Ethyl 2,4-dimethyl-1,3-dioxolane-2-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:

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 acute algae ErC50 for the ester Fraistone is predicted to be 35 mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 1.718, molecular weight of 188.23 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.
Fraistone is in the applicability domain of the ECOSAR prediction because: a) Fraistone is a chemical class presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this chemical class); b) its log Kow is 1.718 (=< 6.4); c) its MW is 188.23 (< 1000); and; d) the toxicity predicted is below its measured water solubility of >1000 mg/L.
The measured and predicted log Kows of Fraistone are in the same range and do not present uncertainty for the predictions. In the ECOSAR training set a substance with a comparable MW (194) and predicted log Kow (1.7) is dimethyl phthalate for which the predicted EC50 is ca. 39 mg/L compared to a measured value of 313 mg/L.
The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Fraistone 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 (see attached report). The adequate and reliable documentation supports this prediction.

Qualifier:

according to guideline

Guideline:

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

Deviations:

not applicable

GLP compliance:

no

Specific details on test material used for the study:

SMILES: O=C(OCC)CC(OCC1C)(O1)C

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.:

35 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: ECOSAR

Remarks:

class: Esters

Details on results:

ECOSAR v1.11 predicts that the 72-h ErC50 of Fraistone to green algae is 35 mg/L.

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:

ECOSAR v1.11 predicts that the 72-h ErC50 of Fraistone to green algae is 35 mg/L.

Executive summary:

The executive summary is presented in the section 'Justification of information'.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

ErC10 at 72h

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 chronic algae for the ester Fraistone is predicted to be 8.2 mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 1.718, molecular weight of 188.23 and the equation: Log 96h ChV (mmol/L) = -0.5583 (log Kow) - 0.4017. The 96-h ChV is considered equivalent to the 72-h ErC10/NOEC as defined in OECD TG 201.
Fraistone is in the applicability domain of the ECOSAR prediction because: a) Fraistone is a chemical class presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this chemical class); b) its log Kow is 1.718 (=< 8.0); c) its MW is 188.23 (< 1000); and; d) the toxicity predicted is below its measured water solubility of >1000 mg/L.
The measured and predicted log Kow values of Fraistone are in the same range and do not present uncertainty for the predictions. In the ECOSAR training a substance with a comparable MW (194) and predicted log Kow (1.3) is Pentyl lactate for which the predicted chronic value is ca. 12 mg/L compared to a measured value of 11 mg/L.
The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Fraistone 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 (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

Deviations:

not applicable

GLP compliance:

no

Specific details on test material used for the study:

SMILES: O=C(OCC)CC(OCC1C)(O1)C

Test organisms (species):

other: green algae

Water media type:

freshwater

Total exposure duration:

72 h

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

8.2 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: ECOSAR

Remarks:

class: Esters

Details on results:

ECOSAR v1.11 predicts that the 72-h ErC10 of Fraistone to green algae is 8.2 mg/L.

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:

ECOSAR v1.11 predicts that the 72-h ErC10 of Fraistone to green algae is 8.2 mg/L.

Executive summary:

The executive summary is presented in the section 'Justification of information'.

Description of key information

ECOSAR v1.11 for esters predicts that the 72h-EC50 of Fraistone to green algae is 35.0 mg/L.

ECOSAR v1.11 for esters predicts that the 72h-ErC10 of Fraistone to green algae is 8.2 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

35 mg/L

EC10 or NOEC for freshwater algae:

8.2 mg/L

Additional information

The executive summaries are presented in the sections "Justification for type of information".