2-methoxy-2-methylheptane

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:

15 Dec 2017 - 18 Jan 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures

Version / remarks:

OECD series on testing and assessment number 23, 2000.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-methoxy-2-methylheptane

EC Number:

816-311-7

Cas Number:

76589-16-7

Molecular formula:

C9H20O

IUPAC Name:

2-methoxy-2-methylheptane

Test material form:

liquid

Specific details on test material used for the study:

Identification: DAIKON ETHER
Chemical name (IUPAC), synonym or trade name: 2-Methoxy-2-methylheptane
CAS number: 76589-16-7
EC name: 2-methoxy-2-methylheptane
Appearance: Colorless liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Frequency at t=0 h and t=48 h
Volume 6.0 mL from the approximate centre of the test vessels
Storage Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility. On the day of analysis, the test samples were thawed at room temperature. The samples were extracted in a 3:1 (v:v) ratio with n-hexane and analyzed. The shaking time was 30 seconds. If necessary, the samples were further diluted with n-hexane to obtain concentrations within the calibration range.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
- Eluate:
- Differential loading:
- Controls:
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)):
- Evidence of undissolved material (e.g. precipitate, surface film, etc.):

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

180 mg/L

Test temperature:

20 - 21°C

pH:

6 - 9

Nominal and measured concentrations:

Nominal concentrations: 10, 18, 32, 56 and 100% of the SS prepared at a loading rate of 100 mg/L
Measured concentrations: 5.5, 12, 22, 34 and 69 mg/L

Details on test conditions:

Test duration 48 hours
Test type Static
Test vessels 60 mL, all-glass, air-tight closed without headspace
Medium Adjusted ISO medium
Number of daphnids 20 per concentration
Loading 5 per vessel containing 60 mL of test solution
Light 16 hours photoperiod daily
Feeding No feeding
Aeration No aeration of the test solutions.
Introduction of daphnids Within 28 minutes after preparation of the test solutions.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

24 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

95%-confidence interval (mg/L): 22 - 26
The test conditions remained within the limits prescribed by the study plan (pH:6-9, not varying by more than 1.5 units; oxygen: ≥ 3 mg/L at the end of the test).
The temperature continuously measured in a temperature control vessel varied between 20 and 21°C during the test, and complied with the requirements as laid down in the study plan (18-22°C, constant within 2°C).
See attachment

Results with reference substance (positive control):

The actual responses in this reference test with K2Cr2O7 are within the ranges of the expected responses at the different concentrations, i.e. the 48h-EC50 was between 0.3 and
1.0 mg/L. Hence, the sensitivity of this batch of D. magna was in agreement with the historical data collected.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In conclusion, the 48h-EC50 for Daphnia magna exposed to the test item was 24 mg/L based on average exposure concentrations (95% confidence interval between 22 and 26 mg/L).