Dr John Briffa: The faucet saga

Statistics show that our thirst for mineral water is ever growing and has swelled the bottled-water industry to a billion-pound-a-year business in the UK. Recently, however, the Drinking Water Inspectorate (DWI) has gone on the offensive in an effort to persuade us that tap water is every drop as good as bottled varieties. The DWI is keen to point out that the vast majority of water samples pass industry standards for levels of impurities. Our attention has also been drawn to the fact that, unlike bottled water, tap water is 'fresh' every day, and a fraction of the price to boot. Those of us inclined to swallow the recent wave of media attention could be forgiven for thinking that shelling out for bottled water is simply chucking money down the drain.

A big believer in keeping the diet as natural and unadulterated as possible, I have been an inveterate drinker of mineral water for the past decade. It is pretty much all we have drunk for the vast majority of our evolution on this planet. Legally, mineral water must emerge from the ground in a state fit to drink. In contrast, tap water starts out life as polluted water and must undergo multi-step processing before it is deemed safe. Several times in the past few years this cleansing process has failed, causing contaminated water to be piped into numerous homes. But my major misgiving is that the cleansing process can leave tap water quite tainted.

The prime disinfecting agent used in the processing of tap water is chlorine. In water, chlorine can morph into other compounds known as the trihalomethanes that can be harmful. A review of 10 studies found that drinking chlorinated water was associated with an increased risk of bladder and rectal cancer of 21 and 38 per cent respectively. Consumption of trihalomethanes has also been linked to pregnancy-related problems such as birth defects and miscarriage.

Another potential contaminant is aluminium. A fair amount of science points to this metal as a risk factor for dementia. Research presented this year at a scientific meeting in San Diego showed a link between aluminium in drinking water and risk of Alzheimer's disease. Research published in the American Journal of Epidemiology found a much greater risk of dementia and Alzheimer's disease in individuals whose drinking water contained aluminium at a concentration of 100 micrograms per litre (mcg/l).

I note that the DWI permits twice this level in our tap water.

To my mind, the DWI's claim that tap water is 'fresh' is meaningless; it's what's in the water that counts. I reckon mineral water's natural cleanliness and greater freedom from chemical cleansers sink tap water out of sight. At the very least, I recommend filtering tap water through a jug or plumbed-in unit prior to drinking. I, for one, remain unconvinced by the recent claims for tap water's clean bill of health.

Thanks to guardian.co.uk who have provided this article. View the original here.