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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 208-901-2 | CAS number: 546-46-3
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
Key value for chemical safety assessment
Additional information
In accordance with Column 2 of REACH Annex VIII, the activated sludge respiration inhibition study (required in Section 9.1.4) does not need to be conducted as the substance is readily biodegradable and the applied test concentrations are in the range that can be expected in the influent to a sewage treatment plant.
Trizinc dicitrate will dissociate in solution to the metal ion and citrate anion (H7C6O7 -), so exposure of microorganisms will be to the citrate and the metal ions separately. The effect of trizinc dicitrate is not expected to significantly differ from the effects of metal ion and citrate separately. While the toxicity of citric acid is considered to be negligible (toxicity threshold value of >10000 mg/l), zinc toxicity (EC50) has been found to be 5.2 mg/l (cited from zinc metal RAR 2008). Therefore, the toxicity of trizinc dicitrate will be driven by the toxicity of zinc.
It is possible to extrapolate the data from zinc to trizinc dicitrate by converting the zinc results taking into consideration the molecular weight of both substances*. The EC50 value of 5.2 mg Zn/l is equivalent to an EC50 value of 15.08 mg/l trizinc dicitrate. This value was obtained by multiplying with a conversion value of 2.9*.
* Molecular weight of trizinc dicitrate/(molecular weight of zinc)*3 = 547/(65*3) = 2.9
The EC50 for zinc metal was obatained from set of data on toxicity tests with bacterial and protozoans.The available toxicity data were subjected to pair review and the most reliable data from the peer reviwed published study (Zinc metal RAR 2008) has been selected as key study. The bacterial studies gave an EC50 value ranging from 0.74 mg/l to 900 mg/l. In another study conducted using bacterium Pseudomonas putida, an EC10 values of 1.8 and 0.3 mg/l was obtained (Zinc RAR 2008). The toxicity test results (LC50) of zinc on protozoans ranges from 0.25 mg/l to 50 mg/l.
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.
