Methyl o-toluate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

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:

Executive summary:
The acute Daphnia EC50 for the ester Ylanganate is predicted to be 24.1 mg/l based on the ECOSAR SAR for esters using an estimated log Kow of 2.375, molecular weight of 150 and the equation: Log 48h-LC50 (mmol/L) = -0.6305 (log Kow) + 0.7049
Ylanganate is in the applicability domain of the ECOSAR prediction because: a) Ylanganate is an ester presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this chemical class); b) its log Kow is 2.375 (≤ 5); c) its MW is 150 (≤1000); and; d) the toxicity predicted is below its water solubility of 572.9 mg/l.
The fit in the applicability domain results in limited uncertainty of the Ylanganate 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 Daphnia toxicity on esters (see attached report). The adequate and reliable documentation, presented below, 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).

GLP compliance:

no

Specific details on test material used for the study:

O=C(OC)c(c(ccc1)C)c1

Test organisms (species):

Daphnia sp.

Water media type:

freshwater

Total exposure duration:

48 h

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

24.1 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: ECOSAR class: Esters

The acute Daphnia toxicity of Ylanganated is 24.1 mg/l when using the ECOSAR-Ester equation

Validity criteria fulfilled:

yes

Remarks:

The ECOSAR-Ester equation is valid when using the OECD criteria. In addition, N=40 and R2 is 0.798

Conclusions:

The Daphnia 48-h EC50 is 24.1 mg/L

Executive summary:

The acute Daphnia EC50 for the ester Ylanganate is predicted to be 24 mg/l based on the ECOSAR SAR for esters using an estimated log Kow of 2.4, molecular weight of 150 and the equationLog 96-h EC50 (mmol/L) = -= -0.6277 (log Kow) + 0.7017. Ylanganateis in the applicability domain of the ECOSAR prediction because: a) Ylanganate is an ester presenting a toxicity by its ester functionality and by its bioavailability (i.e. without fragments that activate this ester), b) its log Kow is 2.4 (< 5); and c) its MW is 150 (< 1000). Fairly close analogues are available in the ECOSAR training set is Ethylhexenyl lactate and diethylphthalate all with a log Kow of 2.7 and molecular weight around 200-222. They have experimental toxicity of circa 85 mg/l and an ECOSAR prediction of 20 mg/l, presenting the limited uncertainty of the prediction for these training set substances and thus also for Ylanganate.The fit in the applicability domain and the availability of analogues in the training set, results in limited uncertainty of the Ylanganate prediction. This shows that the prediction is reliable and a Klimisch 2 can be assigned. In accordance with Annex XI,  the validity of the (Q)SAR is documented in a QMR for acute Daphnia toxicity on esters. The adequate and reliable documentation supports this prediction.

Description of key information

Acute Daphnia EC50: 24.1 mg/l

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

24.1 mg/L