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Insensitivity of the routine dimethylglyoxime test for detecting release of nickel from earrings
The Science of the Total Environment 224 Ž1998. 161]165
Insensitivity of the routine dimethylglyoxime test for detecting release of nickel from earrings Antti Ponka ¨ ¨U , Asta Ekman Helsinki City Centre of the En¨ ironment, Helsinginkatu 24, 00530 Helsinki, Finland Received 4 August 1998; accepted 24 September 1998
Abstract The Helsinki City Centre of the Environment tested two methods, dimethylglyoxime ŽDMG. and atomic absorption spectrometry ŽAAS., for detecting nickel release in piercing earrings. The DMG screening test was performed in two slightly different ways, with and without ethanol and heat prehandling. All 30 pairs of earrings tested, totalling 66 objects, were negative. However, according to our AAS test, 25 of the 66 objects Ž38%. released G 0.05% of nickel, the mean amount being 2.1% and the maximum 12%. When measured by AAS after artificial sweat treatment, 11 objects released more than 0.5 m grcm2 per week of nickel, the mean amount being 3.4 m grcm2 and the range - 0.1]84 m grcm2. After this sweat treatment, nine of the objects Ž14%. were positive in DMG tests. These findings indicate that the DMG test is unreliable for detecting nickel release from jewelry. Quality control of consumer items should be performed by laboratories that have quantitative analysis methods for such investigations. Q 1998 Elsevier Science B.V. All rights reserved. Keywords: Dimethylglyoxime test; Nickel; Piercing earrings; Atomic absorption spectrometry; Artificial sweat
1. Introduction Nickel is reported to be the most common cause of contact allergy in several countries ŽMaibach and Menne, 1989.. In 1991 in Denmark, 11.1% of the female population and 2.2% of the male population were reported to have nickel allergy ŽNielsen and Menne, 1993.. In 1987]1988 in Finland, research among school children showed that 16% of girls and 2% of boys were
U
Corresponding author. Fax: q358 9 7312 2705.
hypersensitive to nickel ŽPeltonen and Terho, 1989.. In 1992]1993 in Norway, the corresponding figures are as high as 21.9 and 8.5% ŽDotterud and Falk, 1994.. As reviewed by Basketter et al. Ž1993., the frequency of nickel allergy has increased during the last two decades, especially in the younger age groups. This is obviously due to increased skin contact with nickel alloys in clips, buttons, zippers, buckles, clasps, wrist watches, spectacle frames, jewelry and clip-on earrings or earrings for pierced ears ŽLarsson-Stymne and Widstrom, ¨ 1985; Nielsen and Menne, 1993; Basketter et al.,
0048-9697r98r$ - see front matter Q 1998 Elsevier Science B.V. All rights reserved. PII S0048-9697Ž98.00345-3
162
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
1993; Rasanen et al., 1993.. ¨¨ Ear piercing with equipment containing nickel andror the subsequent use of earrings containing nickel are believed to be important causes of nickel allergy ŽLarsson-Stymne and Widstrom, ¨ 1985; Nielsen and Menne, 1993; McDonagh et al., 1992; Basketter et al., 1993; Rasanen et al., 1993; ¨¨ Meijer et al., 1995; Kerosuo et al., 1996; Nakada et al., 1997.. In the Danish population, sensitivity to nickel was found in 14.8% of people with pierced ears as compared with 1.2% among the control group ŽNielsen and Menne, 1993.. In a UK study of subjects tested for suspected allergic contact dermatitis, the greater frequency of nickel sensitivity among women with pierced ears was significant Ž8.. A European Parliament and Council Directive Ž1994. has been published concerning nickel in certain consumer products Ž12.. According to this, post assemblies for insertion into pierced ears and other pierced parts of the human body must release less than 0.05% Žmrm. of nickel. In addition, products intended to come into direct and prolonged contact with the skin must not release more than 0.5 m grcm2 per week of nickel even after 2 years of normal use of the product. The Council Directive has been confirmed, but implementation awaits the acceptance of standard methods for the analysis required by the directive. The dimethylglyoxime ŽDMG. test has mainly been used for inspecting release of nickel from jewelry and other solid products. The test is rapid, inexpensive and easy to perform. However, because some reports refer to the insensitivity of the method, we compared the results of DMG tests with those of atomic absorption spectrometry ŽAAS. for detecting nickel release from earrings in routine consumer product control. 2. Materials and methods 2.1. Material The objects studied were 30 pairs of piercing earrings. These earrings are used to pierce the earlobe and are left in the hole to keep it open. The earring and the back piece are placed in a piercing device and shot through the earlobe.
Some of the earrings have two back pieces because the back piece that remains in the ear is not strong enough for piercing. Samples were collected from various stores and importer’s warehouses in Helsinki. Our aim was to investigate all types of piercing earrings imported to Helsinki, except those made of gold. Because nickel sensitivity can develop even during piercing, the earrings used for this purpose are supposed to be free of nickel. The earrings imported from Germany, Sweden, UK and the USA, were stated to contain only low amounts of nickel. The purpose of this investigation was also to test the reliability of the information given by the importer to the consumer. The total number of objects included in the study was 66 } 30 piercing earrings and 36 back pieces. 2.2. Methods All tests and analyses were carried out in the laboratory of Helsinki City Centre of the Environment. The DMG test was performed by adding two drops of 10% ammonia in water and 1% DMG in isopropanol to a cotton-tipped applicator. The surface of the object tested was rubbed with the applicator for 30 s. Colour ranging from light rose to strong cerise in the cotton tip indicated release of nickel from the object. The testing panel in the laboratory consisted of three persons with previous experience of the diagnostics. The DMG tests were also performed according the prEN 12471 method. In this method, the object is first cleaned with ethanol and then heated to 508C. After heating, a drop of artificial sweat is applied to the surface. The object is then dried at 50 " 28C for about 15 min. Thereafter, the object is allowed to cool for approximately 5 min. The DMG screening test was performed as described in the previous paragraph, with the exception that the DMG solution used was of 0.8% strength. The DMG test was also repeated after incubation for 1 week in the artificial sweat ŽprEN 1811.. The object was kept in a closed vessel, undisturbed, for a period of 1 week. The object
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
was suspended in the vessel so that it did not touch the inner surface of the vessel and so that it was completely covered with artificial sweat. The total concentration of nickel was measured according to the prEN 1810 method. The weighed object was placed in a beaker, then covered with hydrofluoric acid or aqua regia. The solution was heated gently until dissolution was complete. Both of these solutions, the artificial sweat and hydrofluoric acid or aqua regia, were analyzed after dissolution with atomic absorption spectrometry ŽAAS.. Measurements with AAS were performed using two standard techniques according to the proposals of Finland’s Standardization Union SFS, SFS3047 and SFS5502. Concentrations higher than 0.8 m grcm2 per week were quantified by the flame technique ŽPerkin Elmer 3100., and lower concentrations in a graphite furnace ŽPerkin Elmer Zeeman 5000.. The Laboratory of Helsinki City’s Environment Centre was accredited in 1996 and has a quality assurance system based on EN 45001 and the ISO Guide 25. The laboratory participates in national and international intercalibration programs. The quality of the results was assured by analysing reference samples with known values of nickel alongside the actual samples.
163
when incubated in artificial sweat and then investigated by the DMG test, nine of the 66 objects showed a positive colour reaction ŽTable 1.. Regarding these nine cases the three panel members were unanimous only three times. In one case, all the members of the panel regarded the reaction as strong and in two cases as weak. In one of the nine cases, two of the three panel members regarded the reaction as positive and, in five cases, only one member. 3.2. AAS Complete dissolution measured with AAS showed that in 25 of the 66 objects Ž38%. at least 0.05% of the total mass consisted of nickel ŽTable 1.. The mean concentration was 2.1%, and the highest 12%. In 11 of the 66 objects Ž17%. the amount of nickel dissolved during 1 week in artificial sweat exceeded 0.5 m grcm2 per week. In 10 of these cases, the objects contained at least 0.05% nickel, and in one case 0.04%. The mean amount of dissolved nickel was 3.4 m grm2 per week, and the highest amount was 84 m grm2 per week. 3.3. Comparison of the results of the DMG and AAS methods
3. Results 3.1. DMG The DMG screening tests did not indicate that any of the objects examined released more than 0.5 m g nickelrcm 2 per week ŽTable 1.. However,
The results of the DMG test and the AAS method are presented in Tables 2 and 3. When the weight criterion of AAS was used, only three of the objects gave positive results in the DMG test. With dissolution in artificial sweat as a criterion, the corresponding number was four.
Table 1 Results of the AAS method and the DMG test Method
AASraqua regiarhydrofluoric acid G 0.05% Žmrm. AASrartificial sweat ) 0.5 m grcm2 per week DMG test before exposure to artificial sweat DMG test after exposure to artificial sweat DMG test before exposure to artificial sweat Žaccording to prEN 12471. DMG test after exposure to artificial sweat Žaccording to prEN 12471.
Excessive nickel N
%
25r66 11r66 0r66 9r66 0r46 0r46
38 17 0 14 0 0
164
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
Table 2 Results of tests on 30 piercing earrings and 36 back pieces by the DMG test and AAS method Method
DMG positive and AAS positive DMG positive and AAS negative DMG negative and AAS positive DMG negative and AAS negative
Excessive nickel releaserN
4r66 5r66 7r66 50r66
Amount of nickel Mean
Range
26.7 0.14 4.5 0.08
1.6]84 - 0.1]0.31 0.8]9.1 - 0.1]0.44
The result of the AAS method is considered positive when the amount of dissolved nickel exceeded 0.5 m grcm2 per week.
4. Discussion Our results suggest that the DMG test is insufficiently sensitive to detect the release of nickel from earrings and back pieces. Therefore, only methods based on quantitative techniques, such as AAS, inductively coupled plasma AAS or mass spectrometry should be used for measurement of the nickel release from consumer products. The reason why the DMG screening test shows positive results after the artificial sweat treatment is that the sweat dissolves a protective layer ŽFischer et al., 1984; Emmett et al., 1988.. Plating of a nickel-containing alloy with a thin layer of precious metal does not necessarily protect the user from exposure to nickel ŽFischer et al., 1984.. On the contrary, nickel release, due to galvanic corrosion, may even be enhanced ŽCavelier et al., 1985.. Several previous studies have shown that the DMG test may give false-negative results. Rasanen et al. Ž1993. observed that relatively ¨¨ large amounts of nickel were released into water
from three pairs of studs and clasps of earrings, but only two of these showed positive results in the DMG test. Katz and Samitz Ž1975. found that two objects used in coffee urns and cookingware released nickel into sweat and household detergents, although the DMG test was negative. Menne et al. Ž1987. found that two out of 38 objects intended for use in contact with the skin, which were shown to release nickel by energy dispersive X-ray analysis, were negative in the DMG test. In the ear-piercing procedure and the subsequent use of the piercing earrings, the metal alloy is exposed to both sweat and serum as well as to an inflammatory exudate. These liquids are strong enough to destroy the protective layer and dissolve nickel from nickel-releasing material ŽFischer et al., 1984; Emmett et al., 1988.. The nickel enters the circulation through an open wound and can cause hypersensitivity. To avoid hypersensitivity to nickel, ear piercing should be done with equipment and earrings made from alloys that do not release nickel in a harmful concentration, or at all. Such materials are,
Table 3 Results of 30 piercing earrings and 36 back pieces according to the DMG test compared to nickel amount as weight percentage Methodrresult
Excessive nickelrN
Amount of nickel Ž%. Mean
DMG positive and AAS positive DMG positive and AAS negative DMG negative and AAS positive DMG negative and AAS negative
6r66 3r66 19r66 38r66
The AAS result is considered positive when the nickel content is G 0.05%.
3 0.03 6 0.01
Range 0.05]9.2 0.02]0.03 0.06]12 - 0.001]0.04
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
for example, stainless steel of the highest quality or gold or titanium. Acknowledgements We are indebted to Ms Vuokko Makinen and ¨ Ms Terttu Kumpu for their excellent technical assistance, to Mrs Pirjo Suominen for the sampling of specimens and to Ms Taina Hayrynen for ¨ help in writing the report. References Basketter DA, Briatico-Vangosa G, Kaestner W, Lally C, Bontinck WJ. Nickel, cobalt and chromium in consumer products: a role in allergic contact dermatitis? Contact Dermatitis 1993;28:15]25. Cavelier C, Foussereau J, Massin M. Nickel allergy: analysis of metal clothing objects and patch testing to metal samples. Contact Dermatitis 1985;12:65]75. Dotterud LK, Falk ES. Metal allergy in north Norwegian schoolchildren and its relationship with ear piercing and atopy. Contact Dermatitis 1994;31:308]313. Emmett EA, Risby TH, Jiang L, Ng K, Feinman S. Allergic contact dermatitis to nickel: bioavailability from consumer products and provocation threshold. J Am Acad Dermatol 1988;19:314]322. European Parliament and Council Directive 94r27rEC. Off J Eur Comm No L 188r1]2, 1994. Fischer T, Fregert S, Gruvberger B, Rystedt I. Nickel release from ear piercing kits and earrings. Contact Dermatitis 1984;10:39]41. Katz SA, Samitz MH. Leaching of nickel from stainless steel consumer commodities. Acta Dermatovener ŽStockholm. 1975;55:113]115.
165
Kerosuo H, Kullaa A, Kerosuo E, Kanerva L, Hensten-Pettersen A. Nickel allergy in adolescents in relation to orthodontic treatment and piercing of ears. Am J Orthod Dent Orthop 1996;109:148]154. Larsson-Stymne B, Widstrom ¨ L. Ear piercing}a cause of nickel allergy in schoolgirls? Contact Dermatitis 1985;13:289]293. Maibach HI, Menne T. Nickel and the Skin: Immunology and Toxicology. Boca Raton, FL: CRC Press, 1989. McDonagh AJ, Wright AL, Cork MJ, Gawkrodger DJ. Nickel sensitivity: the influence of ear piercing and atopy. Br J Dermatol 1992;126:16]18. Meijer C, Bredberg M, Fischer T, Widstrom ¨ L. Ear piercing, and nickel and cobalt sensitization, in 520 young Swedish men doing compulsory military service. Contact Dermatitis 1995;32:147]149. Menne T, Andersen KE, Kaaber K, Osmundsen PE, Andersen JR, Yding F, Valeur G. Evaluation of the dimethylglyoxime stick test for the detection of nickel. Dermatosen 1987;35:128]130. Nakada T, Iijima M, Nakayama H, Maibach HI. Role of ear piercing in metal allergic contact dermatitis. Contact Dermatitis 1997;36:233]236. Nielsen N, Menne T. Nickel sensitization and ear piercing in an unselected Danish population. The Glostrup Allergy Study, Denmark. Contact Dermatitis 1993;29:16]21. Peltonen L, Terho P. Nickel sensitivity in schoolchildren in Finland. In: Frosch PJ, Dooms-Goossens, Lachapelle J-M, Rycroft RJG, Scheper RJ, editors. Current Topics in Contact Dermatitis. Berlin: Springer, 1989:184]187. Rasanen L, Lehto M, Mustikka-Maki ¨¨ ¨ UP. Sensitization to nickel from stainless steel ear piercing kits. Contact Dermatitis 1993;28:292]293.
Insensitivity of the routine dimethylglyoxime test for detecting release of nickel from earrings Antti Ponka ¨ ¨U , Asta Ekman Helsinki City Centre of the En¨ ironment, Helsinginkatu 24, 00530 Helsinki, Finland Received 4 August 1998; accepted 24 September 1998
Abstract The Helsinki City Centre of the Environment tested two methods, dimethylglyoxime ŽDMG. and atomic absorption spectrometry ŽAAS., for detecting nickel release in piercing earrings. The DMG screening test was performed in two slightly different ways, with and without ethanol and heat prehandling. All 30 pairs of earrings tested, totalling 66 objects, were negative. However, according to our AAS test, 25 of the 66 objects Ž38%. released G 0.05% of nickel, the mean amount being 2.1% and the maximum 12%. When measured by AAS after artificial sweat treatment, 11 objects released more than 0.5 m grcm2 per week of nickel, the mean amount being 3.4 m grcm2 and the range - 0.1]84 m grcm2. After this sweat treatment, nine of the objects Ž14%. were positive in DMG tests. These findings indicate that the DMG test is unreliable for detecting nickel release from jewelry. Quality control of consumer items should be performed by laboratories that have quantitative analysis methods for such investigations. Q 1998 Elsevier Science B.V. All rights reserved. Keywords: Dimethylglyoxime test; Nickel; Piercing earrings; Atomic absorption spectrometry; Artificial sweat
1. Introduction Nickel is reported to be the most common cause of contact allergy in several countries ŽMaibach and Menne, 1989.. In 1991 in Denmark, 11.1% of the female population and 2.2% of the male population were reported to have nickel allergy ŽNielsen and Menne, 1993.. In 1987]1988 in Finland, research among school children showed that 16% of girls and 2% of boys were
U
Corresponding author. Fax: q358 9 7312 2705.
hypersensitive to nickel ŽPeltonen and Terho, 1989.. In 1992]1993 in Norway, the corresponding figures are as high as 21.9 and 8.5% ŽDotterud and Falk, 1994.. As reviewed by Basketter et al. Ž1993., the frequency of nickel allergy has increased during the last two decades, especially in the younger age groups. This is obviously due to increased skin contact with nickel alloys in clips, buttons, zippers, buckles, clasps, wrist watches, spectacle frames, jewelry and clip-on earrings or earrings for pierced ears ŽLarsson-Stymne and Widstrom, ¨ 1985; Nielsen and Menne, 1993; Basketter et al.,
0048-9697r98r$ - see front matter Q 1998 Elsevier Science B.V. All rights reserved. PII S0048-9697Ž98.00345-3
162
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
1993; Rasanen et al., 1993.. ¨¨ Ear piercing with equipment containing nickel andror the subsequent use of earrings containing nickel are believed to be important causes of nickel allergy ŽLarsson-Stymne and Widstrom, ¨ 1985; Nielsen and Menne, 1993; McDonagh et al., 1992; Basketter et al., 1993; Rasanen et al., 1993; ¨¨ Meijer et al., 1995; Kerosuo et al., 1996; Nakada et al., 1997.. In the Danish population, sensitivity to nickel was found in 14.8% of people with pierced ears as compared with 1.2% among the control group ŽNielsen and Menne, 1993.. In a UK study of subjects tested for suspected allergic contact dermatitis, the greater frequency of nickel sensitivity among women with pierced ears was significant Ž8.. A European Parliament and Council Directive Ž1994. has been published concerning nickel in certain consumer products Ž12.. According to this, post assemblies for insertion into pierced ears and other pierced parts of the human body must release less than 0.05% Žmrm. of nickel. In addition, products intended to come into direct and prolonged contact with the skin must not release more than 0.5 m grcm2 per week of nickel even after 2 years of normal use of the product. The Council Directive has been confirmed, but implementation awaits the acceptance of standard methods for the analysis required by the directive. The dimethylglyoxime ŽDMG. test has mainly been used for inspecting release of nickel from jewelry and other solid products. The test is rapid, inexpensive and easy to perform. However, because some reports refer to the insensitivity of the method, we compared the results of DMG tests with those of atomic absorption spectrometry ŽAAS. for detecting nickel release from earrings in routine consumer product control. 2. Materials and methods 2.1. Material The objects studied were 30 pairs of piercing earrings. These earrings are used to pierce the earlobe and are left in the hole to keep it open. The earring and the back piece are placed in a piercing device and shot through the earlobe.
Some of the earrings have two back pieces because the back piece that remains in the ear is not strong enough for piercing. Samples were collected from various stores and importer’s warehouses in Helsinki. Our aim was to investigate all types of piercing earrings imported to Helsinki, except those made of gold. Because nickel sensitivity can develop even during piercing, the earrings used for this purpose are supposed to be free of nickel. The earrings imported from Germany, Sweden, UK and the USA, were stated to contain only low amounts of nickel. The purpose of this investigation was also to test the reliability of the information given by the importer to the consumer. The total number of objects included in the study was 66 } 30 piercing earrings and 36 back pieces. 2.2. Methods All tests and analyses were carried out in the laboratory of Helsinki City Centre of the Environment. The DMG test was performed by adding two drops of 10% ammonia in water and 1% DMG in isopropanol to a cotton-tipped applicator. The surface of the object tested was rubbed with the applicator for 30 s. Colour ranging from light rose to strong cerise in the cotton tip indicated release of nickel from the object. The testing panel in the laboratory consisted of three persons with previous experience of the diagnostics. The DMG tests were also performed according the prEN 12471 method. In this method, the object is first cleaned with ethanol and then heated to 508C. After heating, a drop of artificial sweat is applied to the surface. The object is then dried at 50 " 28C for about 15 min. Thereafter, the object is allowed to cool for approximately 5 min. The DMG screening test was performed as described in the previous paragraph, with the exception that the DMG solution used was of 0.8% strength. The DMG test was also repeated after incubation for 1 week in the artificial sweat ŽprEN 1811.. The object was kept in a closed vessel, undisturbed, for a period of 1 week. The object
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
was suspended in the vessel so that it did not touch the inner surface of the vessel and so that it was completely covered with artificial sweat. The total concentration of nickel was measured according to the prEN 1810 method. The weighed object was placed in a beaker, then covered with hydrofluoric acid or aqua regia. The solution was heated gently until dissolution was complete. Both of these solutions, the artificial sweat and hydrofluoric acid or aqua regia, were analyzed after dissolution with atomic absorption spectrometry ŽAAS.. Measurements with AAS were performed using two standard techniques according to the proposals of Finland’s Standardization Union SFS, SFS3047 and SFS5502. Concentrations higher than 0.8 m grcm2 per week were quantified by the flame technique ŽPerkin Elmer 3100., and lower concentrations in a graphite furnace ŽPerkin Elmer Zeeman 5000.. The Laboratory of Helsinki City’s Environment Centre was accredited in 1996 and has a quality assurance system based on EN 45001 and the ISO Guide 25. The laboratory participates in national and international intercalibration programs. The quality of the results was assured by analysing reference samples with known values of nickel alongside the actual samples.
163
when incubated in artificial sweat and then investigated by the DMG test, nine of the 66 objects showed a positive colour reaction ŽTable 1.. Regarding these nine cases the three panel members were unanimous only three times. In one case, all the members of the panel regarded the reaction as strong and in two cases as weak. In one of the nine cases, two of the three panel members regarded the reaction as positive and, in five cases, only one member. 3.2. AAS Complete dissolution measured with AAS showed that in 25 of the 66 objects Ž38%. at least 0.05% of the total mass consisted of nickel ŽTable 1.. The mean concentration was 2.1%, and the highest 12%. In 11 of the 66 objects Ž17%. the amount of nickel dissolved during 1 week in artificial sweat exceeded 0.5 m grcm2 per week. In 10 of these cases, the objects contained at least 0.05% nickel, and in one case 0.04%. The mean amount of dissolved nickel was 3.4 m grm2 per week, and the highest amount was 84 m grm2 per week. 3.3. Comparison of the results of the DMG and AAS methods
3. Results 3.1. DMG The DMG screening tests did not indicate that any of the objects examined released more than 0.5 m g nickelrcm 2 per week ŽTable 1.. However,
The results of the DMG test and the AAS method are presented in Tables 2 and 3. When the weight criterion of AAS was used, only three of the objects gave positive results in the DMG test. With dissolution in artificial sweat as a criterion, the corresponding number was four.
Table 1 Results of the AAS method and the DMG test Method
AASraqua regiarhydrofluoric acid G 0.05% Žmrm. AASrartificial sweat ) 0.5 m grcm2 per week DMG test before exposure to artificial sweat DMG test after exposure to artificial sweat DMG test before exposure to artificial sweat Žaccording to prEN 12471. DMG test after exposure to artificial sweat Žaccording to prEN 12471.
Excessive nickel N
%
25r66 11r66 0r66 9r66 0r46 0r46
38 17 0 14 0 0
164
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
Table 2 Results of tests on 30 piercing earrings and 36 back pieces by the DMG test and AAS method Method
DMG positive and AAS positive DMG positive and AAS negative DMG negative and AAS positive DMG negative and AAS negative
Excessive nickel releaserN
4r66 5r66 7r66 50r66
Amount of nickel Mean
Range
26.7 0.14 4.5 0.08
1.6]84 - 0.1]0.31 0.8]9.1 - 0.1]0.44
The result of the AAS method is considered positive when the amount of dissolved nickel exceeded 0.5 m grcm2 per week.
4. Discussion Our results suggest that the DMG test is insufficiently sensitive to detect the release of nickel from earrings and back pieces. Therefore, only methods based on quantitative techniques, such as AAS, inductively coupled plasma AAS or mass spectrometry should be used for measurement of the nickel release from consumer products. The reason why the DMG screening test shows positive results after the artificial sweat treatment is that the sweat dissolves a protective layer ŽFischer et al., 1984; Emmett et al., 1988.. Plating of a nickel-containing alloy with a thin layer of precious metal does not necessarily protect the user from exposure to nickel ŽFischer et al., 1984.. On the contrary, nickel release, due to galvanic corrosion, may even be enhanced ŽCavelier et al., 1985.. Several previous studies have shown that the DMG test may give false-negative results. Rasanen et al. Ž1993. observed that relatively ¨¨ large amounts of nickel were released into water
from three pairs of studs and clasps of earrings, but only two of these showed positive results in the DMG test. Katz and Samitz Ž1975. found that two objects used in coffee urns and cookingware released nickel into sweat and household detergents, although the DMG test was negative. Menne et al. Ž1987. found that two out of 38 objects intended for use in contact with the skin, which were shown to release nickel by energy dispersive X-ray analysis, were negative in the DMG test. In the ear-piercing procedure and the subsequent use of the piercing earrings, the metal alloy is exposed to both sweat and serum as well as to an inflammatory exudate. These liquids are strong enough to destroy the protective layer and dissolve nickel from nickel-releasing material ŽFischer et al., 1984; Emmett et al., 1988.. The nickel enters the circulation through an open wound and can cause hypersensitivity. To avoid hypersensitivity to nickel, ear piercing should be done with equipment and earrings made from alloys that do not release nickel in a harmful concentration, or at all. Such materials are,
Table 3 Results of 30 piercing earrings and 36 back pieces according to the DMG test compared to nickel amount as weight percentage Methodrresult
Excessive nickelrN
Amount of nickel Ž%. Mean
DMG positive and AAS positive DMG positive and AAS negative DMG negative and AAS positive DMG negative and AAS negative
6r66 3r66 19r66 38r66
The AAS result is considered positive when the nickel content is G 0.05%.
3 0.03 6 0.01
Range 0.05]9.2 0.02]0.03 0.06]12 - 0.001]0.04
A. Ponka, ¨ ¨ A. Ekman r The Science of the Total En¨ ironment 224 (1998) 161]165
for example, stainless steel of the highest quality or gold or titanium. Acknowledgements We are indebted to Ms Vuokko Makinen and ¨ Ms Terttu Kumpu for their excellent technical assistance, to Mrs Pirjo Suominen for the sampling of specimens and to Ms Taina Hayrynen for ¨ help in writing the report. References Basketter DA, Briatico-Vangosa G, Kaestner W, Lally C, Bontinck WJ. Nickel, cobalt and chromium in consumer products: a role in allergic contact dermatitis? Contact Dermatitis 1993;28:15]25. Cavelier C, Foussereau J, Massin M. Nickel allergy: analysis of metal clothing objects and patch testing to metal samples. Contact Dermatitis 1985;12:65]75. Dotterud LK, Falk ES. Metal allergy in north Norwegian schoolchildren and its relationship with ear piercing and atopy. Contact Dermatitis 1994;31:308]313. Emmett EA, Risby TH, Jiang L, Ng K, Feinman S. Allergic contact dermatitis to nickel: bioavailability from consumer products and provocation threshold. J Am Acad Dermatol 1988;19:314]322. European Parliament and Council Directive 94r27rEC. Off J Eur Comm No L 188r1]2, 1994. Fischer T, Fregert S, Gruvberger B, Rystedt I. Nickel release from ear piercing kits and earrings. Contact Dermatitis 1984;10:39]41. Katz SA, Samitz MH. Leaching of nickel from stainless steel consumer commodities. Acta Dermatovener ŽStockholm. 1975;55:113]115.
165
Kerosuo H, Kullaa A, Kerosuo E, Kanerva L, Hensten-Pettersen A. Nickel allergy in adolescents in relation to orthodontic treatment and piercing of ears. Am J Orthod Dent Orthop 1996;109:148]154. Larsson-Stymne B, Widstrom ¨ L. Ear piercing}a cause of nickel allergy in schoolgirls? Contact Dermatitis 1985;13:289]293. Maibach HI, Menne T. Nickel and the Skin: Immunology and Toxicology. Boca Raton, FL: CRC Press, 1989. McDonagh AJ, Wright AL, Cork MJ, Gawkrodger DJ. Nickel sensitivity: the influence of ear piercing and atopy. Br J Dermatol 1992;126:16]18. Meijer C, Bredberg M, Fischer T, Widstrom ¨ L. Ear piercing, and nickel and cobalt sensitization, in 520 young Swedish men doing compulsory military service. Contact Dermatitis 1995;32:147]149. Menne T, Andersen KE, Kaaber K, Osmundsen PE, Andersen JR, Yding F, Valeur G. Evaluation of the dimethylglyoxime stick test for the detection of nickel. Dermatosen 1987;35:128]130. Nakada T, Iijima M, Nakayama H, Maibach HI. Role of ear piercing in metal allergic contact dermatitis. Contact Dermatitis 1997;36:233]236. Nielsen N, Menne T. Nickel sensitization and ear piercing in an unselected Danish population. The Glostrup Allergy Study, Denmark. Contact Dermatitis 1993;29:16]21. Peltonen L, Terho P. Nickel sensitivity in schoolchildren in Finland. In: Frosch PJ, Dooms-Goossens, Lachapelle J-M, Rycroft RJG, Scheper RJ, editors. Current Topics in Contact Dermatitis. Berlin: Springer, 1989:184]187. Rasanen L, Lehto M, Mustikka-Maki ¨¨ ¨ UP. Sensitization to nickel from stainless steel ear piercing kits. Contact Dermatitis 1993;28:292]293.