Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Basic Red 046 Bromide was not readily biodegradable, however it was concluded to have potential for inherent, primary biodegradability.

Additional information

By the nature of their design and use, textile dyes are not intended to be readily biodegradable as this would assist in the rapid destruction of the dyestuff, 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 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.

However, Basic Red 046 Bromide was evaluated for biodegradation potential in experimental studies conducted according to OECD Guideline 301A, OECD Guideline 302B and studies evaluating BOD5 and COD as per the ISO guidelines. Studies evaluating ready biodegradability (i.e. conducted according to OECD 301A and BOD5/COD ratio obtained), clearly indicated that the substance is not readily biodegradable. However, the substance underwent degradation upto 55.2 % in a modified Zahn-Wellens test conducted according to OECD Guideline 302B, thus indicating potential for inherent, primary biodegradability.