tetrasodium 4-{4-[(9,10-dioxo-4-{[4-(2-sulfophenoxy)phenyl]amino}-9,10-dihydroanthracen-1-yl)amino]phenoxy}benzene-1-sulfonate 4-{4-[(9,10-dioxo-4-{[4-(4-sulfophenoxy)phenyl]amino}-9,10-dihydroanthracen-1-yl)amino]phenoxy}benzene-1-sulfonate

Endpoint summary

Description of key information

FAT 21030 is considered to be 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 21030 was tested over the years in several Zahn Wellen tests as well as tests evaluating Biological Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD).

The BOD5/COD ratios for FAT 21030/C (0/1271), FAT 21030/B (0/1278) and FAT 21030/A (0/1017, 0/1091) were all equal to 0, hence indicating that the substance is not rapidly biodegradable.

In the available Zahn Wellen Tests with FAT 21030/C and FAT 21030/A, the bioelimination observed at the end of exposure period was 0 %.

Taking the above information into account, FAT 21030 should regarded as not readily biodegradable.