Pentasodium bis[5-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-4-hydroxy-3-[(2-hydroxy-5-nitrophenyl)azo]naphthalene-2,7-disulphonato(4-)]chromate(5-)

Endpoint summary

Description of key information

The chemical class of reactive dyes is generally not considered to be biodegradable at all. For the present substance Reactive Orange 013, only few data are available to cover this endpoint. In the past BOD5 and COD values have been determined to assess the behavior of the test substance in industrial sewage treatment plants. The calculated BOD5/COD quotient is used to estimate the rate of biodegradation within the sewage treatment plant.

In the light of percentage degradation observed in water in screening tests the test item FAT 40210 is considered not to be readily biodegradable.

Additional information

By the nature of their design and use, reactive dyes are not intended to be readily biodegradable as this would assist in the rapid destruction of the chemical, rendering it unfit for purpose. As such, it is accepted that such substances are not readily biodegradable under relevant environmental conditions. A published study (Pagga & Brown, 1986) describes the results of the testing of 87 dyestuffs in short-term aerobic biodegradation tests. The authors of this publication concluded that dyestuffs are very unlikely to show any significant biodegradation in such tests and that there seems little point in carrying out such test procedures’ on dyestuffs.

There are ISO, European, American (AATCC) and national standards available for the colour fastness of dyes. Dyes are required to have specific fastness properties. If the dyes were biodegradable, it would not be possible for them to have these fastness properties.

 

References:

Pagga U, Brown D (1986) The degradation of dyestuffs: Part II. Behaviour of dyestuffs in aerobic biodegradation tests. Chemosphere 15: 479-491.