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Ecotoxicological information

Long-term toxicity to fish

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Endpoint:
fish early-life stage toxicity
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
Please refer to read-across justification attached.
Reason / purpose for cross-reference:
read-across source
Key result
Duration:
35 d
Dose descriptor:
NOEC
Effect conc.:
50 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Endpoint:
fish early-life stage toxicity
Data waiving:
other justification
Justification for data waiving:
other:
Justification for type of information:
Justification of not submitting the requested information by the deadline given by ECHA:

Following ECHA´s final Decision on a Compliance Check and considering animal welfare reasons the Registrant aims to fulfil this information requirement by applying data from the read-across substance CAS 53220-22-7. However, final results of the main study with the read-across substance are not available yet.

A special analytical method for the determination of the substance in ecotoxicological medium was developed in an in-house laboratory by one of the registrants of the substance. As the water solubility of the substance is in the µg/L range and the substance is very adsorptive, a very sensitive method had to be developed. To achieve very low sensitivity of the LC-MS method, Tetrahydrofuran (THF) was used as a solvent for the samples and as a mobile phase for the LC-MS device. Whit this solvent and mobile phase an LOQ of 5 µg/L (the water solubility) was achieved. Using this method the Long-term toxicity test to Daphnia was conducted in the in-house laboratory of the registrant. For the Fish Early Life Stage (FELS) test a GLP CRO was commissioned. Unfortunately, after many pre-test measurements using two different LC-MS devices (Xevo TQ-XS LC/MS device from Waters, Inc. and LC/MS/MS ABSciex from Waters, Inc. and AB Sciex, Inc.) no sufficiently sensitive method for the detection of the substance in aqueous media could be validated. In the pre-tests THF and Acetonitrile (ACN) were used as solvents and mobile phases, and still the obtained LOQ was in the mg/L range.
Due to the unsuccessful analytical measurements and the approaching CCh deadline, all actions at this CRO had to be aborted and a new CRO had to be commissioned with the FELS study. Unfortunately, no established CRO was willing to validate an analytical method using THF as a mobile phase, due to the corrosive properties of THF and the high risk of damaging the devices. The producers of the devices (Waters, Inc. and AB Sciex, Inc.) were contacted for a consultation and all of them advised against using THF with their devices. At the end, no GLP CRO was able to replicate the sensitive analytical method developed by the registrant. Therefore, more time and effort is needed to develop an acceptable analytical method at the CRO to be able to perform the FELS study.
Due to the analytical struggles and the substances properties, the performance of the FELS study has been postponed in time and thus, the CCh deadline could not be met accordingly. As soon as any results from the CRO are available, the technical dossier will be accordingly updated.

Description of key information

The main test on the endpoint Long-term toxicity to Fish with the read-across substance will be submitted later based on ECHA communication/decision number CCH-D-2114453448-42-01/F.

Key value for chemical safety assessment

Additional information

The study was planned for the read across substance 53220 -22 -7.

Due to the analytical struggles and the substances properties, the performance of the FELS study has been postponed in time and thus, the CCh deadline could not be met accordingly. As soon as any results from the CRO are available, the technical dossier will be accordingly updated. Below presents results from the pretest.

FELS Pre-test with read-across substance CAS 53220-22-7

The toxicity of the test item in the Early-Life Stage Toxicity Test with Danio rerio was tested under flow-through conditions according to OECD 210 in a pre-test. The water solubility of the test item was estimated as 1 – 5 µg/L. Therefore, this study was performed with the concentrations 5 µg/L and 50 µg/L. Because of the poor water solubility of the test item, acetone was used to spike the test solutions. Dilution water was added with flow meters. Stock solutions of the test item were added with syringe pumps. The stock solutions were dosed with the syringe pumps directly into the flowing dilution water. 20 fertilised eggs were added to each replicate of the solvent control and each replicate of the treatments. After 35 days the surviving fishes were counted. The tested concentrations showed no toxicity. The surviving rate in the highest concentration was even slightly higher than in the solvent control. No abnormal appearance or behavior of the surviving fishes was observed. The validity criteria of the guideline, hatching success in the controls greater than or equal to 70 % and post-hatch success greater than or equal to 75 % were fulfilled. The NOEC is expected to be around 50 µg/L.