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Short-term toxicity to aquatic invertebrates

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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:
The 48h acute Daphnia EC50 for the neutral organic substance Octacetal is predicted to be 8.07 mg/L based on the ECOSAR SAR for neutral organics using an estimated Log Kow of 3.17, a molecular weight (MW) of 174.28 and the equation: 48h-EC50 (mg/L) = MW * 10^(-0.858 Log Kow + 1.3848).
Octacetal is in the applicability domain of the ECOSAR prediction because: a) Octacetal is an acetal presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this acetal); b) its estimated Log Kow is 3.17 (=< 5); c) its MW is 174.28 (=< 1000); and d) the toxicity predicted is below its water solubility of 210.5 mg/L.
The fit in the applicability domain and the availability of analogues in the training set results in limited uncertainty of the Octacetal 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 neutral organics (see attached report). The adequate and reliable documentation, presented in the study record, further supports this prediction.
Reference:
Composition 1
Qualifier:
according to
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 v1.11'. United States Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington DC (2012).
GLP compliance:
no
Test material information:
Composition 1
Test organisms (species):
Daphnia sp.
Water media type:
freshwater
Total exposure duration:
48 h
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
8.07 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: ECOSAR class: Neutral organics
Validity criteria fulfilled:
yes
Remarks:
The substance is in the applicability domain of the model.
Conclusions:
The Daphnia 48-h EC50 is 8.07 mg/L
Executive summary:

The 48h acute Daphnia EC50 for the neutral organic substance Octacetal is predicted to be 8.07 mg/L based on the ECOSAR SAR for neutral organics using an estimated Log Kow of 3.17, a molecular weight (MW) of 174.28 and the equation: 48h-EC50 (mg/L) = MW * 10^(-0.858 Log Kow + 1.3848).

Octacetal is in the applicability domain of the ECOSAR prediction because:  a) Octacetal is an acetal presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this acetal); b) its estimated Log Kow is 3.17 (=< 5); c) its MW is 174.28 (=< 1000); and d) the toxicity predicted is below its water solubility of 210.5 mg/L.

The fit in the applicability domain and the availability of analogues in the training set results in limited uncertainty of the Octacetal 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 neutral organics (see attached report). The adequate and reliable documentation, presented in the study record, further supports this prediction.

Description of key information

Acute Daphnia EC50, according to ECOSAR-Neutral Organics: 8.07 mg/L

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
8.07 mg/L

Additional information