High toxin levels found in city's bottled water

Industry Says Ground Water May Be To Blame

High levels of certain carcinogens were found in bottled drinking water samples in Mumbai, according to a study conducted by the Bhabha Atomic Research Centre (BARC) at Trombay .

A BARC team of four scientists checked 90 samples from 18 brands of bottled water sold by various manufacturers in the city. They found 27% samples contained higher than World Health Organisation-permitted limits of bromates, a salt containing bromide that is a by-product of the disinfection. The International Agency for Research on Cancer (IARC) classifies bromates as Group 2B ca rcinogens that could possibly cause cancer in humans.Some samples had bromate levels four times the WHO limit of 10 microgram per litre (see box inside).

The BARC findings were published in the January 10 issue of Current Science Journal, a peer-reviewed Indian science publication. Its objective was to check the water for chemical by-products caused by disinfecting processes. A Bhabha Atomic Research Centre study, which found carcinogenic chemicals in bottled water samples in the city, says the paper should be used to recommend standards for disinfection by-products.

Technically speaking, the findings don’t mean bottled water samples are contaminated or below standards. The Bureau of Indian Standards has stringent limits on presence of chemicals and radioactive substances in bottled water, these don’t include disinfection by-products like bromates and chlorates.

Using ozone in disinfection can form bromates if the water had bromine to begin with. Similarly, certain hypochloride salts can form chlorites and chlorates. “Bottled water is in many cases drawn from ground water, which, in our country, is known to contain heavy metals that can cause chronic diseases like dementia, heart problems as well as hypertension,” said Dr Altaf Patel from Jaslok Hospital, who conducted several studies on heavy metal poisoning.

“Of the samples analyzed for bromates, 38 did not contain any detectable residues and the rest had detectable levels ranging from 0.7 to 43 microgram per litre. There are no regulatory limits prescribed in India for drinking water. Therefore, the presence of bromate in a sample does not violate any Indian standard for drinking water,’’ said a BARC spokesperson.

On WHO limits of 10 micrograms per litre for bromates in drinking water, the spokesperson said: “Only five samples of five brands showed bromate levels exceeding this limit. Even other bottles of the same brand did not have levels above WHO limits.’’ The spokesperson also said since data presented in the paper is limited to one city, generalized inferences should not be drawn from the paper.

The bottled water industry has faced allegations of the presence of toxins in the past as well. Ramesh Chauhan, chairman of Bisleri International, said, “Is the problem with the packing or water? If it's the latter, then it's the city water that is bad. There have been no objections with bottles.’’ He said the city’s piped drinking water contains chlorine which is harmful.

“We don’t allow chlorine in our process, but we do use ozone for disinfection,’’ he added.