Trans-2-{4-[difluoro(3,4,5-trifluorophenoxy)methyl]-3,5-difluorophenyl}-5-(trans-4-propylcyclohexyl)-1,3-dioxane

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:

from January 4, 2016 - January 28, 2016

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)

Version / remarks:

2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Council Regulation (EC) No. 440/2008 laying down test methods pursuant to Regulation (EC) No. 1907/2006 of the European Parliament and the council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Remarks:

The test material concentration was not quantified at the start and the end of this study due to the very low water solubility. Because of the low water (calculated 2.64e-6 mg/L), the compound cannot be detected with standard analytical methods.

Vehicle:

yes

Remarks:

reconstituted water

Details on test solutions:

Macro nutrients (mg/L)
CaCI2 •2H20 293.80
MgSO4•7H20 123.30
NaHCO3 64.80
KCI 5.80
Na2SiO3•9H20 10.00
NaNO3 0.27
KH2PO4 0.14
K2HPO4 0.18

Trace elements (mg/L)
B 0.5000
Fe 0.2000
Mn 0.1000
Li, Rb and Sr 0.0500
Mo 0.0250
Br 0.0125
Cu and Zn 0.0063
Co and I 0.0025
Se 0.0010
V 0.0003

Macro nutrients (mg/L)
Na2EDTA • 2H20 2.50

Vitamins (µg/L):
Thiamine 75.00
B12 1.00
Biotin 0.75

- pH: 7.77

Preparation of the Test Item:
The test medium (reconstituted water and test item) was prepared freshly. For that purpose, 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.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna Straus
Culture conditions: The clone is bred in the laboratories of Merck KGaA.
Parental daphnids are used for reproduction until they are about 6 weeks old. Thereafter, they are replaced by neonates.
Daphnids are kept individually in 100 mL glass vessels containing approximately 60 mL reconstituted water (ELENDT M4 medium) at a water temperature of 20 ± 2 °C and a 16 hour light and 8 hour dark regime to ensure similar conditions as in the experiment. Offspring are removed from the vessels at least twice per week.
Feeding: The parental daphnids are fed ad libitum with unicellular green algae Desmodesmus subspicatus three times per week.
Age: Offspring less than 24 hours old were used for the study.
Acclimation period: same as test

Feeding during test: None

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

19.7 - 20.1 °C

pH:

7.77 - 8.07

Dissolved oxygen:

7.69 - 8.03 mg/L

Nominal and measured concentrations:

Nominal 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass test tubes
- Type: open
- Material, size, headspace, fill volume: 20 mL glass test tubes containing 20 mL medium
- Aeration: no
- 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: reconstituted water (ELENDT M4 medium according OECD 202)
- Culture medium different from test medium: no
- Intervals of water quality measurement: at start and end of exposure

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16h light / 8h dark
- Light intensity: The mean light intensity measured immediately before start of the study was 688 Lux and 681 Lux at the end of the study.

EFFECT PARAMETERS MEASURED : Immobilisation (daily)

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 100 mg/L
- Results used to determine the conditions for the definitive study: no immobilisation observed at 100 mg/L

Reference substance (positive control):

no

Remarks:

No positive control used in this study. The accuracy and reliability of the test method is demonstrated periodically as recommended by guidelines with potassium dichromate.

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: EC50 >2.64e-6 mg/L, based on water solubility

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

Remarks on result:

other: EC50 >2.64e-6 mg/L, based on water solubility

Details on results:

An aqueous solution of nominal 100 mg/L of the test item revealed no aquatic toxicity in the test system.

The 48-h EC50 exceeded the water solubility of 2.64e-6 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.

- Behavioural abnormalities: no
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Abnormal responses: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no

Results with reference substance (positive control):

Study design:
The study was performed with the test item Art. 104864 (Potassium dichromate) as positive control to check the sensitivity of the test system as recommended by guidelines.
Groups of Daphnia magna were exposed to different concentrations of the test item in reconstituted water for 48 hours. The daphnids were observed for immobilization, 24 and 48 hours after placing in the test medium. The study comprised of four test vessels per concentration containing five daphnids, i.e., 20 daphnids per concentration. Additionally, one control group (20 daphnids) was used.
Test item concentrations of 0.31, 0.46, 0.69, 1.02 and 1.52 mg/L were used in this study.

Results:
Potassium dichromate is the recommended positive control substance and thus no analysis was carried out.

EC50 values with 95 % confidence intervals:
24h EC50 0.753 mg/L (0.646 – 0.883 mg/L)
48h EC50 0.602 mg/L (0.525 – 0.689 mg/L)

Conclusion:
Under the given experimental conditions, the test item Art. 104864 (Potassium dichromate) showed a 24h EC50 value which was within the range of the published data of 0.6 to 1.7 mg/L (Council Regulation (EC) No. 440/2008) and 0.6 to 2.1 mg/L (OECD Guideline No. 202).

Results

The test item concentration in the reconstituted water was not quantified at the start and the end of this study. Because of the low water solubility (2.64e-6 mg/L), the compound cannot be detected with standard analytical methods and the development of an analytical method with a sufficiently low detection and quantification limit is complex.

Due to the absence of any adverse effects at the saturation concentration, the study was performed without analytical concentration verification.

 

Daphnids exposed to an aqueous preparation of a nominal concentration of 100 mg/L of the test item were not affected.

 

For the test item the following EC50 values were determined:

EC50 (24h) >2.64e-6 mg/L (nominal >100 mg/L)

EC50 (48h) >2.64e-6 mg/L (nominal >100 mg/L)

 

Conclusion

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no aquatic toxicity in the test system.The 48h EC50 was >2.64e-6 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no aquatic toxicity in the test system.
The 48-h EC50 was >2.64e-6 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.

Executive summary:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 202. Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no aquatic toxicity in the test system. The 48-h EC50 was >2.64e-6 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.

Description of key information

Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no aquatic toxicity in the test system (reference 6.1.3-1).

The 48-h EC50 was >2.64e-6 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.

Additional information

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 202 (reference 6.1.3-1). Under the conditions of the present study, an aqueous solution of nominal 100 mg/L of the test item revealed no aquatic toxicity in the test system. The 48-h EC50 was >2.64e-6 mg/L (nominal >100 mg/L) and, thus, could not be determined in this study.