![]() Phosphate buffer: 22.8 g/l K 2HPO 4.3H 2O, adjusted to pH 8.0 ± 0.1 with phosphoric acid de-aeration Whole surfaces of defined geometrical surface areas small pieces, cut into sizes of approximately 2 × 2 × 1 mm 3 ![]() Powdered (by SiC grinding), undefined surface area The aim of this study was to quantify the release of Cr(III) and Cr(VI) from differently tanned, unfinished leather samples, and to investigate the influence of stipulated test conditions of the ISO 17075 standard, and other key exposure parameters, such as temperature, duration, surface area, and solution de-aeration. It has been observed in several studies that different Cr(III) and Cr(VI) compounds have different skin diffusion properties, skin solubility, and sensitizing potential, characteristics that depend on many factors such as charge, size, and speciation ( 4, 33– 35). However, this depends on many factors (condition of the skin, skin diffusion properties of the compound, concentration, and sensitizing species). This means that a person who is Cr-allergic may react to both Cr(III) and Cr(VI). Cross-reactivity between Cr(III) and Cr(VI) in Cr-allergic individuals has been suggested ( 5, 32), as chromate can be reduced to Cr(III) in the skin. The main arguments are that Cr(III) is assumed to be retained within the leather, whereas Cr(VI) is soluble ( 27, 28), that chromate is considered to be a more potent allergen, and that Cr(VI) compounds are able to induce allergy and dermatitis at lower exposure levels than most Cr(III) compounds ( 6, 27, 29, 30).Ĭr contact dermatitis requires a Cr(III)–protein conjugate to be formed in the skin ( 5, 31). The scientific literature, the ISO standard and the restriction all focus on the release of Cr(VI) from leather, without considering the release of Cr(III). It is based on the ISO 17075 standard ( 26) for leather products, which stipulates Cr(VI) determination in leather by extraction of leather powder in de-aerated phosphate buffer for 3 hr. A limitation of Cr(VI) in leather was initially proposed by Denmark ( 24), and it is anticipated that a restriction will enter into force within the EU in 2015 ( 25). Between 7% and 50% of ∼ 9500 leather products tested and reported since the year 2000 contain Cr(VI) at concentrations above the limit of detection (3 mg/kg leather) of the ISO 17075 standard ( 19– 23). More than 90% of the leather produced worldwide (∼ 2 billion m 2) is Cr-tanned ( 16– 18). Leather products have, since the 1990s, attracted increasing attention as a cause of Cr allergy and dermatitis ( 14, 15). Published recommendations on the Cr content in detergents and cosmetics suggest that the level should normally not exceed 1 ppm ( 12, 13). Annex II lists substances that are prohibited in cosmetic products, including several Cr compounds. ![]() Annex IV of the Cosmetic Products Regulation ( 11) lists Cr-containing colorants allowed in cosmetic products under certain conditions, such as that they are rinse-off products or free from Cr ions. Cr compounds may be present in cosmetic products. Prevention of Cr allergy among construction workers by limiting Cr(VI) in cement has been shown to be successful in Nordic countries and Germany ( 9, 10). Cr(VI) in cement has been an important cause of Cr allergy in construction workers. It is a severe allergy with a poor prognosis ( 7, 8). Contact allergy to Cr is the third most common metal allergy, after allergy to nickel and cobalt, affecting approximately 1–3% of the adult general population ( 6). Cr(III) oxalate), are key parameters for both ecotoxicological and human health considerations ( 1– 5). The amount of chromium (Cr) released from leather, and its oxidation state (trivalent or hexavalent) and speciation (chemical form, e.g.
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