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Ecotoxicological information

Long-term toxicity to fish

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Reference
Endpoint:
long-term toxicity to fish, other
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: A QSAR model, ECOSAR was used to estimate long-term toxicity to fish.
Justification for type of information:
QSAR prediction from reliable model
Qualifier:
no guideline required
Principles of method if other than guideline:
The QSAR model, Ecological Structure Activity Relationships (ECOSAR) Class Program was used to estimate the long-term toxicity to fish. The following measured values were used in the model: log Kow = 4.33 and water solubility = 21.7 mg/L.
Test organisms (species):
other: fish
Water media type:
freshwater
Key result
Duration:
30 d
Dose descriptor:
other: chronic value (geometric mean of NOEC and LOEC)
Effect conc.:
1.675 mg/L
Key result
Duration:
30 d
Dose descriptor:
NOEC
Effect conc.:
1.184 mg/L
Details on results:
As per REACH Guidance Ch 10, a NOEC can be calculated from the chronic value by dividing the chronic by the square root of 2. Therefore, the calculated NOEC = 1.184 mg/L and will be used in the assessment.
Conclusions:
Using a reliable QSAR model, Ecological Structure Activity Relationships (ECOSAR) Class Program was used to estimate the 30d ChV for fish to be 1.675 mg/L.
Executive summary:

A reliable QSAR model (Ecological Structure-Activity Relationship (ECOSAR) version 1.11) was used to predict the chronic aquatic toxicity of 2 -butyloctanoic acid to fish. The 30 day chronic value (the geometric mean of the NOEC and LOEC) was 1.675 mg/L for the neutral organic class. As per REACH Guidance Ch 10, a NOEC can be calculated from the chronic value. Therefore, the calculated NOEC = 1.184 mg/L and will be used in the assessment.

Description of key information

The long-term toxicity of 2 -butyloctanoic acid was estimated using a QSAR model.  The 30 day ChV was 1.675 mg/L and the calculated NOEC was 1.184 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
1.184 mg/L

Additional information

No reliable experimental long-term toxicity studies with fish are available for o-tert-amylphenol. However reliable (Klimisch 2) modeled data are available and included in the dossier.

Sasol (2017) provided reliable (Klimisch 2) data for o-tert-amylphenol using the QSAR model, Ecological Structure Activity Relationships (ECOSAR) Class Program to estimate long-term toxicity to fish. The ECOSAR model estimates aquatic toxicity based on the structural similarity to chemicals for which aquatic studies are available. In addition, the log Kow and molecular weight of o-tert-amylphenol are within the criteria (max log Kow = 7 for acute, 8 for chronic and max molecular weight = 1000) and domain of the model. The measured log Kow of 4.33 was used in the model. Model results indicate a 30 day chronic value (the geometric mean of the NOEC and LOEC) to be 1.675 mg/L using the baseline toxicity equation. As per REACH Guidance Ch 10, a NOEC can be calculated from the chronic value. Therefore, the calculated NOEC is 1.184 mg/L.