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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Study Initiation Date 05 August, 2016 - Study Completion Date (final report signature) 06 March, 2017. Experimental Phase : 22 September 2016 to 30 November 2016
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Deviations:
no
Principles of method if other than guideline:
There were no Deviations to the Study Plan.
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
(E)-cyclohexadec-5-enone
Cas Number:
35951-24-7
Molecular formula:
C16H28O
IUPAC Name:
(E)-cyclohexadec-5-enone
Constituent 2
Chemical structure
Reference substance name:
(Z)-cyclohexadec-5-enone
Cas Number:
21944-95-6
Molecular formula:
C16H28O
IUPAC Name:
(Z)-cyclohexadec-5-enone
Specific details on test material used for the study:
Name (as stated in the report): Velvione
Batch: VE00413992
Expiration date: January 01, 2017

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
For the determination of the actual test item concentrations, duplicate samples were taken from each test concentration and the solvent control at the start and at the end of the two 24-hour test medium renewal periods. At sampling, samples of 50 mL exposure solution were extracted with 10 mL of MTBE (Tert-butyl Methyl Ether) fortified with an Internal Standard (1,4-Dichlorobenzene) at a concentration of 8.03 mg/L. The samples (aqueous-phase + MTBE) were stored frozen until analysis. The storage stability under these conditions had been confirmed during the pre-study phase. The concentrations of VELVIONE were analyzed in one of the duplicate test medium samples from the solvent control and all test concentrations from the start and end of both test medium renewal periods.

Test solutions

Vehicle:
yes
Remarks:
N,N-dimethylformamide (DMF)
Details on test solutions:
Due to the low solubility and suspected instability of the test item VELVIONE to be subjected to prolonged periods of slow-stirring, the organic solvent N,N-dimethylformamide (DMF) was used to dose the test item. The solvent was chosen based on its solubilizing properties and its relative non-toxicity to daphnia.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
The study was performed with young daphnids of the species Daphnia magna Straus which were less than 24 hours old at the beginning of the experiment and not from first brood progeny. A clone of this species (originally from the Daphnia Collection of the University of Basel/Switzerland in 2015) is successfully bred in IES Ltd Laboratories under temperature and light conditions identical to those of the tests.

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
250 [mg/L] as CaCO3
Test temperature:
20°C
pH:
7.7 - 8.0
Dissolved oxygen:
8.4 - 8.7 [mg/L]
Nominal and measured concentrations:
The nominal test item concentrations tested were 0.18, 0.27, 0.40, 0.60 and 0.90 mg/L.
The mean measured test item concentrations were 0.071, 0.12, 0.18, 0.24 and 0.36 mg/L.
Details on test conditions:
The test was performed in a temperature-controlled room with continuous monitoring of the room temperature. The water temperature was maintained at 20 °C.
The daphnids were not fed during the test.
A 16-hour light to 8-hour dark cycle with a 30-minute transition period was used. Light intensity during the light period was approximately between 15 and 18 μmol m-2 s-1.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.24 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
0.18 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
0.36 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
A clear dose-response effect was observed with 100% immobilization of daphnids observed at the highest mean measured test concentration of 0.36 mg/L after 48 hours exposure, 50% immobilization at 0.24 mg/L and 0% immobilization at the three lower tests concentrations.

Any other information on results incl. tables

The measured concentrations of VELVIONE in the test media of the nominal test concentrations of 0.18 to 0.90 mg/L were between 82 and 104% of the nominal values at the start of the two test medium renewal periods. Thus, the correct dosage of the test item could be verified. During the test periods of 24 hours, the test item concentrations in the test media decreased. At the end of the two test medium renewal periods, 11 to 30% of the nominal values were found.

Due to the decrease of test item concentrations during the renewal periods, the biological results were based on the mean measured concentrations. These were calculated as follows: For each test medium renewal period (i.e. Day 0-Day 1, Day 1-Day 2), the mean concentration was calculated as the geometric mean of the test item concentrations measured at the start and the end of the test medium renewal period. From the two geometric mean values obtained, the mean measured test item concentration during the test period of 48 hours was calculated as arithmetic mean.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
The test is considered to be valid, as in the control and solvent control no daphnids showed immobilization or other signs of disease or stress and the dissolved oxygen concentration at the end of the renewal periods was > 3 mg/L in all test vessels.
Conclusions:
The 48-hour EC50 was determined to be at the test concentration of 0.24 mg/L with 95% confidence limits of 0.23 and 0.26 mg/L (based on mean measured concentrations). The 48-hour EC0 and EC100 were, respectively, 0.18 mg/L and 0.36 mg/L, based on mean measured concentrations of the test substance.
Executive summary:

The test item VELVIONE had acute toxic effects on Daphnia magna in a 48-hour semi-static test according to the OECD 202 guideline.

The 48-hour EC50 was determined to be at the test concentration of 0.24 mg/L with 95% confidence limits of 0.23 and 0.26 mg/L (based on mean measured concentrations).