4-isopropyl-1-methylcyclohexene

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:

The study was conducted between 19 August 2017 and 27 September 2017 (biological phase).

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 guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-isopropyl-1-methylcyclohexene

EC Number:

226-841-5

EC Name:

4-isopropyl-1-methylcyclohexene

Cas Number:

5502-88-5

Molecular formula:

C10H18

IUPAC Name:

1-methyl-4-(propan-2-yl)cyclohex-1-ene

impurity 1

Reference substance name:

rel-(1R,4R)-1-isopropyl-4-methylcyclohexane

Cas Number:

1678-82-6

Molecular formula:

C10H20

IUPAC Name:

rel-(1R,4R)-1-isopropyl-4-methylcyclohexane

impurity 2

Reference substance name:

rel-(1S,4S)-1-isopropyl-4-methylcyclohexane

Cas Number:

6069-98-3

Molecular formula:

C10H20

IUPAC Name:

rel-(1S,4S)-1-isopropyl-4-methylcyclohexane

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Details on test solutions:

Frequency and Duration of Administration, Treatment Levels, and Replication
Based on the results of a preliminary non-GLP range finding test, the following concentrations in a geometrical series (spacing factor: 2.2) were tested in the definitive test (DT2):
4.27, 9.39, 20.7, 45.5 and 100% of a saturated solution at a loading rate of 200 mg/L.
The test period (exposure of test organisms to the test solutions in a semi-static system) was 48 hours.
Additionally, daphnids were exposed under control conditions (non-treated test medium without solvent).
Four replicates were used for the test item concentrations and the control. Each replicate vessel contained five daphnids.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Test System

• Species: The test system used in this study was Daphnia magna STRAUS (clone M10), a water flea, cultured at ECT Oekotoxikologie GmbH since December 22, 2011.
• Origin: The organisms were originally supplied by KU Leuven, Belgium.

The health of the Daphnia culture and the overall quality of the test organisms is monitored regularly by using the reference toxicant potassium dichromate (K2Cr2O7) in an acute test design in order to determine the sensitivity of the organisms from the culture and to demonstrate that the test conditions are appropriate.

The most recent reference test with potassium dichromate performed in a separate study (Study No. IDA1705) resulted in an EC50(24 h) of 1.29 mg/L.

According to the OECD guideline No. 202 (OECD, April 2004) EC50(24 h)-values for potassium dichromate obtained from different laboratories should range between 0.6 mg/L and 2.1 mg/L. The toxicity of the reference item is within this range. Therefore the results of this reference test are acceptable and the test conditions are reliable and the sensitivity of the test system could be demonstrated.

Study design

Test type:

semi-static

Water media type:

other: Elendt medium M4 was used to dilute the test item and to keep the daphnids during the period of the test.

Total exposure duration:

48 h

Test conditions

Test temperature:

20.2 - 21.2 °C

pH:

7.5 - 7.8

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.292 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI: 0.253 to 0.367 mg/L

Effect concentrations 2

Duration:

48 h

Dose descriptor:

other: EC20

Effect conc.:

0.229 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

0.195 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.137 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the statistical evaluation of biological results and geometric measured concentrations of the test item, the 48-hour EC50 for Daphnia magna was 0.292 mg/L (95% confidence limits: 0.253 - 0.367 mg/L).

Executive summary:

The acute toxicity of the test item Menthene,-1, para to Daphnia magna was determined in a 48-hour test according to the OECD Guideline for Testing of Chemicals, No. 202 (2004) and the Commission Regulation (EC) No. 440/2008, Part C.2.

Based on the statistical evaluation of biological results and mean measured concentrations of the test item, the 48-hour EC50 for Daphnia magna was 0.292 mg/L (95% confidence limits: 0.253 - 0.367 mg/L).