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PBT assessment

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PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB
Justification:

The target substance 2 -butyloctanoic acid was demonstrated to be readily biodegradable in an OECD guideline 301 B-test.

Therefore the substance is not considered to be persistent (P).

All Category members including 2 -butyloctanoic acid have calculated BCF of 3.162, meaning the BCF, meaning the BCF << 2000, therefore the substances are considered not to be bioaccumulative according to the PBT-criteria.

A reliable QSAR model (Ecological Structure-Activity Relationship (ECOSAR) version 1.00) was used to predict the aquatic toxicity of the test item 2 -butyl octanoic acid to fish. The 96 hour LC50 was 13.297 mg/L.

In the key study (Daphnia magna, OECD 202, GLP compliant) with the target substance 2-butyloctanoic acid the 48h-EC50 was 31 mg/l (95% confidence interval between 22 and 42 mg/l). In the ECOSAR calculation a value of 48 h-EC50 of 9.363 mg/L is predicted for an algae test with 2-butyl octanoic acid. The toxicity of the Source substance 1, Reaction mass of n-undecanoic-acid and 2-methyl-decanoic-acid and 2 -ethyl-nonanoic-acid and 2-propyl-octanoic-acid and 2 -butyl-heptanoic-acid, was assessed in a fresh water algal groth inhibition test with Pseudokirchnerella subcapitata according to OECD guideline 201. The ErC10 of 2.7 mg/L (95% CL 2.0 – 3.5 mg/L), NOErC of 1.3 mg/L and the ErC50 of 13 mg/L (95% CL 11 – 15 mg/L) after 72 hours of exposure can be considered reliable without restrictions. The ECOSAR calculation of the test substance 2-butyl octanoic acid confirms that range of toxicity with a 96 h EC50 value of 16.975 mg/L and a calculated 96 h NOEC of 5.067 mg/L.

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.

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 daphnids. The 21 day chronic value (the geometric mean of the NOEC and LOEC) was 1.662 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 = 1.175 mg/L and will be used in the assessment as the key value for long-term toxicity to aquatic invertebrates.

Toxicity Aquatic toxicity tests do not indicate that any of the Category members including 2 -butyloctanoic acid meets the criteria to be regarded as toxic (T). Furthermore all Category members including 2 -decyltetradecanoic acid are not classified as carcinogenic, germ cell mutagenic, or toxic for reproduction or STOT.

Hence the substance does not meet the criteria to be regarded as a PBT or vPvB substance.

An emission characterisation for 2 -butyloctanoic acid is not needed because it is not a PBT.