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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

There is no test performed with Tert-amyl hydroperoxide. The toxic effects on microorganisms of this substance is read-across from data obtained with1,1,3,3-Tetramethylbutyl hydroperoxide (OECD 209 guideline): EC50-3h = 138 mg/L, EC10-3h = 33 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
138 mg/L
EC10 or NOEC for microorganisms:
33 mg/L

Additional information

There is no test performed with Tert-amyl hydroperoxide. The toxic effects on microorganisms of this substance is read-across from data obtained with1,1,3,3-Tetramethylbutyl hydroperoxide.

In order to predict effects of chemicals in the environment and in biological waste water treatment plants, an activated sludge respiration inhibition test was performed. The toxicity to activated sludge was determined in accordance with OECD Test Guideline 209, and in compliance with the OECD principles of Good Laboratory Practice. The reference substance and test substance were measured on two subsequent days. The test is valid as shown by the EC50 of the reference compound, 3,5- dichlorophenol (8 mg/L), the coefficient of variation of the replicates of the control oxygen uptake rates (2% on first day and 3% on second day) and the average oxygen uptake rate for the control replicates of 15 mg O2/g dry weight/hour on the first day and 26 mg O2/g dry weight/hour on the second day. The oxygen uptake rate on the first day is slightly lower than prescribed. Accurate oxygen uptake rate measurements were very well possible as shown by the very low coefficient of variation. Therefore this is a minor deviation which does not invalidate the test. The toxicity of 1,1,3,3-tetramethylbutyl hydroperoxide to activated sludge was determined at a contact time of 3 hours, using various concentrations of the test substance. The inhibitory effect of 1,1,3,3-tetramethylbutyl hydroperoxide at a particular concentration is expressed as a percentage of the two controls.

The EC50 of 1,1,3,3-tetramethylbutyl hydroperoxide for activated sludge after 3 hours contact time is 138 mg/L with 95% confidence limits of 53 and 327 mg/L. The EC10 of 1,1,3,3-tetramethylbutyl hydroperoxide for activated sludge after 3 hours contact time is 33 mg/L with 95% confidence limits of 4 and 78 mg/L. The EC20 and EC80 are 54 and 349 mg/L, respectively.1,1,3,3-tetramethylbutyl hydroperoxide is therefore considered harmless to activated sludge.