Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

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Link to relevant study record(s)

Description of key information

Microorganisms were exposed to the analogue, o-sec-butylphenol, where the 3 hr EC50 was > 10 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
10 mg/L

Additional information

There are no reliable toxicity studies available for toxicity of o-tert-butylphenol to activated sludge microorganisms. However, reliable data are available for the analogue, o-sec-butylphenol and are included in the dossier.

Horton et al. (1991) conducted a reliable study on the toxicity of the analogue, o-sec-butylphenol, to activated sludge microorganisms following OECD 209 guidelines. Activated sludge microorganisms were exposed to the a control and 10 mg/L of the test substance for 3 hrs. Oxygen consumption was measured to determine the 3 hr EC50 of > 10 mg/L. Consequently, this value is taken to fullfil the toxicity to microorganisms endpoint.