Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

FAT 40278/A is not readily biodegradable.

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. 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. 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. Nevertheless, biodegradbility of FAT 40278 was tested in a Zahn Wellen test as well as tests evaluating Biological Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD).

In a study performed as per Zahn-Wellen test procedure which is similar to OECD guideline 302 B, FAT 40278/A was assessed for biodegradation potential at the end of the 28-days experimental period. The initial test substance concentration was 145 mg/l TOC. At the end of 28 days 49 % TOC was observed, indicating the test substance FAT 40278/A as not readily biodegradable.

The BOD5 and COD for FAT 40278/A were determined to be 47 and 1394 mg/g O2, respectively. Hence, the BOD5/COD ratio was 0.03, indicating it to be not readily biodegradable.