Health risk Assessment for Bromate in Bottled Drinking Water and Natural Mineral Water

Abstract

         Bromate is mutagenic and possibly carcinogenic to humans. It may be found in drinking water as by-product of water disinfection with ozone. The maximum limit for bromate in drinking water by WHO is 10 g/L. Despite its toxicity, no regulatory limit has been estsblished in Thailand. This study was conducted to encourage the establishment of regulatory measure to protect consumers from bromate. In this study, an ion chromatographic method for determination of bromate in drinking water was developed and validated, concentrations of bromate in bottled drinking water and natural mineral water were determined, and finally, the health risk from bromate in these waters was estimated. Results of the validation study showed that the performance characteristics of the method were fit for the intended use with the LOD and the LOQ of 1 and 3 g/L, respectively. By using this method, 100 samples of bottled drinking water and 54 samples of local and imported natural mineral water were analyzed. The results showed that 20% (20 samples) of bottled drinking water and 39% (21 samples) of natural mineral water were ozonated and contained bromate in the range of <3-178 g/L and <3-133 g/L respectively, with the median of 14.9 g/L and 20.5 g/L respectively. The health risk assessment showed that the bromate levels in 65% of ozonated bottled water and 72% of ozonated natural mineral water were associated with the excess cancer risks higher than the WHO acceptable risk of 5 x 10^-5. It is recommended that the national authority establish regulatory limit for bromate to protect the consumers.