Submitted to: Journal of Food Composition and Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2003
Publication Date: 10/1/2003
Citation: Miller-Ihli, N.J., Pehrsson, P.R., Cutrufelli, R.L., Holden, J.M. 2003. Fluoride content of municipal water in the united state: What percentage is fluoridated?. Journal of Food Composition and Analysis. 16:621-628
Interpretive Summary: A study was conducted to evaluate the fluoride content of nationally representative water samples. Samples collected 3 times during the year from 16 cities in 11 states were analyzed. Because municipalities determine locally if they want to fluoridate their public water supply, the distribution of fluoride is bi-modal (either no detectable fluoride is seen or approximately 1 ppm is present). Fluoride has both beneficial and negative health impact with recent concerns focusing on fluorosis when too much is ingested. This study showed that approximately 40% of the samples analyzed showed fluoridation with an average concentration of 1 ppm. This work is important because it demonstrates the importance of evaluating the distribution of fluoride in the water supply. Epidemiologists and health professionals can use these data to support requests for further characterization of the US municipal water supplies. These data also highlight the challenges associated with generating mean values which are intended to be representative of national consumption when a bi-modal distribution is observed for the analyte of interest.
Technical Abstract: Recently a study was conducted to look at the trace element content of municipal waters sampled around the United States. This was a collaborative project defined by representatives of the Nutrient Data Laboratory and the Food Composition Laboratory of the United States Department of Agriculture. As part of the study, the fluoride content of nationally representative water samples was measured since water is one of the principal sources of fluoride in the U.S. diet. Samples were analyzed using a separate reference electrode and ion selective electrode with TRIS II buffer. The calibration range was from 0.5 to 3.0 ppm. Accuracy of the method was validated by analyzing NIST SRM 2671a Fluoride in Freeze-Dried Urine. Results from the municipal water study clearly showed that the distribution of fluoride in U.S. municipal waters is bi-modal. That is to say, because of the fact that ambient levels are typically extremely low, the concentration of fluoride is basically quantized. Either the water is fluoridated and contains approximately 1 ppm of fluoride or it is not fluoridated and typically has an undectable fluoride concentration. This study revealed that approximately 40% of the water samples from this nationwide sampling were fluoridated with a mean concentration of 1.01 +/- 0.15 ppm