Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Phototransformation in air/water/soil has not been investigated because direct and indirect exposure of the environmental compartments to Direct Red 81 is unlikely, based on the CSR and risk management measures reported.

However, a possible primary source of environmental pollution of DRed81 can be represented by accidental releases of industrial waste water and secondary by release during washing of dyed textile. Photodegradation does not seem to be a relevant process for the degradation of DRed81. However, it has been reported that the addition of oxidants to aqueous solutions of commercial azo dyes, increases the photodegradation rate of azo dyes substantially (see 5.6, Clausen et al, 2009).


Due to the same reasons given above, i.e. direct and indirect exposure of the environmental compartments to DRed81 is unlikely, hydrolysis is not expected to be an important removal process that characterizes DRed81 in the aquatic environment.

A read across was proposed with the structural analogue similar substance 01 which undergoes slow hydrolysis, with a half-life greater than one year at 25 °C and pH values of 4, 7, 9. At 50°C and after 2.4 hours only around 1% of the sample was hydrolysed at pH 4, 7, 9. Therefore, hydrolytic degradation is unlikely, given that tests indicate a lack of hydrolysis under any of the tested conditions (CIBA, 1992).