Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

The substance is considered to be neither readily nor inherently biodegradable.

Additional information

By the nature of their design and use, 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.

Nevertheless, the target substance has been investigated for biodegradation potential. In a study for inhrerent biodegradability, the substance was found to have degraded 4% over the period of 28 days. In studies conducted to determine BOD5 and COD, the BOD5/COD ratios were calculated to be 0.009 (1993) and 0.069 (1974), thus further indicating the substance being neither readily nor inherently biodegradable.