Isopropyl 2-ethylhexanoate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

From 2018-01-29 to 2017-01-29

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 water solubility value given as input to the Ecotox module of the iSafeRat® Holistic HA-QSAR falls within the applicability domain of the model.

Justification for type of information:

1. SOFTWARE
iSafeRat® HA-QSAR toolbox v2.4

2. MODEL (incl. version number)
iSafeRat® holistic HA-QSAR v1.8

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CCCCC(CC)C(=O)OC(C)C

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not applicable

Remarks:

(QSAR model)

Test guideline 2

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 immobility of the daphnids was determined using a validated QSAR model for the Mechanism of Action (MechoA) in question (MechoA 2.1, i.e. pronarcosis). The QSAR model is based on validated data for a training set of 41 chemicals derived from 48-hour test on daphnids, for which the concentrations of the test item had been determined by chemical analyses over the test period. The QSAR is a simple linear regression of sub-cooled liquid solubility versus 48-h EC50 for daphnia and is valid within the applicability domain defined in the QMRF.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Isopropyl 2-ethylhexanoate

EC Number:

266-549-5

EC Name:

Isopropyl 2-ethylhexanoate

Cas Number:

67024-46-8

Molecular formula:

C11H22O2

IUPAC Name:

isopropyl 2-ethylhexanoate

Test material form:

liquid

Specific details on test material used for the study:

No additional information

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Not applicable

Test solutions

Vehicle:

no

Details on test solutions:

Not applicable

Test organisms

Test organisms (species):

Daphnia sp.

Details on test organisms:

Not applicable

Study design

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

Test conditions

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 (>60% of the air-saturation value throughout the duration of the test). In exceptional cases where studies with oxygen concentrations lower than 60% were used, all aspects of the study were thoroughly evaluated in order to satisfy the evaluator that the effects found were not due to reduced oxygen concentration (i.e. the study would correctly receive a Klimisch score of 2 under the REACH Regulation [REACH, 2006]).

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:

Preferentially results from semi-static studies were used. However, substances tested using a static design were accepted (preferably accompanied by analytical measurements over the study period). For suspected volatile substances, only tests performed in closed vessels were accepted unless accompanying analytical monitoring proved such a design was not necessary.

Reference substance (positive control):

no

Remarks:

QSAR model

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 5.1-7.0 mg/L

Details on results:

The water solubility value given as the input to the Ecotox module of the iSafeRat® Holistic HAQSAR falls within the descriptor domain of the model between a log water solubility (in log (mol/L)) of - 4.79 to 0.93.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

95% CL: 5.1-7.0 mg/L
QSAR statistical parameters are given in the QMRF and the QPRF.

Any other information on results incl. tables

No additional information

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48-h EC50 based on mobility was determined to be 6.0 mg/L with 95%-Confidence Limit between 5.1 and 7.0 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. 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 Mecanism of Action in question, (MechoA 2.1, mono-/poly-esters whose hydrolysis products are narcotics

). The QSAR is based on validated data for a training set of 41 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 value given as the input to the Ecotox module of the iSafeRat® Holistic HA-QSAR falls within the descriptor domain of the model between a log water solubility (in log (mol/L)) of - 4.79 to 0.93.

The 48-h EC50 based on mobility was determined to be 6.0 mg/L with 95%-Confidence Limit between 5.1 and 7.0 mg/L.