Bromate formation in bromide-containing waters irradiated by gamma rays

The formation of bromate, a classified potential carcinogen, is of great concern when disinfection processes are used for treating high-bromide drinking waters. Bromide-containing aqueous solutions with various additives were irradiated by Co-60 gamma source. With a 2.0 kGy irradiation of N2O-saturated solutions at initial bromide concentrations of 180.2 mu g l(-1), 416.9 mu g l(-1), 663.1 mu gl(-1) and 823.9 mu gl(-1). 79.5%, 84.0%, 87.3% and 88.3% of bromide ions were transformed to bromate, respectively. Addomg CO32-/HCO3- or NO3- ions into N2O-saturated bromide solutions, the amount of bromate ions formed decreased with increasing concentrations of the additives. On the other hand, the bromate concentration was all below the detection limit of 1 mu gl(-1) whenever N2O was not added to quench e(aq)- and .H. The results indicated that gamma-rays irradiation could be used as a disinfection process, instead of ozonation, to comply with upcoming more stringent regulations, especially in waters containing high concentrations of bromide.