Methyl 2,4-dihydroxy-3,6-dimethylbenzoate

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:

July 2016

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 Fish LC50 for the ester substance Veramoss is predicted to be 5.2 mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 3.2, molecular weight of 196.2 and the equation: Log 96h-LC50 (mmol/L) = -0.584 (log Kow) + 0.2941
Veramoss is in the applicability domain of the ECOSAR prediction because: a) Veramoss is an ester presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this ester); b) its log Kow is 3.2 (=< 5); c) its MW is 196.2 g/mol (< 1000); and; d) the toxicity predicted is below its measured water solubility of 18 mg/L.
In the ECOSAR training set esters are available with log Kows around the Veramoss value. A substance with a somewhat similar predicted log Kow (3.1) is ethyl salicylate with a predicted LC50 of 5.1 and a measured value of 19.6 mg/L, indicating a conservative prediction.
The fit in the applicability domain and the availability of a log Kow analogue in the training set results in limited uncertainty of the Veramoss 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 Fish 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

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: O=C(OC)c(c(cc(O)c1C)C)c1O

Test organisms (species):

not specified

Water media type:

freshwater

Total exposure duration:

96 h

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

5.2 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: QSAR predicted value

Remarks:

ECOSAR class: Esters

Validity criteria fulfilled:

yes

Remarks:

The ECOSAR-Ester equation is valid when using the OECD criteria. In addition, N=87 and R2 is 0.79

Conclusions:

ECOSAR v1.11 predicted that the 96h-LC50 of Veramoss is 5.2 mg/L

Executive summary:

See section 'Justification of information'.

Description of key information

The acute Fish LC50 for the ester substance Veramoss is predicted to be 5.2mg/L based on the ECOSAR SAR for esters using an estimated log Kow of 3.2,molecular weight of 196.2 and the equation:Log 96h-LC50 (mmol/L)= -0.584 (log Kow) + 0.2941

Veramoss is in the applicability domain of the ECOSAR prediction because: a) Veramoss is an ester presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this ester); b) its log Kow is 3.2 (=< 5); c) its MW is 196.2 g/mol (< 1000); and; d) the toxicity predicted is below its measured water solubility of 18 mg/L.

In the ECOSAR training set esters are available with log Kows around the Veramoss value. A substance with a somewhat similar predicted log Kow (3.1) is ethyl salicylate with a predicted LC50 of 5.1 and a measured value of 19.6 mg/L, indicating a conservative prediction.

The fit in the applicability domain and the availability of a log Kow analogue in the training set results in limited uncertainty of the Veramoss 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 Fish toxicity on esters (see attached report). The adequate and reliable documentation, presented below, further supports this prediction.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

5.2 mg/L