Chrome (VI) in consumer products

Four official methods exist for the analysis of Cr (VI) at the moment. These are DS/EN 420 (1994 for glove leather), DIN 53314 (1996), IUC 18 (1995 but revised 1996) and SLC 22 (identical to IUC 18). The methods are based on the same principle (colourometric analyses using diphenyl carbazide). Furthermore, at the moment, work is going on at the Comité Européen de Normalisation (CEN TC 289, WG2, TG1) to develop a general test method for hexavalent chromium in leather. An often-used method in publications about hexavalent chromium in leather is the German DIN-method. There are several reasons for this, the first being that Germany is the only country with legislation regarding Cr (VI) in leather (which refers to the DIN-method). The second reason is that there have been several research activities initiated by the chemical industry in Germany where a major part of the chemical supply to the leather industry is based. DIN 53314 has been used in this investigation to determine the content of hexavalent chromium in leather. The reason for choosing the DIN-method is that it is a national standard and applicable for all types of leather. The analyses of hexavalent chromium in this project were carried out by the German Leather Institute, Lederinstitut Gerberschule Reutlingen, which is accredited for this particular analysis and has major experiences in performing it. Results Forty-three products were bought in the Copenhagen area and analysed for their Cr(VI) content. The products investigated are presented in table 1. The results from the analyses show that 35% (15 out of 43) of the leather products contained Cr (VI) in levels above the detection limit of 3mg/kg. The concentration of hexavalent chromium varied from 3.6mg/kg to 14.7mg/kg. The number of leather samples containing hexavalent chromium was unexpected, especially taking into consideration that hexavalent chromium can be avoided by relatively simple process changes. It can be noted that one baby shoe contained hexavalent chromium (6.4mg/kg). Since babies can be expected to suck on their shoes, they can potentially be exposed to Cr (VI). Due to the finding of hexavalent chrome in one baby shoe, ten more baby shoes were purchased and analysed for their content of hexavalent chrome. Two of the shoes were also analysed for migration of chromium. None of these shoes contained hexavalent chromium. Three out of five working gloves contained hexavalent chromium. The product is expected to be in contact with the human skin and concentrations varied between 4.0-14.7mg/kg. Two out of five watch straps contained hexavalent chromium. The products are used every day by the consumer and are obviously expected to be in constant contact with the human skin. The concentration of hexavalent chromium varied between 3.6-3.7mg/kg. Two leather tops have been analysed and both contained hexavalent chromium. This product type is also expected to be in constant contact with the human skin. The content of hexavalent chromium varied between 4.9-5.0mg/kg. One out of five pairs of gloves contained hexavalent chromium. The gloves are obviously expected to have direct skin contact. The concentration of hexavalent chromium was 6.3mg/kg. One out of two leather skirts contained hexavalent chromium and the only leather hat which was tested contained hexavalent chromium. The concentration of hexavalent chromium in the leather hat was 9.1mg/kg. Leather skirts are often in contact with the skin during wear and the concentration of hexavalent chromium in the leather was 8.5mg/kg. Two out of five shoes contained hexavalent chromium. In Denmark, there are today around 200-300 new cases of severe chromium allergy every year due to footwear (Menne 2001). Shoes are not normally in direct contact with the skin, except in some shoes for ladies and in sandals. The concentration of hexavalent chromium varied from 6.3-10.7mg/kg Two out of eight leather jackets contained hexavalent chromium although jackets are not normally in contact with the human skin when worn. The concentration of hexavalent chromium varied from 6.8-10.8mg/kg. None of the five tested leather trousers contained hexavalent chromium. As mentioned before, ten additional baby shoes were purchased and sent for analysis for hexavalent chromium content. Two of these shoes were also analysed for migration of chromium according to DS/EN 71 part 3: Dec 1994 - Migration of certain elements. ICP-AES was used as the detection method. The sole and the upper leather from the shoes were analysed separately. The results follow in table 2. It can be seen that the samples do not comply with the stated safety requirements of the European Standard on Safety of Toys EN 71 Part 3: Dec. 1994 2 rev. Discussion The number of leather products containing hexavalent chromium was surprisingly high, especially taking into consideration that the issue has been discussed in the leather journals in recent years. The results were also surprising to the Danish authorities, who initiated the study. The Danish EPA made a press release in connection with this report. The press release quoted Steen Gade, director general of the Danish EPA who stated: 'Of course it's possible to manufacture leather without chromium (VI). The proof is right at hand, ie the 65% of leathergoods that do not contain the substance - even if their total chromium contents are the same. 'This is why it surprised us to find such a high proportion contains chromium (VI) all the same. My advice to importers and the retail trade is that they should check the content of the dangerous chromium compounds in their products - and they should make their requirements known to the manufacturers. My advice to citizens in relevant situations is that they should visit their doctors if they find that they itch or develop a rash in connection with leather.' It can be expected that the Danish authorities will continue to focus on both the content of hexavalent chromium in leather products and the migration of chromium in leather products in the future. The Danish EPA has already initiated new activities related to leather products and its content of chromium. Future work The Danish EPA has started new activities related to hexavalent chromium in leather. The newly-established Allergies Know-how Centre at Gentofte Hospital, which deals with allergies to chemical substances in consumer products, is running a project intended to reveal the relationship between chromium allergies and the chromium content of leathergoods. The project will, therefore, be able to give information of which levels of hexavalent chromium in leather may provoke allergy. These studies and risk assessment studies will form the basis of possible regulation within the EU. Dr Stefan Rydin recently left the Danish Technological Institute to join Rovesta Environment I/S, Betonvej 12, DK-4000 Roskilde, Denmark. Rovesta are the largest Danish environmental company and are owned jointly by local authorities. When Rydin left, he took with him all leather-related work, including co-ordination of Tannet, the European network for the leather industry.