Eau no, bottled water isn’t better

The £170,000 spent by our tax collectors, HMRC, on bottled water leads us to ask what they got for their money.

Bottled water consumption has grown massively over the last 20 years and, although consumption has declined slightly in the last few years, we still drink around 40 litres for every man woman and child in the country.

Fortunately for the UK economy, over three quarters of this is British.

But what is in bottled water?

The first point to make is that nobody drinks pure water.

The purest water available is distilled or deionised water sold in garages to add to car batteries. This is water from which most of the minerals have been removed and is pretty much tasteless.

The bottled water product Dasani, withdrawn from UK sales after only five weeks in 2004, was purified water to which minerals were then added to make it palatable.

The taste of the water, whether tap or bottled, comes from the minerals in the water. This is why water in different parts of the country has a slightly different taste.

In this region, where the water mostly comes from reservoirs fed by rainfall over the Pennine hills, the water is relatively soft whereas in areas where the water is from underground sources the water will be hard, that is with higher levels of salts and particularly calcium and magnesium.

There are particular definitions for bottled water in the UK.

Mineral water is water originating in an underground deposit or aquifer, which emerges or is extracted from a source at a natural or bore exit. The source must be officially recognised, be microbiologically wholesome (no harmful micro-organisms) and have been protected from all possible pollution.

Spring water may come from any spring (not necessarily an official one) and like mineral water, must be bottled at the source. Spring water must meet certain hygiene standards, but unlike mineral water may be further treated.

Tap water supplied by the water companies is completely safe to drink and much cheaper than bottled water. It has to be analysed and to be sure that it is safe from bacteria it is treated, usually with chlorine.

It is the chlorine that some people are concerned about but very little residual chlorine remains in drinking water.

In contrast, bottled water which is not treated in this way sometimes has been shown to contain higher levels of bacteria.

A study in Canada earlier this year showed that levels of bacteria in 70 per cent of bottled water on sale were higher than recommended levels for drinking water, with some up to 100 times higher.

This is not to say that they are disease-causing bacteria, but that there is a potential risk.

It is the low levels of minerals which give the water its characteristic taste and these are usually at higher levels in bottled water. The levels of most of these elements are controlled by legislation.

One element for which a limit has not been set is uranium and is of concern in some parts of the world. It is a natural element found in granite rocks and so is present in water sources from these regions. It is radioactive and toxic so there is a guideline level for drinking water.

Recent analysis of British mineral waters showed that they were all below this level and almost all well below the level. This is in contrast to some bottled water from other countries which have somewhat higher levels.

Contamination of water is possible whether supplied by tap or bottle and analytical chemists use techniques that are so sensitive that they are able to detect minute levels of contamination.

A few years ago an American laboratory, using bottled Perrier water to compare with what they thought might be polluted local water, was taken by surprise when it found traces of highly-toxic benzene in the Perrier water.

Perrier quickly discovered the source and solved the problem.

Other more widespread concerns are the presence of antimony in drinks in plastic (PET) bottles and lead in tap water in older houses which still have their supply through lead pipes.

There is no reason to believe that either bottled or tap water is unsafe, but there is certainly no evidence that bottled water, whether mineral or spring, is any better for you.




Dr Roger Jewsbury is Head of chemical and biological sciences at the University of Huddersfield