Effect of drinking waters of high fluorine content on the urinary fluoride level.

The urinary fluoride level has been studied in 307 subjects consuming drinking waters of different fluoride concentrations. The urinary fluoride level was found to increase with the fluoride content of the drinking water. The urinary F level of the population group drinking water of optimum fluoride concentration was 1.14 mg of fluoride per litre. Thus, in regions where the drinking water contains an insufficient amount of fluoride, the fluoride content of domestic salt must be adjusted so as to ensure an about 1.14 mg/litre urinary F level of the population.