1-ethynylcyclohexyl acetate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

ErC50 at 72h

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

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 QSAR prediction is presented in the endpoint summary. The QMRF and QPRF documentation files are included in the Attached justification section.

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 Program MS Windows v1.11'. United States Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington DC (2012).

Deviations:

not applicable

GLP compliance:

no

Remarks:

not required

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.:

5.3 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: log Kow 2.82; ECOSAR class: Esters

Validity criteria fulfilled:

yes

Remarks:

The ECOSAR-Ester equation is valid when using the OECD criteria. In addition, N=20 and R2 is 0.86

Conclusions:

The 72h-ErC50 of the substance to green algae is 5.3 mg/L.

Executive summary:

The acute algae ErC50 for the ester Herbacet #1 is predicted to be 5.3 mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 2.82, molecular weight of 166.2 and the equation: Log 96-h EC50 (mmol/L) = -0.6993 (log Kow) + 0.4715. The 96h-EC50 is considered equivalent to the 72h ErC50 as defined in OECD TG 201.

 

Herbacet #1 is in the applicability domain of the ECOSAR prediction because: a) Herbacet #1 is an ester; b) its log Kow is 2.82 (=< 6.4); c) its MW is 166.2 (< 1000); and; d) the toxicity predicted is below its measured water solubility of 739 mg/L.

The measured and predicted log Kow’s of Herbacet #1 are very similar (2.8 and 2.82, respectively). The closest analogue in the training set is Octyl lactate, with a log Kow of 2.8 and a molecular weight of 202. The predicted EC50 value of this ECOSAR analogue is 7.0 mg/L and the measured value is 7.6 mg/L, presenting the limited uncertainty of the prediction for Octyl lactate and therefore for Herbacet #1.

The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Herbacet #1 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 esters. The adequate and reliable documentation, presented in the Attached justification section, further supports this prediction.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

ErC10/NOEC

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

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 QSAR prediction is presented in the endpoint summary. The QMRF and QPRF documentation files are included in the Attached justification section.

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 Program MS Windows v1.11'. United States Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington DC (2012).

Deviations:

not applicable

GLP compliance:

no

Remarks:

not required

Test organisms (species):

other: green algae

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.8 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: log Kow 2.82; ECOSAR Class: Esters

Validity criteria fulfilled:

yes

Remarks:

The ECOSAR-Ester equation is valid when using the OECD criteria. In addition, N=13 and R2 is 0.74

Conclusions:

The 72h-ErC10 of the substance to green algae is 1.8 mg/L.

Executive summary:

The long-term algae toxicity value for the ester Herbacet #1 is predicted to be 1.8 mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 2.82, molecular weight of 166.2 and the equation: Log 96h ChV (mmol/L) = -0.5583 (log Kow) - 0.4017. The endpoint is considered equivalent to the 72h-ErC10/NOEC as defined in OECD TG 201.

Herbacet #1 is in the applicability domain of the ECOSAR prediction because: a) Herbacet #1 is an ester; b) its log Kow is 2.82 (=< 8.0); c) its MW is 166.2 (< 1000); and; d) the toxicity predicted is below its measured water solubility of 739 mg/L.

The measured and predicted log Kow’s of Herbacet #1 are very similar (2.8 and 2.82, respectively). The closest analogue in the training set is Octyl lactate, with a log Kow of 2.8 and a molecular weight of 202. The predicted long-term algae toxicity value is 2.3 mg/L while the measured value is 3.2 mg/L, presenting the limited uncertainty of the prediction for Octyl lactate and therefore for Herbacet #1.

The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Herbacet #1 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 esters. The adequate and reliable documentation, presented in the Attached justification section, further supports this prediction.

Description of key information

Short-term toxicity to algae:

The acute algae ErC50 for the ester Herbacet #1 is predicted to be 5.3 mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 2.82, molecular weight of 166.2 and the equation: Log 96-h EC50 (mmol/L) = -0.6993 (log Kow) + 0.4715. The 96h-EC50 is considered equivalent to the 72h ErC50 as defined in OECD TG 201.

Herbacet #1 is in the applicability domain of the ECOSAR prediction because: a) Herbacet #1 is an ester; b) its log Kow is 2.82 (=< 6.4); c) its MW is 166.2 (< 1000); and; d) the toxicity predicted is below its measured water solubility of 739 mg/L.

The measured and predicted log Kow’s of Herbacet #1 are very similar (2.8 and 2.82, respectively). The closest analogue in the training set is Octyl lactate, with a log Kow of 2.8 and a molecular weight of 202. The predicted EC50 value of this ECOSAR analogue is 7.0 mg/L and the measured value is 7.6 mg/L, presenting the limited uncertainty of the prediction for Octyl lactate and therefore for Herbacet #1.

The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Herbacet #1 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 esters. The adequate and reliable documentation, presented in the Attached justification section of the study record for Short-term toxicity to algae, further supports this prediction.

Long-term toxicity to algae:

The long-term algae toxicity value for the ester Herbacet #1 is predicted to be 1.8 mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 2.82, molecular weight of 166.2 and the equation: Log 96h ChV (mmol/L) = -0.5583 (log Kow) - 0.4017. The endpoint is considered equivalent to the 72h-ErC10/NOEC as defined in OECD TG 201.

Herbacet #1 is in the applicability domain of the ECOSAR prediction because: a) Herbacet #1 is an ester; b) its log Kow is 2.82 (=< 8.0); c) its MW is 166.2 (< 1000); and; d) the toxicity predicted is below its measured water solubility of 739 mg/L.

The measured and predicted log Kow’s of Herbacet #1 are very similar (2.8 and 2.82, respectively). The closest analogue in the training set is Octyl lactate, with a log Kow of 2.8 and a molecular weight of 202. The predicted long-term algae toxicity value is 2.3 mg/L while the measured value is 3.2 mg/L, presenting the limited uncertainty of the prediction for Octyl lactate and therefore for Herbacet #1.

The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Herbacet #1 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 esters. The adequate and reliable documentation, presented in the Attached justification section of the study record for Long-term toxicity to algae, further supports this prediction.

Key value for chemical safety assessment

EC50 for freshwater algae:

5.3 mg/L

EC10 or NOEC for freshwater algae:

1.8 mg/L