Itching for money

Scientists discover why Euro coins cause allergic reaction

Last Updated: Saturday 04 July 2015

-- (Credit: European Commission)Frank Nestle of the University of Zurich in Switzerland and colleagues have found how euro coins are violating European Union's (EU)rules. It is commonly known that the coins release up to 320 times more amount of nickel than what is permitted by the eu nickel directive, which states legal limits for the amount of nickel to be released by items such as earrings that are normally in prolonged contact with the skin. The amount released by the euros is the highest measured till now for any coins.

According to the researchers, the metal is released in such large quantities because in a sweaty palm, each coin acts like a tiny battery. When sweat gets between two different alloys of the central pill and outer ring of the euro coins, metal ions flow between them. This makes the coins corrode, releasing nickel ions, which can set off itching and redness in up to 30 per cent of the population. When the researchers bathed a euro coin in artificial human sweat for 36 hours, it became brown and corroded.

Nickel is the most important allergen in the environment. Dermatologists have been lobbying for many years to reduce nickel exposure. But they have failed in their endeavours. "It is a great pity that this is happening," says Andrew Finlay, consultant dermatologist at the University Hospital of Wales in Cardiff, the uk.

There are advantages to putting nickel into coins, explains Nestle's colleague Hannes Speidel. Nickel is magnetic, which helps vending machines to identify the coins. Using two alloys also makes the euro coins harder to counterfeit.

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