Reference values of renal excretion of fluoride.

Fluoride was measured in the spontaneous urine of a group of persons (n = 397) occupationally non-exposed to fluoride. At a concentration less than 2 . 10(-4) g/kg fluoride in drinking water the mean fluoride excretion in urine is 0.61 mg/l F with an upper limit of 2.00 mg/l F. The 95-percentile of normal fluoride excretion is 1.0 mg/l F. By correcting the values for the specific gravity of 1.024 the mean value of the fluoride excretion is 0.74 mg/l F with an upper limit of 3.9 mg/l F. The measured pH and calcium contents had no influence on the fluoride excretion.