New British coins bring greater risk of allergy
In 2011, the HM British Treasury decided to reissue some of the old cupronickel (copper-nickel alloy) coins in much cheaper nickel-plated steel. A study from Karolinska Institutet now shows that four times as much nickel rubs off on the skin from these new coins as it did from the cupronickel coins, increasing the risk of allergy and eczema.
"The Swedish Riksbank has decided to take the precisely opposite course," says study co-author Anneli Julander, researcher at Karolinska Institutet's Institute of Environmental Medicine. "According to a decision taken in 2011, all Swedish coins are to be nickel-free within the space of a few years, given the health risks that nickel-based coins are known to pose. This applies to the current five and one-krona coins, which are made of cupronickel."
Nickel allergy is found in 15 to 20 per cent of women and is one of the main causes of hand eczema. The EU regulation on chemicals (called REACH) therefore imposes a limit on how much nickel can be released from jewellery, watches, buttons and other objects that come into a prolonged contact with the skin. This limitation does not, however, apply to coins despite their known links with nickel eczema.
The HM British Treasury decided in 2011 to change the composition of its five and ten pence coins. The old cupronickel versions (containing 75 per cent copper and 25 per cent nickel) are now being replaced by cheaper nickel-plated steel. The Royal Mint has examined how much nickel was released from the coins when exposed to artificial sweat during one week, concluding that the new coins posed no greater health risk than their cupronickel predecessors.
Four times as much nickel
However, this conclusion has been challenged by researchers at the Institute of Environmental Medicine of, who in a study published in the scientific journal Contact Dermatitis show that the new nickel-plated coins constitute a much greater health risk than cupronickel coins. Studying the quantity of nickel that rubs off on the hands when the coins are handled as they would be at a till, for example, the researchers found that four times as much nickel ends up on the skin as in the case of cupronickel coins. The reason is that there is much more nickel on the surface of the nickel-plated coins, which has been verified by surface-sensitive analysis performed in co-operation with the Royal Institute of Technology in Sweden.
The research team also measured how much nickel is released from coins after exposure in artificial sweat over periods of a week and less. They found that a relatively large amount of nickel is released during the first few minutes when the rate of release is high, which explains why brief contact with objects can lead to high levels of nickel on the skin.
Increased risk of allergy
"Our conclusion is that the new nickel-plated coins now being introduced in the UK constitute an increased risk of allergy for the public, especially people whose jobs entail handling coins on a daily basis", says research team member Carola Lidén, Professor of occupational and environmental dermatology at the Institute of Environmental Medicine. "It's important to understand that brief, regular contact with coins and other objects can cause nickel allergy, and eczema of the hands for people who are already allergic to nickel."
The study was financed by a grant from the Swedish Council for Working Life and Social Research (FAS). The coins used in the study were on loan from the Royal Mint.
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New UK nickel-plated steel coins constitute an increased allergy and eczema risk.
Contact Derm. 2013 Jun;68(6):323-30