Comparison of Fluoride Levels in Drinking Water in South Africa

Objective: The purpose of this study was to compare the fluoride levels as supplied by municipalities with that determined independently by the Oral and Dental Research Institute (ODRI) on drinking water samples as supplied by the various municipalities. Methods: A detailed list of the municipalities in each province was obtained. A questionnaire requesting information about recorded fluoride levels, water source, population served was posted to all of the 281 municipalities. Within these 281 municipalities 870 potential water supply authorities were identified. This resulted in 870 plastic sample bottles being sent out. Results: Of the 870 bottles 586 containing water samples were returned, constituting a response rate of 67%. Out of the 586 samples the responding municipalities supplied fluoride levels for 147, which could be used to compare the ODRI determined fluoride values with. No difference in fluoride level between the municipal and ODRI determinations were found in 26 (18%) of the compared samples. In 82 (56.5%) of the samples the municipal F values were higher than the ODRI determinations. In 33 (40%) of these the municipal value was more than a 100% higher than the ODRI determination and the remaining 49 (60%) were between 0 and 100% higher. The municipal values were lower than the ODRI determinations in 37 (25.5%) of the samples. Of these lower values 10 (27%) of the municipal determinations were more than a 100% lower than the ODRI values while the remaining 27 (73%) of the municipal values were between 0 and 100% lower than the ODRI determinations. Conclusion: The majority (75%) of responding municipalities did not supply fluoride values. Great variation exist between the drinking water fluoride levels as supplied by municipalities and the independently (ODRI) determined values. A definite need exists for the standardisation and / or centralisation of fluoride determinations to ensure consistency.