have high levels of the anion in the water due to the volcanic eruptions that occurred thousands of years ago. Water samples were collected from 18 sources and analysis was performed using an ion selective electrode (ISE). Concentration levels ranged from 0.78 mg/L (river water) to 11 mg/L (borehole water). A locally manufactured de-fluoridizer made of charred bone particles was evaluated for its ability to remove F- from water. Generally, more than 99% F- was removed by the de-fluoridizer. Apart from removing the target anion, F-, some metal cations are also removed at various extents, while others are added into the water apparently from the bone char through leaching. (Journal of Civil Engineering, JKUAT: 2002 8: 79-88