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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Acid Blue 225 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, the biodegradbility of Acid Blue 225 was tested in several studies. FAT 21036/B is found to have degraded up to 22 % in a Zahn-Wellens test. Thus, FAT 21036/B fulfils the criteria for inherent, primary biodegradability.

BOD5 and COD value of 20 and 1230 mgO2/g test mat. was determined for FAT 21036/B. Based on the BOD5/COD quotient which is not >0.5, the substance is considered to be not readily biodegradable.