Survey of azo-colorants in Denmark

1. Introduction

Background

The Danish Environmental Protection Agency (Danish EPA) published in 1996 a position paper on the status and perspectives of chemicals (Miljøstyrelsen, 1996c). The Agency stated that there is a need for additional information, in particular, regarding toxicity for man and environment, but also regarding consumption and use of approximately 100 chemicals, among them azo colorants.

Azo colorants are both nationally and internationally regulated, especially for use in drugs, cosmetics, food and in connection with packaging of food. In France, the Netherlands, Austria and Germany restrictions on the use of azo colorants in textiles (leather and leather goods) have been or are being implemented. Some restrictions concern the individual azo colorants, like e.g. the Dutch restrictions. In Germany, however, the restrictions are related to the possible presence of intermediates/metabolites, i.e. the 22 potentially carcinogenic aromatic amines in the working environment (MAK Werte Liste) and in consumer’s goods.

The reason for the concern about the azo colorants is that during the phases of production, processing and consumption there is a risk of exposure for man and environment to potentially carcinogenic aromatic amines. The exposure may take place as a result of cleavage of the colorants to their metabolites or from impurities of the colorants.

With reference to the position paper and in the light of the general international legislative development, a list of undesirable chemicals, including azo colorants, has been proposed by the Danish EPA. On this back- ground a survey of consumption and use of azo colorants in Denmark as well as an evaluation of health and environmental properties/effects have been carried out.

Objective of the survey

The objective of the survey was to summarise present knowledge concerning toxicological and environmental properties of the azo colorants. Furthermore, the objective was to establish an overview of the consumption and the use of azo colorants in Denmark, aiming at establishment of a preliminary mass flow balance.

Based on the overview of consumption and use, the survey also aimed at, on a provisional and qualitative level, identifying and assessing the human and ecotoxicological risks associated with the actual use.

Scope of the survey

Azo colorants belong to the group of organic colorants and constitute the dominant part of these. There are more than 3,000 single azo colorants and more than 10,000 commercially available products (for colouring) containing azo colorants.

Azo colorants may be subdivided into two groups: the azo dyes and the azo pigments. In some aspects they have the same attributes but in general the two groups are very different with respect to the physico-chemical properties and thereby applications. Both groups are included in the present survey. Because of the major differences it is important to distinguish between them, and the two groups are treated separately.

The azo colorants are used for colouring of plastics, leather, textiles, cosmetics and food, for manufacturing of paints and lacquers, for printing purposes and in drugs. Thus, the azo colorants have a very broad application field and are used in a great variety of products, e.g. plastic bowls, T-shirts, hair dyes and ball pens.

Azo colorants consumed and applied in the drug, cosmetic and food industries have been omitted from the survey, because they are already subject to legislation.

The survey has further been limited/confined to include the trades, which manufacture colorants or are primary users of colorants, i.e. the dye industry, the industries for processing of plastics, leather and leather products, textiles, pulp and paper, printing, paints and lacquers. As a consequence end-users, i.e. users of colorants in application, e.g. the iron and steel industry’s use of azo pigments containing paints and lacquers for surface treatment, are not included.

The survey includes both imported, domestic manufactured and exported products and semi-finished goods within the encompassed trades.

The overview of consumption and use does not include the cleavage pro- ducts (metabolites/intermediates) - aromatic amines - of the colorants. However, the human health effects and the environmental toxicity of the cleavage products (metabolites) of the colorants, i.e. the 22 potentially carcinogenic aromatic amines, are included in the survey.

With regards to impurities associated with colorants, they encompass e.g. PCB, heavy metal, dioxins etc. The survey focuses on the aforementioned 22 aromatic amines, because the properties and the effects of the other compounds have been investigated elsewhere.

Content

The applied methodology of the survey is thoroughly presented and discussed in chapter 2.

In addition the survey includes a presentation of:

	Technical aspects of the azo colorants.
	Consumption and use in Denmark and mass flow balances for dyes and pigments, respectively.
	Physico-chemical properties, toxicity, environmental fate and toxicity of azo dyes.
	Physico-chemical properties, toxicity, environmental fate and toxicity of azo pigments.
	Overall conclusions and recommendations.

Each chapter or main section ends with a summary/conclusion