4-ethoxy-2,3-difluoro-4'-propyl-1,1'-biphenyl

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:

2014-06-13 to 2014-06-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: test item concentration and control, at start of study and after 24 and 48 h
- Sampling method: 1 L sample volume of test item preparation and control were taken at respective times. Samples used for analysis were not in contact with daphnids due to technical reasons (high volume of test item preparation).
- Sample storage conditions before analysis: Samples were mixed with 300 mL methanol and stored tightly closed, dark and at room temperature. Samples were shipped at the end of the experimental study part to an analytical laboratory for analysis under GLP.

Vehicle:

yes

Remarks:

reconstituted water

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test medium (reconstituted water and test item) was prepared freshly. Therefore, the calibrated flask with test medium was treated in an ultrasonic device for 1 hour. Subsequently, the preparation was stirred with a magnetic stirrer for further 23 hours. Afterwards, the formulation was passed through a membrane filter with a pore size of 0.2 µm. The filtrate was used for the study.
- Controls: untreated control and separate test using positive control potassium dichromate
- Chemical name of vehicle: reconstituted water; For details please refer to "Any other information on materials and method".
- Concentration of vehicle in test medium: The vehicle is the medium used in the study.
- Test concentration separation factor: not applicable as limit test was performed
- Evidence of undissolved material: no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia
- Strain/clone: Daphnia magna Straus
- Age at study initiation (mean and range, SD): not older than 24 h
- Method of breeding: Parent animals kept individually in 100 mL test vessels containing approximately 60 mL reconstituted water. The daphnids were fed ad libitum with unicellular green algae Desmodesmus subspicatus three times per week.
- Source: the parent generation was originally bred by IBACON GmbH, Germany
- Age of parental stock (mean and range, SD): max. 6 weeks old
- Feeding during test: Daphnids were not fed during the experimental phase.

ACCLIMATION
- Acclimation period: No. To avoid an acclimation phase before start of the study, reconstituted water was used during culture as well as during the study.

QUARANTINE (wild caught): not applicable

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

not applicable

Hardness:

about 250 mg/L CaCO3

Test temperature:

20.8 - 21.4 °C

pH:

control: at start pH 7.81, after 48 h pH 7.78
100 mg/L: at start pH 7.74, after 48 h pH 7.76

Dissolved oxygen:

control: at start 8.11 mg O2/L, after 48 h 8.24 mg O2/L
100 mg/L: at start 8.06 mg O2/L, after 48 h 8.18 mg O2/L

Salinity:

not applicable

Conductivity:

below 5 µS/cm

Nominal and measured concentrations:

nominal: 100 mg/L
geometric mean measured: 43.5 µg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: test tubes
- Type: open
- Material, fill volume: glass, at least 20 mL/vessel
- Volume of solution: at least 20 mL/vessel (corresponding to 4 mL/daphnid)
- Aeration: no
- Type of flow-through: not applicable
- Renewal rate of test solution: not applicable
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The water was composed according to ELENDT (1990). The reconstituted water contained the chemicals (analytical grade) listed in Table 1, which were dissolved in fully demineralized water with a conductivity below 5 µS/cm to obtain the concentrations listed in Table 1. Please refer to “Any other information on materials and method” for Table 1. After preparation the reconstituted water was aerated for 24 hours. Hardness: about 2.5 mmol/L (about 250 mg/L CaCO3), pH: 7.9 ± 0.3, after an aeration of 24 hours.
- Culture medium different from test medium: no
- Intervals of water quality measurement: not specified

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light/8 h dark
- Light intensity: The mean light intensity measured immediately before start of the study was 618 Lux and 651 Lux at the end of the study.

EFFECT PARAMETERS MEASURED: 24 and 48 hours after the daphnids had been placed into the respective test vessels, they were visually examined for their ability to swim. Those daphnids that did not make any swimming movements within 15 seconds after the test vessel had been gently agitated, were regarded as immobilized.

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: 100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate (separate study)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 43.5 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 43.5 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: nominal 100 mg/L

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 43.5 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: nominal 100 mg/L

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

> 43.5 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: nominal 100 mg/L

Details on results:

- Behavioural abnormalities: No effects detected.
- Other biological observations: No effects detected.
- Mortality of control: No effects detected.
- Other adverse effects control: No effects detected.
- Immobilisation of control: No effects detected.
- Abnormal responses: No effects detected.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No remarkable observations were made concerning the appearance of the solution of the test item preparation. The test medium was a clear preparation and stayed unchanged throughout the study.
- Effect concentrations exceeding solubility of substance in test medium: No effects were observed up to the solubility limit.

Results with reference substance (positive control):

Potassium dichromate:
24 h EC50 0.982 (0.868-1.134) mg/L
48 h EC50 0.656 (0.573-0.750) mg/L

Validity criteria fulfilled:

yes

Conclusions:

Under the given experimental conditions, the test material showed no aquatic toxicity. The 48 hours NOEC to Daphnia magna is > 100 mg/L (nominal concentration), or > 43.5 µg/L (analytical concentration).

Executive summary:

The objective of this study was to evaluate the influence of the test item on the immobilization of Daphnia magna.

This study was performed according to GLP and the methods applied are fully compliant with OECD 202. For this purpose, juvenile daphnids were exposed to a nominal test item concentration of 100 mg/L (limit test) over 48 hours, in an open static system. The daphnids were observed for immobilization 24 and 48 hours after placing in the aqueous test item solution. The study comprised of one test item group with four test vessels containing five daphnids each, i.e. 20 daphnids in total. Additionally, one control group (20 daphnids) was used.

The analytically determined test item concentration immediately after preparation of the medium was 126.0 µg/L and 48 hours thereafter 21.9 µg/L.
Nominal and corresponding analytical concentrations and the geometric mean are given in the following table:

Nominal Concentrations [mg/L]	Analytical Concentrations / [µg/L]
	0 hours	24 hours	48 hours	geometric mean
0.0	0.116	0.990	0.223	0.399
100.0	126.0	35.9	21.9	43.5

During the experimental phase of the study, the test item concentration could not be maintained within ± 20 % of the initial analytical concentration. Therefore, the EC values were calculated with the geometric mean exposure concentration.
The daphnids were not affected after exposure to an aqueous preparation of a nominal concentration of 100 mg/L of the test material.

The following EC50 and NOEC values for daphnids were determined:

24h EC50  > 43.5 µg/L (nominal 100 mg/L)
48h EC50  > 43.5 µg/L (nominal 100 mg/L)
NOEC (24h) > 43.5 µg/L (nominal 100 mg/L)
NOEC (48h) > 43.5 µg/L (nominal 100 mg/L)

The test material, solved in reconstituted water, was tested in an open static test system. Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of test material revealed no aquatic toxicity in the test system.
The 48h EC50 was > 43.5 µg/L (nominal 100 mg/L) and, thus, could not be determined in this study.

Description of key information

No adverse effects on daphnids were observed up to the water solubility of the test item. Thus, an aqueous solution of nominal 100 mg/L of the test item revealed no toxicity to daphnids. The 48h EC50 was > 43.5 µg/L (nominal 100 mg/L) and, thus, could not be determined in this study. The 48 hours NOEC to Daphnia magna was > 100 mg/L (nominal concentration), or > 43.5 µg/L (analytical concentration).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 100 mg/L

Additional information

The objective of this study was to evaluate the influence of the test item on the immobilization of Daphnia magna.

This study was performed according to GLP and the methods applied are fully compliant with OECD 202. For this purpose, juvenile daphnids were exposed to a nominal test item concentration of 100 mg/L (limit test) over 48 hours, in an open static system. The daphnids were observed for immobilization 24 and 48 hours after placing in the aqueous test item solution. The study comprised of one test item group with four test vessels containing five daphnids each, i.e. 20 daphnids in total. Additionally, one control group (20 daphnids) was used.

The analytically determined test item concentration immediately after preparation of the medium was 126.0 µg/L and 48 hours thereafter 21.9 µg/L.
Nominal and corresponding analytical concentrations and the geometric mean are given in the following table:

Nominal Concentrations [mg/L]	Analytical Concentrations / [µg/L]
	0 hours	24 hours	48 hours	geometric mean
0.0	0.116	0.990	0.223	0.399
100.0	126.0	35.9	21.9	43.5

 

During the experimental phase of the study, the test item concentration could not be maintained within ± 20 % of the initial analytical concentration. Therefore, the EC values were calculated with the geometric mean exposure concentration.
The daphnids were not affected after exposure to an aqueous preparation of a nominal concentration of 100 mg/L of the test material.

The following EC50 and NOEC values for daphnids were determined:

24h EC50  > 43.5 µg/L (nominal 100 mg/L)
48h EC50  > 43.5 µg/L (nominal 100 mg/L)
NOEC (24h) > 43.5 µg/L (nominal 100 mg/L)
NOEC (48h) > 43.5 µg/L (nominal 100 mg/L)

The test material, solved in reconstituted water, was tested in an open static test system. Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of test material revealed no aquatic toxicity in the test system.
The 48h EC50 was > 43.5 µg/L (nominal 100 mg/L) and, thus, could not be determined in this study.