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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

It should be noted that the test substance is not considered as posing a hazard to the aquatic environment. Indigo is a natural dye which is gained from Indigofera tinctoria and Indigofera suffruticosa and is known to be not readily biodegradable. The structurally identical synthetic Indigo as well is a solid under all environmental conditions and is insoluble in water (< 0.05 mg/L) with an n-octanol/water partition coefficient of log Kow = 2.7. It has a low volatility based on a vapour pressure of < 3.5E-5 Pa at 100°C and sublimes at ca. 170°C before melting; thus compartmentalising into air compartment is not expected.

Based on the physico-chemical data of Indigo, it is expected to be found predominantly in soil with an estimated half-life of 75 days (PBT-profiler) – to a low extent in water and not in sediment. It is very efficiently adsorbed in wastewater treatment plants (88% to 97%) as shown in adsorption studies. However, with a log Koc of 2.85 it has a comparably low affinity for soil/sediment.

The measured bioconcentration factor for aquatic bioaccumulation (log BCF) for Indigo is < 4.5 and does not exceed the bioconcentration criteria. Furthermore, there is no indication of bioaccumulation in mammals from kinetic or toxicity studies. Therefore, Indigo is not regarded as bio-accumulative.Indigo was nottoxic in mammalian studies therefore in the event of exposure to environmental organisms, effects due to secondary poisoning can be excluded.