A strategy to assess short and frequent skin contacts with nickel

Abstract

Background. In order to protect the public health, the EU nickel regulation sets a limit for certain consumer products not to release more nickel than 0.5 μg/cm2/week. However, nickel remains the most frequent cause of skin allergy. Objectives. To design and develop an experimental strategy for assessment of short and frequent skin exposure to nickel containing consumer products in daily life. Methods. The research strategy includes: screening for nickel exposure in daily life using the dimethylglyoxime (DMG) spot test for direct qualitative detection of nickel, and assessment of nickel skin dose from relevant nickel-containing materials in two contact test models using modified skin sampling methods. Future tests for measurement of nickel release in artificial sweat were planned for in the strategy but not performed within this master thesis project. Results. In 3 different home environments, 28% of different kinds of metallic consumer products were DMG test positive. The chemical compositions of DMG positive items were mostly detected as combinations of Ni/Cu/Zn, Ni/Fe/Cu or Ni/Fe. The lowest nickel skin dose detected as DMG test positive was 0.05 μg/cm2. The presence of nickel on the skin was identified qualitatively after single contact with all the selected nickel-containing materials except for stainless steel. Conclusion. The presented strategy will provide new and important knowledge for better understanding the allergy risk from short and repetitive skin contacts with nickel-releasing materials. Such data can be used for safety assessment and more protective restriction of nickel release from items intended also for short and frequent contact with the skin.