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

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

April 6th, 2016 to May 23rd, 2016.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Remarks:

Similar to OECD recommendation except the fish species used. Gobiocypris rarus is a species of cyprinid fish endemic to China. The substance is adequately identified.

Qualifier:

according to guideline

Guideline:

other: The Guidelines for the Testing of Chemicals, Effects on Biotic Systems, 203 Fish Acute Toxicity Test. (China Environmental Press 2013, Second Edition).

Deviations:

not specified

GLP compliance:

yes

Remarks:

GLP compliance statement

Specific details on test material used for the study:

- Solubility in water: 7879.0±103.0mg/L (pH=5); 7020.2±85.8mg/L (pH=7); 2262.6±8.80mg/L (pH=9)
- Partition coefficient: 2.20±0.03 (at any pH)
- Storage conditions: between 3-5℃, keep this product in full and tightly closed containers in a dark cool place.

Analytical monitoring:

yes

Remarks:

Not all the measured concentrations of test item in test solutions were maintained within 80%-120% of nominal concentration, the calculation of effect concentration was based on the arithmetic mean of measured concentration.

Details on sampling:

- Concentrations: The test item includes two isomers (named as ISOMER1and ISOMER2), the measured concentration of test item was calculated as the sum of concentrations of two isomers.
Based on the result of the preliminary test, the limit test was conducted at the concentration of 100mg/L and blank control was set in parallel.

- Sampling method: Samples of test item treatment and blank control groups were taken at the beginning of exposure (0 h), at the end of exposure (96 h) and 48h (before and after test solution renewal) for concentration analysis.
Two samples were taken for test item treatment group and one for blank control. The volume of each sample was 5mL.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test solutions were prepared twice during the test. The test water was pre-aerated and the test containers were full of test water (the headspace of the test container was maintained as little as possible.). 1.0565g and 1.0564g of test item was weighed and added into 10.5L test water to make the test solution with the nominal concentration of 100mg/L respectively. And then, the test containers were sealed, placed on the magnetic stir and kept stirring for about one hour to obtain the test solution.
- Controls: For blank control, the volume of 10.5L test water was added to the test container.

Test organisms (species):

other: Rare minnow (Gobiocypris rarus)

Details on test organisms:

TEST ORGANISM
- Common name: Rare minnow
- Strain: Gobiocypris rarus
- Source: Rare minnow (Code No.: Rare minnow C20150628) were reproduced and cultured in the test facility of CTI-CSERC.
- Age at study initiation (mean and range, SD): not specified
- Length (length definition, mean, range and SD): At the beginning of the test, the length of fish was in the range of 2.0-4.0cm. At the end of the test : The total length of the fish was in the range of 3.17-3.55cm (mean±SD:3.39±0.15cm).
- Weight (mean and range, SD): At the end of the test, the wet weight was in the range of 332-359mg (mean±SD:346±11 mg).

ACCLIMATION
- Acclimation period: 7 days
- Acclimation conditions (same as test or not): yes
- Feeding frequency during acclimation: The fish were fed daily and were not fed 24 hours before the test.
- Health during acclimation (any mortality observed): During the 7 days acclimation prior to the test, no disease treatment was administered and the total mortality of fish was 0%. The fish could be used.

Test type:

semi-static

Water media type:

freshwater

Remarks:

The tap water dechlorinated by activated carbon and sterilized by UV lamp will be used as test water, the pH value of the water was in the range of 6.0-8.5 and the total hardness was 10-250 mg/L (calculated as CaCO3).

Limit test:

yes

Total exposure duration:

96 h

Hardness:

Total hardness was 10-250 mg/L (calculated as CaCO3).

Test temperature:

During the period of the exposure, the water temperature was maintained in the range of 23.2-23.9°C.

pH:

The pH value was in the range of 7.65-8.40.

Dissolved oxygen:

The dissolved oxygen was in the range of 63.5%-99.0% ASV (air saturation value).

Salinity:

Not applicable

Conductivity:

Not applicable

Nominal and measured concentrations:

Not all the measured concentrations of test item in test solutions were maintained within 80%-120% of nominal concentration, the calculation of effect concentration was based on the arithmetic mean of measured concentration. According to calculation, the arithmetic mean of measured concentration was 115mg/L for the nominal concentration of 100mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 10L narrow mouth glass bottle with the fully loaded volume of 10.0-11.1L.
- Type (delete if not applicable): open / closed
- Aeration: During preparation of test solutions, the test water was pre-aerated and the test containers were full of test water (the headspace of the test container was maintained as little as possible).
- Renewal rate of test solution (frequency/flow rate): The test solution was renewed every 48 hours during the test.
- No. of organisms per vessel: 7 fish were used for each group and no replicate.
- No. of vessels per concentration (replicates): 7 fish for the limit test (100 mg/L) and 7 fish for the blank control.
- No. of vessels per control (replicates): 1
- Biomass loading rate: <1g fish/litre

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Test water: the tap water dechlorinated by activated carbon and sterilized by UV lamp will be used as test water, the pH value of the water was in the range of 6.0-8.5 and the total hardness was 10-250 mg/L (calculated as CaCO3).

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 12 hours light:12 hours dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Test concentrations: limit test, 100 mg/L
- Results used to determine the conditions for the definitive study: The preliminary test was conducted using the test concentrations of 10 and 100 mg/L, the test container with volume of 10L (fully loaded and kept sealing) were used and five fish were placed in each test container. After 96 hours of exposure, the mortality of the test fish was 0% and there was no toxic symptom.
The concentration was analyzed during the test, the result of analysis showed that for the nominal concentration of 10 and 100 mg/L, the measured concentration of test item in the test solution was in the range of 98%-101% of initial concentration after 24 hours of exposure and was in the range of 95%-100% of initial concentration after 48 hours of exposure under the test condition.
The result of preliminary test indicated that the definitive test could be conducted as a limit test under semi-static condition and the test solution was renewed every 48 hours.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 115 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: At the end of exposure, the mortality of test fish was 0% and there was no abnormal symptom at the nominal concentration of 100mg/L.
- Observations on body length and weight: See table 1 of "Any other information on materials and methods inlc. tables".
- Mortality of control: 0%
- Analytical measurements: The result of concentration analysis showed that the test item was not detected in the blank control solutions. After 48 and 96 hours of exposure, the measured concentration of test item in the old solution was maintained in the range of 94%-97% of that in the new solution. And the measured concentration of test item in the new solution at 48 hours was 95% of the initial (0h) measured concentration.
Not all the measured concentrations of test item in test solutions were maintained within 80%-120% of nominal concentration, the calculation of effect concentration was based on the arithmetic mean of measured concentration.

Sublethal observations / clinical signs:

Table 5: Result of Mortality and Symptoms Observation of Test Fish during the Test

Nominal concentration （mg/L)	Initial number of test fish	Exposure time
		3h			24h			48h			72h			96h
		Dead	Symp	Mort	Dead	Symp	Mort	Dead	Symp	Mort	Dead	Symp	Mort	Dead	Symp	Mort
				(%)			(%)			(%)			(%)			(%)
Blank control	7	0	7A	0%	0	7A	0%	0	7A	0%	0	7A	0%	0	7A	0%
100	7	0	7A	0%	0	7A	0%	0	7A	0%	0	7A	0%	0	7A	0%

Table 6: Sample concentration analysis result

Nominal con.  (mg/L)	Replicates	Measured concentration (mg/L)												Arithmetic mean of measured con.(mg/L)
		0h (N)			48h (O)			48h (N)			96h (O)
		ISOMER1	ISOMER2	Sum	ISOMER1	ISOMER2	Sum	ISOMER1	ISOMER2	Sum	ISOMER1	ISOMER2	Sum
Blank control	1	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	NA
100	1	39.761	77.533	117.294	38.149	74.254	112.403	39.706	77.431	117.137	36.845	70.908	107.753	115
	2	41.649	82.008	123.657	39.016	76.109	115.125	37.688	73.441	111.129	38.551	74.379	112.930
	Mean	/	/	120.476	/	/	113.764	/	/	114.133	/	/	110.342

Validity criteria fulfilled:

yes

Remarks:

See "Overall remarks, attachments"

Conclusions:

In this study, based on the arithmetic mean of measured concentration, the LC50 of test item to Rare minnow was more than 115mg/L.

Executive summary:

The influence of the test substance on mortality of Rare minnow (Gobiocypris rarus) was investigated according to the Guidelines for the Testing of Chemicals, Effects on Biotic Systems, 203 Fish Acute Toxicity Test. (China Environmental Press 2013, Second Edition), with GLP compliance statement. Fish were exposed to the test item under semi-static conditions, for 96 h.

Based on the results of a preliminary test, one control and a limit test (100 mg/L), both testing 7 fish, were performed.

The result of concentration analysis showed that the test item was not detected in the blank control solutions. After 48 and 96 hours of exposure, the measured concentration of test item in the old solution was maintained in the range of 94%-97% of that in the new solution. And the measured concentration of test item in the new solution at 48 hours was 95% of the initial (0h) measured concentration. Not all the measured concentrations of test item in test solutions were maintained within 80%-120% of nominal concentration, the calculation of effect concentration was based on the arithmetic mean of measured concentration. According to calculation, the arithmetic mean of measured concentration was 115mg/L for the nominal concentration of 100mg/L.

At the end of exposure, the mortality of test fish was 0% and there was no abnormal symptom at the nominal concentration of 100mg/L and blank control groups. Therefore, the LC50 of test item was more than 115 mg/L.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

October 02nd, 2019

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® toolbox – in Silico Algorithms For Environmental Risk And Toxicity version 2.4

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

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CC1(O)CC(OCC1)C(CC)CC
The toxicity of the test item was predicted using the iSafeRat® Ecotox module providing the Subcooled Liquid Water Solubility (SLWS) as the input. The SLWS has been derived using a holistic approach: 6886 mg/L (or -1.432 in log (mol/L)).

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

Reason / purpose for cross-reference:

reference to other study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

not applicable

Remarks:

QSAR model

Principles of method if other than guideline:

The purpose of this QSAR model is to accurately predict the acute toxicity to fish as would be expected in a laboratory experiment following the OECD Guideline 203 and EC method C.1 for specific named modes of action. The model provides an in silico prediction for the 96-hour LC50 value that can effectively be used in place of an experimentally derived 96-hour LC50 value. The regression based method used to achieve this has been fully validated following the OECD (2004) 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: Danio rerio, Oncorhynchus mykiss, Lepomis macrochirus, Pimephales promelas, Oryzias latipes, Leuciscus idus

Details on test organisms:

No difference in terms of toxic mechanism of action between fish freshwater species is expected. Any observed differences may be attributed to lifestyle related parameters (e.g. relative differences in storage lipid content between species) 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:

96 h

Remarks on exposure duration:

Only results from a test duration of 96 hours were included in the training set of the model.

Post exposure observation period:

None

Hardness:

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

Test temperature:

The temperatures varied from approximately 14 to 25 °C depending on the fish species used to construct the algorithm. While it is recognized that this may contribute to some extent to the variability of the LC50 values found in experimental data, KREATiS has not observed a clear trend suggesting that normalization to temperature would necessarily improve the algorithm (say for trout as opposed to warm water species like fathead minnow for example) for monoconstituents.

pH:

Test results were taken from studies with measured pHs between 6.0 - 8.5.

Dissolved oxygen:

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

Salinity:

Not applicable

Conductivity:

No data

Nominal and measured concentrations:

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

Details on test conditions:

A variety of test designs were accepted: Preferentially results from semi-static experiments with daily renewal of test solutions and the control or from flow-through tests were used. However, for stable, low volatility substances a static design was
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):

not required

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

164 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95%CL: 148 - 183 mg/L

Details on results:

The test item falls within the applicability domain of the model and can therefore be considered a reliably prediction for acute toxicity (96h-LC50) to fish. Therefore, this endpoint value can be considered valid for use in risk assessment and classification and labelling.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

95% confidence interval (α = 0.05): 148 – 183 mg/L.
QSAR statistical parameters are given in the QMRF and the QPRF

Sublethal observations / clinical signs:

Analysis of the Applicability Domain

Descriptor domain:

The water solubility value (-1.432 in log (mol/L)) 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 -4.63 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.

Validity criteria fulfilled:

yes

Conclusions:

The test item falls within the applicability domain of the model and can therefore be considered a reliably prediction for acute toxicity (96h-LC50) to fish. Therefore, this endpoint value can be considered valid for use in risk assessment and classification and labelling.
The 96h-LC50 of the test item to fish was predicted as 164 mg/L.
95% confidence interval (α = 0.05): 148 – 183 mg/L.

Executive summary:

A Quantitative Structure Activity Realtionship (QSAR) model was used to calculate the acute toxicity to fish exposed to the test item. This 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 Guideline for Testing of Chemicals No. 203, "Fish Acute Toxicity Test" (OECD, 1992), referenced as Method C.1 of Commission Regulation No. 440/2008 (European Commission, 2008). The criterion predicted was the LC50 (Median Lethal Concentration), a statistically derived concentration which is expected to cause mortality in 50% of test animals within a period of 96hours.

The acute toxicity to fish was determined using a validated QSAR for the Mechanism of Action (MechoA) in question (MechoA 1.1, i.e. non-polar narcosis) (Bauer et al., 2018). The QSAR is based on validated data for a training set of 67 chemicals derived from 96-hour test on fish, for which the concentrations of the test item had been determined by chemical analyses over the test period.

The result below is the toxicity value anticipated during a 96-hour LC50 study on fish based on measured concentrations.

The 96h-LC50 of the test item to fish was predicted as 164 mg/L.

95% confidence interval (α = 0.05): 148 – 183 mg/L

Description of key information

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

96h-LC50 fish = 164 mg/L (95% confidence interval: 148 – 183 mg/L)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

164 mg/L

Additional information

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

The experimental study (CTI, 2016) was considered as reliable without restriction. In this Chinese study, the influence of the registered substance on mortality of Rare minnow (Gobiocypris rarus) was investigated according to Chinese test Guideline (203 Fish Acute Toxicity Test, China Environmental Press 2013, Second Edition) with GLP compliance statement. Fish were exposed to the test substance (at a limit test concentration of 100 mg/L, nominal) under semi-static conditions, for 96 hours. Under the test conditions, the mortality of test fish after 96 hours was 0% and there was no abnormal symptom at the blank control groups and the nominal concentration of 100 mg/L, corresponding to 115 mg/L based on arithmetic mean of measured concentration. Therefore, the 96h-LC50 value of the test substance to Gobiocypris rarus was more than 115 mg/L, based on measured concentrations. This result supports the (more quantitative) key data presented below.

The QSAR prediction (KREATiS, 2019) was considered as reliable and was used as key data. 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 203. The acute toxicity to fish 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 67 chemicals derived from 96-hour LC50 test on fish, for which the concentrations of the test item had been determined by chemical analyses over the test period. The result below is the toxicity value anticipated during a 96-hour study on fish based on measured concentrations. Therefore, this endpoint value can be considered valid for use in risk assessment and classification and labelling.

The 96h-LC50 of the test item to fish was predicted as 164 mg/L (95% CI: 148 – 183 mg/L).

This quantitative value was considered as the key value for chemical safety assessment.