Dyes may be defined as substances that, when applied to a substrate provide color by a process that alters, at least temporarily, any crystal structure of the colored substances [1,2]. Such substances with considerable coloring capacity are widely employed in the textile, pharmaceutical, food, cosmetics, plastics, photographic and paper industries [3,4]. The dyes can adhere to compatible surfaces by solution, by forming covalent bond or complexes with salts or metals, by physical adsorption or by mechanical retention [1,2]. Dyes are classified according to their application and chemical structure, and are composed of a group of atoms known as chromophores, responsible for the dye color. These chromophore-containing cen‐ ters are based on diverse functional groups, such as azo, anthraquinone, methine, nitro, aril‐ methane, carbonyl and others. In addition, electrons withdrawing or donating substituents so as to generate or intensify the color of the chromophores are denominated as auxo‐ chromes. The most common auxochromes are amine, carboxyl, sulfonate and hydroxyl [5-7].

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Textile Dyes: Dyeing Process and Environmental Impact

Detoxification of azo dyes in the context of environmental processes.

Fernando Oliveira (SFRH/BD/65254/2009) acknowledges Fundacao para a Cioncia e Tecnologia, Portugal, for its doctoral grant financial support. Andrea Zille (C2011-UMINHO-2C2T-01) acknowledges funding from Programa Compromisso para a Cioncia 2008, Portugal.

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Plasma Treatment in Textile Industry

Genotoxic, mutagenic and cytotoxic effects of the commercial dye CI Disperse Blue 291 in the human hepatic cell line HepG2

In view of compliance with increasingly stringent environmental legislation imposed by regional, national, and supranational (e.g., European Union) authorities, innovative environmental technologies for the treatment of dye-contaminated effluents are necessary in the color industry. In this study, effluents of an industrial dye producer were subjected to distinct treatment trains following an initial qualitative characterization. The effectiveness of ozonation and a treatment using white rot fungi (WRF) and their enzymes were compared with respect to parameters such as residual color, toxicity on human cells, and genotoxicity. A combined ozonation/WRF process was also investigated. The effluent exhibited significant toxicity that was reduced by only 10% through ozonation, whereas the fungal treatment achieved a 35% reduction. A combined treatment (ozone/WRF) caused an abatement of the toxicity by more than 70%. In addition, the initial genotoxicity of the effluent was still present after the ozone treatment, while it was completely removed through the fungal treatment.

Decolorization, cytotoxicity, and genotoxicity reduction during a combined ozonation/fungal treatment of dye-contaminated wastewater.

Within an EU-funded research project, 281 textile dye products in use at 9 textile finishing companies from 8 European countries were assessed for potential mutagenic properties. Most of the dyes belonged to the so-called existing substances. Data sources considered were data published in the literature, unpublished industrial data provided by dye producing companies and laboratory testing. Data on mutagenicity are virtually absent for many of the dyes. Unpublished test results performed on behalf of the dye manufacturing industry proved to be an important data source, which is not accessible under usual circumstances. Four dye stuffs contained in seven dye products in use at the textile finishing companies were judged to be mutagenic based on published data from literature. Mutagenicity testing using Salmonella typhimurium, strains TA98 and TA100, revealed positive results for about 28% (15 out of 53) of the dye products investigated. Upon further testing with the mouse lymphoma assay (L5178Y/TK +/- ) 67% (6 out of 9) of Ames-positive dyes proved to be mutagenic in this mammalian cell test. All data sources combined led to an overall assessment as being mutagenic for 14 dye products out of 281. For 16 there is a suspicion of mutagenicity due to positive responses in one test. Still, 71 of the dye products are without any data on mutagenicity. This paper describes the data aggregation process, evaluation criteria, the overall assessment, and exemplifies controversial evaluations.

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Mutagenicity of textile dye products.

Textile dyes used within the European Union (EU) were examined for available published and unpublished mutagenicity data. Fifty-three dye products that had so far not been investigated for mutagenicity were tested in the bacterial reverse mutation assay with Salmonella typhimurium (Ames test) according to a modification of the OECD 471 guidelines (instead of five strains, only TA98 and/or TA100 were used with and without metabolic activation (S9-mix)). About 28% (15 out of 53) of the dye samples were positive in the Ames test. Fifteen samples showed positive results with TA98, two were positive in TA100. The mutagenicity of nine Ames-positive textile dye products was further investigated in the mouse lymphoma assay (MLA) (OECD 476). Sixty-seven percent (6 out of 9) induced genotoxic effects in the MLA. The induction rates (IR) were between 2.1 and 132 in the bacterial reverse mutation assay and between 2.1 and 15.2 in the MLA. The results confirm previous findings that dye products are marketed that are not sufficiently tested and that show mutagenic effects in in vitro tests.

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Mutagenicity of different textile dye products in Salmonella typhimurium and mouse lymphoma cells

The roots of Rubia tinctorum L. have a long tradition of being used in dyeing processes of textiles from centuries ago until the present time. The colouring principles belong to the class of hydroxyanthraquinones. Concern arose because several of these compounds were recognised as mutagenic in vitro and even carcinogenic in rodents. To assess the possible risk to humans caused by coloured textiles, mutagenicity was investigated with two madder root samples of different origin (Iran and Bhutan) along the entire dyeing process from root extracts to the dyed wool. The Salmonella/microsome test (Ames assay) with the strains TA98, TA100 and TA1537 was used. Significant mutagenic effects could be detected in madder root extracts and also in the final product, the dyed wool. Madder root from Iran showed considerably higher mutagenic responses than samples from Bhutan. Analytical investigations of the extracts by HPLC showed the presence of a spectrum of anthraquinones typical for madder root. Three mutagenic compounds, lucidine, rubiadine and purpuroxanthine, together with the non-mutagenic alizarine could be detected. The mutagenic response of the different samples was positively correlated with the concentration of the mutagenic anthraquinones, and with lucidine in particular. Based on these investigations a risk to dye-house workers and users of textiles dyed with R. tinctorum must be anticipated.

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The mutagenic potential of madder root in dyeing processes in the textile industry.

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Mutagenic dyes in textile finishing

Die Umsetzung des EU Weisbuches zur Chemikalienpolitik soll mehr Sicherheit und mehr Transparenz beim Umgang mit Chemikalien bewirken. Bisher fehlten bei der Altstoffbewertung oft Informationen zu den Anwendungsfeldern der Chemikalien und den hier auftretenden Expositionen. Im Weisbuch wird deshalb die ‘geteilte Verantwortung’ gefordert. Die Weiterverarbeiter und die gewerblichen Anwender von Stoffen sind viel starker als bisher in die Risikobewertung mit einbezogen. Sie sollen Daten zu Anwendungen von Stoffen und Expositionen zur Verfugung stellen, zum Teil selber auch Expositionsabschatzungen und Risikobeurteilungen vornehmen. Konsequenzen dieses Ansatzes werden im Beitrag anhand der Analyse von Fallbeispielen aufgezeigt. In der aktuellen Diskussion wird vielfach befurchtet, dass kleine und mittelstandige Unternehmen mit diesen Aufgaben vollig uberfordert sind. Es wird vermutet, dass viele Chemikalien fur kleinvolumige Anwendungen nicht mehr zur Verfugung stehen, da die Hersteller diese Anwendungen in ihrer Registrierung — aus Kostengrunden — nicht berucksichtigen. Das Weissbuch ist in seinen Formulierungen nicht genau genug, um abschatzen zu konnen, wie aufwendig die geforderte verstarkte Kommunikation sein wird. Notwendig ist in dieser Situation die Analyse von Beispielstoffen und ihren Anwendungen, um das Prinzip der geteilten Verantwortung besser zu verstehen. Die konkrete Untersuchung mehrerer Produktketten hat gezeigt, dass der hier geforderte Informationsfluss zwischen Herstellern und Anwendern im Rahmen des REACH-Verfahrens durchaus moglich ist. Fur die Hersteller von Chemikalien wird die Informationsbeschaffung zu Anwendungsfeldern und Expositionen durch die starkere Kommunikation vermutlich einfacher werden. Um Uberforderungen der Anwender zu vermeiden, sind aber praxisnahe Ausgestaltungen der Registrierungs-Anforderungen, Schwerpunktsetzungen und gemeinschaftliche Anstrengungen der Anwender auf Verbands-und Branchenebene erforderlich. Hierbei muss auch der Schutz von Unternehmens-Know-how gesichert werden. Die Umsetzung des Prinzips der geteilten Verantwortung kann in der Praxis zu einer verstarkten Kommunikation zwischen Herstellern und Anwendern von Chemkalien fuhren. Dies kann Expositionsabschatzungen und Risikobeurteilungen wesentlich erleichtern. Erforderlich sind handhabbare Vorgehensweisen, die auch von kleinen und mittelstandigen Unternehmen umsetzbar sind. Hierzu liegen inzwischen viele Vorschlage und umfangreiche Bezugsmaterialien vor.

Ismene Jäger

Papers

Mutagenicity of textile dye products.

Mutagenicity of different textile dye products in Salmonella typhimurium and mouse lymphoma cells

The mutagenic potential of madder root in dyeing processes in the textile industry.

Mutagenic dyes in textile finishing

Die Umsetzung des EU Weißbuches zur Chemikalienpolitik