Elevated concentrations of bromate in Drinking water and groundwater from Kuwait and associated exposure and health risks

Drinking water is an important source of human exposure to bromate, an ubiquitous environmental contaminant and a suspect human carcinogen. Nevertheless, little is known with regard to bromate exposure from water produced by thermal desalination of seawater. The purpose of this study was to determine the occurrence of bromate in desalinated drinking water and groundwater from Kuwait and estimate associated exposure and health risks to consumers. In this study, 194 tap and ground water samples collected from Kuwait were analyzed for the presence of bromate and bromide (reduced form of bromine). Bromate was found in almost all tap water samples with a mean concentration of 19.6 mu g/L, which is higher than the maximum acceptable contaminant level (MCL) of 10 mu g/L. The mean concentration of bromide in tap water samples was 46.2 mu g/L. In bottled water, lower mean bromate concentration was found (2.89 mu g/L) with mean bromide levels at 76.1 mu g/L. Saline brackish water had bromate concentration at 9.48 mu g/L while bromate was not detected in saline groundwater/ well water samples. The mean estimated daily intake (EDI) of bromate by the Kuwaiti population through tap water and commonly consumed bottled water was 21.7 mu g/d and 3.21 mu g/d, respectively. Among the five age groups, 3 to 5-year-old children had the highest EDI of bromate at 15.4 mu g/d. The excess cancer risk due to ingestion of bromate in tap water was estimated to be 3.92 x 10(-4), which is approximately one order of magnitude higher than the maximum acceptable level of risk (2 x 10(-5)). This study highlights the significance of desalinated water as a source of bromate exposure.