2-(1-(3',3'-dimethyl-1'-cyclohexyl)ethoxy)-2-methyl propyl propanoate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 9 February 1995 to 23 March 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

This study was carried out according to international OECD Guideline No. 202 with GLP statement. All validity criteria were fulfilled. This study is reliable without restriction.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

, 2 groups of 10 animals each were performed instead of 4 groups of 5 animals each. This deviation is minor and not affect the results

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

1994-01-31

Specific details on test material used for the study:

- Storage condition of test material: metal bottle at room temperature

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Water samples were taken from the solvent control and the 0.10, 0.32, 1.0, 3.2 and 10 mg/L test groups (replicates pooled) at 0 and 48 hours for quantitative analysis.
- Sampling method: An aliquot of each test sample was extracted with three portions (3 x 50 mL) of dichloromethane, each extract being filtered through anhydrous sodium sulphate. The combined extracts were evaporated to dryness and the residue re-dissolved in ethyl acetate to give a final theoretical test material concentration of 25 mg/L.
- Sample storage conditions before analysis: no data

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: For the purpose of the definitive study the test material was prepared using a preliminary solution in 10% v/v Tween 80-dimethylformamide. The test material (1.00 g) was dissolved in 10% v/v Tween 80-dimethylformamide and the volume adjusted to 10 mL to give a 1.00 g/10 mL solvent stock solution. An aliquot (500 µL) of this stock solution was dispersed in reconstituted water and the volume adjusted to 5 litres to gi ve the 10 mg/L test concentration from which dilutions were made to give the remainder of the test series of 0.10. 0.18. 0.32. 0.56. 1.0. 1.8. 3.2 and 5.6 mg/L.
- Eluate: solvent
- Differential loading: 1.00 g of test material/10 mL solvent
- Controls: 2 controls (control + solvent control)
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): dimethylformamide
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 10% v/v Tween 80 - dimethylformamide
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no data

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: no data
- Source: Institut National de Recherche Chimique Appliquée (IRCHA)
- Age at study initiation (mean and range, SD): 1st instar Daphnia magna
- Weight at study initiation (mean and range, SD): no data
- Length at study initiation (length definition, mean, range and SD): no data
- Valve height at study initiation, for shell deposition study (mean and range, SD): no data
- Peripheral shell growth removed prior to test initiation: no data
- Method of breeding: no data
- Feeding during test: no

ACCLIMATION
- Acclimation period: no data
- Acclimation conditions (same as test or not): Adult Daphnia were maintained in polypropylene vessels containing approximately 2 litres of reconstituted water at a temperature of 21°C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle. Each culture was fed daily with a suspension of mixed algae (predominantly Chiarella spp.). Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated 24 hours prior to the initiation of the test. the young daphnids produced overnight were then removed for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.
- Type and amount of food: a suspension of mixed algae (predominantly Chiarella spp.).
- Feeding frequency: daily
- Health during acclimation (any mortality observed): no data

QUARANTINE (wild caught)
not applicable

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

none

Post exposure observation period:

None

Hardness:

The reconstituted water has an approximate theoretical total hardness of 270 mg/L as CaCO3.

Test temperature:

Temperature was maintained at 21°C throughout the study.

pH:

The pH varied between 7.6 to 7.8 throughout the study

Dissolved oxygen:

The Dissolved oxygen varied between 7.9 to 8.4 mg O2/L throughout the study.

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0.10, 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6 and 10 mg/L.
Measured concentrations: Analysis of the test preparations at 0 and 48 hours (See table 1 in "Any other information on results incl. tables") showed the measured test concentrations to be in excess of the required 80% of nominal.

Details on test conditions:

TEST SYSTEM
- Test vessel: ground glass stoppered conical flasks
- Type (delete if not applicable): stoppered
- Material, size, headspace, fill volume: 250 mL
- Aeration: the test vessels were not aerated
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): not applicable
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: 25 mL of each of solutions (CaCl2.2H2O= 11.76 g/L; MgSO4.7H2O= 4.93 g/L; NaHCO3 = 2.59 g/L; KCL = 0.23 g/L) were added to each litre (final volume) of deionised water (conductivity <5µS cm-1). pH equal to 7.8 ± 0.2, adjust (if necessary) with NaOH or HCl. The reconstituted water was aerated until the dissolved oxygen concentration was approximately air-saturation value.
- Total organic carbon: no data
- Particulate matter: no data
- Metals: no data
- Pesticides: no data
- Chlorine: no data
- Alkalinity: no data
- Ca/mg ratio: no data
- Conductivity: <5µS cm-1
- Culture medium different from test medium: no
- Intervals of water quality measurement: no data

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light and 8 hours darkness
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Any immobilisation or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: average 1.75
- Justification for using less concentrations than requested by guideline: not applicable
- Range finding study: yes (0.10, 1.0, 10 mg/L)
- Test concentrations: 0.10, 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6 and 10 mg/L.
- Results used to determine the conditions for the definitive study: The results of the range finding study showed no immobilisation at the test concentrations of 0.10 and 1.0 mg/L. However, immobilisation was observed at 10 mg/L.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 2.7-3.9 mg/L

Duration:

48 h

Dose descriptor:

other: The highest concentration tested without observed effect

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: There were no adverse reactions to exposure
- Observations on body length and weight: no data
- Other biological observations: none
- Mortality of control: 0%
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

No data

Table 6.1.3/1: Verification of test concentrations

Samples	Nominal concentration (mg/L)	Concentration found (mg/L)	Expressed as a % of the nominal concentration
0 hours	Solvent control 0.10 0.32 1.0 3.2 10	< LOQ 0.096 0.295 1.002 2.869 8.715	- 96 92 100 90 87
48 hours	Solvent control 0.10 0.32 1.0 3.2 10	< LOQ 0.087 0.274 0.802 2.569 8.163	- 87 86 80 80 82

LOQ: Limit of detection

Table 6.1.3/2: Cumulative immobilisation in the definitive study

Nominal concentration (mg/L)	Cumulative immobilized Daphnia (initial population: 10 per replicate)
	24 hours				48 hours
	R1	R2	Total	%	R1	R2	Total	%
Control Solvent control 0.10 0.18 0.32 0.56 1.0 1.8 3.2 5.6 10	0 0 0 0 0 0 0 0 2 4 9	0 0 0 0 0 0 0 0 1 3 9	0 0 0 0 0 0 0 0 3 7 18	0 0 0 0 0 0 0 0 15 35 90	0 0 0 0 0 0 0 1 5 9 10	0 0 0 0 0 0 0 2 4 8 10	0 0 0 0 0 0 0 3 9 17 20	0 0 0 0 0 0 0 15 45 85 100

R1 -R2 = Replicates 1 and 2

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test substance to the freshwater invertebrate Daphnia magna has been investigated and gave a 48 hour EC50 value of 3.3 mg/L with 95% confidence limits of 2.7 -3.9 mg/L. The highest concentration tested without observed effect at 48 hours was 1.0 mg/L.

Executive summary:

This study was performed to assess the acute toxicity of the test material to Daphnia magna. The method followed that described in the OECD Guideline No. 202.

Following a preliminary range-finding study, twenty daphnids (2 replicates of 10 animals) were exposed to an aqueous dispersion of the test material at concentrations of 0.10, 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6 and 10 mg/L for 48 hours under static test conditions. The number of immobilised Daphnia were recorded after 24 and 48 hours.

The 48 hour EC50 for the test material to Daphnia magna based on nominal test concentrations was 3.3 mg/L was 95% confidence limits of 2.7 -3.9 mg/L. The highest concentration tested without observed effect was 1.0 mg/L.

Analysis of the test solutions at 0 and 48 hours showed the measured test concentrations to be in excess of the required 80% of nominal and so the results are based on nominal test concentrations only.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Remarks:

QSAR result on the C6 isomers of the transformation product of the registered substance

Adequacy of study:

supporting study

Study period:

Run on 2016-01

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Remarks:

(Q)SAR method with established scientific validity. The substance, C6 isomers of the transformation product of the registered substance, falls within the applicability domain of the model.

Justification for type of information:

1. SOFTWARE
EPISUITE v4.1

2. MODEL (incl. version number)
ECOSAR v1.11

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C6 isomers of the transformation product of the registered substance: C1C(C)(C)CCCC1C(C)OC(C)(C)COH
log Pow: 4.33 (experimental result)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Neutral Organics SAR document in "Attached background material".

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Qualifier:

according to guideline

Guideline:

other: REACH guidance on QSARs R.6, May 2008

Deviations:

no

Principles of method if other than guideline:

See attached QPRF

GLP compliance:

no

Remarks:

(not relevant)

Specific details on test material used for the study:

- log Pow: 4.33 (experimental result)

Details on sampling:

Not applicable

Details on test solutions:

Not applicable

Test organisms (species):

Daphnia sp.

Details on test organisms:

None

Test type:

not specified

Water media type:

not specified

Total exposure duration:

48 h

Remarks on exposure duration:

none

Post exposure observation period:

Not applicable

Hardness:

Not applicable

Test temperature:

Not applicable

pH:

Not applicable

Dissolved oxygen:

Not applicable

Salinity:

Not applicable

Nominal and measured concentrations:

Not applicable

Details on test conditions:

Not applicable

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

1.07 mg/L

Remarks on result:

other: ECOSAR Class: Neutral Organics

Details on results:

Validity of model:
1. Defined Endpoint: short term toxicity to aquatic invertebrates (Daphnid).
2. Unambigous algorithm: Linear regression QSAR; Log 48h-LC50 (mmol/L) = -0.858*log Kow + 1.3848.
To convert the LC50 from mmol/L to mg/L, multiply by the molecular weight.
3. Applicability domain: applicable to chemicals with log Kow less than 5.0 and molecular weight less than 1000 g/mol. The model can be suitable for chemicals class of neutral organic.
4. Statistical characteristics: N = 98 + 31 and the coefficient of determination R² = 0.7704.
5. Mechanistic interpretation: related to the partitioning of the substance from water into the organisms lipid phase.

Adequacy of prediction: the substance falls within the applicability domain described above and therefore the predicted value can be considered reliable. For more information, see Neutral Organics SAR document in "Attached background material".

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

N = 98 + 31 and the coefficient of determination R² = 0.7704.

No additional information

Validity criteria fulfilled:

yes

Conclusions:

The C6 isomers of the transformation product of the registered substance was predicted to have an 48h-LC50 of 1.07 mg/L to daphnid after 48h of exposure. The substance falls within the applicability domain and therefore the predicted value can be considered reliable.

Executive summary:

The short term toxicity to daphnid of the C6 isomers of the transformation product of the registered substance was estimated using the ECOSAR v1.11 QSAR model available from the U.S. EPA.

The estimation 48h-LC50 was 1.07 mg/L (neutral organics class), calculated from a measured log Kow value (4.33) and a linear regression:

Log 48h-LC50 (mmol/L) = -0.858*log Kow + 1.3848

The substance falls within the applicability domain and therefore the predicted value can be considered reliable.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Remarks:

QSAR result on the C6 isomers of the transformation product of the registered substance

Adequacy of study:

supporting study

Study period:

From 2016-01-05 to 2016-01-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

QSAR value. The substance, C6 isomers of the transformation product of the registered substance, falls into the applicability domain of the QSAR model.

Justification for type of information:

1. SOFTWARE
iSafeRat® HA-QSAR based on a holistic approach for predicting physicochemical and ecotoxicological endpoints: Short-term toxicity to Daphnia (immobilisation)

2. MODEL (incl. version number)
iSafeRat® holistic HA-QSAR v1.5

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C6 isomers of the transformation product of the registered substance: C1C(C)(C)CCCC1C(C)OC(C)(C)COH
Water solubility = 35.0 mg/L (KREATIS internal study, 2015), derived using the log Kow experimental value at 4.33

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not applicable

Remarks:

(QSAR model)

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

not applicable

Remarks:

(QSAR model)

Principles of method if other than guideline:

The purpose of this QSAR is to accurately predict the acute toxicity to daphnid as would be expected in a laboratory experiment following OECD Guideline 202 and EC method C.2 for specific, named modes of action (e.g. non-polar narcotics) to provide a value that can effectively replace a 48-hour EC50 value from an experimental study. The regression based method used to achieve this has been fully validated following the OECD (2004) recommendations (refer to the QMRF with JRC/KREATIS QMRF identifier: Q19-46-51-448 for further details).

GLP compliance:

no

Specific details on test material used for the study:

- Mode of action: non-polar narcotic (MOA 1 or MechoA 1.1)
- Log Kow = 4.33 (from experimental study)
- Water solubility = 35.0 mg/L (KREATIS internal study, 2015)

Analytical monitoring:

no

Details on sampling:

Not applicable

Vehicle:

no

Details on test solutions:

Not applicable

Test organisms (species):

other: Daphnia magna, Daphnia pulex

Details on test organisms:

Results from the following species were used in the regression: Daphnia magna, Daphnia pulex.
Following the principles of Phase Equilibrium Thermodynamics, for narcotic substances, no difference in relationship between solubility and ecotoxicity between invertebrate (or indeed other) aquatic species is expected. Any observed differences may be attributed to lifestyle related parameters (e.g. shell closing in molluscs) and relative duration of study versus bodysize rather than to a specific toxic mechanism causing species differences. In this case, for MOA 1 or MechoA 1.1, no differences were observed in activity based toxicity for the 2 species used.

Test type:

other: QSAR

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

none

Post exposure observation period:

Not applicable

Hardness:

The QSAR is based on data from studies performed at acceptable hardness to ensure control survival.

Test temperature:

The temperatures varied from approximately 20 to 23 °C depending on the species used to construct the algorithm. This small difference is not expected to contribute to the variability of the EC50 values found in experimental data.

pH:

The QSAR is based on data from studies performed at acceptable pH between 6.0 - 9.0.

Dissolved oxygen:

The QSAR is based on data from studies performed at acceptable oxygen concentrations (generally >60%).

Salinity:

Not applicable.

Nominal and measured concentrations:

The QSAR is based on data from studies performed using measured concentrations or with acceptable stability.

Details on test conditions:

Not applicable

Reference substance (positive control):

no

Remarks:

QSAR model

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 2.5-3.0 mg/L

Details on results:

The water solubility value given as input to the Ecotox module of the iSafeRat® Holistic HA-QSAR falls within the descriptor domain of the model between log water solubility (in log (mol/L)) of -4.70 to 0.87. Moreover the test substance is attributed to the class of non-polar narcotic compounds.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

95% CL: 2.5-3.0 mg/L
QSAR statistical parameters are given in the QMRF and the QPRF

No additional information

Validity criteria fulfilled:

yes

Remarks:

The substance falls into the applicability domain of the QSAR model.

Conclusions:

The 48-h EC50 of the C6 isomers of the transformation product of the registered substance, based on mobility and measured concentrations, was determined to be 2.7 mg/L with 95%-Confidence Limit between 2.5 and 3.0 mg/L.

Executive summary:

A QSAR prediction was performed to assess the acute toxicity of the test substance to daphnid. This QSAR has been validated to be compliant with the OECD recommendations for QSAR modelling (OECD, 2004) and predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following OECD Guideline 202 and EU Method C.2. The criterion predicted was the EC50 (Median Effective Concentration), a statistically derived concentration which is expected to cause immobility in 50% of test animals within a period of 48 hours.

 

The immobility of the daphnids was determined using a validated QSAR for the Mode of Action in question, (MOA 1 or MechoA 1.1, non-polar narcosis). The QSAR is based on validated data for a training set of 58 chemicals derived from 48-hour tests on daphnids, for which the concentrations of the test substance had been determined by chemical analyses over the test period. The water solubility of the substance given as input was predicted by the iSafeRat® solubility module using the experimental log Kow value of the substance, measured at 4.33. The substance falls within the applicability domain of the model as demonstrated in the QPRF.

The 48-h EC50 of the C6 isomers of the transformation product of the registered substance, based on mobility and measured concentrations, was determined to be 2.7 mg/L with 95%-Confidence Limit between 2.5 and 3.0 mg/L.

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Remarks:

QSAR result on the C7 isomer of the transformation product of the registered substance

Adequacy of study:

supporting study

Study period:

Run on 2016-03

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Remarks:

(Q)SAR method with established scientific validity. The substance, the C7 isomer of the transformation product of the registered substance, falls within the applicability domain of the model.

Justification for type of information:

1. SOFTWARE
EPISUITE v4.1

2. MODEL (incl. version number)
ECOSAR v1.11

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C7 isomer of the transformation product of the registered substance: OCC(C)(C)OC1CC(C)(C)CCCC1C
log Pow: 4.40 (KREATIS QSAR - iSafeRat v1.5, 2016)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Neutral Organics SAR document in "Attached background material".

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Qualifier:

according to guideline

Guideline:

other: REACH guidance on QSARs R.6, May 2008

Deviations:

no

Principles of method if other than guideline:

See attached QPRF

GLP compliance:

no

Remarks:

(not relevant)

Specific details on test material used for the study:

- log Pow: 4.40 (KREATIS QSAR - iSafeRat v1.5, 2016)

Details on sampling:

Not applicable

Details on test solutions:

Not applicable

Test organisms (species):

Daphnia sp.

Details on test organisms:

None

Test type:

not specified

Water media type:

not specified

Total exposure duration:

48 h

Remarks on exposure duration:

none

Post exposure observation period:

Not applicable

Hardness:

Not applicable

Test temperature:

Not applicable

pH:

Not applicable

Dissolved oxygen:

Not applicable

Salinity:

Not applicable

Nominal and measured concentrations:

Not applicable

Details on test conditions:

Not applicable

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.93 mg/L

Remarks on result:

other: ECOSAR Class: Neutral Organics

Details on results:

Validity of model:
1. Defined Endpoint: short term toxicity to aquatic invertebrates (Daphnid).
2. Unambigous algorithm: Linear regression QSAR; Log 48h-LC50 (mmol/L) = -0.858*log Kow + 1.3848.
To convert the LC50 from mmol/L to mg/L, multiply by the molecular weight.
3. Applicability domain: applicable to chemicals with log Kow less than 5.0 and molecular weight less than 1000 g/mol. The model can be suitable for chemicals class of neutral organic.
4. Statistical characteristics: N = 98 + 31 and the coefficient of determination R² = 0.7704.
5. Mechanistic interpretation: related to the partitioning of the substance from water into the organisms lipid phase.

Adequacy of prediction: the substance falls within the applicability domain described above and therefore the predicted value can be considered reliable. For more information, see Neutral Organics SAR document in "Attached background material".

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

N = 98 + 31 and the coefficient of determination R² = 0.7704.

No additional information

Validity criteria fulfilled:

yes

Conclusions:

The C7 isomer of the transformation product of the registered substance was predicted to have an 48h-LC50 of 0.93 mg/L to daphnid after 48h of exposure. The substance falls within the applicability domain and therefore the predicted value can be considered reliable.

Executive summary:

The short term toxicity to daphnid of the C7 isomer of the transformation product of the registered substance was estimated using the ECOSAR v1.11 QSAR model available from the U.S. EPA.

The estimation 48h-LC50 was 0.93 mg/L (neutral organics class), calculated from an estimated log Kow value (4.40) and a linear regression:

Log 48h-LC50 (mmol/L) = -0.858*log Kow + 1.3848

The substance falls within the applicability domain and therefore the predicted value can be considered reliable.

Reference 5

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Remarks:

QSAR result on the C7 isomer of the transformation product of the registered substance

Adequacy of study:

supporting study

Study period:

From 2016-03-14 to 2016-03-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

QSAR value. The substance, The C7 isomer of the transformation product of the registered substance, falls into the applicability domain of the QSAR model.

Justification for type of information:

1. SOFTWARE
iSafeRat® HA-QSAR based on a holistic approach for predicting physicochemical and ecotoxicological endpoints: Short-term toxicity to Daphnia (immobilisation)

2. MODEL (incl. version number)
iSafeRat® holistic HA-QSAR v1.5

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C7 isomer of the transformation product of the registered substance: OCC(C)(C)OC1CC(C)(C)CCCC1C
Water solubility = 29.1 mg/L (KREATiS – Internal Study (2016))

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not applicable

Remarks:

(QSAR model)

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

not applicable

Remarks:

(QSAR model)

Principles of method if other than guideline:

The purpose of this QSAR is to accurately predict the acute toxicity to daphnid as would be expected in a laboratory experiment following OECD Guideline 202 and EC method C.2 for specific, named modes of action (e.g. non-polar narcotics) to provide a value that can effectively replace a 48-hour EC50 value from an experimental study. The regression based method used to achieve this has been fully validated following the OECD (2004) recommendations (refer to the QMRF with JRC/KREATIS QMRF identifier: Q19-46-51-448 for further details).

GLP compliance:

no

Specific details on test material used for the study:

- Mode of action: non-polar narcotic (MOA 1 or MechoA 1.1)
- log Kow : 4.40 (KREATIS, 2016)
- Water solubility = 29.1 mg/L (KREATIS internal study, 2016)

Analytical monitoring:

no

Details on sampling:

Not applicable

Vehicle:

no

Details on test solutions:

Not applicable

Test organisms (species):

other: Daphnia magna, Daphnia pulex

Details on test organisms:

Results from the following species were used in the regression: Daphnia magna, Daphnia pulex.
Following the principles of Phase Equilibrium Thermodynamics, for narcotic substances, no difference in relationship between solubility and ecotoxicity between invertebrate (or indeed other) aquatic species is expected. Any observed differences may be attributed to lifestyle related parameters (e.g. shell closing in molluscs) and relative duration of study versus bodysize rather than to a specific toxic mechanism causing species differences. In this case, for MOA 1 or MechoA 1.1, no differences were observed in activity based toxicity for the 2 species used.

Test type:

other: QSAR

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

none

Post exposure observation period:

Not applicable

Hardness:

The QSAR is based on data from studies performed at acceptable hardness to ensure control survival.

Test temperature:

The temperatures varied from approximately 20 to 23 °C depending on the species used to construct the algorithm. This small difference is not expected to contribute to the variability of the EC50 values found in experimental data.

pH:

The QSAR is based on data from studies performed at acceptable pH between 6.0 - 9.0.

Dissolved oxygen:

The QSAR is based on data from studies performed at acceptable oxygen concentrations (generally >60%).

Salinity:

Not applicable.

Nominal and measured concentrations:

The QSAR is based on data from studies performed using measured concentrations or with acceptable stability.

Details on test conditions:

Not applicable

Reference substance (positive control):

no

Remarks:

QSAR model

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 2.2-2.7 mg/L

Details on results:

The water solubility value given as input to the Ecotox module of the iSafeRat® Holistic HA-QSAR falls within the descriptor domain of the model between log water solubility (in log (mol/L)) of -4.70 to 0.87. Moreover the test substance is attributed to the class of non-polar narcotic compounds.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

95% CL: 2.2-2.7 mg/L
QSAR statistical parameters are given in the QMRF and the QPRF

No additional information

Validity criteria fulfilled:

yes

Remarks:

The substance falls into the applicability domain of the QSAR model.

Conclusions:

The 48-h EC50 of the C7 isomer of the transformation product of the registered substance, based on mobility and measured concentrations, was determined to be 2.4 mg/L with 95%-Confidence Limit between 2.2 and 2.7 mg/L.

Executive summary:

A QSAR prediction was performed to assess the acute toxicity of the test substance to daphnid. This QSAR has been validated to be compliant with the OECD recommendations for QSAR modelling (OECD, 2004) and predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following OECD Guideline 202 and EU Method C.2. The criterion predicted was the EC50 (Median Effective Concentration), a statistically derived concentration which is expected to cause immobility in 50% of test animals within a period of 48 hours.

 

The immobility of the daphnids was determined using a validated QSAR for the Mode of Action in question, (MOA 1 or MechoA 1.1, non-polar narcosis). The QSAR is based on validated data for a training set of 58 chemicals derived from 48-hour tests on daphnids, for which the concentrations of the test substance had been determined by chemical analyses over the test period. The water solubility of the substance given as input was predicted by the iSafeRat® solubility module. The substance falls within the applicability domain of the model as demonstrated in the QPRF.

The 48-h EC50 of the C7 isomer of the transformation product of the registered substance, based on mobility and measured concentrations, was determined to be 2.4 mg/L with 95%-Confidence Limit between 2.2 and 2.7 mg/L.

Description of key information

OECD Guideline 202, GLP, key study, validity 1:

48h-EC50 (Daphnia magna) = 3.3 mg/L, based on analytically confirmed nominal concentrations.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3.3 mg/L

Additional information

One valid key study, according to OECD Guideline No. 202 with GLP standards, is available to assess the acute toxicity of the registered substance on the aquatic invertebrates Daphnia magna. Following a preliminary range-finding study, twenty daphnids (2 replicates of 10 animals) were exposed to an aqueous dispersion of the test substance at concentrations of 0.10, 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6 and 10 mg/L for 48 hours under static test conditions. The number of immobilised daphnids were recorded after 24 and 48 hours. Analysis of the test solutions at 0 and 48 hours showed the measured test concentrations to be in excess of the required 80% of nominal and so the results are based on nominal test concentrations. The 48 hour EC50 was 3.3 mg/L with 95% confidence limits of 2.7 -3.9 mg/L. The highest concentration without observed effect was 1.0 mg/L.

In addition, the acute toxicity of the transformation product (C6 and C7 isomers) of the registered substance to daphnids was estimated using two QSAR models. The two QSAR models were ECOSAR v1.11 and iSafeRat holistic approach v1.5. Both QSAR results were considered reliable as the substances, C6 and C7 isomers of the transformation product of the registered substance, fall within the applicability domain of the models. The estimated 48h-L(E)C50 values for C6 isomers were 1.07 mg/L and 2.7 mg/L, using ECOSAR v1.11 and iSafeRat holistic approach v1.5, respectively. The estimated 48h-L(E)C50 values for C7 isomer were 0.93 mg/L and 2.4 mg/L, using ECOSAR v1.11 and iSafeRat holistic approach v1.5, respectively. The worst case endpoint value, estimated at 0.93 mg/L for C7 isomer, is chosen as key data for the short-term toxicity of the transformation product to aquatic invertebrates.

These additional data demonstrate that the transformation product of the registered substance is not Toxic (non-T) in the context of PBT assessment.