Phthalaldehyde

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2018-05-29

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 adequate and reliable documentation / justification

Justification for type of information:

For the endpoint short-term toxicity to fish four different, scientifically valid QSAR models were applied within a weight-of-evidence approach.

Principles of method if other than guideline:

QSAR modelling with VEGA QSAR Models, core version 1.2.3.
Models used:
- Fish Acute (LC50) Toxicity classification (SarPy/IRFMN) 1.0.2
- Fish Acute (LC50) Toxicity model (KNN/Read-Across) 1.0.0
- Fish Acute (LC50) Toxicity model (NIC) 1.0.0
- Fathead Minnow LC50 96h (EPA) 1.0.7

GLP compliance:

no

Specific details on test material used for the study:

Compound SMILES: O=Cc1ccccc1(C=O)

Analytical monitoring:

not required

Vehicle:

no

Test organisms (species):

not specified

Test type:

other: QSAR modelling

Limit test:

no

Dose descriptor:

other: predicted toxicity class

Effect conc.:

>= 10 - <= 100 mg/L

Remarks on result:

other: QSAR prediction

Remarks:

Fish Acute (LC50) Toxicity classification (SarPy/IRFMN) 1.0.2

Dose descriptor:

LC50

Effect conc.:

34.92 mg/L

Nominal / measured:

estimated

Basis for effect:

not specified

Remarks on result:

other: QSAR prediction

Remarks:

Fish Acute (LC50) Toxicity model (KNN/Read-Across) 1.0.0

Dose descriptor:

LC50

Effect conc.:

4.43 mg/L

Nominal / measured:

estimated

Basis for effect:

not specified

Remarks on result:

other: QSAR prediction

Remarks:

Fathead Minnow LC50 96h (EPA) 1.0.7

Dose descriptor:

LC50

Effect conc.:

89.65 mg/L

Nominal / measured:

estimated

Basis for effect:

not specified

Remarks on result:

other: QSAR prediction

Remarks:

Fish Acute (LC50) Toxicity model (NIC) 1.0.0

Details on results:

See report attached.

Sublethal observations / clinical signs:

Fish Acute (LC50) Toxicity classification (SarPy/IRFMN) 1.0.2

Compound: Molecule 0

Compound SMILES: O=Cc1ccccc1(C=O)

Experimental value: -

Predicted toxicity class: Toxic-3 (between 10 and 100 mg/L)

Structural alerts: Toxicity class 3 alert no. 3; Toxicity class 3 alert no. 24

Reliability: the predicted compound is into the Applicability Domain of the model

Remarks: none

 

Conclusion: The predicted compound is into the Applicability Domain of the model (AD index = 0.954) and thus, the read across assessment supports with a reasonable documentation that the QSAR prediction is realistic. There are chemicals with very good similarity in the training set. All similarity values (n=6) > 0.868 (similarity index= 0.91). All similar chemicals of the training set have an experimental value.

 

 

Fish Acute (LC50) Toxicity model (KNN/Read-Across) 1.0.0

Compound: Molecule 0

Compound SMILES: O=Cc1ccccc1(C=O)

Experimental value [-log(mg/L)]: -

Predicted toxicity [-log(mg/L)]: -1.54

Predicted toxicity [mg/L]: 34.92

Molecules used for prediction: 4

Experimental value [mg/L]: -

Reliability: the predicted compound is outside the Applicability Domain of the model

Remarks: none

 

Conclusion: The predicted compound is outside the applicability domain of the model, nevertheless, the read across assessment supports with a reasonable documentation that the QSAR prediction is realistic. Strongly similar compounds with known experimental values in the training set have been found. All similarity values (n=6) > 0.892 (similarity index= 0.907). The experimental values of the similar compounds (n=6) are between -0.938 [-log(mg/L)] and -2.612 [-log(mg/L)].

 

Fish Acute (LC50) Toxicity model (NIC) 1.0.0

Compound: Molecule 0

Compound SMILES: O=Cc1ccccc1(C=O)

Experimental value [log(1/(mmol/L))]: -

Predicted fish toxicity [log(1/(mmol/L))]: 0.17

Predicted fish toxicity [mg/L]: 89.65

Molecular Weight: 133.8

Experimental value [mg/L]: -

Reliability: the predicted compound is outside the Applicability Domain of the model

Remarks: none

 

Conclusion: The predicted compound is outside the applicability domain of the model, nevertheless, the read across assessment supports with a reasonable documentation that the QSAR prediction is realistic. There are chemicals with strong similarity with known experimental value in the training set. All similarity values (n=6) > 0.892 (similarity index= 0.914). All of the chemicals of the training set have a similar fish toxicity.

 

Fathead Minnow LC50 96h (EPA) 1.0.7

Compound: Molecule 0

Compound SMILES: O=Cc1ccccc1(C=O)

Experimental value [-log(mol/l)]: -

Predicted toxicity [-log(mol/l)]: 4.48

Predicted toxicity [mg/L]: 4.43

Molecular Weight: 133.8

Experimental value [mg/L]: -

Reliability: the predicted compound is outside the Applicability Domain of the model

Remarks: none

 

Conclusion: The predicted compound is outside the applicability domain of the model, nevertheless, the read across assessment supports with a reasonable documentation that the QSAR prediction is realistic. There are chemicals with very good similarity in the training set. All similarity values (n=6) > 0.861 (similarity index= 0.902). Most of the chemicals of the training set have a similar fish toxicity.

Validity criteria fulfilled:

not applicable

Conclusions:

The lowest estimated LC50 for ortho-phthalaldehyde is 4.43 mg/L using QSAR tool VEGA model Fathead Minnow LC50 96h (EPA) 1.0.7.

Executive summary:

For the endpoint short-term toxicity to fish four different, scientifically valid QSAR models were applied within a weight-of-evidence approach.

The acute toxicity of ortho-phthalaldehyde to fish was estimated with the models Fish Acute (LC50) Toxicity classification (SarPy/IRFMN) 1.0.2, Fish Acute (LC50) Toxicity model (KNN/Read-Across) 1.0.0, Fish Acute (LC50) Toxicity model (NIC) 1.0.0 and Fathead Minnow LC50 96h (EPA) 1.0.7 implemented in the QSAR tool VEGA.

The following predictions were made:

- Fish Acute (LC50) Toxicity classification (SarPy/IRFMN) 1.0.2: Predicted toxicity [mg/L]: between 10 and 100 mg/L;

- Fish Acute (LC50) Toxicity model (KNN/Read-Across) 1.0.0: Predicted toxicity [mg/L]: 34.92;

- Fish Acute (LC50) Toxicity model (NIC) 1.0.0: Predicted toxicity [mg/L]: 89.65;

- Fathead Minnow LC50 96h (EPA) 1.0.7: Predicted toxicity [mg/L]: 4.43

The most sensitive LC50 value derived is the LC50 of 4.43 mg/L using the Fathead Minnow LC50 96h (EPA) 1.0.7, which is used as key value in a worst-case approach.

This prediction is reliable, it is generated by a scientifically valid model.

Description of key information

For the endpoint short-term toxicity to fish four different, scientifically valid QSAR models were applied within a weight-of-evidence approach. The lowest estimated LC50 for ortho-phthalaldehyde is 4.43 mg/L using QSAR tool VEGA model Fathead Minnow LC50 96h (EPA) 1.0.7.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

4.43 mg/L