Urinary fluoride levels in Saudi individuals drinking tap and bottled water

The fluoride concentration in the urine samples of 130 Saudi individuals aged 16-70 years old living in Riyadh was determined using a fluoride-specific electrode (0.9262 +/- 0.703 microg ml^-1, 0.16-4.68 microg ml^-1). There were differences in the urinary fluoride levels of the subjects. About 45.5% of the subjects had urinary fluoride less than 0.7 microg ml^-1. Conversely, 22.3% of the screened subjects had urinary fluoride levels higher than 1.2 microg ml-1; this could increase the risk of dental and skeletal fluorosis. Since drinking water is considered to be the major source of fluoride, it was measured in 88 drinking water samples. Significant correlation between fluoride in urine and drinking water was found (r = 0.4341, p = 0.0237). Bottled water had significantly higher fluoride content (0.5205 +/- 0.322 microg ml^-1) than tap drinking water (0.1046 +/- 0.0447 microg ml^-1). About 67% of the screened water samples had low fluoride concentrations (< 0.3 microg ml^-1) which is far below the recommended level for caries control.