Effect of domestic water filters on water fluoride content and level of the public water supply in Bauru, Brazil.

PURPOSE: The purpose of this study was to evaluate the extent to which domestic, activated carbon water filters remove fluoride from water and to analyze the fluoride level of the public water supply in Bauru, province of São Paulo, Brazil. METHODS: Samples of filtered and nonfiltered tap water were collected from 180 houses in 9 different regions in the city; each served with its own water treatment facility. Fluoride was analyzed with the ion specific electrode (Orion 9609). RESULTS: Of the filters presented in the 180 houses, only 12 removed fluoride from water, either totally (3) or partially (9). Water fluoride concentrations in 6 regions were within the acceptable range (0.5 to 1.0 ppm). Overfluoridation was observed in 1 area, and underfluoridation was seen in 2 areas. CONCLUSIONS: Most domestic activated carbon filters did not remove fluoride from water. Children who drank filtered water did not need fluoride supplementation. As has been shown in other studies, the fluoride level in the public water supply in some regions of Bauru was not adequate on the day analyzed.