Disodium 1,1'-isopropylidenedi-p-phenylene bis[2-[[5-amino-3-methyl-1-(3-sulphonatophenyl)-1H-pyrazol-5-yl]azo]benzenesulphonate]

Endpoint summary

Description of key information

The chemical class of acid dyes is generally not considered to be biodegradable at all. For the present substance Acid Yellow 079, only few data are available to cover this endpoint. Among these one study was selected as key study to cover this endpoint. FAT 21015 was investigated to determine the biological oxygen demand (BOD5) and the chemical oxygen demand (COD). BOD5 of FAT 21015 was found to be 0 mg/g O2 and COD was found to be 1289 mg/g O2. The corresponding BOD5/COD quotient can be calculated to 0 %, which demonstrates the substance to be not biodegradable.

By the nature of their design and use, acid 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.