1,1-dimethoxyethane

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source

Justification for type of information:

1 Substance
1.1 CAS number 534-15-6
1.2 EC number 208-589-8
1.3 Chemical name
IUPAC 1,1-dimethoxyethane
Other (ISO) dimethyl acetal
Other
1.4 Structural formula
1.5 Structure codes
SMILES COC(C)OC
InChI 1S/C4H10O2/c1-4(5-2)6-3/h4H,1-3H3
Other
Stereochemical features Not applicable

2 General Information
2.1 Date of QPRF 29 May 2018
2.2 Author and contact details Dr. Stefan Pudenz, Envigo CRS Switzerland Ltd.,
Rheinstrasse 74, 4414 Füllinsdorf, Switzerland,
Email: [e-mail]

3 Prediction
3.1 Endpoint (OECD Principle 1)
Endpoint Algae acute toxicity (96 hour EC50)
Dependent variable Log 96-h EC50 (mmol/L)
3.2 Algorithm (OECD Principle 2)
Model or submodel name Algae 96-h EC50. Due to structural classification of the query structure submodels are:
SAR Neutral Organics
Model version ECOSAR v1.11 and submodels
SAR Neutral Organics 5/2012
Reference to QMRF There is no QMRF available. Information to ECOSAR models can be found at https://www.epa.gov/chemicalresearch/toxicity-estimation-software-tool-test. For information similar to those provided in the QMRF it is also referred to section Interpreting ECOSAR QSAR.
Predicted values (model result) Class Neutral organics: 532.088 mg/L
Predicted values (comments) -
Input for prediction Smiles
Calculated descriptor values Experimental water solubility, 1.E06 mg/L, and predicted log
Kow, 0.223
3.3 Applicability domain (OECD Principle 3)
Domains i. The predicted compound is in the Applicability Domain of the models log Kow< 5.
ii. Structure belongs to class neutral organic
iii. SAR based on structural classes
Structural analogues ECOSAR does not provide information on structural analogues due to the nature of the regression algorithm.
Neutral organics: Model equation based on 98 structures
Consideration on structural analogues
Not applicable, see above.
3.4 The uncertainty of the prediction (OECD principle 4)
The coefficient of determination, R2 = 0.6782, suggests low confidence.
3.5 The chemical and biological mechanisms according to the model underpinning the predicted
result (OECD principle 5)
SAR based on structural classes

4 Adequacy (Optional)
4.1 Regulatory purpose Acute toxicity to algae endpoint for providing information on aquatic pelagic toxicity.
4.2 Approach for regulatory interpretation of the model result Unit conversion provided by the software.
4.3 Outcome The prediction suggests an EC50 of 532.088 mg/L but there is only low confidence in the prediction.
4.4 Conclusion The prediction is considered to be of low reliability and may be used together with other QSARs in a weight of evidence conclusion.

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: QSAR prediciton of Acute toxicity to algae
- Short description of test conditions: n/a
- Parameters analysed / observed: EC50

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

532.088 mg/L

1 Substance

1.1 CAS number 534-15-6

1.2 EC number 208-589-8

1.3 Chemical name

IUPAC 1,1-dimethoxyethane

Other (ISO) dimethyl acetal

Other

1.4 Structural formula

1.5 Structure codes

SMILES COC(C)OC

InChI 1S/C4H10O2/c1-4(5-2)6-3/h4H,1-3H3

Other

Stereochemical features Not applicable

2 General Information

2.1 Date of QPRF 29 May 2018

2.2 Author and contact details Dr. Stefan Pudenz, Envigo CRS Switzerland Ltd.,

Rheinstrasse 74, 4414 Füllinsdorf, Switzerland,

Email: [e-mail]

3 Prediction

3.1 Endpoint (OECD Principle 1)

Endpoint Algae acute toxicity (96 hour EC50)

Dependent variable Log 96-h EC50 (mmol/L)

3.2 Algorithm (OECD Principle 2)

Model or submodel name Algae 96-h EC50. Due to structural classification of the query structure submodels are:

SAR Neutral Organics

Model version ECOSAR v1.11 and submodels

SAR Neutral Organics 5/2012

Reference to QMRF There is no QMRF available. Information to ECOSAR models can be found at https://www.epa.gov/chemicalresearch/toxicity-estimation-software-tool-test. For information similar to those provided in the QMRF it is also referred to section Interpreting ECOSAR QSAR.

Predicted values (model result) Class Neutral organics: 532.088 mg/L

Predicted values (comments) -

Input for prediction Smiles

Calculated descriptor values Experimental water solubility, 1.E06 mg/L, and predicted log

Kow, 0.223

3.3 Applicability domain (OECD Principle 3)

Domains i. The predicted compound is in the Applicability Domain of the models log Kow< 5.

ii. Structure belongs to class neutral organic

iii. SAR based on structural classes

Structural analogues ECOSAR does not provide information on structural analogues due to the nature of the regression algorithm.

Neutral organics: Model equation based on 98 structures

Consideration on structural analogues

Not applicable, see above.

3.4 The uncertainty of the prediction (OECD principle 4)

The coefficient of determination, R2 = 0.6782, suggests low confidence.

3.5 The chemical and biological mechanisms according to the model underpinning the predicted

result (OECD principle 5)

SAR based on structural classes

4 Adequacy (Optional)

4.1 Regulatory purpose Acute toxicity to algae endpoint for providing information on aquatic pelagic toxicity.

4.2 Approach for regulatory interpretation of the model result Unit conversion provided by the software.

4.3 Outcome The prediction suggests an EC50 of 532.088 mg/L but there is only low confidence in the prediction.

4.4 Conclusion The prediction is considered to be of low reliability and may be used together with other QSARs in a weight of evidence conclusion.

Conclusions:

The prediction suggests an EC50 of 532.088 mg/L but there is only low confidence in the prediction.
The prediction is considered to be of low reliability and may be used together with other QSARs in a weight of evidence conclusion

Description of key information

Acute Algae Toxicity

Prediction of acute algae toxicity with OECD Toolbox failed as no meaningful category could be established. ECOSAR predicted the EC50 to be 532.09 mg/L but there is only low confidence in the prediction. For structurally similar acetal dimethoxymethane an EC50 study result of 6000 mg/L and predictions between 874.12 mg/L (96 h) and 9120 mg/L (72h) are reported in the ECHA dossier. Taking additionally into account the prediction results for acute fish and daphnia toxicity and corresponding expertimental results for diethoxymethane and dimethoxymethane it is considered unlikely that 1,1.dimethoxyethane qualifies for classification.

Prediction results of acute algae toxicity of 1,1-dimethoxyethane

Model	Algae toxicity EC50[mg/L], 96h	Reliability
ECOSAR	532.09	low

Key value for chemical safety assessment

EC50 for freshwater algae:

532.09 mg/L