The water we drink

Where is the problem?

In Western Europe, there is no critical problem, but there are many controversial issues that I will try to clarify. Here are some of them:

• Bottled water versus tap water
• The taste of water
• Nitrate
• Chlorine
• Hardness, calcium and scaling
• Boiled water
• Recycled water
• Some mineral waters are not drinking water
• Brita and other home filters
• Environmental considerations
• The price of water
• Links

So what is there in the water?

See in a separate page the composition of natural water with details about minerals, oligo-elements as well as various contaminants.

The table below gives come characteristics of drinking water. The values shown are concentrations of the most common inorganic ions, expressed in milligrams per litre.

Bottles or tap?

I wrote a note in French on this subject in June 2006 in my "Réactions" page. The discussion has become quite animated after Cristaline launched their advertising campaign in January 2007. As you can see, the campaign was provocative. Newspapers and the Internet began to boil with comments from their readers. For those understanding French, here is a selection. The readers express their guts feelings. Many of them have but a very remote understanding of the scientific aspects of the debate.

The taste of water

A quite subjective issue. Nevertheless, here are two criteria:

• Salinity (concentration of dissolved minerals)
• Chlorine content

Waters with more than one gram of dissolved salts (see Vichy for instance) may have a salty taste. Chlorine becomes noticeable when its cconcentration exceeds about 0.2 mg/L. Anything else is more psychological. In the case of Cristaline, there cannot be a common taste, as the different bottling sources have big differences in salinity.

Newborns do not eat cured ham

What? The issue is nitrate, and I mean three different things:

• Infants should not have nitrate in their food or drinks, including water. Otherwise they may suffer from a serious illness called methemoglobinaemia, also known as blue baby syndrome.
• Nitrate and nitrite salts have been extensively used for centuries—and still are—in cured meats. Smoked and raw ham and similar meats usually contain potassium or sodium nitrate and nitrite.
• Whenever you eat the famous "Bündnerfleisch" (dried meat) of Switzerland or Parma ham, you ingest nitrates and nitrites. Don't be too critical, then, if the water you drink contains a few milligrams of nitrate.

Nitrate and nitrite salts, formerly called salpeter, are used to prevent the growth of harmful bacteria that can cause a deadly illness: botulism. Besides—and this is commercially important—they preserve the red colour of meat. Permitted doses are 300 mg/kg of nitrate and 150 mg/kg of nitrite, to be compared wiith 50 mg/kg (= mg/L) nitrate and 3 mg/L nitrite recommended by WHO for drinking water. This being said, an excessive consumption of nitrate containing products such as cured meats is probably not healthy.

The nitrate found in surface and underground water originates from an excessive use of fertilisers. Additionnally, extensive pig farming is also a big polluter. The underground water of French Britanny is heavily contaminated with nitrates, and the farming lobby is strong enough to prevent the implementation of restrictive regulations.

Chlorine and Co

Drinking water stations must guarantee that the water they distribute is free from pathogenic bacteria. The classical way to kill the germs is an injection of chlorine in the water. As chlorine itself is a gas, hazardous and difficult to handle, sodium hypochlorite—a source of chlorine—is used instead. This is what everyone knows under the name of domestic bleach. Unfortunately, chlorine has a bad taste (remember the swimming pool) and also creates obnoxious by-products such as chloramines. Chlorine dioxide produces fewer of these and is more efficient altogether.

Ozone can also be used instead of chlorine. Once dissolved in the water it has no taste. All these chemicals are strong oxidants, but have a low toxicity at the commonly used dosage.

For continous and permanent efficiency, one of these oxidants must be present in the water up to the tap in our house or flat. There are several ways to eliminate chlorine in the tap water before you drink it:

• Pour the water in an open jug or carafe and wait a few hours (not days!)
• Boil the water (not really smart or ecological, but efficient)
• Filter the water on activated carbon
• Filter the water in a commercial houshold filter (Brita and others), see below.

Other products or methods can be used to prevent the growth of bacteria, but they are more expensive or difficult to apply for a city or village. On a small scale, silver salts or ultra-violet lamps can be used, and of course in emergency cases the water can be boiled.

Calcium, hardness and scaling

Most consumer think that calcium is good for health, and they are right. Several mineral water producers advertise the calcium content of their products as healthy. They are not totally right, as the human body does not assimilate well the calcium present in drinking water. The calcium in dairy products, green vegetables and other food is assimilated more easily.

The same consumers know that "hard" water causes whitish deposits of scale in the kettle and in the water pipes and hot water boiler. What many don't realise is that the scale is precisely made of calcium carbonate. In other words, calcium is good for my bones but bad for the electric coffee machine.

Many years ago, a battle was staged against the evils of water softening. The arguments were that water without calcium was unhealthy, and the increased sodium concentration of the soft water was harmful. These arguments did not hold, though: first the people drinking water with low calcium content (as found in Britanny, Scotland and many other regions of the world) did not suffer from specific ailments when compared to those drinking calcium-rich water, and second, the quantity of sodium (from table salt) that you ingest when eating french fries, ham or salted fish is much higher than that in a few glasses of water.

Summary:
• Don't worry about the calcium or sodium in the water you drink
• If hard water causes problems in your household, use a filter for specific applications (see below)

Boiling water

No, this is normally not necessary in our region. However, when one is not sure of the bacteriological quality of the water, boiling it for 10 to 15 minutes (a long time...) will ensure that all harmful bacteria and viruses are killed.

Caution: boiling the water does little else: it does not remove inorganic (heavy lmetals etc.) or organic (pesticides etc.) contaminants. However, it does remove dissolved gases, such as chlorine, carbon dioxide and oxygen; it also precipitates the temporary hardness in form of calcium carbonate.

Drinking recycled water?

All the water we drink, be it from the tap or from bottles, has been recycled by mother nature. See here a detailed picture of the hydrological cycle. Our tap water comes either from underground sources (deep wells) or from rivers or lakes. For distribution as drinking water, the surface waters are submitted to various treatments, mainly filtration and disinfection. In some cases—and this also applies to deep wells— additional treatments are carried out to eliminate specific contaminants such as arsenic, heavy metals, nickel, uranium, boron, and more frequently nitrate. The technologies used are mainly filtration on semi-permeable membranes (nanofiltration or reverse osmosis) or ion exchange. See for instance the Rohm and Haas site.

Vichy water is not drinking water

This is one example, from France where I am living, but there are many other cases in different countries. See the Ukrainian example in the table above. Vichy is a mineral water sold for its claimed therapeutic or prophylactic properties.

Component	Concentration	Comments
Bicarbonate	4368	The recommended values given by the World's Health Organisation (WHO, 2004) are listed in the attached large PDF file. Total salinity of this water is about 6.5 g/L (6500 mg/L), a high value, although there is no official limit. The fluorine content at 9 mg/L is very high. The recommended concentration is 1.5 mg/L or less. This single property makes the Vichy water non-potable.
Sodium	1708
Chlorure	322
Potassium	132
Sulphate	174
Calcium	90
Fluoride	9
Magnesium	11
Dry residue at 180°C	4474
pH	6.6

Vichy water is sold in the pharmacy and has been authorised by the French government based on its claimed beneficial effects on the liver and pancreas. Interestingly, the site "Eaux de Vichy, Auvergne", shows a warning: "In addition, one should remember that thermal water is a very active medicine: drinking it without a medical advice given by a competent doctor may result either in the cure being inefficient, or sometimes in serious incidents."

See the Wikipedia definitions of drinking water and bottled water.

The Brita filter

I am mentioning Brita because it is the filter I have in my kitchen. There are many other brands. I use the filtered water exclusively for tea and coffee: with the filtered water, tea is transparent, whereas if I prepare it from Paris tap water it is slightly cloudy due to the precipitation of calcium carbonate. And my Nespresso coffee machine is as new after four years and never requires de-scaling. If I had to use bottled water instead, I should take one wiith low salinity or at least low calcium.

These items are sold as jugs that contain the filter cartridge itself. The cartridge is filled with activated carbon, that removes the chlorine and some of the organic molecules, and with an ion exchange resin that removes the hardness. Traces of silver are incorporated in the carbon as a bacteriostatic agent that should prevent the growth of germs in the filter. As my consumption is moderate, I change the cartridge only every six to eight weeks.

When I want to drink a glass of water, however, I draw it from the tap without using the filter. In the district where I live, the tap water has no noticeable taste.

Ecological and political aspects

In Western Europe, we are lucky to live incountries where drinking water is available everywhere, where it is very carefully and severely controlled, and where its cost is very low (see below). When I go to India, I don't enjoy this luxury, and I drink exclusively bottled water. I consider as absurd and dangerous the reluctance that many French people have to drink tap water. Absurd, because as we have just seen, its quality is excellent and its price low. Dangerous, because if the population continues to mistrust the tap water, this could lead the authorities to reduce their efforts to produce excellent quality drinking water at the tap.

The consumption of bottled water has many disadvantages, in addition to its high cost. The drawbacks are more due to the bottle than to its content:

• The production of bottles consumes oil and energy
• The empty bottles, of which billions are discarded, are a serious source of pollution
• Transportation of the full bottles consumes fuel and creates carbon dioxide

The price of water

In France, the price of drinking water varies between 1 and 6 €. In Paris, a cubic metre (1000 litres) of water costs 2.69 €/m³ in January 2007. The large difference between the local prices is due to the distance between the source and the point of distribution, and to the type of treatment. In 2007, the mean tap water cost in France should be around 3 € per cubic metre. In Germany, it is about 4.50 €, in Italy less than 1 €, and in Spain, about 1.50 €. As a comparison, the following table lists the price of bottled water in a typical large French supermarket (in 2007):

Type	Price in €/L
Tap (Paris)	0.003
Cristaline bottled water	0.170
Evian	0.660
Vittel	0.660
Vichy St-Yorre	0.900
Badoit	0.970
Perrier	1.050

The cheapest bottled water is Cristaline, and costs 57 times more than the average tap water. Evian costs 220 times more and Badoit 323 times.

Of course one can indulge in luxury from time to time: I love the Perrier water bubbles in my Scotch (blended) whisky.

Links

• See the 31 May 2007 article of IDS Water: "Bottled Water Boom is Hurting the World’s Environment".
• Another IDS Water publication (5 Sep 2007) on bottled water in the USA released from Tucson Citizen.
• Another article published in the Philadelphia Inquirer dated 10 Nov 2007 on bottled water: the tap water's fine!
• On a separate page, I am listing the consumption of drinking water for many countries.