4-methyl-2-(pentan-3-yl)tetrahydro-2H-pyran-4-ol

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:

disregarded due to major methodological deficiencies

Study period:

2009-11-14 to 2009-11-30

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

This study was performed according to OECD Guideline 202 with GLP certificate. All validity criteria were fulfilled. The substance is adequately identified, but some data on composition is missing. This study is not reliable due to high concentration of solvent used. Indeed, acetone was used as solvent in this study. Because of the potential for interaction with the test chemical resulting in an altered response in the test, solvent use should be restricted to situations where no other acceptable method of test solution preparation is available. The use of solvent is not the best method at the time being. Considering the sufficiently high water solubility of the substance (6.89 g/L) and the concentrations used in this study, this method could have been avoided. Furthermore, solvents are generally not appropriate for multiconstituent substances, like the test substance (which is a mixture of isomers), where the use of the solvent can give preferential dissolution of one or more components and thereby affect the toxicity. Then, the concentration/quantity of solvent used in the treatment solutions was 5 mL/L , corresponding to 3.95 g/L (with a density of 0.79), which is 50 times higher than the recommended maximum level of solvent (below 0.1 mL/L; OECD No. 23) and represents almost half of the EC50 of acetone to daphnids (which was reported in the ECHA disseminated dossier at 8.8 g/L). Acetone is suspected to have affected the definitive results. Some solvent/substance interactions may have occurred in this study with this high concentration of acetone. No reproduction between replicates for the test item solutions were observed, especially at 16 mg/L (nominal) with high differences for immobilisation after 48 hours: 0% (rep1), 20% (rep2), 40% (rep3) and 60% (rep4).

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

Inspection on 23-24 July 2009, implementation on 24 July 2009.

Specific details on test material used for the study:

- Storage condition of test material: Room temperature protected from direct sun light

Analytical monitoring:

yes

Details on sampling:

- Nominal concentrations: five treatments: 16.0 mg/L, 32.1 mg/L, 64.1 mg/L, 128.3 mg/L, 256.6 mg/L
- Sampling method: Test item concentration was measured at least in one replicate vessel at the highest and lowest concentrations, at the beginning and at the end of the incubation period.

Vehicle:

yes

Remarks:

Acetone was used as vehicle.

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
Solution 5 : To prepare the highest concentration (256.6 mg/L), 0.5916 g of test item were mixed with acetone qsp 10 mL. 0.05 mL were taken and completed to 10 mL.
Solution 4 : To prepare solution 4 (128.3 mg/L), 0.05 mL of solution 5 were taken and completed to 10 mL.
Solution 3 : To prepare solution 3 (64.1 mg/L), 0.05 mL of solution 4 were taken and completed to 10 mL.
Solution 2 : To prepare solution 2 (32.1 mg/L), 0.05 mL of solution 3 were taken and completed to 10 mL.
Solution 1 : To prepare solution 1 (16.0 mg/L), 0.05 mL of solution 2 were taken and completed to 10 mL. 0.05 mL of solution 1 were removed from it.

- Controls: Water control : The control tubes were made with 10 mL of reconstituted water. Solvent control : composed of 9.95 mL of reconstituted water and 50 µL of acetone.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Acetone was used as solvent.
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): The solvent control was composed of 9.95 mL of reconstituted water and 50 µL of acetone.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnid
- Source: received from a commercial breeder
- Not fed during the test
- Food type: Living cells of green algae Desmodesmus subspicatus

Test type:

static

Water media type:

other: reconstituted water

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

None

Post exposure observation period:

No

Hardness:

The total hardness of the reconstituted water was measured at 240-250 mg/L.

Test temperature:

Temperature was continuously controlled using a calibrated thermo-recorder. Values ranged between 20.1 and 20.3 °C.

pH:

The pH of reconstituted water was 7.6.
During the test, values ranged between 7.82 and 7.92.

Dissolved oxygen:

Values ranged between 79.7% and 96.7% of the air saturation value

Salinity:

Not applicable

Conductivity:

No data

Nominal and measured concentrations:

Nominal concentrations : 16.0 mg/L, 32.1 mg/L, 64.1 mg/L, 128.3 mg/L, 256.6 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass tubes
- Type (delete if not applicable): loosely capped test tubes
- Material, size, headspace, fill volume: 15 mL capacity glass tubes, filled with 9.95 mL of reconstituted water
- No. of organisms per vessel: 5 daphnids / unit
- No. of vessels per concentration (replicates): four replicate unites for each five treatment concentrations
- No. of vessels per control (replicates): 4 replicates for the water control and 4 replicates for the solvent control.
- Reference item treatment : Potassium dichromate was tested at three different concentrations and with four replicates per concentration.

RANGE-FINDING STUDY
- Test concentrations: 99.8 mg/L, 10.0 mg/L, 1.0 mg/L, 0.10 mg/L, 0.010 mg/L
- Results used to determine the conditions for the definitive study: In the range finding study, the mobility of the daphnids was not affected for test item treatment up to and including 10 mg/L. In the 99.8 mg/L test item treatment, 20 % of the daphnids (1 out of 5) were immobilized after 24 h of testing. Recording at 48h showed that swimming was reduced.

Reference substance (positive control):

yes

Remarks:

Three distinct concentrations of reference item (potassium dichromate) between 0.6 and 1.7 mg/L, and four replicates per concentration were performed to confirm the function of the test system.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

37.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % confidence interval

Duration:

48 h

Dose descriptor:

other: The highest tested concentration without observed effect

Effect conc.:

16 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Other biological observations: Each test tube was checked for immobilized daphnids 24 and 48 hours after the start of the test. Any abnormal behaviour or appearance, if any, was reported.
- Immobility was less than 10 % in the control tubes.

Results with reference substance (positive control):

- ECx: EC50 = 1.00 mg/L (95 % confidence interval)
NOEC = 0.6 mg/L

Reported statistics and error estimates:

An F-variance analysis at a 5 % confidence level was used to determine any significant difference between the mean percentage immobilization in the treatment and the control groups.

Table 2 : Assay of the test solutions

Aqueous nominal concentration  (mg/L)	Measured concentration (mg/L)			Mean % of the nominal value
	Injection 1	Injection 2	Mean
Test initiation
16.0	16.05	16.15	16.10	100.4 %
32.1	32.29	31.79	32.04	99.9 %
64.1	62.77	63.16	62.97	98.2 %
128.3	126.47	126.96	126.71	98.8 %
256.6	249.83	251.78	250.81	97.8 %
End of test
16.0	16.21	16.11	16.16	100.8 %
32.1	30.82	32.09	31.45	98.1 %
64.1	62.89	63.53	63.21	98.6 %
128.3	124.68	126.32	125.50	97.8 %
256.6	241.60	248.30	244.95	95.5 %

Results based on analytically confirmed nominal concentrations.

Table 3 : Range finding test

% immobilization	24 h	48 h
Water control	0	0
Solvent control	0	0
Test 0.01 mg/L	0	0
Test 0.1 mg/L	0	0
Test 1.0 mg/L	0	0
Test 10.0 mg/L	0	0
Test 99.8 mg/L	20	20

Table 4 : Definitive test

	% immobilization after 24 h				% immobilization after 48 h
	Rep 1	Rep 2	Rep 3	Rep 4	Rep 1	Rep 2	Rep 3	Rep 4
Water control	0	20	0	0	0	20	0	0
Solvent control	0	20	0	0	0	20	0	0
Mugane
16.0 mg/L	0	0	20	0	0	20	40	60
32.1 mg/L	0	0	20	0	40	60	80	80
64.1 mg/L	0	20	20	0	80	60	80	80
128.3 mg/L	0	40	40	20	60	80	80	100
256.6 mg/L	20	20	0	40	100	100	80	100

Validity criteria fulfilled:

yes

Remarks:

Controls showed not more than 10 % of immobilized daphnids, as a mean. Dissolved oxygen concentration exceed 75% in the control and test tubes and was therefore > 6.75 mg/L. The test item treatments are maintained between 80-120 % of the nominal values.

Conclusions:

The EC50 (48h) for the immobilization of Daphnia magna by the test substance was 37.1 mg/L (based on analytically confirmed nominal concentrations).
However, this study is not reliable due to high concentration of solvent used.

Executive summary:

The influence of the test substance on immobilisation of Daphnia magna was investigated according to OECD Guideline 202, with GLP statement. Daphnids were exposed to the test item under static conditions, for 48 h.

Based on the results of a range finding test, five nominal concentrations and two controls were tested : 16.0 mg/L, 32.1 mg/L, 64.1 mg/L, 128.3 mg/L, 256.6 mg/L.

The concentration of the test item was measured on one replicate vessel, at least, for the highest and for the lowest treatment concentrations used for the definitive test. The concentrations were determined at the beginning and at the end of the incubation period, to verify the intial concentrations and the maintenance of the exposure concentrations during the test.

Measured concentrations at the beginning and at the end of the test were within the range 80-120 % of the nominal loadings.

Effects on immobilization were determined after 24 and 48 hours. After 48 hours, the percent immobilization were 30 %, 65 %, 80 % and 95 % at the respective concentrations of 16.0 mg/L, 32.1 mg/L, 64.1 mg/L, 128.3 mg/L and 256.6 mg/L. The EC50 was 37.1 mg/L, based on analytically confirmed nominal concentrations.

Even if all validity criteria were fulfilled, this study is considered not reliable for the following reasons:

- Acetone was used as solvent in this study. Because of the potential for interaction with the test chemical resulting in an altered response in the test, solvent use should be restricted to situations where no other acceptable method of test solution preparation is available.  The use of solvent is not necessary or even useful to test soluble test substances.

- Considering the high water solubility of the substance (6.89 g/L) and the concentrations used in this study, this method could have been avoided.

- Solvents are generally not appropriate for multiconstituent substances, like this test substance (which is a mixture of isomers), where the use of the solvent can give preferential dissolution of one or more components and thereby affect the toxicity.

- The concentration/quantity of solvent used in the treatment solutions was 5 mL/L, corresponding to 3.95 g/L (with a density of 0.79), which is 50 times higher than the recommended level of solvent (below 0.1 mL/L; OECD No. 23) and represents almost half of the EC50 of acetone to daphnids (which was reported in the ECHA disseminated dossier at 8.8 g/L). Acetone is suspected to have affected the definitive results. Some solvent/substance interactions may have occurred with this high concentration of acetone.

- No reproducibility between replicates for the test item solutions was observed, especially at 16 mg/L (nominal) where high differences between reps for immobilisation were seen after 48 hours: 0% (rep1), 20% (rep2), 40% (rep3) and 60% (rep4).

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2019-01-30

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

Justification for type of information:

1. SOFTWARE
iSafeRat® High-Accuracy-Quantitative Structure-Activity Relationship (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 v1.8

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES: CC1(O)CC(OCC1)C(CC)CC

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

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 1.1, i.e. non-polar narcosis) (Bauer et al., 2018). The QSAR model is based on validated data for a training set of 58 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 purpose of this QSAR model is to accurately predict the acute toxicity to daphnids as would be expected in a laboratory experiment following OECD Guideline 202 for specific named mechanisms of action. The model provides an in silico prediction for the 48h-day EC50 value that can effectively be used in place of an experimental value. The regression based method used to achieve this has been fully validated following the OECD recommendations.

GLP compliance:

no

Specific details on test material used for the study:

- log KOW = 2.20 (Phytosafe, 2009; EU Method A.8, Shake Flask Method)
- Water solubility: 6886 mg/L at 25°C (KREATiS, 2019)
- Mechanism of action: MechoA 1.1: non-polar narcosis (Bauer et al., 2018)

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:

No difference in terms of toxic mechanism of action 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.

Test type:

other: QSAR model

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

Results from a test duration of 48 hours only were used for daphnid species.

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:

Test results were taken from studies with measured pHs between 6 - 9.

Dissolved oxygen:

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

Salinity:

Not applicable

Conductivity:

Not applicable

Nominal and measured concentrations:

Studies were used only where sufficient evidence was presented to determine that the substance was stable under test conditions (i.e. maintained within ± 20 % of the nominal) or, if not, the result was based on measured concentrations as geometric mean.

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

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

136 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95%CI [124 ; 150]

Details on results:

The test item falls within the applicability domain of the model and was therefore reliably predicted for its acute toxicity (48h-EC50) to daphnids. Therefore, this endpoint value can be considered valid for use in risk assessment and classification and labelling.
The 48h-EC50 of the test item to daphnids was predicted as 136 mg/L.

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

95% confidence interval (α = 0.05): 124 – 150 mg/L.
QSAR statistical parameters are given in the QMRF and the QPRF

Applicability Domain of the model

Descriptor domain:

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 -4.70 to 0.87.

Structural fragment domain:

All chemical groups within the molecular structure are taken into account by the model.

Mechanistic domain:

Currently, the ecotoxicity module of the iSafeRat® Holistic HA-QSAR can reliably predict the aquatic toxicity for

chemicals with the following mechanisms of action of toxicity (MechoA):

• non-polar narcosis (MechoA 1.1)

• polar narcosis of alkyl-/alkoxy-phenols (MechoA 1.2)

• polar narcosis of aliphatic amines (MechoA 1.2)

• cationic narcosis of quaternary ammoniums (MechoA 1.3)

• mono-/poly-esters whose hydrolysis products are narcotics (MechoA 2.1)

• hard electrophile reactivity (MechoA 3.1)

• RedOx cycling of primary thiols (MechoA 4.4)

• Proton release of carboxylic acids (MechoA 5.2)

The MechoA of molecules is predicted directly from the structure. The test item as a simple hydroxylated ether is expected to exert a MechoA 1.1 and can be taken into account by the model (Bauer et al., 2018).

See QMRF in "attached background material".

Validity criteria fulfilled:

yes

Remarks:

The test item falls within the applicability domain of the model and can therefore be considered a reliably prediction for acute toxicity (48h-EC50) to daphnids.

Conclusions:

The test item falls within the applicability domain of the model and was therefore reliably predicted for its acute toxicity (48h-EC50) to daphnids. Therefore, this endpoint value can be considered valid for use in risk assessment and classification and labelling.
The 48h-EC50 of the test item to daphnids was predicted as 136 mg/L.
95% confidence interval (α = 0.05): 124 - 150 mg/L.

Executive summary:

A Quantitative Structure-Activity Relationship (QSAR) model was used to calculate the acute toxicity of the test item to daphnid. This QSAR model has been validated to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004a) and predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the Guideline for Testing of Chemicals No. 202, "Daphnia sp., Acute Immobilisation Test" (OECD, 2004b), referenced as Method C.2 of Commission Regulation No. 440/2008 (European Commission, 2008). 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 model for the Mechanism of Action (MechoA) in question (MechoA 1.1, i.e. non-polar narcosis) (Bauer et al., 2018). The QSAR model is based on validated data for a training set of 58 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 48h-EC50 of the test item to daphnids was predicted as 136 mg/L.

95% confidence interval (α = 0.05): 124 - 150 mg/L.

Description of key information

iSafeRat® High-Accuracy-Quantitative Structure-Activity Relationship, KREATIS, 2019 :

48h-EC50 daphnid = 136 mg/L (95% confidence interval: 124 - 150 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

136 mg/L

Additional information

One experimental study and one QSAR prediction are available to assess the short-term toxicity of the registered substance to aquatic invertebrates.

The experimental study (Phytosafe, 2009) was considered as not reliable and was disregarded due to major methodological deficiencies. Indeed, Acetone was used as solvent in this study. Because of the potential for interaction with the test chemical resulting in an altered response in the test, solvent use should be restricted to situations where no other acceptable method of test solution preparation is available.  The use of solvent is not the best method at the time being. Considering the sufficiently high water solubility of the substance (6.89 g/L) and the concentrations used in this study, this method could have been avoided. Furthermore, solvents are generally not appropriate for multiconstituent substances, like the test substance (which is a mixture of isomers), where the use of the solvent can give preferential dissolution of one or more components and thereby affect the toxicity. Then, the concentration/quantity of solvent used in the treatment solutions was 5 mL/L , corresponding to 3.95 g/L (with a density of 0.79), which is 50 times higher than the recommended maximum level of solvent (below 0.1 mL/L; OECD No. 23) and represents almost half of the EC50 of acetone (which was reported in the ECHA disseminated dossier at 8.8 g/L). Therefore, solvent/substance interactions may have occurred in this study with this high concentration of acetone and the result cannot be considered fit for use.

The QSAR prediction (KREATiS, 2019) was considered as reliable. The QSAR model has been validated to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004) and predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the OECD Guideline 202. The immobility of the daphnids was determined using a validated QSAR model for the Mechanism of Action (MechoA) in question (MechoA 1.1,i.e.non-polar narcosis) (Bauer et al.,2018). The QSAR model is based on validated data for a training set of 58 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 test item falls within the applicability domain of the model and was therefore reliably predicted for its acute toxicity (48h-EC50) to daphnids. Therefore, this endpoint value can be considered valid for use in risk assessment and classification and labelling.

The 48h-EC50 of the test item to daphnids was predicted as 136 mg/L (95% CI: 124 - 150 mg/L).