Monitoring of fluoride content in bottled mineral and spring waters by ion chromatography

Water and mineral components dissolved in it play an important role in nutrition. Fluoride in drinking water, besides arsenic and nitrate, is reported as chemical causing widespread health effects in humans as a consequence of exposure when present in excessive quantities. Due to significant impact of fluoride on human health and differentiation concentration in water depending on many chemical and geological factors, we decided to establish the fluoride content in Polish bottled waters. In this study, forty commercially available mineral and spring bottled waters, sold under various brand names in Poland have been analysed. The used ion chromatographic method was validated in the range 0.04-2.0 mg L-1 and verified with certified reference material. The obtained results were compared with contents declared by producer, some world standards and results reported by other investigators. Validation of the method showed a good within run repeatability, stability and accuracy. The limit of detection (LOD) in our research was found to be 0.016 mg L-1, while the limit of quantification amounts to 0.049 mg L-1. Content of fluoride in 40 studied bottled waters was higher in mineral (24 samples, 0.302 +/- 0.291 mg L-1) than in spring waters (16 samples, 0.159 +/- 0.072 mg L-1), but only in one tested mineral water (No 39, Java, with pH 9.16) slightly exceeded the permission level for infant consumption (1.5 mg L-1) and amounted to 1.566 +/- 0.0188 mg L-1. No bottled water exceeded the permitted norm. The measured fluoride concentration was in line with these declared on product label, it means difference in less than +/- 20%, only in 47% of tested waters. The concentration of fluoride was negatively correlated with pH values of waters. In comparison to other countries, the Polish bottled waters characterized low content of fluoride (mean 0.240 +/- 0.237 mg F-L-1).