Ethyl trans-2,2,6-trimethylcyclohexanecarboxylate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 April 1993 to 23 April 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Stability of test Concentrations
Verified by chemical analysis of the solvent control and all test groups at 0 and 48 hours. The solvent stock solution used to prepare the test series at 0 hours was also analysed. Data relating to the identity, purity and stability of the supplied test material are the responsibility of the Sponsor.

Vehicle:

yes

Details on test solutions:

Method of Preparation
Preliminary solution in 1% v/v Tween 80-ethanol. 2 g of test material was dissolved in solvent and the volume adjusted to 10 ml to give a 2.00 g/10 ml stock solution. 500 ul of this stock solution was dispersed in aged dechlorinated tap water and the volume adjusted to 5 litres to give a 20 mg/l test concentration from which dilutions were made to give the test series.
Stability of test Concentrations
Verified by chemical analysis of the solvent control and all test groups at 0 and 48 hours. The solvent stock solution used to prepare the test series at 0 hours was also analysed. Data relating to the identity, purity and stability of the supplied test material are the responsibility of the Sponsor.

Test organisms (species):

Daphnia magna

Details on test organisms:

Name Daphnia magna Straus.
Source Laboratory culture originating from a strain supplied by the Institut National de Recherche Chimique Appliquee, (I.R.CH.A), France.
Culture At 21°C in polypropylene vessels containing two litres of aged and dechlorinated tap water.Cultures were fed daily with a suspension of mixed algae (predominantly Chlorella spp.) . Culture conditions ensure that reproduction is byparthenogenesis.
Selection Gravid adults were isolated 24 hours prior to initiation of the test. Young daphnids produced overnight were used for testing.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Total hardness approximately 50 mg/ L as CaCO3

Test temperature:

21°C

pH:

7.6-7.8

Dissolved oxygen:

7.3-8.3 mg O2/ L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations:0.20, 0.36, 0.64, 1.12, 2.0, 3.6, 6.4, 11.2 and 20 mg/l. These test concentrations were assigned following a preliminary range-finding study where 10 daphnids were exposed for a period of 48 hours to each of the following test concentrations:0.010, 0.10, 1.0, 10 and 20 mg/l. The results showed immobilisation at the test concentrations of 10 and 20 mg/l and no effect at 0.010, 0.10 and 1.0 mg/l indicating the choice of test concentration employed in the test.
Verification of test concentrations showed that at 0 hours the measured test concentrations were all greater than or equal to 80% of nominal value with the exception of the 0.20 mg/l test group which showed a measured concentration of 77% of nominal value. This decline in measured concentration is considered to be caused by losses due to the volatile nature of the test material.
Analysis of the solvent stock solution used to prepare the test series at 0 hours showed the concentration to be near nominal value.
Chemical analysis of the 48-hour old test media showed the measured test concentrations to be in excess of 80% of nominal value with the exception of the 0.20, 0.36 and 0.64 mg/l test groups which showed measured concentrations of 70%, 68% and 78% of nominal value respectively. This decline is considered to be due to the volatile nature of the test material despite carrying out the study in sealed test vessels.

Details on test conditions:

Exposure Conditions
Test vessels : Glass conical flasks each containing approximately 300 ml test solution to fill the flasks and sealed with ground glass stoppers to reduce evaporation.
Experimental design . 9 test concentrations of 1 control and 1 solvent control (including 100 uL/ L auxiliary solvent), each in duplicate. 20 animals per concentration.
Method of initiation : Daphnia were placed in the test solutions after addition of the test material.
Loading 30 ml test solution per organism.
Photoperiod 16h light : 8h dark.
Temperature . 21 +/- 1°C.
Aeration. None.
Environmental Measurements Temperature was recorded daily. pH and dissolved oxygen concentrations were recorded at initiation and termination of the study.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.12 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

See attached document

Chemical analysis of the 48-hour old test media showed that at the "No Observed Effect Concentration" at 48 hours and the test concentrations above this level where immobilisation was observed, the measured concentrations were all in excess of 80% of nominal value. Therefore it was considered justifiable to calculate the EC50 values in terms of nominal test concentrations only.

Validity criteria fulfilled:

yes

Conclusions:

"No Observed Effect Concentration" (NOEC) at 48h = 1.12 mg/l

Executive summary:

TEST SPECIES Daphnia magna Straus tested in the 1st instar.

TEST TYPE Acute toxicity 48h EC50 (immobilisation).

TEST CONDITIONS Static test conditions according to OECD Guide1ine No. 202, referenced as Method C.2 of Commission Directive 84/449/EEC (which constitutes Annex V of Counci1 Directive 67/548/EEC).

Results

The following results are based on nominal test concentration
Duration	Endpoint	Effect conc.	Nominal/Measured	Conc. based on	Basis for effect	Remarks (e.g. 95% CL)
24 h	EC50	8 mg/L	nominal	test mat.	mobility
48 h	EC50	3.2 mg/L	nominal	test mat.	mobility
48 h	NOEC	1.12 mg/L	nominal	test mat.	mobility

Description of key information

TEST SPECIES Daphnia magna Straus tested in the 1st instar.

TEST TYPE Acute toxicity 48h EC50 (immobilisation).

TEST CONDITIONS Static test conditions according to OECD Guide1ine No. 202, referenced as Method C.2 of Commission Directive 84/449/EEC (which constitutes Annex V of Counci1 Directive 67/548/EEC).

Results

The following results are based on nominal test concentration
Duration	Endpoint	Effect conc.	Nominal/Measured	Conc. based on	Basis for effect	Remarks (e.g. 95% CL)
24 h	EC50	8 mg/L	nominal	test mat.	mobility
48 h	EC50	3.2 mg/L	nominal	test mat.	mobility
48 h	NOEC	1.12 mg/L	nominal	test mat.	mobility

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3.2 mg/L