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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 617-779-3 | CAS number: 85940-94-9
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
The key study carried according to OECD Guideline provides a 72h-EC50 value above 8.1 mg/L (nom.). Therefore, the registered substance (HDI Trimer MEKO-blocked) is not considered as harmful to Desmodesmus subspicatus at the limit of water solubility.
Key value for chemical safety assessment
Additional information
Solubility and stability of HDI Trimer MEKO-blocked in water
The test material was insoluble in water (far from 100 mg/L). Thus, test material meets the definition of poorly water soluble mixture and has to be considered as a "difficult mixture to test" according to OECD Guidance No 23 (2000) on aquatic toxicity testing of difficult substances and mixtures.
Nevertheless, the registered substance (HDI Trimer MEKO-blocked) with a half-life of 139 d (for pH 7 and 25 °C, calculated from experimental data at 50, 65 and 80 °C), is stable in water for short-term testing.
Study design of Algae ecotoxicity testing on HDI Trimer MEKO-blocked (Weyers, 2007)
Test solutions were prepared by direct addition in water using ultra turrax, magnetic stirrer and filter as auxiliaries. Nominal test concentrations were 4.0 and 8.1 mg/L.
The study design included analytical determination of concentration. The preparation of the test solutions met recommendations from OECD Guidance No 23 (2000):
i. solution concentration higher than theoretical water solubility limit to achieve the maximum dissolved substance
ii. separation of undissolved test substance from the test solution
iii. direct addition to water and use of mixing techniques such as shaking and stirring
Results of Algae ecotoxicity (Weyers, 2007)
According to OECD Guidance No 23, the effect concentration should be determined and expressed relative to the geometric mean of the measured concentrations. However, in this study the observed recovery of the registered substance was variable. This variability might be explained by difficulties in preparing media leading more to a dispersion of test material rather than solution of test item. As a result, EC50 values are based on nominal test concentration.
Conclusion
The registered substance (HDI Trimer MEKO-blocked) is not harmful to Desmodesmus subspicatus at the limit of water solubility.
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.
