Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

The test substance was not readily biodegradable under the test conditions. A study was conducted to evaluate the biodegradation potential of the test substance (of 74.5 % purity) via BOD5 and COD determination. The BOD5 was determined to 56 mg O2/g test material, the COD was calculated to 878 mg O2/g test material. The ratio of these values was equivalent to 0.06 (= 6 %), indicating that the substance was not readily biodegradable under the test conditions.

Additional information

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

 

References:

Pagga U, Brown D (1986) The degradation of dyestuffs: Part II. Behaviour of dyestuffs in aerobic biodegradation tests. Chemosphere 15: 479-491.