3(or 4)-(4-methylpenten-3-yl)cyclohex-3-ene-1-methyl acetate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, to GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3(or 4)-(4-methylpenten-3-yl)cyclohex-3-ene-1-methyl acetate

EC Number:

276-650-6

EC Name:

3(or 4)-(4-methylpenten-3-yl)cyclohex-3-ene-1-methyl acetate

Cas Number:

72403-67-9

Molecular formula:

C15H24O2

IUPAC Name:

[3-(4-methylpent-3-en-1-yl)cyclohex-3-en-1-yl]methyl acetate; [4-(4-methylpent-3-en-1-yl)cyclohex-3-en-1-yl]methyl acetate

Test material form:

other: liquid

Details on test material:

Test substance name: Myraldyl acetate
CAS number: 72403-67-9
Molecular formula: C15H24O2
Molecular weight: 236.3
Vapour pressure: 0.046 Pa at 20 ºC
Water solubility: 2.50 mg/L at 20 ºC
Octanol water partition co-efficient (Log Pow): 5.6 to 5.7
Description: Colourless liquid
Storage: Refrigerated (2 - 8 °C)

Sampling and analysis

Details on sampling:

Concentrations of myraldyl acetate in Elendt M4 medium were determined by gas chromatography with flame ionisation detection (GC-FID), following extraction from the media with hexane.
At the start of the test (0 hours) and at media renewal at 24 hours, 40 mL samples of freshly prepared test media were taken from the control and each test media preparation flask for chemical analysis.
At 24 and 48 hours, 40 mL samples were also taken for chemical analysis from the pooled expired test media at each test concentration including the control.
In each case duplicate samples were taken, one for chemical analysis and one as a ‘back-up’ should further analysis be required.

Test solutions

Details on test solutions:

The test substance was prepared from an initial 100 mg/L, stirred for ca 24 hours and filtered to give a nominal test concentration of 100% saturated solution.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Juvenile Daphnia magna (Straus), less than 24 hours old, were taken from healthy parental laboratory cultures, held and maintained at the test facility. The culture was originally obtained from Smithers Viscient, Shawbury, UK.

Study design

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

48 h

Post exposure observation period:

none

Test conditions

Test temperature:

The temperature was maintained between 20.7 – 21.3 °C. Continuous temperature measurement of the test area by use of a digital maximum / minimum thermometer.

pH:

Water quality determinations for pH during the definitive test are presented in Table 2 (see attached report).

Dissolved oxygen:

Water quality determinations for dissolved oxygen (% ASV and mg/L) during the definitive test are presented in Table 2 (see attached report).

Salinity:

No (freshwater)

Nominal and measured concentrations:

Range finding test:
Nominal concentration (% saturated solution): 0.1, 1.0, 10, 100 % v/v saturated solution

Definitive test:
Nominal concentrations: 1, 3.2, 10, 32, 100 % v/v saturated solution
Time-weighted mean measured concentrations: 0.025, 0.053, 0.16, 0.52, 2.2 mg/L

Details on test conditions:

Preliminary Solubility Trial
The test substance was known to have limited solubility in water (2.50 mg/L at 20 ºC). Initial visual solubility work was conducted which indicated that the highest attainable concentration was 1.0 mg/L using an initial solvent spike method of preparation.

A media preparation trial indicated that the most appropriate method of preparation for the test substance was the use of a saturated solution method of preparation. Analysis of a saturated solution prepared from an initial 100 mg/L loading rate followed by filtration gave a measured concentration of 1.07 to 1.31 mg/L indicating this to be the limit of solubility of the test substance in Elendt M4 media.

The test substance was therefore prepared from an initial 100 mg/L, stirred for ca 24 hours and filtered to give a nominal test concentration of 100% saturated solution.

Test Procedures

Range-finding Test
The range-finding test was conducted at nominal test substance concentrations of 0.10, 1.0, 10 and 100% saturated solution under semi-static test conditions. Due to the possible volatile nature of the test substance, the test vessels were completely filled and sealed. A control group was also included. Duplicate test vessels were prepared for the control and each test concentration. Based on nominal concentrations, the results of the range-finding test suggested that the 48-hour EC50 value would be less than 100% saturated solution.

Definitive Test
Based on the results of the range-finding test, for which the key results only have been reported, the definitive test was conducted at nominal test concentrations of 1.0, 3.2, 10, 32 and 100% saturated solution.

The test was conducted using semi-static test conditions with renewal of test media after 24 hours.

The test vessels (nominal volume 60 mL) were glass jars. Due to the possible volatile nature of the test substance, the test vessels were completely filled and sealed. Four replicate test vessels were prepared for the control and each test concentration.

At the start of the test, the 100% saturated solution test concentration was prepared by weighing ca 100 mg of test substance and adding to 1000 mL of Elendt M4 medium. This was stirred slowly for ca 24 hours. Following the stirring period, the preparation was allowed to settle for ca 1 hour. The test media was siphoned from the mid-section of the flask and then filtered through a 0.45 μm filter to give the 100% saturated solution test concentration. Dilutions were then prepared from the 100% saturated solution, in Elendt M4 medium, to give the remainder of the nominal test concentrations of 1.0, 3.2, 10 and 32% saturated solution. A control treatment was prepared by adding Elendt M4 medium only to the control vessels.

Five juvenile Daphnia magna, less than 24 hours old, were added to each test vessel, using a wide bore glass pipette to avoid damaging the animals during transfer. The Daphnia magna were not fed during the test. After 24 and 48 hours, the Daphnia magna in each test vessel were observed for
evidence of immobility. The observations differentiated between mobile and immobile daphnids. An individual was considered immobile if, when the contents of the test vessel were briefly agitated, it did not swim during a 15-second period of observation. In addition, Daphnia magna submerged in the body of the test media and those that were held at the surface of the test media were also recorded.

Water Quality and Environmental Conditions

The test was conducted with a 16-hour light: 8-hour dark photoperiod.
The pH, dissolved oxygen concentration (% air saturation value (ASV) and mg/L) and temperatures were determined in freshly prepared test media at the start of the test and at media renewal at 24 hours and in the old media at 24 and 48 hours. Continuous temperatures were measured using a digital (min/max) thermometer in an additional vessel maintained in the study area.
At the end of each exposure period the test water quality measurements were conducted using pooled replicate samples of old test media.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.01 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 0.55-1.32

Effect concentrations 2

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

0.52 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.16 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

After 48 hours, the concentration at which no significant (≤10%) dose related immobility occurred was 0.16 mg/L. The NOEC was considered to be 0.16 mg/L. After 48 hours 100% immobility was recorded at the highest test concentration of 2.2 mg/L.

In terms of time-weighted mean measured concentrations the 48-hour EC50 value was determined to be 1.01 mg/L.

The validity criteria for control immobility (≤10%) and dissolved oxygen (≥3 mg/L) were both satisfied. The test is therefore considered valid.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour acute toxicity of myraldyl acetate to the freshwater planktonic crustacean, Daphnia magna, was determined in accordance with the requirements of OECD Chemicals Testing Guideline No. 202 Daphnia sp. Acute Immobilisation Test (adopted April 13 2004).
The validity criteria for control immobility (≤10%) and dissolved oxygen (≥3 mg/L) were both satisfied. The test is therefore considered valid.

Based on time-weighted mean measured concentrations, the 48-hour EC50 value was determined to be 1.01 mg/L. The corresponding No Observed Effect Concentration (NOEC) was considered to be 0.16 mg/L.