Bromate ion is a possible carcinogen that is regulated by the US EPA at a Maximum Contamination Level (MCL) of 10 ug/L in drinking water. In order to propose an improved scientifically appropriate bromate ion MCL, a more rigorous scientific methodology is needed for determining low level dose health risks. The objectives of this research project were to measure bromate ion with oxidizing and/or reducing agents typically ingested in foods and drinking water.
The loss of bromate ion in HCl is too slow for significant reduction in the stomach. Addition of 10-5 M H2S, a gastric juice component, decreases the half-life from 153 to 14 minutes. The ingested reducing agents iodide ion, nitrite ion, and iron(II) decrease the lifetime of bromate ion in the stomach. Chlorine, monochloramine, and iron(III) have little actual effect on the lifetime of bromate ion. The measured rates and chemical details of the reactions are discussed.