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In Summary:

Only the two bottles made by the manufacturer Sigg, market leader in both Switzerland and Germany, showed no traces of aluminum... the manufacturer Sigg shows that it is possible to avoid residue from synthetic coating. Rolf Kothrade, responsible for aluminum bottles at Sigg, explains that his company changed the entire production process two years ago and now uses a water-based interior coating

We recommend aluminum bottles from an ecological point of view because they are durable: "If the coating is not damaged, they have an unlimited useful life,"

For complete article read on...

Aluminum drinking bottles are a popular alternative to disposable packaging. But substances which give cause for concern in terms of health can actually dissolve out of some bottles. But that does not have to be the case, as one manufacturer shows.

In 1845, the discoverer, John Franklin, left London with three excellently equipped ships looking for a new sea route, the legendary North-west Passage. Neither he nor any of his 128 men returned.

His misfortune occupied man's imagination for more than a century. The failure of the expedition remained a mystery until 1985 when science solved it: the tins Franklin had taken with him had carelessly been soldered with lead. The metal contaminated the meat and ruined the men's health after only a few months. This problem has now been solved - it is a long time since lead was used in tins - but modern tins are not without their problems. When ÖKÖ-TEST tested beer cans last year, they revealed traces of BADGE. The substance comes from the synthetic material used to coat the inside of cans and is thought to cause cancer. A year ago, tins of fish with considerable traces of BADGE were withdrawn for this very reason in Switzerland.

Aluminum drinking bottles also usually have a synthetic coating on the inside. But there are manufacturers who only anodise the aluminum, i.e. cover it with a synthetic oxide film. Hikers, bikers, mountain climbers and pupils use the light, unbreakable bottles as an alternative to disposable packaging. "They are much better than the synthetic bottles we used to have that were never really leak-proof and tasted of plastic," says Andreas Keller of the leisure equipment company McTrek in Frankfurt, Germany.

We wanted to know whether the aluminum from the bottles contaminated the drink. We also tested whether BADGE or any other synthetic residue dissolved out of the containers with synthetic coatings. Our laboratories also tested whether the coatings, inscriptions or tops of the bottles contained PVC which is harmful to the environment or were manufactured from material containing formaldehyde resin.

The result: BADGE could not be found in any of the ten bottles tested. Six of the eight bottles with synthetic coatings, however, were shown to have traces of the substance, Bisphenol A, which irritates the skin and which, like BADGE, originates from synthetic material. Drinks in the bottles with no coating showed a concentration of aluminum way above the limit of the drinking water decree. Only the two bottles made by the manufacturer Sigg, market leader in both Switzerland and Germany, showed no traces of aluminum. But a PVC imprint on the Sigg bottle prevented them from receiving a perfect rating. [New water based lining eliminates this]

We devalued two bottles that released aluminum when our laboratory filled them with a mixture of apple juice and fizzy mineral water. The limit of the EU and the drinking water decree of 0.2 milligram per litre was exceeded considerably both by the small and the large Markill bottle made by VauDe: there was 1.13 milligram per litre in the first bottle, 0.91 milligram in the second. "That could well be due to an error during anodisation of this lot," explains Rainer Fischer who is responsible for the bottles at VauDe. "Correctly anodised bottles are resistant to acids." A subsequent test with two other bottles, however, resulted in even higher values than were obtained in the first test: our laboratory traced 3.2 and 1.6 milligrams of aluminum per litre of the apple juice/mineral water mixture. "We will now analyse and improve the production process so that we adhere to the drinking water limit," promised Fischer's colleague, Stefan Engers.

The fact that aluminum is thought to cause Alzheimer's disease has not been substantiated in recent years. Dr. Lutz Frölich, secretary of the Alzheimer Foundation in Frankfurt says, "It is probably insignificant as a risk factor," claiming that the increased level of aluminum found in the brains of Alzheimer patients could possibly be the result of incorrect measurements. Professor Hermann Dieter from the Umweltbundesamt (the Federal Environment Agency) shares that opinion: "A link between aluminum and Alzheimer's disease has not been proved, in fact there is more evidence against the theory."

Scientists are of varied opinions on other effects of aluminum on the health. New tests are showing that a high aluminum content in food can cause arteriosclerosis and is detrimental for the phosphate metabolism, and experiments on animals have shown aluminum to be a neurotoxin.

Nevertheless Dr. Irene Lukassowitz from the Bundesinstitut für Verbraucherschutz und Veterinärmedizin (BgVV) (The Federal Institute for Consumer Protection and Veterinary Medicine) in Berlin explains that, "The values measured in the apple juice/mineral water mixture can be ignored from a health point of view. The limit of the drinking water decree is exceeded but the World Health Organisation (WHO) limit is one milligram of aluminum intake per kilogram of body weight a day." A biker weighing 70 kg would have to drink between 20 and 77 litres from his non-coated bottle to reach this value." Dr. Lutz Frölich from the Alzheimer Foundation does not share her opinion: "Aluminum is a potential danger to your health; unnecessary amounts should be avoided." And aluminum residue can actually be avoided in drinking bottles: according to the test results, a synthetic coating prevents the metal dissolving into the drink. But synthetic material itself is problematic. The Lefo Institute in Ahrensburg found residue of Bisphenol A (a substance used in the production of synthetic material) in most bottles.

Dr. Ulrich Nehring, whose institute specialises in food packaging, is "not surprised" that our tests show residues of substances from the coating. In the manufacture of synthetic material, as in all chemical reactions, not all original substances react entirely with one another. "There is always some unused residue," explains the chemist Udo Kasel from the Lefo Institute.

Bisphenol A irritates the skin. Scientists, however, believe that the substance is not as dangerous as BADGE. Experiments on animals have not shown that it causes cancer or has any gene-modifying effect. The Bisphenol A content in the aluminum bottles also decreases each time the bottle is used as the superfluous synthetic material from the coating is eventually washed out. This is why many manufacturers recommend that customers wash out the bottles thoroughly before use. Our tester, Udo Kasel, feels this tip is sensible, but still the test results are not acceptable because the law on food and consumer goods states that substances should only be allowed to dissolve into food when this cannot be avoided technically. But the manufacturer Sigg shows that it is possible to avoid residue from synthetic coating. Rolf Kothrade, responsible for aluminum bottles at Sigg, explains that his company changed the entire production process two years ago and now uses a water-based interior coating.

Other companies are also busy working on alternatives: "We have known that substances like BADGE and Bisphenol A can dissolve out of synthetic coatings since February 1996," explains, for example, Volker Fehn, sales manager at Schmalbach-Lubeca, the tin manufacturer. "We have been testing alternative coating systems at our plant in Cuxhaven, where we manufacture tins for the food industry, since April 1996," says Fehn.

Improvements could also be made to some of the tops: some are made of polyoxymethylene (POM) which results in very accurate, tight-fitting parts. "This synthetic material is, however, manufactured with the help of formaldehyde," explains our scientific adviser, Dr. Dieter Wundram. "If formaldehyde, which is responsible for various allergies and is suspected of causing cancer, comes into direct contact with liquids, it can dissolve - and the bottle tops come into direct contact with the drinks."


Karin Elbl-Weiser, spokesperson for BASF in Ludwigshafen, confirms, "In our tests, POM was no longer resistant with 10% lemon acid between 60 and 80 degrees." But the bottles do not have to withstand such pressure in normal daily use. Pure lemon juice is only 7% acid, which means that you could even fill containers with POM tops with hot tea with lemon without there being any danger.

But Sigg looked for an alternative without formaldehyde. The new material is scheduled to be used in series in five months' time. As Sigg tops can be bought individually, they can already be exchanged for the valve top which is manufactured without POM.

The laboratories also examined the outside of the bottles. Some have imprints with PVC; one has a PVC sticker on it. The amounts of the ecologically harmful material are low, "but even small amounts should consistently be avoided," says Dr. Dieter Wundram. With aluminum drinking bottles, there is another reason for not using PVC: "Burning PVC together with aluminum releases a lot of dioxins."

We recommend aluminum bottles from an ecological point of view because they are durable: "If the coating is not damaged, they have an unlimited useful life," says Rolf Kothrade from Sigg. Olaf Bandt, responsible for the subject of refuse at the German Bund für Umwelt- und Naturschutz (Association for the Protection of Nature and the Environment), is also in favour of aluminum drinking bottles: "If one aluminum product replaces a lot of disposable packaging, it is really sensible from an environmental point of view."

But just how long disposable tins can spoil the landscape could be seen as early as John Franklin's expedition: the empty tins are still lying on the island in the very north of Canada where, three years after he set out, his journey so very tragically ended.

Author: Richard Breum

For test results by fax: 0190-252150100

© 2001 by ÖKÖ-TEST GmbH, Frankfurt, Germany.