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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

NOEC (14 d): ≥ 14.2 mg/L for activated sludge microorganisms (OECD 301B)

Key value for chemical safety assessment

Additional information

Since no studies on the toxicity to aquatic microorganisms are available a ready biodegradability study is used to derive a NOEC for the toxicity to aquatic microorganisms. If a compound degrades well in a ready biodegradability test, or does not inhibit the degradation of a positive control at a certain concentration, this concentration can be used as a NOEC value. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA, 2012).

A substance can be assumed to be not inhibitory to aquatic microorganisms, if in the toxicity control of a ready biodegradation test, more than 25% degradation based on CO2 evolution occurred within 14 days (OECD guideline 301). For 2-octyldodecyl isooctadecanoate (CAS 93803-87-3) a biodegradation test conducted according to OECD guideline 301B is available (Desmares-Koopmans, 1998). The test includes a toxicity control, which contains 14.2 mg/L of the test substance and 39.85 mg/L of the reference material. The toxicity control attained 78.1% degradation after 14 days of incubation. Hence, the substance is not toxic to aquatic microorganisms and a NOEC of ≥ 14.2 mg/L was derived.