Vinte e quatro meses de heterocontrole da fluoretação das águas de abastecimento público de Pelotas Rio Grande do Sul Brasil

Abstract

The aim of the present study was monthly evaluation of fluoride levels in the public water supply in Pelotas, Rio Grande do Sul State, Brazil, and the validity of forming external control groups. Pelotas was divided into 16 geographic regions, including the three public water tre a tmentstations. Water samples were collected from November 1999 to October 2001. Two samples were drawn from each region . Samples were sent to the Fluoride Health Surveillance La boratory at Un i versidade do Vale do It a jaí. Fluoride analysis used an electrometric method(Orion 920 A/El e c t rometer Orion 9609). After 24 months , 764 samples were collected, de monstrating a discontinuity in the fluoride leve l s. T h e re was an increase in the number of samples with an ideal concentration of fluoride. How e ver, several points with exc e s s i ve fluoride leve l s (> 0.9ppmF) also appeare d . Based on these results it was concluded that external control is essential for monitoring fluoride levels in the public water supply.