Azocolorants in Textiles and Toys

Environmental and Health Assessment

Contents

Danish preface and summary

English preface and summary

1 Introduction
1.1 Background
1.2 Aim

2 Azo-colorants in Textile Dyeing and Printing
2.1 Azo-colorants
2.2 Azo-dyestuffs and azo-pigments on the market
2.3 Conclusion

3 Health and Environment in the Consumer Situation
3.1 General remarks
3.2 Health
3.2.1 Allergy
3.2.2 Carcinogenicity
3.3 Exposure
3.3.1 Levels of aromatic amines found in samples
3.3.2 Duration of exposure
3.4 Risk
3.4.1 Cancer risk
3.4.2 Allergy risk
3.4.3 Discussion of allergy risk
3.5 Conclusion

4 Environmental Hazard Assessment of Azo-colorants
4.1.1 Introduction
4.1.2 Description of sulfonated azo dyes and pigments
4.1.3 Degradation of sulfonated azo dyes and pigments
4.1.4 Ecotoxicology of sulfonated azo dyes and pigments
4.1.5 Conclusions

5 Sampling and Test Results
5.1 Criteria of selection and purchasing
5.2 Survey of samples
5.3 Test procedure
5.4 Test results
5.5 Conclusion

6 Conclusion

7 Literature

Enclosure 1 The Dutch List

Enclosure 2 Regulations

Enclosure 3 Chemical Constitution

Enclosure 4 Test Method and Discussion

Forord

Denne rapport er et resultat af et projekt omhandlende en miljø- og sundhedsrnæssig undersøgelse af azo-farvestoffer i tekstiler.

Projektet er udarbejdet på baggrund af en teoretisk del, i form af videnindsamling, og en praktisk del, som er en undersøgelse af tekstilprodukter, herunder legetøj.

Projektet er udført af Dansk Teknologisk Institut (DTI), Beklædning og Textil, Dansk Toksikologi Center samt VKI. Projektet er finansieret af Miljøstyrelsen.

Projektgruppen bestod af.

• Telam.ing. Charlotte H. Brarup, Akad.ing. Anette Drøjdahl og Civ.ing. John Hansen fra DTI Beklædning og Textil.
• Cand. brom. Helle Buchardt Boyd fra Dansk Toksikologi Center.
• Civ.ing. ph. d. Anne Rathmann Pedersen og Cand. scient. Henrik Fred Larsen fra VKI.

Projektet er blevet fulgt af en følgegruppe bestående af:

• Elisabeth Paludan, Miljøstyrelsen
• Anne Nielsen, Miljøstyrelsen
• Lars Nørgaard, Miljøstyrelsen
• Aage K. Feddersen, Dansk Textil & Beklædning
• Hans Dankert, Dansk Beklædnings- og Textilarbejderforbund
• Connie Brandt, Dansk Textil Union
• Mette Herget, Handelskammeret
• Ann Lehnmann Eriksen, Forbrugerstyrelsen
• John Hansen, DTI Beklædning og Textil

Rapportens kapitler er løbende blevet diskuteret med følgegruppen. Ansvarlig for indholdet i rapportens kapitler er imidlertid alene projektgruppen.

Dansk Teknologisk Institut

DTI Beklædning og Textil

August 1998
 

Resumé

I denne rapport undersøges azo-farver i tekstiler. Rapporten indeholder en teoretisk del, sundheds- og miljømæssige vurderinger, samt en praktisk del, der består af en undersøgelse af tekstilprodukter, herunder legetøj.

Rapporten indledes med et generelt afsnit om azofarver til tekstilfarvning og trykning.

Derefter følger tre centrale afsnit.

Det første afsnit omfatter sundhedsmæssige vurderinger af azo-farver med fokus på allergi og carcinogenicitet. Mulighederne for eksponering for azo-farver eller deres nedbrydningsprodukter diskuteres, og er baggrunden for de testopløsninger, der anvendes i analysedelen.

Det andet afsnit omfatter miljømæssige vurderinger. Som resultat af den sundhedsmæssige vurdering fokuseres på sulfonerede azo-farver. Ved emissioner til det vandige miljø forudsættes at vaskeprocessen er hovedkilden, og nedbrydningsprocesserne af azo-farver diskuteres.

Det tredje afsnit omfatter analysedelen. Her beskrives baggrunden for udvælgelsen af de 59 stikprøver, hvilke testmetoder der anvendes og resultaterne fra analysen fremlægges.

Konklusion

At dømme efter den danske undersøgelse, ud fra indholdet af aromatiske aminer, er risikoen for at få kræft ved eksponering for visse azo-farvede tekstiler lille, men den eksisterer.

Som en foreløbig vurdering angives, at risikoen for at få allergi for nogle azo-farvestoffer kan være betydelig, specielt hvis forbrugeren ikke vasker tekstilet før brug.

Alternativet til azo-farvestoffer kunne være sulfonerede azo-farvestoffer (med få undtagelser) da de sulfonerede aromatiske aminer ikke synes at besidde det samme cancerogene potentiale som de aromatiske aminer.

Da den officielle tyske analysemetode ikke efterligner den faktiske fysiologiske eksponering, anbefales det at modificere metoden med simuleret sur sved og alkalisk sved.

Den miljømæssige vurdering af de sulfonerede azo-farvestoffer og - pigmenter viste, at disse stoffer generelt udviser lav toksicitet.

Det er nødvendigt med yderligere undersøgelser for at klarlægge metabolitternes skæbne samt deres effekt, som kan være vigtige for risikovurdering af azo-farvestoffer i vandige miljøer.
 

Preface

This report presents an environmental and health assessment of azo-colorants in textiles.

The project has been based partly on existing available knowledge and partly on analysis of selected textile products including toys.

The project has been carried out by the Danish Technological Institute (DTI) Clothing and Textile, the Danish Toxicology Centre (DTC) and VKI with support from time Danish Environmental Protection Agency.

The authors are (the project group):

• Charlotte H. Brarup, B. Sc. (Chem. Eng.), Anette Drøjdahl, B. Sc. (Chem. Eng.) and John Hansen, M.Sc. (Chem. Eng.) from DTI Clothing and Textile.
• Helle Buchardt Boyd, M. Sc. (Food-Science) from DTC.
• Anne Rathmann Pedersen, M. Sc. (Chem. Eng.) Ph. D. and Henrik Fred Larsen, M. Sc. (Biology) from VKI.

The project has been followed by an Advisory Committee with the following members:

• Elisabeth Paludan, the Danish Environmental Protection Agency
• Anne Nielsen, Danish Environmental Protection Agency
• Lars Nørgaard, Danish Environmental Protection Agency
• Aage K. Feddersen, Danish Textile & Clothing
• Hans Dankert, the Danish Garment and Textile Workers- Union
• Connie Brandt, the Organisation of Danish Textile Retailers
• Mette Herget, the Danish Chamber of Commerce
• Ann Lehnmann Eriksen, the National Consumer Agency of Denmark
• John Hansen, DTI Clothing and Textile

The chapters in the report have currently been discussed with the Advisory Committee. However, the project group alone is responsible for the content of the chapters in the report.

Danish Technological Institute

DTI Clothing and Textile

August 1998
 

Summary

In this report azo-colorants in textiles are studied. The report contains a theoretical part, a part dealing with health and environmental assessments, and a practical part, an analysis of textile products, including toys.

Following the Introduction, chapter 2 is a general section about azo-colorants for dyeing and printing of textiles, followed by three central sections.

Chapter 3 concerns health assessments of azo-colorants with focus on allergy and carcinogenicity. The risks of exposure to azo-colorants or their degradation products are discussed, and form the background for the choice of the test solutions used in the analysis.

Chapter 4 concerns environmental assessments. Based on the results of the health assessment, focus is on the sulphonated azo-colorants. It is presumed that the washing process is the main source of emission to the aquatic environment, and the degradation processes of azo-colorants are discussed.

Chapter 5 concerns the analysis. The background for the selection of the 59 samples is described together with the test methods used, and the results of the analysis are presented.

Conclusion

Judging from the contents of aromatic amines found in the present survey, the risk of getting cancer from exposure to certain azo-dyed textiles is small, but existing.

A preliminary assessment indicates that the risk of getting allergies against some of the azo-dyes may be substantial, especially if the consumer does not launder the textiles before wearing them.

Alternatives to azo-dyestuffs could be sulphonated azo-dyestuffs (with a few exceptions), since the sulphonated aromatic amines do not seem to possess the same carcinogenic potential as the aromatic amines themselves.

Because the German official procedure for analysis does not simulate the actual physiological exposure, it is recommended to modify the method with artificial acid sweat and artificial alkaline sweat extractions.

The environmental assessment of the sulphonated azo-dyestuffs and pigments show that they in general exhibit a low toxicity. Future studies are needed to clarify the fate of the metabolites and their effects, which may be important for the risk assessment of azo-dyestuffs in the aquatic environment.
 

1 Introduction

1.1 Background

In recent years there has been discussions about the carcinogenic potential of a certain group of colorants

Azo-dyestuffs and pigments (azo-colorants), as the group is classified chemically, are among other things used in the dyeing and printing of textiles. It is the largest group of synthetic dyestuffs coming to 70% of the organic dyestuffs on the market.

Azo-colorants are used for natural, regenerated and synthetic fibres. Owing to the potential carcinogenic effect of certain azo-colorants, their health and environmental properties are under suspicion.

Regulations exist in some countries (Enclosure 2) defining certain groups, socalled aromatic amines, which are known or suspected to be carcinogenic.

The aromatic amines may be split off from certain azo-colorants by the reductive cleavage process.

This project is an attempt to elucidate the human and ecotoxicological characteristics of the aromatic amines in order to give a background for a health and environmental evaluation of aromatic amines in azo-colorants.

1.2 Aim

The aim of the project is to describe those azo-colorants which are of relevance to textile dyeing and printing in both Denmark and abroad.

Furthermore the health and environmental problems in the end-use phase caused by dyestuffs and pigments used for textile products are evaluated on the background of existing knowledge and specialist literature.

As mentioned above the project is limited to concern the aspect of end-use including washing or cleaning. Consequently, only those health and environmental problems are considered which are relevant when textile products are used by the consumer. Thus aspects in the production phase are excluded.

In addition, the aim is to identify the aromatic amines which may be split off.

The practical part is to be carried out by sampling and analysis of a total about 60 textile products, of which 20 belong to the category toys.

The selection of the samples is based on the results of the abovementioned evaluations with a relevant country of origin (both Denmark and foreign countries), and relevant analysis parameters are selected on the basis of the health and environmental evaluations.

The intention is to elucidate if aromatic amines, which could harm health or environment, can be released from textiles on the Danish market.

In the present project the term azo-colorants includes both azo-dyestuffs and azo-pigments.
 

2. Azo-colorants in Textile Dyeing and Printing

2.1 Azo-colorants

Definition

Azo-dyestuffs and azo-pigments are referred to collectively as azo-colorants.

Azo-colorants are a group of chemical compounds, containing one ore more azo-group(s). The azo-group contains a double bond between two nitrogen atoms.

Figure 2.1
Azo-group (Verband der chemischen Industrie).

-N = N-

Azo-colorants are subdivided in azo-dyestuffs, which are soluble in the application medium, and azo-pigments, which are insoluble in the application medium. Azo-dyestuffs can also subdivided in water-soluble (hydrophilic) and fat-soluble (lipophilic) (Verband der chemischen Industrie).

The characteristic property of pigments is their extremely low solubility in organic solvents and in the substrate. They generally exhibit very low solubility in organic solvents and for this reason they remain almost totally in the solid form during time dyeing process and when applied to the substrate (Anliker, 1986).

Azo-dyestuffs are used for both dyeing and printing, whereas azo-pigments are used for printing only.

Manufacture of azo-colorants

Azo-colorants are manufactured by a so-called diazotization process. First the aromatic amine (in Figure 2.2 also called diazo component) is transformed into a diazonium compound. The reaction proceeds at low temperature and in the presence of sodium nitrite and for example hydrochloric acid.

Figure 2.2
The reaction in the manufacture of azo-colorants (Verband der chemischen Industrie).

The diazonium component then reacts with the coupling component (which may be a phenol, a naphtol or an amine) to form the actual dyestuff (Peter, 1989).

Because of the free choice between a large number of both diazo and coupling components, the range of variation in the manufacture of azo-colorants is very wide. The number of combinations further increases because a dyestuff may contain more than one azo-compound. This results in a wide range of shades, applications and fastness properties.

The azo-colorants all share the -N=N- group. To this functional group a large variety of aromatic constituents can be linked so as to give colorants of appropriate characteristics.

The behaviour of the azo-colorant is determined by thie character of substituent groups rather than by the presence of the azo group.

In the case of certain azo-colorants it is also known that the aromatic

amine can be split off again by reductive cleavage of the N-N bond.

2.2 Azo-dyestuffs and azo-pigments on the market

According to time German textile industry the finishing and dyeing of textiles involves some 600 different finishing and auxiliary agents, in addition to about 800 colorants (Platzek, 1996).

The Colour Index, which is the recognized international register of commercial dyestuffs and pigments, assigns names to dyestuffs, not based upon the chemical class of the molecule, but based upon the method of application or the end-use. Azo-dyestuffs are named as Acid, Basic, Mordant, Reactive, Disperse, Direct, Solvent or Food dyestuffs, but not all Acid-dyestuffs are azo-dyestuffs, etc.

The Dutch Regulations contain a list (Enclosure 1) of azo-dyestuffs, which can split off the aromatic amines forbidden in Germany and the Netherlands. A similar list is not included in the German Regulations, and the German authorities do not intend to prepare such a list.

The German Regulations (Enclosure 2) do not specify which dyestuffs or pigments are forbidden, but instead specifies which aromatic amines are forbidden.

The reason is that countless colorants (several hundred) are used, and it would be neither possible nor justifiable to prove the suspicion in each case by the required experiments on animals. (Moll, 1995).

According to the Bundesgesundheitsministerium, other reasons for not intending to prepare a list are:
- the list would be difficult to keep up to date, because new developments are frequently announced
- some dyestuff manufacturers will not publish detailed information about the chemical composition of their products because they wish to keep them confidential.

ETAD (Ecological and Toxicological Association of the Dyes and Organic Pigments Manufacturers) is of the same opinion.

Experience also show that such a list would be difficult to maintain, because dyestuffs and pigments are withdrawn and new dyestuffs and pigments are constantly put on the market because of changes in fashion.

According to (AQUIRE DATABASE, 1993) about 100 azo-dyestuffs, which are affected by the prohibition in the German Regulations, are on the market. Table 2.1 shows the distribution of these azo-dyestuffs grouped according to their content of the 20 aromatic amines, which are forbidden in the German Regulations, and a further two aromatic amines (o-anisidine, p-aminoazobenzol), both categorised as carcinogenic in the EU.

Table 2.1
Commonly used azo-dyestuffs (generic types) on the market, which by reductive cleavage processes can split off carcinogenic aromatic amines considered carcinogenic by the German authorities.

(Figure - 14 Kb)

According to Table 2.1 azo-dyestuffs, which can split off the aromatic amines 2,4,5-trimethylaniline, 2,4-diaminoanisole, 2-naphthylamine, 3,3’dimethyl-4,4’-diaminodiphenyl-methmane, 4,4’-methylene-bis-(2-chloraniline), 4,4’-oxydiarmiline, 4-aminodiphenyl and p-cresidine, should not be present on the market.

DTI knows by experience, that particularly in the Far East some local dyestuff manufacturers exist. There is no control of the produced colorants, and it is not known what types of colorants the manufacturers are producing. Production statistics etc. from such manufacturers do not exist. This means that in this case there would actually be a risk of presence of azo-colorants based on one or more of the 20 aromatic amines prohibited in Germany.

Figure 2.3
Azo-dyestuffs classified by dye class (AQUIRE DATABASE, 1993).

Marketable azodyes which under reducing conditions can cleave off carcinogenic aromatic amines.

(Figure - 2 Kb)

Number of individuals (generic names) which are still manufactured today. The inquiries are made on Colour Indeks and internal databases.

Figure 2.3 shows that direct dyestuffs with 61 % make up the greatest part of the azo-dyestuffs which can split off carcinogenic aromatic amines, followed by acid and disperse dyes. Additional literature of more recent date with similar information does not exist. As was the case for Table 2.1, Figure 2.3 is based on the 20 aromatic amines prohibited in Germany and the Netherlands and the 2 aromatic amines (o-anisidine, p-aminoazobenzol) both categorised as carcinogenic in the EU (AQUIRE DATABASE, 1993).

Figure 2.4 lists the dye classes with respect to their application to the different textile materials.

According to Figure 2.4, direct dyestuffs are mainly used for dyeing of cotton and regenerated cellulose, acid dyestuffs are mainly used for dyeing of wool, natural silk and polyamide. Disperse-dyes are mainly used for dyeing of acetate, polyamide and polyester.

The relationship between azo-colorants and the textile material for which they may be used (Figure 2.3 and 2.4) is one of the points considered in the selection of samples (chapter 5).

Figure 2.4
The dye classes and their application to different fibre (Sørensen, 1996).

Note: XX Is used widely, X Is used and (X) Is used as an exception.

According to (Klaschka, 1994) azo-dyestuffs based on benzidine have not been manufactured in Germany nor in other EU-countries for decades. However, they may still be present in goods imported from other countries. This confirms the experience of DTI. According to Table 2.1 (AQUIRE DATABASE, 1993) the most frequently occurring azo-dyestuffs on the world market are in fact based on benzidine.

2.3 Conclusion

The reasons that azo-colorants make up the majority of colorants used for textiles are the vast nurnber of shades and applications available and the fastness properties.

Due to the vast number of azo-colorants used it is not possible to work out a list of banned azo-colorants. In addition it is often difficult to get any information from suppliers regarding the chemical constitution of some of their products because such information is kept confidential. The use of both azo-dyestuffs and azo-pigments also depends on changes in fashion, in that new colorants appear and old disappear constantly. This means that a list of forbidden azo-colorants would be difficult to maintain.

The relationship between azo-colorants and the textile materials for which they may be used is taken into consideration in the selection of samples for analysis.
 

3. Health and Environment in the Consumer Situation

3.1 General remarks

The following assessment is primarily based on several different reviews. However, original test reports and case reports have been scrutinized whenever deemed necessary. When reviewing the literature in the field of azo-colorants one is greatly hindered by nomenclature complexity. As Burg and Charest (1980) put it: There is a variation in use of old and established names versus modem nomenclature; there are multiple generic terminologies for identical preparations; there exists a multitude of brand names for identical preparations (sometimes even from the same manufacturer); different nomenclatures exist dependent upon the country of origin; many products have very similar names and there is a real probability of error within the literature in reporting results; there are often inadequate descriptions of combination products in which only the major dye ingredient is identified and variations in the salt form, concentration, diluents, surfactants, dedusters, pH modifiers and biocides are not reported; and there exist different materials all described with the same brand name. In some papers, several investigators have tested a particular dye twice under two different trivial names without realizing that they were actually dealing with only one dye.

Names of colorants given in the following text refer to C.I. Generic Name and, where available, C. I. Constitution No. Also where available, CAS number has been added for easier reference.

3.2 Health

The toxicological effects to be dealt with in this chapter are mainly allergy and carcinogenicity. Other effects of some azo-colorants, e.g. irritative and teratogenic effects have been descnibed, but the further investigation into these effects are beyond the scope of this report.

Although some azo dyes have induced teratogenic effects, such effects have not generally been observed across the universe of azo dyes. There is no evidence for teratogenicity associated specifically with the azo or bisazobiphenyl moiety. However, it should be mentioned that the following bisazobiphenyl dyes are teratogenic in animals (Burg and Charest, 1980):

Direct Blue 14
Direct Blue 1
Direct Blue 6
Direct Blue 15
Direct Blue 53
Afridol Blue
Direct Red 28
Direct Blue 25 (embryotoxic)

lt is beyond the scope of this report to assess the risk of these dyes exerting a teratogenic effect on humans, if the dyes are used in textiles and toys.

3.2.1 Allergy

Numerous cases of skin sensitization have been reported in the later years. From 1930 to 1988 the numbers of patients with textile dye dermatitis were small (Feinman and Doyle, 1988). From 1990 and on quite a number of cases have been described. The case descriptions found during our literature search have been summarized in Table 3.1 after checking for repeated description of the same cases. It should be noted, that most cases are due to the use of disperse dyes on synthetic fabrics which do not provide sufficient dye fastness. None of the cases found are caused by pigments, only dyes. All the cases pertain to the final users of the textiles and not textile workers.

Typical clothing mentioned in the cases are tights, panty hoses and leggings, but also wig lining, wrist watch leather straps, bed linen, T-shirts and bodies have caused reactions. Reactions are not limited to atopic individuals, and outbreaks may be severe, requiring emergency treatment and 2-3 weeks of recuperation.

From Table 1 it can be seen, that the most frequent sensitizers are Disperse Black 1, Disperse Blue 106, Disperse Blue 124, Disperse Orange 3, Disperse Orange 76, Disperse Red 1, Disperse Red 17, Disperse Yellow 3, Disperse Yellow 9, p-aminoazobenzene, and p-dimethylaminoazo-benzene. These dyes have all been described as sensitizers by two or more authors independently.

If one has acquired allergy towards a single colorant, one may cross-react to several others within the same category. For instance, people who are sensitized towards Disperse Blue 124 may cross-react to Disperse Blue 106 as they both belong to the azo-azoyl-paraphenylenedlamine group. Among the groups within which cross-reactions may take place are the aminoazobenzene group ( Disperse Red 1, Disperse Red 17, Disperse Brown 1 etc.), the paraphenylenediamine group (paraphenylenediamine and Disperse Orange 3) and the benzothiazol-azoyl-paraphenylenediamine group (2 dyes in Disperse Red 153) (Nakagawa et al., 1996).

Table 3.1
Cases of allergy observed for different colorants 1990-1996.

3.2.2 Carcinogenicity

There are two aspects of carcinogenicity of azo-colorants:

1. The carcinogenicity of time colorant as is, and
2. The carcinogenicity of the aromatic amines which may occur as degradation products upon reductive cleavage of the azo group.

Far from all azo-colorants have been tested sufficiently to determine whether they should be regarded as carcinogens or not. In Table 3.2 below is a list of those azo-colorants which should be regarded as carcinogens. In Table 3.3 is a list of those azo-colorants which are probably not carcinogenic to humans, corresponding to classification in group 4 in the IARC (International Agency for Research on Cancer, World Health Organization) evaluation system. Group 4 is used for agents or mixtures for which there is evidence suggesting lack of carcinogenicity in humans and in experimental animals. In some instances, agents or mixtures for which there is inadequate evidence of carcinogenicity in humans but evidence suggesting lack of carcinogenicity in experimental animals, consistently and strongly supported by a broad range of other relevant data may be classified in this group.

If a colorant is not mentioned on either Table 3.2 or Table 3.3 there has not been found sufficient data to allow for a classification as carcinogen or non-carcinogen. Of course, this leaves us with a large amount of azo-colorants of which we can not determine the carcinogenicity with a reasonable degree of certainty.

The data summarized in the Table 3.2 and 3.3 have been taken from review articles, since time has not allowed to review the large amount of original test reports for all these azo-colorants. Doing so, we are relying on the reviewers ability to distinguish between satisfactory and inadequate methods used in the studies.

Table 3.2
Azo-colorants which should be regarded as carcinogens.

*IARC categories: Group 1 - The agent is carcinogenic to humans. The exposure circumstance entails exposures that are carcinogenic to humans.
Group 2A- The agent is probably carcinogenic to humans. The exposure circumstance entails exposures that are probably carcinogenic to humans.
Group 2B - The agent is possibly carcinogenic to humans. The exposure circumstance entails exposures that are possibly carcinogenic to humans.
** NOEL= No Observed Effect Level or Maximum No-Effect Dose
 

Table 3.3
Azo-colorants which should not be regarded as human carcinogens.

Azo-colorants may form aromatic amines upon reductive cleavage of one or more azo groups. Most often the aromatic amine degradation products are the same as the ones from which the azo-colorant was manufactured, but there are important exceptions. If an aromatic amine is used as the »diazo component« in the manufacturing process the degradation product will be the same aromatic amine, but not necessarily if it is used as the coupling component. Examples to illustrate this distinction are:

a) CI Acid Red 21, formed under coupling diazotised 6-methoxy-mtoluidine to 1 -naphthol-3,8-disulphonic acid is cleaved to 6-rnethoxy-mtoluidine, which falls under the German ordinance, and 2-amino- 1 naphthol-3,8-disulphonic acid, sodium salt:

(Image - 2 Kb)

b) CI Disperse Red 3 1, formed by coupling diazotised p-nitroaniline to 6-methoxy-m-toluidine is cleaved to p-nitroaniline and 4-amino-6-methioxy-m-toluidine

(Image - 2 Kb)

(ETAD, 1995)

The formation of carcinogenic amines is regarded to be the major causative factor of the carcinogenicity of a given dye. Typical examples are benzidine dyes, which are metabolized to the known human carcinogen benzidine (LKRC group 1). Benzidine-based dyes have Malso been placed in group 2A (probably carcinogenic to humans) by IARC. Aromatic amines which may be considered carcinogenic are listed in Table 3.4 below. The list is not exhaustive, since there is a multitude of aromatic amines, which may be formed during break-down of azo-colorants, and not all aromatic amines have been sufficiently tested to allow for an evaluation of carcinogenicity.

Table 3.4
Aromatic amines which may be considered carcinogenic.

All of the aromatic amines in Table 3.4 are also on the German prohibition list, except o-anisidine and p-aminoazobenzene.

5-Nitro-o-toluidine, CAS 99-55-8, and 2,4,5-Trimethyl-aniline, CAS 137-17-7, are both on the German prohibition list, but they are only classified in group 3 (not classifiable) by IARC.

Substitution alternatives

The altemative to using the aromatic amines in the manufacture of colorants could be to use the sulphonated aromatic amines instead. Jung et al. (1992) carried out a comparison of the genotoxicity and carcinogenicity data on sulphonated aromatic amines and their unsulphonated analogues. The comparison showed that the sulphonated aromatic amines generally have no or very low genotoxic effects.

3.3 Exposure

Exposure to either azo-colorants or their degradation products such as aromatic amines may take place via ingestion, e.g. by infants mouthing their toys, and by skin contact,. e.g. by rubbing or extraction via sweat.

Stomach acid

When analyzing textile samples for content of aromatic amines it makes sense to try to mimic the actual conditions of exposure. It is generally known that the environment in the human bowel is acidic, and therefore the analysis can be made on hydrochloric acid solution at pH 1.5.

Sweat

Sweat is secreted by two types of sweat glands, the small, eccrine (minores) and the larger, apocrine (majores) ones. The eccrine sweat glands are far greater in number and are found mostly in hairless skin areas, while the apócrine ones are found more in hairy regions (particularly in the armpits). Eccrine sweat is clear, watery and odorless. Apocrine sweat is cloudy, viscous, often slightly yellow and fluorescent, at times bluish or nearly black. Sterile apocrine sweat is odorless but quickly takes on a characteristic odor due to the action of bacteria.

pH of sweat

At a low rate of sweating, eccrine sweat is acid as a result of the high rate of lactic acid secretion: with increasing flow it turns alkaline owing to bicarbonate secretion. pH at low rates is 5-7, while pH at high sweat flow is 7- 8. Apocrine sweat, because of its higher ammonia content, is somewhat less acidic than eccrine sweat. Sweat from children is generally less acidic than sweat from adults and has pH 6-8 (Lentner, 1981).

These conditions can be mimicked by subjecting the textile sarnples to two different simulants: a »sour sweat« solution at pH 5.5, and an »alkaline sweat« solution at pH 8.

3.3.1 Levels of aromatic amines found in samples

A detailed account of what has been found in samples of textile goods on the Danish market is given in chapter 5.

In the Danish survey some samples have been subjected to treatment with »stomach acid« simulant, some with »sour sweat« simulant, and all of the samples have been subjected to treatment with »alkaline sweat« simulant. The latter treatment produced the largest proportion of positive findings, indicating that clothes being worn while sweating profusely for a long time give time largest exposure to aromatic amines.

Aniline was found in 13 out of 59 samples in total. Levels found were 0.4-160 mg/kg textile. The sample with the largest content was a pink cotton sheet.

Aromatic amines listed in Table 4 was found in 17 out of the 59 samples. Lowest positive finding was 0.1 mg o-toluldine/kg textile and the highest finding was 70 mg o-toluldine in a child cotton sweater of dark olive color. The same sweater also had a content of a variety of the other amines listed in Table 4 and aniline and p-phenylenediamine (which is allergenic).

Benzidine or isomers hereof were found at a level of 300 mg/kg in two samples, one was a burgundy lady silk pajamas, and the other was a pair of brown cotton boxer shorts.

A recent Swedish survey of 11 pieces of children’s clothes found a content of »hazardous« azo-colorants in two out the 11 samples. The report does not state the identity and quantity of the azo-colorants, but it says that certain hazardous aromatic amines were found, which may be formed from certain azo-colorants. In addition to this a content of 27 mg of chromium was found in a pair of baby pants, and up to 0.22 mg of lead/kg and 37 mg of copper/kg was found. Also, rather high pH values, above 8 in 5 out of the 11 samples. The highest pH measured was 9.4 (Meisner, 1997). With high pH values in the clothes it is not necessary to sweat alkaline sweat in order to extract aromatic amines. The exposure can come about just by to spilling water, food or the like on the clothes, as children often do.

3.3.2 Duration of exposure

Textiles for clothing will normally provide a peak exposure the first time they are worn, if they are not laundered by the consumer before wearing. Shoes will, however, provide a constant exposure, since shoes are rarely laundered. Since feet can get very sweaty, and provide an alkaline environment there is a good chance of extracting aromatic amines from any azo colorants used in the shoe material. Unfortunately, we have not had access to results of test for amines carried out on shoes, be it leather ot other material.

ETAD (1997) has carried out a study on extractability of dyestuffs from textiles over a normal lifetime of use, which has been set at 50 wearing-washing cycles for any piece of textile. Three disperse dyes, Disperse Yellow 3, Disperse Blue 3 and Acid Red 114 were chosen- to dye polyamide for the experimental study. This is to be regarded as a worst case study since deep shade dyeing with disperse dyes on polyamide gives poor fastness. The study showed that measured migration was much lower than what could be predicted when applying the following default model proposed by the German BgVV:

External exposure (predicted) in µg/kg/day =
1 m (textile) x  D x 50 x 0.001 x 106 µg/kg bw./day
70 kg (person)

where

The study also showed that:

• for a typical reference dyeing strength, a fastness of approximately 4 results in an average exposure of ca. 1 µg /kg bw./day,
• the predicted average exposure calculated on the basis of 0.1% migration of the dyestuff can be as high as 2500 µg/kg bw./day, and
• that the measured amount of migrating dyestuffs declines over the normal lifetime of use.

One of the reasons for the high discrepancy between measured average exposure and predicted average exposure could be that due to alkalinity of laundering agents the free aromatic amines and surplus dyes are extracted fairly rapidly.

3.4 Risk

3.4.1 Cancer risk

In connection with the findings of aromatic amines in toy animals the risk of cancer was calculated by the National Food Agency of Denmark (1996). Under the preconditions that a child is exposed to a dose of 0.1 mg of o-toluidine, corresponding to the maximum finding in 1 kg of toy animal, the calculated risk is 1-2 x 10^-7. Since absorption via the skin or by ingestion from 1 kg of toy animal must be considered extreme, there appears to be a fairly good margin of safety. A risk of 1 x 10^-6 is normally considered an acceptable risk of cancer following consumer exposure. At that risk level a limit of 10 mg o-toluldine/kg textile may be considered acceptable under the assumption of exposure to only 100 g of toy animal or textile and a linear relationship between exposure and risk of cancer.

Due to limitations in time and data, risk calculations for other relevant amines have not been carried out. However, it should be borne in mind that the carcinogenic potency of o-toluidine is relatively small, compared to some of the other aromatic amines as e.g. benzidine. Furthermore, there is an estimated uncertainty on the risk calculations for o-toluldine of a factor 10, cornpared to other linear models.

The US-EPA (IRIS, 1997) has calculated the risk of cancer from oral exposure to benzidine expressed as a slope factor of 2.3 x 10² per mg/kg/day. The slope factor is the result of application of a low-dose extrapolation procedure and is presented as the risk per mg/kg bodyweight /day. This translates to an exposure of 4.3 x 10^-6 µg benzidine/kg/bodyweight/day at the normally accepted risk level of 1 x 10^-6. Under the conditions that a child of 10 kg bodyweight consumes 100 g of textile in the course of e.g. 2 years a resulting limit of 3.1 x 10^-1 µg benzidine/kg textile can be calculated. This is far below the analytical detection limits.

Therefore, applying the principle of caution, a general limit of 0.1 mg aromatic amines/kg textile and a limit specifically for benzidine as »not detectable« by the most sensitive analytical method available is hereby recommended.

3.4.2 Allergy risk

The risk of getting allergic reactions to certain azo dyes and amines from textiles must be regarded as substantial, deeming from the number of cases recently reported by several independent authors in different countries in Europe and Japan.

The most frequent sensitizers reported are Disperse Black 1, Disperse Blue 106, Disperse Blue 124, Disperse Orange 3, Disperse Orange 76, Disperse Red 1, Disperse Red 17, Disperse Yellow 3, Disperse Yellow 9, p-aminoazobenzene, and p-dimethylaminoazobenzene. Contents of Phenylendiamines, such as those found in our survey of textiles on the Danish market, may also cause allergic reactions, either directly or as cross-reactions owing to allergy to Disperse Orange 3 for instance.

3.4.3 Discussion of allergy risk

When characterizing risk, both the probability of the effect and the severity of time effect should be considered.

Probability

A quantitative risk assessment would require that we have some knowledge of the number of people exposed to textiles with the dyes, which have resulted in cases of allergic reactions, namely contact dermatitis.

The risk would then be expressed as:

(Image - 3 Kb)

percentage of people expected to react after exposure to azo-dye in textile.

However, we do not have access to data on the number of people exposed. Information on e.g. »number of panty hoses produced with the azo-dyes in question« is not obtainable. Hence, we are not able to express the risk assessment numerically.

On the other hand, judging from our experience with numerous literature searches for allergic cases resulting from exposure to other chemicals than azo-dyes the number of cases found in this study is relatively large. This indicates that we are dealing with a substantial risk, i.e. a risk, which is real, and which is not negligible. If we had found only a few cases of reactions per dye substance, we would have called the risk negligible. We do not know if the risk is »small«, »considerable« or »large«, since we have no idea of the number of people actually exposed nor the actual number of people reacting allergic after exposure. We only know that the people who had reactions have been exposed at least twice, unless we are dealing with cross reactions. It should be noted that there is a clear causal relationship. All cases have been confirmed as far as it is possible with the identification of azo-dyes.

The severity of the effect

Concerning the nature of allergic contact dermatitis it should be noted that:

• Reaction to allergens do usually not occur unless the person has had previous exposure to the specific allergen. The first - and maybe several - exposures is called the sensitization phase during which the immune system is primed for recognition of the allergen. Patients are often surprised to learn that substances to which they have been exposed for years suddenly are identified as the cause of an allergic reaction.
• Reactions during first-time exposure may occur as a result of cross-sensitizations due to close resemblance of the allergens in question. If, for instance, one is sensitized to p-phenylendiamine in hair dyes, a cross reaction to Disperse Orange 3 may occur.
• When a person is sensitized it usually requires a smaller amount of allergen to elicit the reaction than it took to induce the sensitization. This agrees nicely with the following scenario: a person wears a dyed garment a few times before washing it for the first time. During this period the peak exposure takes place. After wash there is only little surplus dye left in the garment, but maybe enough to elicit a reaction, or a reaction may not be elicited until time person is exposed to anotimer garment providing a peak exposure.
• Sensitization lasts for a life time. Desensitization cures (vaccinations) are only feasible for proteinaceous allergens such as pollen or animal hair, and in such cases only with a success rate of about 50%. However, the symptom, i. e. the contact dermatitis, may be relieved by medical treatment and/or avoi­dance of exposure to the allergen, if at all possible.

Azo-dye allergy in perspective

It seems peculiar that the literature search came up within many cases world wide whereas such cases are rarely reported in the Nordic countries. This may be due to a number of reasons of which at least five should be mentioned: First, azo-dyes are not part of the standard test kit used in dermatology clinics. Second, azo-dye contact dermatitis might be subject to publication bias. Some clinicians find cases worthwhile reporting, while others do not. However, the lack of published cases from tlie Nordic countries does not disqualify the findings in other countries. Third, many cases of contact dermatitis are never resolved, and the causal agent remains unknown. If the medical treatment works, and the patient does not return with further eruptions, there is no cause for costly and I uncomfortable further investigations. Fourth the use of hair dye containing p-phenylendiamine may be more prevalent in Southern Europe giving rise to cross-sensitization, which may account for some of the cases. Fifth, the textile quality available and the pattern of use in other countries may be different.

According to Menné (1998) maybe less than five cases a year are seen in one clinic in Denmark. For a clinician who sees a lot more cases caused by other chemicals, such as perfume or nickel, the few cases caused by azo-dyed textiles looks like a relatively small incidence.

When considering the incidence, it should be borne in mind, that although we have established that there is a substantial risk, the risk will not show up as cases if exposure ceases. The offending dyes are not reported as those commonly sold by the European Dye Manufacturers. Of course, textiles dyed with the offending dyes may still be imported from outside Europe. We know that in the period up to 1988 textile dye dermatitis was not considered a problem, and the numbers of patients with textile dye dermatitis was denoted as »small«.

For the period of 1990 - 1996 we have found a relatively high number of cases resulting from exposure to azo dyes via textile contact. We do not know if the number of cases in the future is going to increase, stagnate or decrease. Administratively, there has not been set any acceptability limit for allergic risk, as there has been for cancer risk.

3.5 Conclusion

Judging from contents of aromatic amines found in the present Danish survey the risk of getting cancer from exposure to azo-dyed textiles is small, but existing. However, the majority of azo-colorants and amines have not been adequately tested.

The risk of getting allergies against some of thie azo dyes may be substantial, especially if the consumer does not launder the textiles before wearing them, since it is the first wearing which provides the peak exposure that usually causes sensitization.

The most frequent sensitizers reported are Disperse Black 1, Disperse Blue 106, Disperse Blue 124, Disperse Orange 3, Disperse Orange 76, Disperse Red 1, Disperse Red 17, Disperse Yellow 3, Disperse Yellow 9, p-aminoazobenzene, and p-dimethylaminoazobenzene. Contents of Phenylendiainines, such as those found in our survey of textiles on the Danish market, may also cause allergic reactions, elther directly or as cross-reactions owing to allergy to Disperse Orange 3 for instance.

Alternatives to the azo-dyes giving off time offending aromatic amines could be sulphonated azo dyes (with a few exceptions), since the sulphonated analogues to the aromatic amines do not seem to possess the same carcinogenic potential.
 

4. Environmental Hazard Assessment of Azo-colorants

4.1.1 Introduction

Based on the human health assessment pointing out the sulfonated azo dyes and pigments (azo-colorants) as the least toxic azo dye components for dyeing textile, fabrics, etc., this environmental hazard assessment will focus on the sulfonated type. lt is presumed that the main emission to the aquatic en­vironment during the use of dyed textiles originates from the washing process with subsequent aqueous, effluent to the drain. The hazard assessment will be based on the intrinsic properties of the parent chemicals and to some extent the degradation products of the azo-colorants.

In general, after completion of the dyeing process, loss of the dyestuff to the aquatic environment is considered as negligible as the dyestuff is effectively irreversibly bound to the substrate. However, excess dye in fabrics etc. is washed out during initial washes and afterwards conveyed to domestic wastewater.

Azo dyestuffs and pigments are generally resistant to biodegradation under aerobic conditions. The fate of azo-colorants in wastewater treatment plants has been investigated and the general observation is that these are adsorbed to the sludge in biological treatment plants (Clarke & Anliker, 1980). The adsorption of time organic colorants is favoured in the case of azo-groups, whereas the adsorption may be reduced by the presence of sulfo-groups. This is observed in the case of acid dyes but not in time case of reactive and direct dyes (Clarke & Anliker, 1980). In general, all pigments are likely to adsorb onto organic particles. In many wastewater treatment plants the sludge is treated only by anaerobic digestion and afterwards the sludge may be used as fertilizer on agriculture land. Due to the adsorption ability, it is most likely that the dyes, at least initially, will end up in anaerobic environments after discharge to the environment. Degradation under anaerobic conditions are therefore an important factor in assessing the fate of the azo-colorants. The azo dyestuffs are normally primarily degradable under anaerobic conditions, at least slowly, whereas the pigments may be degraded slowly if at all. The azo dyes are reduced to form aromatic amines that are resistant to further biodegradation in the absence of oxygen, and thus accumulation in the environment is likely to occur. Focus on degradation products is therefore very important from a risk assessment point of view. Low water solubility of the azo compounds complicates the ecotoxicology testing, and ecotoxicity data are very sparse. The bioavailability of the colorants for aquatic organisms is also very low because of the low solubility and this results in low toxicity properties. A survey of the fish toxicity of 3000 commercial products by ETAD, members showed that LC50 values were higher than 1 mg/l for 98% of the products (Clarke & Anliker, 1980).

4.1.2 Description of sulfonated azo dyes and pigments

Sulfonated azo pigments are typically beta-oxy-naphthoic acids or betanaphthols. The pigments are water insoluble. The sulfonated azo dyes are water soluble to some extent. These dyes are used for dyeing textile and leather, among others. The acid dyes are anionic dyes with typically 1-3 sulfonic groups. They are applied to wool, silk and polyamide, whereas direct dyes and mordant dyes often composed of polyazo groups are applied for cotton, viscose, etc. (Zollinger, 1991). The sulfonated azo dyes may be composed of naphthalene sulfonic acids, naphthols, naphthoic acids, benzidines etc. Benzidine based azo dyes are in focus because of the carcinogenicity of benzidine. Sulfonated azo dyes based on benzidine are e.g.(Brown & Hamburger, 1987):

Direct Red 28
Direct Blue 1, 14, 15
Acid Red Il 4

4.1.3 Degradation of sulfonated azo dyes and pigments

Degradation studies of azo pigments are very sparse while more studies have been conducted for the water soluble azo dyes. Results from degradation studies of sulfonated azo dyes are listed in Table 4.1.

Aerobic degradation

Azo dyestuffs and pigments are not readily aerobic degradable. The biological degradation of organic dyes (87 different acid, basic, direct, and reactive dyes) was studied using different aerobic degradation tests (Pagga & Brown, 1986). The general conclusion was that the dyestuffs were not readily biodegradable but some were inherently degradable. None of the sulfonated azo dyes Acid Orange 3, Acid Yellow 36, Direct Blue 14, 15, and Direct Red 7 were biodegradable except Direct Blue 14 that was partly degradable (Pagga & Brown, 1986). Bacterial strains with the ability of reducing the azo-bond under aerobic conditions have been isolated from a wastewater treatment plant receiving azo dye-containing effluents (Coughlin et al., 1996). This indicates that rnicroorganisms may develop the ability of degrading azo components after an adaptation period. The degradability potential of the isolated bacterial strains was limited to dyes with only one sulfonate group, indicating that highly charged compounds have difficulties in crossing the cell membrane for degradation (Coughlin et al., 1996).

Anaerobic degradation

The reductive cleavage of the azo-bond may lead to the formation of two aromatic amines. In the case of sulfonated azo dyes, at least one of the metabolites is sulfonated whereas the other part theoretically is similar to the degradation products from non-sulfonated azo dyes. The anaerobic degradation of azo dyes has been studied with subsequent aerobic treatment in order to study the degradation of the metabolites. The first study in a series of studies on the degradation of azo dyestuffs showed that the sulfonated azo dyes Acid Orange 3, Acid Red 114, Direct Blue 15, Di­rect Red 7, Direct Yellow 12, and Mordant Black 9 were primarily degradable under anaerobic conditions (Brown & Laboureur, 1983). Degradation of sulfonated azo dyes (Acid Orange 7, 8,10, Acid Red 14,18) in a two stage anaerobic/aerobic treatment has been investigated (Seshadri et al., 1994; FitzGerald & Bishopo 1995). The dyes were readily reduced in time anaerobic stage, whereas the degradation of the metabolites was not clarifired. The results showed that the metabolites may be absorbed to the biomass (FitzGerald & Bishop, 1995).

Degradation of metabolites

Another study showed that primary anaerobic degradation of the sulfonated azo dyestuffs (Acid Orange 7, Acid Yellow 25, 36, Acid dye, Acid Red 114, Acid Black 24, Direct Red 7, Direct Blue 14, 15, Direct Yellow 12, 50, Mordant Black 9, 11) took place with formation of metabolites that were not further degraded in the absence of oxygen (Brown & Hamburger, 1987). The metabolites were subsequently treated with activated sludge under aerobic conditions. Amino benzene sulfonic acid, amino ethmoxy benzene, diamino dimethoxy biphenyl, and amino methylbenzene phenyl sulfonamid were degraded (>75%), whereas dichloroanilin, aminonaphthalene sulfonic acid, and amino methyl (sulfophenyl) pyrazole were only partly or not degraded (<25%). Tests for inherent biodegradability showed that amino benzene sulfonic acid, amino naphthalene sulfonic acid, and amino ethoxybenzene were inherently degraded, whereas amino napthalene disulfonic acid, amino methylbenzenesulfonic acid and dichloroanilin were not inherently biodegradable (See Table 4. 1) (Brown & Hamburger, 1987). Degradation of the metabolites was also investigated under anaerobic conditions and only diamino dimethmoxy biphenyl was readily degraded (Brown & Hamburger, 1987).

According to MITI (1992), no components with structural similarities to the typical metabolites, aromatic amines (sulfonated or not) are readily biodegradable under aerobic conditions.

Abiotic degradation

Photolysis is considered as insignificant for the degradation of the dyestuffs in the aquatic environment (Clarke & Anliker, 1980).

4.1.4 Ecotoxicology of sulfonated azo dyes and pigments

In general, organic pigments exhibit a low acute aquatic toxicity probably because of the low water solubility of the pigments. However, in presence of fairly high concentrations of pigments, a lethal effect to fish may occur arising from clogging of the gills by the aqueous pigment dispersion (Anliker & Clarke, 1980). The ecotoxicity of the sulfonated azo dyes and pigments is in general very low. The survey of fish toxicity for 3000 azo dyestuff products collected by ETAD summarises the LC0 values (no effect concentration) for a range of dyestuffs. Acid dyes exhibit the highest toxicity level (LC0 values < 100 mg/I observed for 48% of 371 dyes) whereas only 9% of the direct dyes (of 224 dyes) and 38% of the mordant dyes (of 21 dyes) have LC0 values lower than 100 mg/l. Data for some of the sulfonated azo dyes are listed in Table 4.1. Only Mordant Black 11 shows a high fish toxicity in addition to inhibition effects on algal growth and the activated sludge process (Burg & Charest, 1980).

lt is beyond the scope of this preliminary assessment of the environmental effects of azo dyes to consider the toxicity of the metabolites from the anaerobic degradation. In general, the hydrophilic sulfonated aromatic amines have a low toxicity (Anliker, 1989). However, some of the metabolites not sulfonated might have a high toxicity in the aquatic environment e.g. the chlorinated aromatics.

4.1.5 Conclusions

This preliminary hazard assessment of sulfonated azo dyes and pigments is based on the most available literature, so the results here may not necessarily cover the whole spectrum of sulfonated azo colorants. The azo dyes and pigments are likely to adsorb onto organic particles as sludge and sediments and consequently they are likely to end up in anaerobic environments where they normally are primarily degraded. In aerobic wastewater treatment, some dyes may be inherently biodegraded after an adaptation period of the biomass. The anaerobic degradation leads to the formation of metabolites that are resistant to biological degradation in the absence of oxygen. In general, the sulfonated azo dyes and pigments exhibit a low toxicity. Mordant Black 11 is the only dyestuff observed here with a fish toxicity lower than 100 mg/l. The biodegradability and the toxicity of the metabolites are highly dependent on the structural formula, which is very diverse. Some of the metabolites (e.g. chlorinated aromatic amines) may exhibit a high toxicity. In order to clarify the fate and the effects of the metabolites, which may be important for the risk assessment of the azo dyes in the aquatic environment, further studies have to be done.

Table 4.1
Biodegradability and ecoloxicity of some sulfonated azo dyes and pigments and some potential metabolites.

¹Pagga & Brown, 1986 ²Brown & Laboureur, 1983 ³Seshadri et al., 1994,
⁴FitzGerald & Bishop, 1995, ⁵Brown & Hamburger, 1987, ⁶AQUIRE, 1993, ⁷Burg & Charest, 1980,⁸ IUCLID, 1996
 

5 Sampling and Test Results

5.1 Criteria of selection and purchasing

This section describes the criteria for the selection and purchasing of textile articles for the tests. The principal criterion has been to select articles which in use would give the highest possibility that persons could absorb released chemical compounds from the textile products, either by pronounced contact with the skin (adults and babies) or by sucking (babies).

The following types were chosen:

• bedlinen (covers and sheets), bath towels/wash cloths, underwear, nightwear, T-shirts, socks, panty hoses, blouses, trousers, skirts, scarfs, baby clothing, cuddle toys and cloth toys.

The selection of samples within the types of textile products was based on the present knowledge of dyestuffs which can split off aromatic amines commonly considered as harmful, and of the main applications of these dyestuffs.

The fibre content and the colour of the textile products were thus chosen so, that time highest probability of a content harmful dyestuffs was present.

Articles with printed designs and front prints were selected analogously.

Consequently, the selected articles do not constitute a representative random sample of textile products on the Danish market. The selected articles represents rather a worst case situation.

It was attempted to obtain an equal distribution between Danish products and imported articles.

The textile products were purchased in national department stores and chain stores, where a broad section of the population goes shopping.

5.2 Survey of samples

A survey of the samples is presented in Table 5.1.

Table 5.1
Survey of the samples.

Table 5.2
Origin of the articles

Only five articles are labelled »Made in Denmark«. Twenty articles carry a label definitely showing foreign origin. Of the remaining 24 articles, some may be manufactured in Denmark but the majority is of unknown origin.

5.3 Test procedure

Solution »stomach acid« is a hydrochloric acid solution at pH 1.5 (as specifled in DS/EN 71-3:1995 - Safety of toys - migration of certain elements).

This solution simulates the action of stomach acid when babies and infants are sucking textile pro­ducts, and when children and adults are inhaling and swallowing textile dust particles.

Solution »acid sweat« is an artificial sweat at pH 5.5 according to ISO 105-E04:1994 Colour fastness to perspiration.

Solution »alkaline sweat with reduction« is an artificial sweat at pH 8.0 according to above mentioned ISO-standard, in which a reduction treatment is carried out with sodium dithionite.

The two solutions »acid sweat« and »alkaline sweat with reduction« simulate the effects presumed to take place when textiles are in contact with the skin.

Extracts with the alkaline sweat solution were prepared from all articles and analysed for splitt-off aromatic amines by gas chromatography (GC/MS). In certain cases, extracts were also prepared with the stomach acid solution and the acid sweat solution. These extracts were analysed for free aromatic amines.

A detailed description of the test method is given in Enclosure 4, which also lists time detection limits in Table 11.1.

5.4 Test results

In Table 5.3 the test results are presented. In the table the following notations are used:

• Aromatic amines detected in each sample are listed with the concentration given in brackets.
• Aromatic amines with no marks are included in the IARC-list or in the German Regulations:

Amines on both IARC-list and German Regulations list:

• Benzidine
• 4-Chloro-o-toluidine
• 2-Naphthylamine
• 4-Aminobiphenyl
• p-Chloroaniline
• o-Aminoazotoluene
• 4-Methoxy-m-phenylenediainine (2,4-Diaminoanisol)
• 4,4’-Methylene-dianiline (4,4’-Diaininobi-phenylmethane)
• 3,3’-Dichlorobenzidine
• 3,3’-Dimethoxybenzidine (o-Dianisidine)
• 3,3’-Dimetliylbenzidine (o-Tolidine)
• 4,4’-Methylene-di-o-toluidine (3,3’-Di-amino-4,4’-dian-fino-biphenylmethane)
• 6-Methoxy-m-toluidine (p-Cresidine 1 5-methyl-o-anisidine)
• 4,4’-Methylene-bis-[2-chloroaniline]
• 4,4’-Oxydianiline
• 4,4’-Thiodianiline
• o-Toluidine (2-methylaniline)
• 4-Methyl-m-phenylenediamine (2,4-diamino-toluene)

Amines on the IARC-list, but not on the German Regulations list:

• o- Anisidine (o-Methoxyanilin)
• p-Aminoazobeiizene

Amines not on the IARC-list, but on the German Reszulations list:

• 5-Nitro-o-toluidine (2-Amino-4-nitrotoluene)
• 2,4,5-Trimethylaniline
• Aromatic amines marked with *) are other aromatic arnines which are neither on the IARC-list nor on the German Regulations list.
• Test results marked with **) was obtained using a different method of analysis (reduction in alkaline liquid according to Oeko-Tex standard 200). The method is not publicly available.

Table 5.3
Test results.

(Table - 75 Kb)

(Table - 92 Kb)

The full report of the testing is given in the reports Reg.nr. 19721 dated 1996.10.08, 19972 dated 1996.12.19 and 21161 dated 1997.03.05, all issued in Danish by DTI Chemical Technology.

5.5 Conclusion

The detection limits are not the same for every one of the aromatic amines and some of the amines are particularly sensitive to the analysing system, while others are not.

On this background it might be reasonable to assume one common detection limit of not less than 2 ppm (2 mg/kg textile). From an analytical consideration, the assumed detection limit should probably be 5 ppm, to be sure to have a realistic overall detection limit for all amines.

The four samples No. 11, 14, 30 and 40 show appreciable amounts of amines split off (more than 5 ppm), amines which are included in the IARC-list as well as in the German Regulations.

For the samples No. 16, 17, and 34 the tendency is the same but the amounts of amines from the list are smaller (sample No. 34 less than 5 ppm but higher tham 2 ppm; sample No. 16 and 17 less than 2 ppm but higher than 1 ppm. However, for sample No. 16 there is an uncertainty about which isomer of anisidine is present).

In the samples No. 11, 14, 16, 17, 30, 34, 37 and 40 the following amines from one or both of the two lists were found:

4-Chloroaniline
2,4-Diaminotoluene
4-Aminobiphenyl
o-Toluidine
o-Diarmisine
o-Tolidin
2-Amino-4-nitrotoluene
o-Anisidine (or p-Anisidine which is not on any of the two lists)
Benzidine (or its isomers which are not on any of the two lists)

Very appreciable amounts (300 ppm) of benzidine or its isomers were found in sample No. 37 and 40. Benzidine is included in both lists, but it was not possible to determine whether benzidine itself was in fact present.

Several samples split off very high amounts of amines which are not included neither in the IARC-list nor in the German Regulations list. This is time situation for the samples No. 2, 15, 16, 22, 23, 26, 28, 30, 37, 40, 43, 46 and 49.

The amines which are not included in any of the two lists but are found in rather high amounts are:

Aniline
m- and p-Toluidine Isomers of Benzidine m- and p-Anisidine
Isomers of Chlorophenylenediamine
p-Phenylenediamine
Aminocresole
Isomers of Trichloroatmiline
Dodecylaniline
p-Phenetidine
Chloroisomers of o-Trifluoromethylaniime

The analysis shows only very little tendency to find free amines in the textiles.

Both dyed and printed textiles were represented in time group of five samples (No 11, 14, 30, 34 and 40) for which listed amines were found in amounts of 2 ppm or more.

One dyed sample was made of polyester, the remaining four were made of cotton and two of these were dyed and two were printed.

It is not known whether the print is pigment printed or printed with a dyestuff.

The thirteen samples (No. 2, 15, 16, 22, 23, 26, 28, 30, 37, 40, 43, 46 and 49) which split off other amines than the listed ones are all dyed, but two of them do have additional print on time dyed fabric.

The majority of thiese dyed samples are made of cotton, but nylon, silk and wool are represented as well.
 

6 Conclusion

This project shows that aromatic amines, which are suspected to be harmful to the health, can be released from textiles on the Danish market.

An evaluation of the contents of aromatic amines found in the analysis indicates that the risk of getting cancer from exposure to certain azo-dyed textiles is small, but existing. The risk of getting allergies against some of the azo dyes may be substantial, especially if the consumer does not launder the textiles before wearing them the first time.

The analysis shows the presence of aromatic amines which are included on the IARC list as well as in the German regulation, but it is also shown that several samples split off high amounts of amines which are on neither of the two lists.

The analysis shows that the detection limits are not the same for every one of the aromatic amines and some of the amines are particularly sensitive to the analysing system while others are not.

From an analytical consideration the assumed detection limit should therefore probably be 5 ppm to be sure to have a realistic overall detection limit for all amines. From a health point of view a detection limit at 5 ppm is, however, unacceptably high. There seems therefore to be a need for better analytical me­thods.

Alternatives to the azo-dyes giving off the offending aromatic amines could be sulphonated azo dyes, which do not seem to possess the same carcinogenic potential, and which also seem not to be en­vironmentally harmful.
 

7 Literature

Anliker R., Safety in use and mammalian and aquatic toxicity of colorants, In Chemistry of functional dyes, Yoshida Z. & T. Kitao (Eds), Mita Press, Tokyo 1989

Anliker R., Toxic Hazard Assassment of Chemicals, The Royal Society of Chemistry, 1986, p. 166-187, Organic Colorants-, Interpretation of Mammalian, Geno-, and Exo-Toxicity Data in Terms of Potential Risks

Anliker R. & Clarke E.A., The ecology aimd toxicology of synthetic organic pigments, Chemosphere 1980, 9:595-609

AQUIRE DATABASE, US-EPA, Environmental Research Laboratory, Duluth 1993, N1N 55804

Aspland J.R., Azoic Combinations: Chemical Principles, Textile Chemistry & Colorist, 24 No. 8, 1992

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Enclosure 1

The Dutch List

Indicative list of dyestuffs whose use in textile is forbidden, because from these the aromatic amines, mentioned in the Dutch Regulations, can be formed.

In Table 8.1 the following abbreviations are used for the aromatic amines formed:

Table 8.1

2) concerns dyestuff itself
 

Enelosure 2

Regulations

The German Regulations

At present the German legislation consists of the Regulations on Commodities and five amendments.

The Regulations do not only contain a prohibition of aromatic amines in textiles, but only that subject shall be mentioned in this project.

On account of the many amendments it can be difficult to see through the Regulations on Commodities. Therefore the deadlines for the manufacture and sale of consumer goods are listed in the two tables below.

Table 9.1
Manufacture of consumer good (ETAD, 1995).

Table 9.2
Sale of consumer goods.

* = The deadline is revoked

The goods, which the Regulations apply to, are specified in Table 9.3. Futhermore, the analysis, to determine the aromatic amines has to be carried out using a certain analytical method mentioned in (German competent authorities, 1996). The German Regulations specify a limit value of 30 mg/kg textile for any of the aromatic amines listed in Table 9.3.

The Regulations established a ban on the use of azo dyestuffs, which can split off the aromatic amines listed in Table 9.3. Garments, which are produced after March 31st 1996, are fully covered by the Regulations, and a deadline of December 31st 1998 is established for the sale of garments manufactured before March 31st 1996.

Table 9.3
The list of the 5th amendment containing the banned aromatic amines (Bundesrat) (chemical constitution, se enclosure 3).

* Infants means children under 12 months, and small children means children between one and tree years old.

The deadline for second-hand goods, protective clothing and uniforms, not for private use, was revoked, with the argument, that gradually fewer articles containing the banned aromatic amines will be on the market because of the prohibition in the German Regulations against the use of azo dyestuffs, which can split off the banned amines.

The deadline for both manufacture and sale of recycled textiles is December 31st 1999. This also include furs, leather, accessories.

The deadline for azo pigments is March 31st 1998 for both manufacturing and import, and for the retail the deadline is September 30th 1998.

Table 9.3 contains essentially the same amines as the German MAK-IIIA1 and A2 list, annually published in Bundesarbeitblatt. The amines are classified as follows:

A1: Clearly proven to be carcinogenic
A2: Shown by experience to be carcinogenic
B: Justified suspicion of carcinogenic potential

The MAK-list contains two additional aromatic amines. One belongs to the MAK-IIIA2 group and the other has not been classified yet. These two amines are not included in the Germarm Regulations (AQUIRE DATABASE, 1993).

At present, an analytical method for determining aromatic amines in textile products (cotton, viscose, wool, silk, leather) has been established. For other materials a test method will be established.

The Dutch Regulations

The Regulations came into force August 1st 1996

The Dutch Regulations seems to be derived from the German Regulations, but the Dutch Regulations do not include azo pigments. The reason given is, that pigments are insoluble and only migrates under forced conditions. It is not defined, what is meant by such conditions.

The Regulations are valid for:

• clothes
• footwear
• bedding

As far as the manufacturing industry is concerned, the following categories of companies are involved:

- Producers of textiles and textile products, for use in the manufacture of clothing and bedding

- Producers of leather and leather articles, for use in time manufacture of footwear and clothing

The trade in the above mentioned product groups includes importers, mail order companies, the wholesale trade, chain store businesses and the retail trade.

As already mentioned, the Regulations also contain a list of banned azo dyestuffs. lt should be noted, that according to (Staatscourant, 1996) this list is incomplete. The list also includes other aromatic amines than the 20 banned amines.

The following deadlines are established:

• any clothing, footwear and bedding which contain the azo dyes referred to in article 3, subsection 1 (the same as the 20 banned aromatic amines in the German Regulations) and which were put onto the market prior to the date of commencement, or with regard to which the seller can make a reasonable case through the production of documentary evidence, that they were ordered before said date, can be sold up to 1 September 1997.
• Second-hand clothing, footwear and bedding, as well as any clothing, footwear and bedding that also serve as personal means of protection as referred to in article 1 subsection a of the Netherlands Consumer Goods Act Degree governing personal means of protection and clothing, footwear and bedding made from recycled fibres that contain the azo dyes referred to in article 3, subsection 1, can be sold up to and including 31 December 1999.

The analytical method referred to in the Regulations to determine the banned aromatic amines is identical with the German analytical method.

The French Regulations

The French Regulations appear to be the same as time equivalent legislation in Germany and the Netherlands. The French test method has not yet been published, and it is not clear, whether colorants include pigments. The French Regulations have already been notified. There has been some comments and objections and before the end of September the French Regulations have to be modified.

Regulations in other countries

EU also considers guiding rules banning the use of azo dyes based on those aromatic amines categorised as carcinogenic in EU (AQUIRE DATABASE, 1993) for dyeing of clothes and shoes,

Futhermore, in Turkey and at the latest also in India it has been prohibited to manufacture, import and use dyes based on the forbidden aromatic amines in the German Regulations (AQUIRE DATABASE, 1993).

In Turkey there is a proposal for a contract, which shall be used between the dye manufacturer and the buyer.

The contract is used in connection with disputes about the 20 aromatic amines banned in the 2nd amendment to the German Regulations. The contract also contains a confirmation from the dyestuff manufacturer of compliance with the rules in the above-mentioned 2nd amendment (Turkish Clothing Manufactures’Association, 1996).
 

Enclosure 3

Chemical Constitution

Aromatic amines considered as carcinogenic by IARC Ph = phenylgroup, Me methylgroup

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4-Aminodiphenyl CAS-NR 92-67-1

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Benzidine CAS-NR 92-87-5

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4-Chloro-o-toluldine CAS-NR. 95-69-2
 

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2-Naphtylainine CAS-NR, 91-59-8
 

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o-Aminoazotoluene CAS-NR. 97-56-3
 

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p-Chloraniline CAS-NR. 106-47-8
 

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2,4-Diaminoanisole CAS-NR. 615-05-4
 

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4,4’-Diaminodiphenylmethane CAS-NR. 10 1-77-9
 

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3,3’-Dichlorobenzidine CAS-NR. 91-94-1
 

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3,3’-Dimethoxybenzidine CAS-NR. 119-90-4
 

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3,3’-Dimethylbenzidine / CAS-NR. 119-93-7
 

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3,3’-Dimethyl-4,4’-Diaminodiphenylmethane CAS-NR. 838-88-0
 

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p-Cresidin CAS-NR. 120-71-8
 

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4,4’-methylenebis[2-chloroaniline] CAS-NR. 101-14-4
 

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4,4’-Oxydianiline / CAS-NR. 101-80-4
 

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4,4’-Thiodianiline / CAS-NR. 139-65-1
 

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o-Toluidine CAS-NR. 95-53-4
 

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2,4-Toluy]enediamine CAS-NR. 95-80-7
 

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o-Anisidine / CAS-NR. 90-04-0
 

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p-Aminoazobenzene CAS-NR. 60-09-3
 

Enclosure 4

Test Method and Discussion

The Danish Method

Reductive cleavage of azodyes

Approx. 1 g of sample was cut into smaller pieces and placed in a 50 ml Pyrex-flask containing 17 ml preheated basic-sweat simulator; intemal standard (isotope labelled aniline) was then added. As some of the samples were very water absorbent another 2-3 ml of simulator was added to cover the sample.

The samples were heated for 30 min at 70°C, at which point 3 ml of a freshly prepared solution of sodium dithionite in water (approx. 0.2 g/l) was added. The samples were then heated for another 30 min at 70°C. After cooling to laboratory temperature the samples were worked up on Extrelut-columns and concentrated by the same procedure as the German Method with the modification that the samples were evaporated on a Kuderna-Danish evaporator to approx. 2 ml, i.e. they were not evaporated and blown to dryness and then redissolved in 2 ml methanol.

A blind sample and a control standard for recovery analysis at low levels (corresponding to 0. 5 -1 mg/kg) were prepared in the same way.

Free arylamines (grown up articles)

Approx. 1 g of sample was cut into smaller pieces and placed in a 50 ml Pyrex-flask containing 17 ml preheated acidic-sweat simulator; internal standard (isotope labelled aniline) was then added.

The samples were heated for 1 hour at 70° C. After cooling to laboratory temperature the samples were worked up by the same procedure as for the reductive cleavage.

A blind sample and a control standard for recovery analysis at low levels (Corresponding to 0.5-1 mg/kg) were prepared in the same way.

Free arylamines (baby articles)

Approx. 1 g of sample was cut into smaller pieces and placed in a 100 ml Pyrex-flask, added 5 0 ml 0.07 M hydrochloric acid and internal standard (isotope labelled aniline).

The samples were shaken for 1 hour at laboratory temperature and then subsequently heated for 1 hour at 37°C.

The extracts were basified by addition of approx. 2.5 ml 1 M potassium carbonate in water, and 10 g of sodium chloride was then added and dissolved. The samples were subsequently extracted with 5 ml of teri-butyl methylether and the organic phase dried over sodium sulfate.

A blind sample and a control standard for recovery analysis at low levels (corresponding to 0. 5 -1 mg/kg) were prepared in the same way.

Analysis and quantification

The analyses were carried out by capillary column gas chromatography combined with mass spectrometric detection in full scan rnode (GC-MS). Samples, blind sample and control standard were analysed together with external standards of arylamines prepared in pure solvent containing internal standard. The quantification has been carried out against the external standards using the internal standard as a correcting factor.

Comments

Under the conditions of the reductive cleavage, o-aminoazotoluene and 2-amino-4-nitrotoluene are cleaved to o-toluldine and 2,4-diaminotoluene respectively.

The detection limits has been estimated from the recovery tests and external standards at low levels.

Experimental conditions

Table 11.1
Detection limits for the analysis for aromatic amines

Discussion of the Danish Method versus the German method

The Danish Method (described under »The Danish Method«) is a modification of the German Method (Amtliche Sammlung von Untersuchungsverfahren nach § 35 LMBG, B 82.02-2, Sept. 1996). The two major modifications are:

1. the Danish Method uses a different buffer-solution and at different pH from what is used in the German Method
    
2. the Danish method uses an intemal standard

The established detection limits for the Danish Method has been based on two considerations:

1. the analytical detection limit, i.e. the instrument determined detection limit of the individual aromatic amine in pure solvent
    
2. the recovery of aromatic amines in the extraction step based on a standard at a low concentration level

The uncertainty in the quantification step lies in time fact that the content is quantified against an external standard, i.e. a standard that has not undergone time same extraction procedure as the samples. This means that there has been made no corrections for recoveries less than 100% and at the low concentration levels, the recoveries typically appears between 40 an 80%, highest for the smaller aromatic amines (e.g. o-toluidine, p-chloroaniline etc.) and lowest for the larger aromatic amines (e.g. the benzidines). At higher concentration levels the recoveries typically are 70-90%. Thus, the quantification procedure tends to underestimate the content of aromatic amines.

Ideally, the quantlfication should be carried out against standards that have undergone the same extraction procedure as the samples. Standards at several concentration levels would be required as the recovery tends to become larger at higher concentrations. The general trend of recoveries increasing with concentrations could also mean that one calibration curve has to be established for low concentrations and another calibration curve for higher concentrations. However, the only commercially available solution containing all relevant aromatic amines also contains o-aminoazotoluene and 2-amino-4-nitrotoluene which are reduced to o-toluidine and 2,4-diaminotoluene respectively, already being present in the solution.

In order to gain more knowledge about the uncertainty of the method, especially the reproducibility of the recoveries, it would be necessary to perform a multiple number of recovery experiments with a standard at low concentration level (or more at different, low levels) so that standard deviations can be calculated. For comparison, a table of recoveries of selected aromatic amines are given (* taken from the German Method); it should be noted that the results given are single determination performed by 6 different laboratories. The standards has been at contrition levels 30 mg/kg sample or more. The detection method is not specified (can be GC-FID, GC-MS, UPLC-DAD, CE-DAD or densitometry).

Table 11.2 is taken from »Bundesgesundheitsblatt, Nr. 2, 3 9. Jahrgang, Februar 1996« (here given in English):

Table 11.2
Recoveries (The recovery of the amines 2, 5, 7, 8, 9, 10, 16 and 17 in the calibration solutions were determined in 6 laboratories)

In B 82.02-2 September 1996 it is stated:

The recovery of the amines must fulfil the following minimum requirements:

The numbers of the amines referes to the following list in the same paper:

*Azo-dyes which can split off these two aromatic amines are by the analyse method B 82.02-2 detected as o-toluid ine and 2,4-toluylenediamine respectively.