Assessment of the Impact of Groundwater Fluoride on Human Health: A Case Study of Makindu District in Kenya

Abstract

Assessment of human exposure to the naturally occurring fluoride in groundwater in Kenya has not being exhaustive. This study investigated the extent of human exposure to fluoride and its impact on human health in Makindu District, and evaluated the potential risk of using ground water contaminated by fluoride ion (F- ). The study used an ex post facto design and the data collection tools used were interviews, questionnaires, key informants and observation. Water from three boreholes and a spring in the study areas was analysed for pH, Total Alkalinity, Total Hardness, and concentrations of Fluoride, Chloride, Sulfate, Iron, Calcium, Magnesium, Sodium and Potassium. The collected data was analyzed using the Ms-Excel and Statistical Package for Social Sciences (SPSS). The results show that majority of the respondents relied on tap water from springs. Raw water from Makindu Spring, the main source of drinking water for Makindu Town, had fluoride concentration of 1.1 mg/L, which is below the WHO maximum allowable value of 1.5 mg/L. All the three boreholes covered during the study had fluoride concentration above the WHO maximum allowable value. This implied that the population that relied on boreholes as a source of water was exposed to health risk associated with high fluoride. 38.4% and 33.3% of the respondents, respectively from Kiboko Location and Makindu Location, had moderately to severely mottled enamel, an indication of the impact of fluoride in water. It is recommended that defluoridation systems should be introduced and that alternative sources of water be developed to mitigate the impacts of high fluoride water to the local communities.