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Keywords:

  • allergy;
  • coins;
  • nickel;
  • nickel release;
  • risk assessment;
  • skin dose

Summary

Background

Nickel-plated steel coins have recently been introduced in the United Kingdom.

Objectives

To compare the performance and allergy risk of the new nickel-plated coins (five and ten pence) with those of the cupro-nickel coins being replaced.

Materials and methods

Coin handling studies with assessment of skin exposure and metal release in artificial sweat were performed. Six volunteers participated.

Results

The amount of nickel deposited onto skin during the handling of nickel-plated coins for 1 hr was 7.5 µg/cm2, four times higher than that from cupro-nickel coins. The nickel content in the oxidized surface of nickel-plated coins was higher, explaining the higher skin dose. Initial nickel release rates were 10–27 times higher than 1-week rates, emphasizing that brief and repeated contact results in significant nickel exposure.

Conclusions

Nickel-plated coins deposit higher levels of nickel onto skin than cupro-nickel coins, and hence pose an increased allergy risk. One-week release in artificial sweat is not suitable for determining the risk of handling items with high nickel release that come into short, repeated contact with the skin. The nickel skin dose is recommended for risk assessment. UK citizens are now, because of this change in coinage, unnecessarily exposed to higher levels of nickel on the skin. This is of public health concern.