1-Ethoxy-2,3-difluoro-4-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-benzene

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 20, 2006 - March 23, 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Principles of method if other than guideline:

None

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The test medium (reconstituted water and test material) was freshly prepared. The calibrated flask with test material and vehicle, reconstituted water, was treated in an ultrasound bath for 1 hour. Subsequently, the preparation was stirred with a magnetic stirrer for further 23 hours. Afterwards, the preparation was filtered through a filter funnel with a pore size of 10-16 µm. The filtrate was used for the study.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

The test system used for this study was a green unicellular algae species, Desmodesmus subspicatus, strain No. SAG 86.81, supplied by the "Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universitat Göttingen". This strain is recommended by international guidelines.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

250 mg CaCO3

Test temperature:

23+/-1 °C

pH:

start of exp.: 7.9+/-0.1end of exp.: 9.6+/-0.2

Salinity:

for details see composition of reconstituted water "details on test conditions"

Nominal and measured concentrations:

Nominal concentration of 100 mg/L (limit test); due to very low water solubility and the fact that the study was a limit test, no further analysis was initiated.

Details on test conditions:

The study design included one control and one test material group with three replicates, each containing 100 mL reconstituted water or test medium and about 10,000 cells/mL at the start of the experimental phase.

The study was performed as a limit test in an open static test system. The algae were exposed to a filtrate of nominal 100 mg/L. The growth of the algae was calculated after 24, 48 and 72 hours exposure in the test medium.

The test medium (reconstituted water and test material) was freshly prepared. The light intensity was approximately 7500 to 9500 Lux. The experimental part was started by inoculation of algae to the different groups so that the flasks contained about 10000 cells/mL. The algae were taken from an exponentially growing pre-culture (growth rate 120.7) which was set up 3 days prior to the experimental part under the same conditions as in the final study. Details on composition of the reconstituted water: Macro-nutrients: 50.00 mg/L NaHCO3, 18.00 mg/L CaCl2 x 2 H2O, 15.00 mg/L NH4Cl, 15.00 mg/L MgSO4 x 7 H2O, 12.00 mg/L MgCl2 x 6 H2O, 1.60 mg/L KH2PO4, Trace elements: 100.00 µg/L Na2EDTA x 2 H2O, 80.00 µg/L FeCl3 x 6 H2O, 415.00 µg/L MnCl2 x 4 H2O, 185.00 µg/L H3BO3, 7.00 µg/L Na2MoO4 x 2 H2O, 3.00 µg/L ZnCl2, 1.50 µg/L CoCl2 x 6 H2O, 0.01 µg/L CuCl2 x 2 H2O. The pH of the reconstituted water after aeration is approximately 8.

Reference substance (positive control):

yes

Remarks:

Regularly, a positive control test to check the test system is carried out with potassium dichromate (no results provided in the study report).

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

No results provided in the study report.

Validity criteria fulfilled:

yes

Conclusions:

An aqueous preparation of 100 mg/L (nominal) of the test material revealed no toxic effect in the test system. Analytically, the 72 hours EC50 to Desmodesmus subspicatus could not be determined; it exceeded the maximum solubility of the test material in reconstituted water (< 0.005 mg/L).

Executive summary:

Purpose

The purpose of this assay was to identify the aquatic toxicity potential of the test material in algea to provide a rational basis for hazard estimation for the test item in aquatic environments.

 

Study design

The influence of the test material on the growth and growth rate of the green algae species Desmodesmus subspicatus was tested. The study design included one control and one test material group with three replicates, each containing about 100 mL reconstituted water or test medium and 10,000 cells/mL at the start of the experimental phase. The algae were exposed to a filtrate of nominal 100 mg/L and the study was performed as a limit test in an open static test system. The growth was calculated after 24, 48, and 72 hours exposure in the test medium.

 

Results

The analysis of the saturated aqueous preparation revealed that the water solubility of the test material in reconstituted water was < 0.005 mg/L. The test material concentration in the aqueous medium could not be quantified since it was below the level of detection. For the test material, the following EC50 values and no effect concentration for Desmodesmus subspicatus were determined:

 

72 h EbC50 > 0.005 mg/L (nominal > 100 mg/L)

72 h ErC50 > 0.005 mg/L (nominal > 100 mg/L)

NOEC > 0.005 mg/L (nominal > 100 mg/L)

 

Conclusions

An aqueous preparation of 100 mg/L (nominal) of the test material revealed no toxic effect in the test system. The 72 hours EC50 exceeded the maximum solubility of the test material in reconstituted water (< 0.005 mg/L).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

For this endpoint information from a structural similar compound is available. This study for this similar compound was performed according to GLP and the methods applied are fully compliant with OECD TG 201. See chapter 13 report for a more detailed justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Description of key information

The source substance of this read across revealed no toxic effect on the growth of algae after 72 h at a nominal concentration of 100.0 mg/L. Analytically, the 72 hours EC50 to algae could not be determined; it exceeded the maximum solubility of the test material in reconstituted water (< 0.005 mg/L).

Additional information

No study data with the test item is available for this endpoint. Therefore, a read-across to the read-across source substance with a very similar chemical structure and comparable physico-chemical parameters is used to evaluate the endpoint for the test item.

Purpose

The purpose of this assay conducted according to OECD 201 was to identify the aquatic toxicity potential of the test material in algea to provide a rational basis for hazard estimation for the test item (read-across source substance) in aquatic environments.

 

Study design

The influence of the test material on the growth and growth rate of the green algae species Desmodesmus subspicatus was tested. The study design included one control and one test material group with three replicates, each containing about 100 mL reconstituted water or test medium and 10,000 cells/mL at the start of the experimental phase. The algae were exposed to a filtrate of nominal 100 mg/L and the study was performed as a limit test in an open static test system. The growth was calculated after 24, 48, and 72 hours exposure in the test medium.

 

Results

The analysis of the saturated aqueous preparation revealed that the water solubility of the test material in reconstituted water was < 0.005 mg/L. The test material concentration in the aqueous medium could not be quantified since it was below the level of detection. For the test material, the following EC50 values and no effect concentration for Desmodesmus subspicatus were determined:

 

72 h EbC50 > 0.005 mg/L (nominal > 100 mg/L)

72 h ErC50 > 0.005 mg/L (nominal > 100 mg/L)

NOEC > 0.005 mg/L (nominal > 100 mg/L)

 

Conclusions

An aqueous preparation of 100 mg/L (nominal) of the test material revealed no toxic effect in the test system. The 72 hours EC50 exceeded the maximum solubility of the test material in reconstituted water (< 0.005 mg/L).