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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 completion date 16 May 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report date:
2017

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
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Methyl oct-2-ynoate
EC Number:
203-836-6
EC Name:
Methyl oct-2-ynoate
Cas Number:
111-12-6
Molecular formula:
C9H14O2
IUPAC Name:
methyl oct-2-ynoate
Test material form:
liquid

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 control at the start and at the end of the two 24-hour test medium renewal periods.

However, from the highest test concentration of 7.0 mg/L, samples were taken only from the first renewal period, since all daphnids were dead at the observation time at Day 1.

For sampling from the aged test media, the contents of the respective replicates were combined prior to sampling.

All samples were stored frozen (at -20 ± 5 °C) immediately after sampling. Based on pre-experiments for investigation of the storage stability, the test item was found to be stable in the test water under these storage conditions (see Analytical Procedure, Appendix 1).

The concentrations of FOLIONE were analyzed in one of the duplicate test medium samples from the control and all test concentrations with surviving daphnids from the start and end of both test medium renewal periods.

Test solutions

Vehicle:
no
Details on test solutions:
For determination of the appropriate test concentrations for the main test, a first static range-finding test with nominal test item concentrations of 0.25, 2.5 and 25 mg/L was performed. For this, two replicates per treatment were tested. The test medium of the highest concentration of 25 mg/L was stirred until dissolution for 1 hour at room temperature and in the dark. The test media of the two lower concentrations were prepared in a series of further dilution steps. For a more precise determination of the exposure conditions to be used in the main test, a second static range-finding test with nominal test item concentrations of 0.10, 1.0 and 10 mg/L was performed in a closed system. For this, two replicates per treatment were tested. A stock solution with a nominal concentration of 25 mg/L was stirred until dissolution for 1 hour in a closed vessel at room temperature, in the dark. The test media of the three test concentrations were prepared in a series of further dilution steps.
Based on these range-finding results the following nominal concentrations of FOLIONE were selected for the main test: 0.070, 0.22, 0.70, 2.2 and 7.0 mg/L. Additionally, a control (test water without test item) was tested in parallel.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
For each treatment, 20 daphnids were randomly distributed into four replicates of five daphnids each.

Study design

Test type:
semi-static
Water media type:
other: Reconstituted test water according to ISO 6341 was used in the study. It consisted of analytical grade salts dissolved in purified water.
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
250 mg/L as CaCO3
Test temperature:
The test was performed in a temperature-controlled room with continuous monitoring of the room temperature. The water temperature was maintained at 20 °C.
pH:
Between 7.9 and 8.1
Dissolved oxygen:
Dissolved oxygen was > or 0 8.4 mg/L.
Nominal and measured concentrations:
The measured concentrations of FOLIONE in the test media of the nominal test concentrations of 0.070 to 7.0 mg/L were between 83 and 96% 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 test medium renewal periods, 56 to 81% of the nominal values were found.
The mean measured exposure concentrations determined from the geometric mean values of the analyses from the Day 0 (fresh) / 24 hour (aged) and the renewal solution DAy 1 (fresh) / 48 hour (aged) were determined to be 0.054, 0.16, 0.56, 1.8 and 6.2 mg/L at the 0.070, 0.22, 0.70, 2.2 and 7.0 mg/L (nominal) test concentrations, respectively.
Reference substance (positive control):
yes
Remarks:
Potassium DiChromate

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.62 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CI: 0.42 - 0.92 mg/L
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
0.16 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
other: Sub-lethal effects and behavioural observations (e.g. discolouration, swimming behaviour, etc.)
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
0.16 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
6.2 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
Due to the decrease of test item concentrations during the renewal periods, the biological results are 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 an arithmetic mean.
Results with reference substance (positive control):
For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in October 2016 (24-hour EC50: 1.0 mg/L, IES Laboratories Study 20160278) showed that the sensitivity of the test organisms was within the range given by the guideline (24-hour EC50: 0.60 - 2.1 mg/L).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Executive summary:

The 48-hour EC50was calculated to be 0.62 mg/L.

The 48-hour EC0and NOEC of FOLIONE were both at the test concentration of 0.16 mg/L, since no toxic effect was observed up to and including this test concentration.

The 48-hour EC100was at the test concentration of 6.2 mg/L.