Summary and conclusion

Survey and health assessment of chemical substances in jewelleries

Background and purpose
The survey
Results and main conclusions

Background and purpose

Jewelleries are available in countless variants, including a large number of metal jewelleries with and without a content of precious metal. These jewelleries can potentially contain and release problematic substances as for instance heavy metals. A number of examinations from abroad have proved a problem with the content of large amounts of lead in so-called cheap jewelleries. The seriousness of the problem is confirmed by a 4 year old boy’s death who by accident had swallowed a heart-shaped piece of jewellery containing above 99% lead. The incident lead to a voluntary recall of 300,000 pieces of the jewellery in question (Berg et al., 2006). Furthermore, it has turned out that the textile part of a necklace imported from Turkey contained the substance benzidine which is banned in the EU.

Thus, this project has had the purpose of providing an overview of whether metal jewelleries with a problematic content of heavy metals are available on the Danish market as well as whether this content can be released in an amount that causes health related problems for humans. The purpose was also to clarify whether there was a relation between among other things price (quality), country of origin and content/release of heavy metal. Another element in the project was to examine whether textile necklaces containing benzidine are available on the Danish market.

The survey

The project is carried out by FORCE Technology, the Department for Applied Environmental Assessment, who has been responsible for the survey, the selection of products for analysis as well as the health assessment. The analyses of the jewelleries have been completed by FORCE Technology, the Department for Chemical Analysis.

Metal jewelleries

The survey and purchase of jewelleries were completed in the period April to July 2007. In total 170 pieces of metal jewelleries were purchased, divided between the product types rings, necklaces, bracelets, earrings, piercing jewelleries and ankle chains. These product types were selected as they all are products getting into contact with the skin. All the purchases took place in the area of Copenhagen. The main part of the jewelleries was bought in the following types of shops: 10 kroner’s shops, shops with owners of different ethnic background, jewellery shops, department stores, supermarkets and clothes shops, while a small part was bought in internet shops.

All metal jewelleries were screened for a content of Pb, Hg, Cd, Se, Cr, Sb, As, Ba by use of a XRF device. As metal jewelleries often consist of different metal parts (with a different content of metal and thereby release) each piece of jewellery was screened on 3 different parts as a maximum. Thus, in total 318 jewellery parts were screened.

Based on the screening results 25 jewellery parts were selected for a migration test for release of As, Ba, Cd, Cr, Cu, Hg, Ni, Pb, Sb and Se. The used analysis method was “Migration to artificial sweat” according to DS/EN 1811:2000. The jewellery parts were selected in such a way that they covered the different product types (rings, necklaces, bracelets etc.) and the different product categories (silver-coated, golden-like, non-precious metal etc.) as broadly as possible; however, with the primary criterion that they represented a part of the piece of jewellery being in contact with the skin. As far as possible, the attempt was to select jewellery parts representing the entire concentration span related to the content of lead and cadmium; however, focus was primarily on the low part of the spectrum, i.e. for lead between 100 and 2000 ppm and for cadmium between 75 and 2000 ppm.

Textile necklaces

In total 62 textile necklaces were purchased. The main part of the textile necklaces was purchased at the same time as the metal jewelleries. During the entire purchasing phase focus was on purchasing textile necklaces of different types and colours. Furthermore it was attempted to buy textile necklaces “targeting” children as well as adults.

The 62 pieces of textile necklaces were screened for a content of azo-dye which through reduction may form aromatic amines as for instance benzidine. The screening consisted of lowering the textile necklaces into water (40 degrees) for a period of 4 hours. Coloured extracts in the water are an indication of a possible content of azo-dyes. Hereafter, 10 textile necklaces representing different colourings were selected for a quantitative analysis for a content of benzidine. The analysis method being used was EN 14364-1:2003.

Results and main conclusions

Conclusions from the screening
The most important conclusions from the screening of the metal jewelleries were:

58% of all examined jewelleries contained lead in a concentration above 100 ppm. The maximum content of lead in a jewellery part was 69.6 %.
24% of all examined jewelleries contained cadmium in a concentration above 75 ppm. The maximum content of cadmium in a jewellery part was 29.15%.
2% of all the examined jewelleries exceeded a content of 100 ppm of mercury.
25% of all examined jewelleries turned out to contain nickel in a volume percentage above 1. The maximum content of nickel in a jewellery part was 95%.
Furthermore, a tendency was proved that especially charms, and particularly catches, contain lead and cadmium. Generally, there was no relation between the types of jewelleries (bracelets, earrings etc.) and the content of lead and cadmium.
Based of the present data material it cannot be concluded whether jewelleries bought from a certain country have a larger probability of containing heavy metals. However, it can be mentioned that for the 37 jewelleries which are known to originate from China 30% has turned out to contain above 100 ppm lead while 24% has turned out to contain above 75 ppm of cadmium.
No relation was found between shop type and purchase of jewelleries with a high content of heavy metals.
There seems to be a greater chance of a large content of Pb in the cheaper metal jewelleries (0 – approx. 10 kr. per gram), while for Cd there does not seem to be a direct relation.
The results did not indicate a relation between content of heavy metal and the product category (i.e. gold coated, silver-like, non-precious metal etc.). Thus, it cannot be assumed that jewelleries of for instance gold have a larger probability of containing lead or cadmium than jewelleries made of silver or non-precious metal.
Furthermore, there was no relation between the three superior product categories (gold, silver and non-precious metal) and content of lead and cadmium.

Conclusions from the migration analysis

The jewelleries for the migration test were selected based on an even distribution among the selection criteria, i.e. content of heavy metal, coating, product type and jewellery part.

The results from the migration analysis for artificial sweat showed that lead, cadmium, nickel and copper migrated in a concentration above the detection limit.

Based on the test arrangement used in this project it is not possible to determine whether nickel migrates above 0.2 mg/cm²/week or 0.5 µg /cm²/week in a period of at least two years at normal use; in other words, whether the products comply with the nickel statutory order.

The results from the migration analysis did not show any direct relation between migration and content of the metal, i.e. it cannot be assumed that a high concentration of the metal in the jewellery causes a high migration. However, it shall be noted that nearly no migration of lead has taken place for jewelleries where the content of lead is below approximately 1%. Similar tendency is not seen for the other metals.

As only relatively few migration analyses have been performed it is not possible to determine whether the coating (for instance gold coated or silver-like) has any influence on the migration.

It shall be noted that the result from the sweat test are used for the oral exposure calculations. However, the pH value in the sweat test is 1.5 higher than it would have been in a saliva test. This may indicate that a lesser amount of metal compounds are formed in the sweat test than what would have been formed in a saliva test. In other words this means that the oral exposure in this study is underestimated to a certain degree. However, it is assumed based on a study concerning formation of metal chlorides in seawater (Strandesen et al., 2007) that this difference (in formation of metal chlorides) is in the order of magnitude of 3-4% and therefore is not expected to have significant influence on the results.

Furthermore, it shall be noted that the exposure calculations are associated with some uncertainty as the calculations are based on the assumption that it is primarily inorganic metal compounds (especially metal chlorides) that are formed in sweat (and saliva) that are in contact with the jewelleries. In other words, oral and dermal absorption rates are primarily based on studies concerning inorganic metal compounds. This assumption is based on a study by Menné (1994) (quoted from ATSDR (2005a)) which claims that nickel alloys being in contact with the skin form nickel chlorides. The assumption is likewise based on the Danish Environmental Protection Agency’s risk assessment of nickel from 2005 in which they state that corrosion of metal in sweat primarily is dependent on the chloride and oxygen content.

Finally, it turned out that 2 of the 10 analysed textile necklaces had a content of benzidine of 100 and 1200 mg/kg respectively and thus had a content of benzidine exceeding the legally recognized amount.

Conclusions from the health and risk assessment

Health assessments for lead, cadmium, nickel and copper were performed and followed by exposure calculations for all samples showing migration above the detection limit.

Dermal exposure

Wearing the jewelleries examined in this project does not result in problems related to exposure of lead through the skin (though a number of jewelleries is close to exceed the TDI value). However, many of the examined jewelleries cause problems related to cadmium exposure through the skin while in a few cases there are also problems related to nickel exposure through the skin. The copper content in the jewelleries gave no cause for problems.

Average background exposure

The results show that for nearly all the jewelleries from which cadmium migrated in an amount above the detection limit there is a potential health risk for children (who are already exposed to an average background exposure) by wearing the jewelleries for 16 and 24 hours a day respectively. For two of the jewelleries the total tolerable daily dose is even exceeded by a factor 10. In other words, children wearing these jewelleries get 10 times the tolerable intake of cadmium a day. However, it shall be mentioned that the tolerable daily intake (TDI) states what a person may get daily through an entire lifetime without experiencing health related effects. Thus, for a shorter period the TDI value can be exceeded without this causing any effects - if in a corresponding period later in life an equally lesser amount is taken in. For adults the TDI value related to cadmium for two of the jewelleries is exceeded when the jewelleries are worn for 24 hours – and a single one is close to exceed the TDI value for nickel.

Maximum background exposure

When looking at the population group being exposed to the maximum background exposure the picture looks more serious. Here the results show that the 5% of Danish children being exposed to the maximum background exposure of cadmium already have exceeded the limit of tolerable daily intake of cadmium – without including the contribution from wearing jewelleries. For the 5% of adults being exposed to the maximum background exposure of cadmium the TDI value is not exceeded in advance but when the contribution from wearing the jewelleries is added it turns out that the TDI value is exceeded for four of the jewelleries when being worn for 24 hours.

Oral exposure

Furthermore, the results show that potential health risks are generated relating to cadmium, nickel and lead when a person sucks the jewelleries for two hours. However, most definitely for lead and cadmium as nearly all jewelleries (showing migration of the metal in question) exceed the TDI value related to lead and cadmium (both children and adults). This applies to humans being exposed to an average background exposure. None of the jewelleries gave cause to problems related to copper.

The results show that the lowest content of lead giving cause for health problems by sucking the jewelleries for two hours is a content of lead of 1.77%, i.e. somewhat above the requirements of the lead statutory order on a maximum content of 0.01% of lead. At the same time it is seen that none of the jewelleries containing a maximum of 100 ppm of lead caused health problems.

Furthermore, the calculations have shown that for a single piece of jewellery it turns out that children (being exposed to an average background exposure of lead) can suck the charm for one minute only before the daily tolerable intake is exceeded.

Overall conclusion
Based on the findings of this project it cannot be excluded that by wearing or sucking some of the metal jewelleries examined in this project potential health risks related to especially cadmium and nickel arise. This is valid for people exposed to the background exposure found in Denmark. For lead there are primarily problems when sucking the jewelleries. None of the examined jewelleries gave problems related to copper.

The health related risks associated with the three metals are effects on the kidneys (cadmium), increased mortality risk on foetuses (nickel) and reduced IQ at children (lead).

If the jewelleries comply with the legal demand related to content of lead, the results in this project indicate that no health related risks arise by wearing or sucking the jewelleries.

The jewelleries containing mercury were not examined further in the migration analysis. Therefore, it cannot be excluded that, as for lead and cadmium, there is a health risk by wearing or sucking the jewelleries.

However, there are a number of reservations being decisive whether a health problem will occur. Among other things, the jewelleries have to be worn/sucked every day for a long period as a short exceeding of the tolerable daily intake does not necessarily result in effects hazardous to health - unless an amount equal to the tolerable daily is taken in every day for the rest of the person’s life. In addition, it is assumed in the calculations that the migration of metals from the jewelleries is constant during time. This will decrease in the course of time.

Finally it is in the project concluded that there exist textile necklaces on the Danish market, which contain benzidine in amounts exceeding the allowable.