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Environmental fate & pathways

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Biodegradation in water:

Tert-butyl peroxypivalate was tested for ready biodegradability in the closed bottle test according to OECD guideline 301 D. The test substance was tested using a stock solution of 1 g/litre. Activated sludge was used as inoculum. The test ran for 28 days and was prolonged up to 71 days. The test was valid as shown by an endogenous respiration of 0.3 mg/litre and the total mineralization of the reference compound, sodium acetate. As the degree of biodegradation reached 15% after 71 days, tert-butyl peroxypivalate can be considered as not readily biodegradable.


The performance of a test for bioaccumulation in aquatic species, preferably fish, is scientifically unjustified.

REACH Regulation No. 1907/2006, Annex IX, Sect. 9.3.2, Col. 2, states as follows:

“9.3.2 The study need not be conducted if:

- the substance has a low potential for bioaccumulation (for instance a log Kow <= 3) and/or a low potential to cross biological membranes, or

- direct and indirect exposure of the aquatic environment is unlikely. ”

Direct and indirect exposure of the test item to water is highly unlikely. Due to the unstable nature of organic peroxides, it can be assumed that upon contact with water and organic matter, the test item undergoes rapid degradation resulting in the formation of respective alcohols and acids. Therefore, tert-butyl peroxypivalate was considered to have no bioaccumulation potential. Using EPIWIN 4.10 a BCF of 32.57 L/Kg wwt was calculated indicating no potential for bioaccumulation.

Transport and distribution

According to OECD guideline no. 121 and EU method C.19 the log Koc of tert-butyl peroxypivalate was determined to be 1.59 using the HPLC method.