Assessment of nickel release from earrings randomly purchased in China and Thailand using the dimethylglyoxime test

Abstract

China and Thailand produce large amounts of jewellery that are sold domestically and abroad. To identify nickel release and metal content in earrings purchased in China and Thailand. A total of 557 earrings were randomly purchased from vendors in 11 markets located in Beijing, Chengdu, Bangkok, Patong Beach, and Hat Yai. Earrings were subjected to dimethylglyoxime (DMG) tests and 26 of the DMG negative earrings were further evaluated qualitatively for major and minor metal content using X-ray fluorescence spectrometry. A total of 314 Chinese earrings (31.5%) and 243 Thai earrings (29.2%) were DMG test positive. Three (11.5%) of 29 DMG negative earrings contained nickel as a major component; 7 (26.9%) of 29 DMG negative earrings contained nickel as a minor component. Excessive nickel release was frequent. This may contribute to the high prevalence of nickel allergy in both countries. Increased public education together with the adoption of a regulatory intervention in Thailand may be warranted. In China, enforcement of the 2002 Chinese National Standard GB 11887 may assist in reducing sensitization. These initiatives may eventually result in decreased morbidity among the Chinese and Thai citizens, but can potentially benefit recipient countries of these important earring producing countries.