3,7-dimethyloctan-3-yl acetate

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:

December 2006 - February 2007

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no CoA, data on vapor pressure lacking to conclude relevance for test system

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:

- Sampling method: Just before the start of the test duplicate samples were taken from the test and control medium without Daphnids. After 48 hours duplicate samples were taken from the test and control medium without Daphnids to confirm stability of the substance in water.
- Sample storage conditions before analysis: All samples were deep-frozen (at about -20 °C) immediatly after sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A supersaturated suspension with a loading rate of 100 mg/L was prepared by mixing 100.2 mg test substance into 1000 mL test water. The dispersion was treated with ultrasonification for 15 minutes and was stirred on a magnetic stirrer at room temperature in the dark for 24 hours to dissolve the maximum amount of test substance in the test water. The stirring period of 24 hours was based on the results of the pre-test which showed that the solution equilibrium was reached after this time. After stirring 24 hours the saturated dispersion was filtered through a membrane filter (Schleicher & Schuell, Type NC45, pore size 0.45µm) just before the start of the test. The undiluted filtrate of the dispersion was used as test medium.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Straus (defined by supplier as clone 5)
- Source: supplied by University of Sheffield/UK in 1992.
- Age of parental stock: 6 - 24 hours
- Feeding during test: No

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

2.5 mmol/L = 250 mg/L as CaCO3

Test temperature:

20 °C

pH:

7.9 - 8.0

Dissolved oxygen:

8.2 - 8.6

Nominal and measured concentrations:

Nominal: 100 mg/L
Analytical: 0.09 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beakers
- Fill volume: 50 mL
- Aeration: The test water was aered prior to the start of the study until oxygen saturation was reached. During the study the test water was not aered.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 1 Daphnid/10 mL

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstructed test water containing: CaCl2 * H2O (294 mg/L), MgSO4 * 7H2O (123 mg/L), NaHCO3 (65 mg/L), KCl (5.8 mg/L)
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 4:1 (based on molarity)

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 hour light to 8 hour dark with 30 minute transition period
- Light intensity: approximately 570 and 740 lux.

EFFECT PARAMETERS MEASURED:
Observations were made 24 and 48 hours after exposure for immobility.

VEHICLE CONTROL PERFORMED: not applicable, no solvent used

Reference substance (positive control):

yes

Remarks:

Potassium dichromate, tested June 2006

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.09 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Remarks on result:

other: Substance was tested up to solubility limit. 100 mg/L was the nominal dose

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.09 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Remarks on result:

other: Substance was tested up to solubility limit. 100 mg/L was the nominal dose

Details on results:

The analytical measured test item concentration in the analyzed test medium samples (the undiluted filtrate of the supersatured dispersion) was 0.53 mg/L at the start of the test. In this test medium, the concentration found at the end of the test was below LOQ of the analytical method (LOQ=0.03 mg/L). The mean measured test item concentration (calculated as the average overall measurements in the undiluted filtrate) was 0.09 mg/L.

In the control and at the loading rate of 100 mg/L (mean measured 0.09 mg/L) no immobilized test organisms were observed during the test period of 48 hours.

The 48-hour NOEC and the 48-hour EC0 of the test substance were determined to be at least the loading rate of 100 mg/L. The 48 hour EC50 and the 48-hour EC100 were clearly higher than the loading rate of 100 mg/L. These values could not be quantified, since the test item had no toxic effect on the daphnids up to the highest test item concentration that could be dissolved in water.

No remarkable observations were made concerning the test medium. The test medium was a clear solution throughout the whole test duration.

Results with reference substance (positive control):

The test result of June 2006 (48-hour EC50: 0.67 mg/L) showed that the sensitivity of the test organisms was within historical range of the RCC laboratory (48-hour EC50 from 1996: 0.53 -1.1 mg/L)

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the test, the substance was not acute aquatic toxic up to its solubility limit.

Executive summary:

An acute aquatic toxicity test was performed according to OECD TG 202 and in compliance with GLP. 20 Daphnia Magna (4 replicates, 5 organisms per test vessel) were exposed in a static system to the maximum concentration solvable in water 0.09 mg/L (mean analytical concentration). The laboratory positive control was within the historical range and no remarkable observations were made concerning the test medium. Observations regarding mobility of the Daphnids were made at 24 and 48 hours. The 48-hour NOEC and the 48-hour EC0 of the test substance were determined to be at least the loading rate of 100 mg/L. The 48 hour EC50 and the 48-hour EC100 were clearly higher than the loading rate of 100 mg/L. These values could not be quantified, since the test item had no toxic effect on the daphnids up to the highest test item concentration that could be dissolved in water. Under the conditions of the test, the substance was not acute aquatic toxic up to its solubility limit.

Description of key information

An acute aquatic toxicity test was performed according to OECD TG 202 and in compliance with GLP. 20 Daphnia Magna (4 replicates, 5 organisms per test vessel) were exposed in a static system to the maximum concentration solvable in water 0.09 mg/L (mean analytical concentration). The laboratory positive control was within the historical range and no remarkable observations were made concerning the test medium. Observations regarding mobility of the Daphnids were made at 24 and 48 hours. The 48-hour NOEC and the 48-hour EC0 of the test substance were determined to be at least the loading rate of 100 mg/L. The 48 hour EC50 and the 48-hour EC100 were clearly higher than the loading rate of 100 mg/L. These values could not be quantified, since the test item had no toxic effect on the daphnids up to the highest test item concentration that could be dissolved in water. Under the conditions of the test, the substance was not acute aquatic toxic up to its solubility limit.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L