Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 431-920-4 | CAS number: -
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
Not toxic to algae:
EC50 > 100 mg/L
EC10 > 100 mg/L
NOEC > = 100 mg/L
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 100 mg/L
- EC10 or NOEC for freshwater algae:
- 100 mg/L
Additional information
An aqueous dispersion of Indigo and Cremophor RH 40, which ends up as a deep-blue emulsion in the stock solution (1000 mg/L and 200 mg/L, respectively) has been tested. The tested concentrations are 3.91, 7.81, 15.63, 31.25, 62.5, 125, 250, and 500 mg/L. No information is given on the colour of the tested concentrations, however based on the fact that the stock solution gave a deep blue emulsion, it can be anticipated that the test solutions showed also considerable shades of blue discolouration. The effects on algae growth in this study is hence most likely an algae‑static effect due to light absorption of the dye and not an algae-toxic effect of the test substance. Both, effects of light absorption and the use of an emulsifier which leads to an artificial und untypical emulsion have not been discussed in this study. This study is hence not considered relevant and reliable for the assessment of the registered substance.
Only limited information is given in the OECD SIDS document on this algae study and the original study report is not publically available. Therefore, not sufficient information on the test substance identity and on the study conduct could be gained from the summary report to include this study in the Indigo assessment of the registered substance. The only substance information is the Indigo content of 96% derived from the information on the acute fish test without information on impurities contained. Concentrations of 1.8 to 18 mg/L were tested in presence of the co-solvent DMSO without any information on the amount of DMSO used, the solubility of Indigo in this solvent or effects seen in the vehicle control group. No analytical monitoring took place during the study. The test concentrations used lie above the water solubility reported to be 0.99 mg/L in the OECD SIDS report.
Due to the missing information on substance identity and study conduct, the study was considered not to be reliable and cannot be used for assessment of the registered substance.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
