Fluoride content in drinking water supplies of Riyadh, Saudi Arabia

Groundwater supplies about 34% of the total water demand for the capital city of Saudi Arabia, Riyadh. The other 66% is desalinated seawater. The fluoride level in Riyadh drinking water supplies was evaluated. Samples were collected from selected wells, treatment plants, desalinated seawater, distribution network and 19 locally produced and imported bottled water. The fluoride level in the influent to the seven groundwater treatment plants and their final product water were in the range of 0.63-1.6 and 0.23-1.1 mg/L, respectively. Blending of the plants product water with the desalinated seawater resulted in the fluoride level ranging from 0.01-0.5 mg/L in the distribution network. Ninety percent of the samples collected from the distribution network had fluoride levels less than or equal to the calculated weighted average value of 0.24 mg/L. The locally produced bottled waters as compared to 8 imported ones have shown fluoride levels in the range of 0.2-0.83 and 0.04-0.2 mg/L, respectively. In general, the fluoride level in Riyadh drinking water supplies is below the optimum recommended level of 0.7 to 1.2 mg/L. It is therefore recommended that fluoridation be considered in water treatment plants.