Fluoride in groundwater from high-fluoride areas of Ghana and Tanzania

Abstract

Naturally high concentrations of fluoride are found in groundwater from many parts of the
\nworld, including Africa, and can have an important impact on human health. Chronic ingestion
\nof high concentrations gives rise to dental fluorosis and in extreme cases, skeletal fluorosis.
\nWhile not life-threatening, these can impair quality of life and affect livelihoods, particularly in
\nrural areas. They also pose a considerable constraint on groundwater development. As donors
\nbecome increasingly concerned over groundwater-quality issues, groundwater-development
\nprojects may be halted through concerns over excessive fluoride concentrations. Fluoride
\nproblems tend to be more prevalent in the more arid parts of the world, where water is already a
\nscarce resource.
\nGroundwater fluoride concentrations have been investigated in two study areas in Africa: the
\nBolgatanga area of northern Ghana (Upper East Region) and the Tabora-Singida areas of central
\nTanzania. Both study areas have notable groundwater fluoride problems, with Tanzania being
\nparticularly badly affected. Fluoride concentrations were found to exceed 20 mg L–1 in central
\nTanzania and 4 mg L–1 in northern Ghana. Both these extremes are in excess of the WHO
\nguideline value for fluoride in drinking water of 1.5 mg L–1. In Ghana, 23% of samples analysed
\nexceeded the WHO guideline value, while in Tanzania 57% were in excess. Dental fluorosis is
\ncommon in both areas, particularly in children, and is clearly related to the water supply.