[Evaluation of the fluoride concentration and consumption of mineral water]

Considering that water is an importance source of fluoride intake, and that the consumption of mineral water and prevalence of dental fluorosis have been increasing, the aim of this study was to evaluate the consumption of mineral water and its fluoride concentration.

The study was performed in residential districts of the municipality of Bauru, State of São Paulo, by means of stratified sampling via clusters. Each cluster corresponded to one residential block. For randomization purposes, the residential blocks were numbered within the 17 districts established by the city plan. One thousand homes were thus visited. Mineral water samples were collected using previously labeled 50 ml plastic flasks. Fluoride analysis was done using an ion-sensitive electrode (Orion 9609), after buffering using TISAB II. Information on the consumption of mineral water was obtained by means of applying a questionnaire.

Around 29.72% of the city's population was consuming mineral water. In the 260 samples analyzed from 29 different brands of water, the fluoride concentration ranged from 0.045 to 1.515 mg/l. For one brand, the label stated that the fluoride concentration was 0.220 mg/l, but analysis revealed a concentration of 1.515 mg/l. Moreover, some brands did not specify the fluoride concentration on the label and, for these, the analysis showed concentrations ranging from 0.049 to 0.924 mg/l.

The results demonstrated wide variation in fluoride concentrations and reinforce the importance of the control of such waters by the sanitary surveillance agency.