Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

The hydrolysis of structurally analogous [1,3(or 1,4)-phenylenebis(1-methylethylidene)]bis[1,1-dimethylethyl] peroxide was evaluated in a study performed in accordance with OECD testing guideline 111 and EPA OPPTS 835.2110 under GLP requirements.

The results from the hydrolysis test indicate that 64.6, 71.4 and 77.3% of the reaction were observed after 5 days at pH 4, 7 and 9 solutions respectively, at 50 °C. The test has demonstrated that the substance is hydrolytically stable at pH 2.6 after 24 hours. The degradation rates were calculated using first order kinetics as follows:

 

At 50°C:

pH 4 : half-life = 7.9 d

pH 7: half-life = 10.3 d

pH 9: half-life = 13.4 d

 

Extrapolated values at 25°C, using the Arrhenius equation:

pH 4 : half-life = 56.4 d

pH 7: half-life = 74.7 d

pH 9: half-life = 96.5 d

 

The ready biodegradability of 1,3-bis[1-(tert-butylperoxy)-1-methylethyl]benzene was evaluated in a study performed in accordance with OECD testing guideline 301 D and GLP requirements.

1,3-bis[1-(tert-butylperoxy)-1-methylethyl]benzene is not biodegraded in the closed bottle test, and therefore should not be classified as readily biodegradable. This lack of biodegradation is not due to toxicity of the test compound because the endogenous respiration is not inhibited by 1,3 -bis[1 -(tert-butylperoxy)-1 -methylethyl]benzene.

Sediment and water compartment exposure is likely. Besides, based upon the adsorption potential of the substance of interest, a study was conducted to determine the biodegradation of structurally analogous [1,3(or 1,4)-phenylenebis(1-methylethylidene)]bis[1,1-dimethylethyl] peroxide in water/sediment simulation test, according to US EPA guideline.

The substance was not found in the water layers at all time points. In the sediment layer, an average of 94.7% of the applied dose was detected at day 0. The substance has decreased to an average of 9.7% of the applied dose at day 90. The half-life in sediment/water compartment under anaerobic conditions was determined as 29 days.

Tert-butanol, the main expected breakdown product, was detected in water and sediment layers at all time point (except day 0) but below a quantifiable level until day 90: it represented an average of 61.5% of the test substance applied dose.

The adsorption/desorption behaviour of the structural analogous substance on soil and sewage sludge was evaluated in a study performed in accordance with OECD testing guideline 121 and GLP requirements.

1,3(4)-bis(tert-butylperoxyisopropyl)benzene contains 3 components for which three log Koc values were estimated: 3.1; 4.7 and 4.8.

Additional information