Determination of Fluoride Levels in Groundwater from Selected Communities in Adamawa State, North East Nigeria

Fluoride in drinking water at elevated concentrations is a recognised cause of dental and skeletal fluorosis, conditions that have been documented in several communities reliant on groundwater in the North East geopolitical zone of Nigeria. This study determines fluoride concentrations in groundwater obtained from boreholes and hand-dug wells in five communities across Adamawa State and assesses associated public health risks. Water samples were collected in triplicate from each sampling point and analysed for fluoride using the ion-selective electrode method. Additional physico-chemical parameters including pH, electrical conductivity, total dissolved solids, and hardness were also measured. Results show that fluoride concentrations in several communities exceed the WHO guideline value of 1.5 milligrams per litre, with maximum recorded values of 3.8 milligrams per litre in deep boreholes from the Madagali area, a region underlain by fluoride-rich basement complex rocks. Hydrogeochemical indices suggest that water-rock interaction and evaporation processes are the dominant controls on fluoride enrichment. Hazard quotient calculations indicate non-carcinogenic health risks for children and adults consuming groundwater from affected wells. This study recommends the implementation of appropriate defluoridation treatment technologies, the provision of alternative water sources for high-risk communities, and the integration of fluoride surveillance into routine water quality monitoring programmes in the state. Keywords: fluoride, groundwater, Adamawa State, health risk, water quality