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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 200-296-3 | CAS number: 56-89-3
Short-term toxicity to fish
Administrative data
Link to relevant study record(s)
Description of key information
L-Cystine induced no lethal effects in fish at 100 mg/L or below : the LC50 is > 100 mg/L.
Key value for chemical safety assessment
Additional information
L-Cystine has been tested in a 48 h acute fish toxicity study. The LC50 is > 100 mg/L in Fathead Minnow. The read-across substance L-Cysteine has been tested in an OECD 203 guideline study and showed no acute toxicity to fish in a 96 h limit test with an LC50 > 100 mg/L. The read-across is based on an oxidation study of L-Cysteine in water.
It is known that aqueous solutions of L-Cysteine oxidize readily in air to give L-Cystine at neutral or basic pH (data for Biochemical Research, 3rd ed., Dawson,R. M. C., et al., Oxford University Press (New York, NY: 1986), pp. 12-13). Within this analysis it could also be demonstrated that the initial concentrations of two similar samples of the same batch taken on January 11, 2013 show L-Cysteine levels of 94.69 and 97.60 area % when dissolved in the mobile phase. L-Cystine was present at a range of 0.238 to 0.277 area percent at this starting point. Taken together it can be stated that after 4 h of stirring at room temperature the L-Cysteine has been oxidized nearly completely to L-Cystine.
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.
