The Codex Alimentarius Commissions recommends that there should be no contaminants in water including toxic by-products like bromate. There are a number of countries that permit bromate in drinking water at levels from three to ten micrograms per litre (mg/L) of water. However, in India the Bureau of Indian Standards (BIS) that sets standards for water, has limited levels of bromate in packaged drinking water to a maximum of 0.01 mg/L.
It is important to understand that bromate is not present in water naturally. It is formed as a reaction when ozone is used as a reagent to disinfect water. Conversion of bromide to bromate on ozonation depends on the presence of natural organic matter, pH and temperature. Before water is packaged companies disinfect it by using ozone which transforms the bromine into bromate ions. Some amount of bromate can also be formed by photo activation where sunlight causes liquid or gaseous bromine to react to oxygen which leads to the formations of bromate in the water. Since bromate has been termed a chemical that could be possibly carcinogenic it is important to ensure that levels of bromate in water are within permissible limits.
Recently samples of packaged drinking water tested in Mumbai showed the presence of bromate. This prompted the Bureau of India Standards to enforce a mandatory test for bromate in packaged drinking water. Even if the licensed and known companies carry out the water testing for bromates, it is the unlicensed and illegal water bottling plants that must be brought under the scanner. Most consumers are of the opinion that bottled drinking water is safe and so they do not suspect that the some packaged water could be full of contaminants and toxins.
According to BIS specifications water needs to be tested according to the ‘ion exchange liquid chromatographic method using ISO Method 15061 2001 as that can test even very low levels of bromate. Earlier very small amounts of bromate in water would go undetected but with new methods like ‘ion chromatography with conductivity detection’ even very small amounts of bromate ions can be detected in water. It is now mandatory for all companies who are involved with the packaging drinking water to get the samples of water tested at the recommended prescribed intervals to ensure the absence of bromides.
Bottling plant owners must get the water tested according to the chromatographic system as that can detect even very small amounts of bromate accurately. If bromate cannot be traced to the recommended level of 0.01 mg/L then the test cannot be considered to be fully successful. Through the chromatographic system ground water, surface water and even waste water can be tested.