1,3-dimethyl-3-phenylbutyl 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:

31-08-2015 to 03-09-2015

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Sampling: At the start of the exposure intervals (0 and 24 hours), sampling was carried out after preparation of the loading rates.
At the end of the exposure intervals (24 and 48 hours), samples were taken from additional replicates with test media, but without daphnids, which were incubated under test conditions until sampling, and analysed.
- Concentrations: 4.09, 8.19, 16.9, 34.3 and 67.1 mg/L
- Sample storage conditions before analysis: All samples were stored at 6 ± 2 °C until sample preparation and at room temperature until the start of the analysis, if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A saturated solution with a nominal loading rate of 100 mg/L test item was prepared with dilution water (ISO test water) one day prior to the start of each exposure interval. An appropriate amount of the test item was weighted and transferred with an appropriate amount of dilution water into a measuring flask. The dispersion was stirred for 24 hours at approximately 1100 rpm at room temperature. Undissolved test item was removed from the saturated solution by membrane filtration (membrane filter 0.45 um). During filtration, the filter was always kept covered with the test dispersion. The filtrate (saturated solution) was used as the highest loading rate and further loading rates were prepared by dilution with ISO test water.
- Controls: Dilution water without test item.
- Test concentrations: The saturated solution and further four dilution levels, were prepared from the saturated solution with dilution water in a geometrical series with a separation factor of 2.
Nominal concentrations: 6.25, 12.5, 25, 50 and 100 % of the saturated solution.
Geometric mean measured concentrations:4.09, 8.19, 16.9, 34.3 and 67.1 mg/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Giant water flea
- Strain: STRAUS (Clone 5)
- Source: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu), 14195 Berlin, Germany
- Age at study initiation: 2 to 24 hours old
- Feeding during test: Not fed during study

ACCLIMATION
- Acclimation period: At least 2 hours in dilution water
- Acclimation conditions: Same as test
- Type and amount of food: mix of unicellular green algae with an algae cell density of > 10s cells/mL
- Feeding frequency: 5 times per week

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

260-267 mg CaC03/L

Test temperature:

19-20°C

pH:

7.73-7.95

Dissolved oxygen:

8.45-9.17 mg/L

Salinity:

Not recorded

Nominal and measured concentrations:

Nominal concentrations: 6.25, 12.5, 25, 50 and 100 % of the saturated solution.
Geometric mean measured concentrations: 4.09, 8.19, 16.9, 34.3 and 67.1 mg/L.

At the start of the exposure intervals measured concentrations were within the range of 4.33 to 77.4 mg/L and reflect the dilution factor of 2. At the end of the exposure intervals, the measured concentrations were within the range of 73 to 88 % of the initially measured concentrations. In the saturated solution, the measured test item concentration at the end of the first exposure interval (0 hours) was not within ± 20 % of the initially measured concentration at the start of the respective exposure interval (24 hours), but during the second exposure interval and at all other loading rates measured concentrations were ± 20 % of the initially measured concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (4 (ID) x 7 (H) cm), 50 mL capacity, loosely covered with watch glasses
- Renewal rate of test solution (frequency/flow rate): After 24 hours, as test concentrations in the non-GLP rangefinder decreased markedly within 24 hours.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 20
- No. of vessels per control (replicates): 20

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: ISO Test water, according to OECD 202, Annex 3
- Culture medium different from test medium: Elendt M4 medium, modified to a total hardness of 160 to 180 mg CaCO3/L

OTHER TEST CONDITIONS
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: Diffuse light, light intensity of max. 20 uE-m2/S (max. 1340 lx)

TEST CONCENTRATIONS
- Range finding study: 1, 10, 100 mg/L

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

16.9 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: lower 95% CL: 14.9 upper 95% CL: 19.7

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

24.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: lower 95% CL: 21.7 upper 95% CL: 26.8

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

16.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

34.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 1.92 mg/L (lower 95% CL 1.85 upper 95% CL 1.99)

Reported statistics and error estimates:

The EC10- and the EC50-values after 24 and 48 hours were calculated by sigmoidal dose-response regression.
The respective 95 % confidence limits were calculated from the standard error and the t-distribution. All calculations were carried out from the best-fit values with the software GraphPad Prism5.
The concentration-effect relationships are shown graphically. The EC50-value for the reference item and its 95 % confidence limits were calculated accordingly.

Validity criteria fulfilled:

yes

Remarks:

In the control group, no daphnids were immobilised or showed any signs of disease or stress. The dissolved O2 concentration at the end of the exposure intervals was > 3 mg/L at the test end of the exposure intervals in all test vessels.

Conclusions:

Based on the geometric mean measured concentrations of the test item, the 48 hour-EC50 for Daphnia magna was 24.1 mg/L.

Executive summary:

The toxicity of the test item to Daphnia magna was investigated. This study is GLP compliant and follows OECD guideline 202 and EU method C.2. All validity criteria for the study were met. Therefore, it has been assigned a reliability score of 1 (reliable with no restrictions).

Test solutions were prepared by first preparing a dispersion at a nominal concentration of 100 mg/L, which was stirred for 24 hours at 1100 rpm and then filtered. This was used as the highest loading rate in the test, and further loading rates were prepared by dilution. Analytical verification of test concentrations was conducted using HPLC-UV analysis, and results are based on mean measured concentrations.

Based on the geometric mean measured concentrations of the test item, the 48 hour-EC50 for Daphnia magna was 24.1 mg/L.

Description of key information

Based on the geometric mean measured concentrations of the test item, the 48 hour-EC50 for Daphnia magna was 24.1 mg/L. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

24.1 mg/L

Additional information

The toxicity of the test item to Daphnia magna was investigated (2015). This study is GLP compliant and follows OECD guideline 202 and EU method C.2. All validity criteria for the study were met. Therefore, it has been assigned a reliability score of 1 (reliable with no restrictions). Test solutions were prepared by first preparing a dispersion at a nominal concentration of 100 mg/L, which was stirred for 24 hours at 1100 rpm and then filtered. This was used as the highest loading rate in the test, and further loading rates were prepared by dilution. Analytical verification of test concentrations was conducted, and results are based on mean measured concentrations. Based on the geometric mean measured concentrations of the test item, the 48 hour-EC50 for Daphnia magna was 24.1 mg/L.