Reaction mass of 1-(3,3-dimethylcyclohexyl)ethanone and 2,6,6-trimethylcycloheptanone

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

ErC10/NOEC

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2016-2017

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:

The executive summary of the chronic toxicity to algae is presented here. The accompanying files are present in the study record.
The long-term algae for the neutral organic substance Herbac is predicted to be 1.7 mg/L based on the ECOSAR SAR for neutral organics using the measured log Kow of 3.5, molecular weight of 154.25 and the equation: Log 96h ChV50 (mmol/L) = -0.6029 log Kow + 0.1648. The 96h-ChV is considered equivalent to the EC10/NOEC defined in the OECD guideline 201.
Herbac is in the applicability domain of the ECOSAR prediction because: a) Herbac is a neutral organic presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this neutral organic); b) its measured log Kow is 3.5 (=< 8.0); c) its MW is 154.25 (< 1000); and; d) the toxicity predicted is below its measured water solubility of 639.7 mg/L.
There is limited uncertainty of the prediction. The measured and predicted log Kows of Herbac are similar (3.5 and 2.91, respectively) but because the difference is out of the 0.5 range the measured value is used being conservative. The measured long-term values of the substances in the ECOSAR training with similar log Kows are similar to what is predicted for Herbac.
The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Herbac prediction. This shows that the prediction is reliable and a Klimisch 2 can be assigned. In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for chronic algae toxicity on neutral organics (see attached report). The adequate and reliable documentation, presented in the document attached, further supports this prediction.

Qualifier:

according to guideline

Guideline:

other: REACH Guidance R.6: QSARs and grouping of chemicals. Version May 2008.

Version / remarks:

In the QMR attached the model specifications are presented. In this QMR is referenced to the Methodology document for the ecological Structure-Activity Relationship model (ECOSAR) Class Programm MS Windows v1.1'. United States Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington DC (2011).

Deviations:

not applicable

GLP compliance:

no

Specific details on test material used for the study:

SMILES: CC1(C)CCCC(C1)C(C)=O

Test organisms (species):

other: green algae

Water media type:

freshwater

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC10

Remarks:

ChV is equivalent to EC10/NOEC

Effect conc.:

1.7 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: ECOSAR class: Neutral organics

Validity criteria fulfilled:

yes

Remarks:

The ECOSAR-Neutral organics equation is valid when using the OECD criteria. In addition, N=34 and R2 is 0.70

Conclusions:

ECOSAR v1.11 predicted that the 72h-ErC10 of Herbac to green algae is 1.7 mg/L.

Executive summary:

ECOSAR v1.11 predicted that the 72h-ErC10 of Herbac to green algae is 1.7 mg/L. Please refer to the section "Justification for type of information".

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

ErC50

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2016-2017

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:

The executive summary of the acute algae toxicity is presented below. The accompanying files are also attached here.
The acute algae ErC50 for the neutral organic substance Herbac is predicted to be 4.9 mg/L based on the ECOSAR SAR for neutral organics using a measured log Kow of 3.5, molecular weight of 154.25 and the equation: Log 96h-EC50 (mmol/L) = -0.6922 log Kow + 0.9253. The 96h-EC50 is considered equivalent to the 72h-ErC50 defined in OECD guideline 201.
Herbac is in the applicability domain of the ECOSAR prediction because: a) Herbac is a neutral organic presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this neutral organic); b) its measured log Kow is 3.5 (=< 6.4); c) its MW is 154.25 (< 1000); and; d) the toxicity predicted is below its measured water solubility of 639.7 mg/L.
There is limited uncertainty of the prediction. The measured and predicted log Kows of Herbac are similar (3.5 and 2.91, respectively) but because the difference is > 0.5 the measured log Kow will be used to be conservative. The measured EC50 values of the substances in the ECOSAR training with similar log Kows are similar to what is predicted for Herbac.
The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Herbac prediction. This shows that the prediction is reliable and a Klimisch 2 can be assigned. In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on neutral organics (see attached report). The adequate and reliable documentation, presented below, further supports this prediction.

Qualifier:

according to guideline

Guideline:

other: IR/CSR Guidance R.6 QSARs and grouping of chemicals, May 2008

Version / remarks:

In the QMR attached the model specifications are presented. In this QMR is referenced to the Methodology document for the ecological Structure-Activity Relationship model (ECOSAR) Class Programm MS Windows v1.1'. United States Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington DC (2011).

Deviations:

not applicable

GLP compliance:

no

Specific details on test material used for the study:

SMILES: CC1(C)CCCC(C1)C(C)=O

Test organisms (species):

other: green algae

Water media type:

freshwater

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.9 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: QSAR predicted value

Remarks:

ECOSAR Class: Neutral organics

Validity criteria fulfilled:

yes

Remarks:

The ECOSAR-Neutral organics equation is valid when using the OECD criteria. In addition, N=41 and R2 is 0.68

Conclusions:

ECOSAR v1.11 predicted that the 72h-ErC50 of Herbac to green algae is 4.9 mg/L.

Executive summary:

ECOSAR v1.11 predicted that the 72h-ErC50 of Herbac to green algae is 4.9 mg/L. Please refer to the section "Justification for type of information".

Description of key information

ECOSAR v1.11 predicted that the 72h-EC50 of Herbac to green algae is 4.9 mg/L.

ECOSAR v1.11 predicted that the 72h-ErC10 of Herbac to green algae is 1.7 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

4.9 mg/L

EC10 or NOEC for freshwater algae:

1.7 mg/L

Additional information

Please refer to the section "Justification for type of information".