The accuracy of fluoride measurement in water and its implications for water fluoridation

The accurate measurement of the fluoride concentration in water is an essential prerequisite to stay within the allowable dosing tolerances required by the South African water fluoridation legislation. In the absence of reliable error estimates for fluoride measurement in natural water samples, a study was conducted utilising data from interlaboratory comparison studies conducted by the CSIR, the SABS and MEDUNSA. This study shows that: • natural samples are more difficult to measure than synthetic samples; • technology advances over the last 25 years did not reduce the measurement error significantly; • all analytical methods suffer to some extent when natural samples are analysed; and • the measurement error will have to be appreciably reduced if the legal requirements of the pending water fluoridation are to be met.