Assessment of nickel and cobalt release from 200 unused hand-held work tools for sale in Denmark — Sources of occupational metal contact dermatitis? Jacob P. Thyssen a, ⁎, Peter Jensen a , Carola Lidén b , Anneli Julander b , Morten S. Jellesen c , Torkil Menné a , Jeanne D. Johansen a a National Allergy Research Centre, Department of Dermato-Allergology, Copenhagen University Hospital Gentofte, DK-2900 Hellerup, Denmark b Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden c Department of Mechanical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark abstract article info Article history: Received 7 June 2011 Received in revised form 11 July 2011 Accepted 25 July 2011 Available online 1 September 2011 Keywords: Nickel allergy Cobalt allergy Allergic contact dermatitis Public health Work tools Introduction: Nickel and cobalt allergy remain frequent in dermatitis patients. It is important to determine possible nickel and cobalt exposures at work as these may offer important information to regulators and physicians who perform patch testing. Clinical relevance of metal exposure is usually assessed by the treating physician via the medical history and by presentation of allergic contact dermatitis. Objectives: To screen unused non-powered hand-held work tools for nickel and cobalt release by using colorimetric spot tests. Materials & methods: A random selection of 200 non-powered hand-held work tools for sale in 2 retailers of home improvement and construction products were analyzed qualitatively for metal release using the colorimetric nickel and cobalt spot tests. Results: Nickel release was identified from 5% of 200 work tools using the dimethylglyoxime (DMG) test. In 8 of 10, positive results were located to the metal ring that acts like a cuff and is located at the end of the grip. The positive DMG test results were not related to specific categories of work tools. The cobalt spot test gave no positive test reactions. Conclusions: It appears that the proportion of work tools that release nickel, in amounts that may result in allergic nickel dermatitis, has decreased markedly, when results were compared with a Swedish study performed more than a decade ago. No cobalt release was detected but it should be underscored that hard- metal tools were not examined. Other sources of cobalt may explain the relatively high levels of cobalt allergy in dermatitis patients. © 2011 Elsevier B.V. All rights reserved. 1. Introduction In Denmark, nickel allergy is common in women from the general population as well as in dermatitis patients (Thyssen et al., 2009a, 2009b). We have previously investigated consumer nickel exposure and shown that nickel is often released in high concentrations from jewellery, hair clasps and mobile phones (Thyssen et al., 2008, 2009c, 2010b). Also, 565 unused non-powered hand-held tools were inves- tigated for nickel release in Sweden in the late 1990's by using the dimethyl glyoxime (DMG) test and it was found that 27% had metal parts that were positive (Lidén et al., 1998). These observations may partly explain the persistence of nickel allergy despite regulatory intervention (Thyssen et al., 2011). Patch test reactivity to cobalt is often observed in dermatitis patients and occasionally in the general population (Thyssen et al., 2009a, 2009b). We recently showed that cobalt release was infrequently encountered when jewellery was examined with a novel cobalt spot test (Thyssen et al., 2010a). To explain the high prevalence of cobalt allergy in dermatitis patients, other sources of cobalt exposure should be identified. Occupational exposure to nickel and cobalt has been investigated on several occasions. A visit to 3 different plating firms revealed that 30 cold impregnated aluminium plates gave positive DMG test reac- tions (Lidén, 1994). Staton et al., found high levels of nickel on the fingers in nickel platers and nickel refinery workers but low levels in cashiers, shop assistants, bar staff and hairdressers (Staton et al., 2006). A recent Danish study showed that 1 of 200 scissors and 7 of 13 crochet hooks were DMG test positive, when random hairdresser salons in Copenhagen were visited (Thyssen et al., 2009d). Also, the study showed that the prevalence of nickel allergy was high in hair dressers but it was concluded that was mainly caused by consumer nickel exposure. Using the acid wipe sampling technique (Lidén et al., 2006), deposition of nickel and cobalt on the hands was examined in carpenters, locksmiths, cashiers and secretaries after normal work Science of the Total Environment 409 (2011) 4663–4666 ⁎ Corresponding author at: National Allergy Research Centre, Department of Dermato- Allergology, Copenhagen University Hospital Gentofte, University of Copenhagen, Ledreborg Allé 40, 1. 2820 Gentofte, Denmark. Tel.: +45 3977 7307; fax: +45 3977 7118. E-mail address: jacpth01@geh.regionh.dk (J.P. Thyssen). 0048-9697/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2011.07.056 Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv