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Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
November 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 fish toxicity for Hyacinth body is predicted using ECOSAR Neutral organics. The full justification is presented in the accompanying file attached in the Endpoint summary. The executive summary of the QSAR information is included in the Endpoint summary.

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
Test organisms (species):
other: fish
Water media type:
freshwater
Total exposure duration:
96 h
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
7.2 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Remarks on result:
other: ECOSAR class: Neutral organics
Validity criteria fulfilled:
yes
Remarks:
The substance is within the applicability domain of the model and reliable and adequate documentation is present.
Conclusions:
The 96-h LC50 for fish is 7.2 mg/L.

Description of key information

The LC50 fish is 7.2 mg/l using ECOSAR Neutral Organic prediction.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
7.2 mg/L

Additional information

The 96h acute fish LC50 for the neutral organic substance Hyacinth body is predicted to be 7.2 mg/l based on the ECOSAR SAR for neutral organics using a measured log Kow of 3.5, molecular weight of 194.28 g/mol and the equation: 96h LC50(mg/L) = MW x 10^ (-0.8981 Log Kow + 1.7108).

 

Hyacinth body is in the applicability domain of the ECOSAR prediction because: a) Hyacinth body is a neutral organic presenting the toxicity solely by its bioavailability (i.e. without fragments that activate this neutral organic); b) its measured log Kow is 3.5 (predicted Log Kow = 2.91); c) its MW is 194.28 (=< 1000); and; d) the toxicity predicted is below its predicted water solubility of 152.3 mg/l (measured = 453 mg/L).

 

The results present some uncertainty compared to the data in the training set, because the difference between the predicted and the measured values for log Kow for Hyacinth body is greater than 0.5, which is outside IFF's validity criteria. The measured log Kow results in a more conservative acute fish toxicity value and therefore the measured value is used. 

 

The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the Hyacinth body 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 neutral organics (see attached report). The adequate and reliable documentation presented, further supports this prediction.

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