Bromate

The bromate anion, BrO−
3, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, (NaBrO
3), and potassium bromate, (KBrO
3).

Bromates are formed many different ways in municipal drinking water. The most common is the reaction of ozone and bromide:

Electrochemical processes, such as electrolysis of brine without a membrane operating to form hypochlorite, will also produce bromate when bromide ion is present in the brine solution.

Photoactivation (sunlight exposure) will encourage liquid or gaseous bromine to generate bromate in bromide-containing water.

In laboratories bromates can be synthesized by dissolving Br
2 in a concentrated solution of potassium hydroxide (KOH). The following reactions will take place (via the intermediate creation of hypobromite):

Human health issues

Bromate in drinking water is undesirable because it is a suspected human carcinogen. Its presence in Coca Cola's Dasani bottled water forced a recall of that product in the UK.