Accuracy of Drinking Water Fluoride Concentrations in South Africa

Objective: Comparison of drinking water fluoride (F) concentrations of municipalities with F measurements by the Oral and Dental Research Institute (ODRI). Methods: Questionnaires about recorded F levels and bottles for water sampling was posted to 281 municipalities from which a potential of 870 water supply authorities. Results: 870 bottles were distributed and 586 containing water samples were returned (response rate = 67%). The responding municipalities supplied F levels for 146 samples, to compare with the ODRI determined F values. No significant difference in F levels between the municipal and ODRI determinations were found in 18% (N = 27) of cases. In 56% of samples municipal F values were higher than ODRI determinations. Approximately 23% of which had municipal values that were more than a 100% higher than ODRI determinations. In 25% of samples municipal values were lower than ODRI determinations and 8% of values were more than a 100% lower than ODRI determinations. The majority (75%) of responding distribution authorities did not supply F values. Conclusions: Great variations exist between drinking water F levels supplied by municipalities and independently (ODRI) determined values that can have a major impact on supplementary fluoride dosage. A definite need exists for standardisation and/or centralisation of fluoride determinations to ensure accurate values.