2,5-di-tert-pentylhydroquinone

Endpoint summary

Description of key information

Fate assessment data is discussed.

Additional information

Hydrolysis: in view of its low water solubility, the study was waived.

Biodegradation: 2,5 -bis(1,1-dimethylpropyl)benzene-1,4-diol is not readily nor inherently biodegradable. The outcome of the OECD 309 simulation test is that the substance is not considered to be persistent. It quickly degraded in the surface water to less than 10 % of applied radioactivity within 7 days of incubation in the test systems treated at a low test concentration (10 μg/L) and within 11 days of incubation in the test systems treated at a high test concentration (100 μg/L). It would therefore appear that the substance rapidly degrades via oxidation under the test conditions. The resulting product then leaves the test system via volatisation routes.

Bioaccumulation: The available non-experimental data indicate that 2,5-bis(1,1-dimethylpropyl)-1,4-diol has a BCF which is below the classification threshold of 2000 L/kg for B in the PBT/vPvB assessment.

Transport and distribution: A log Koc value of 3.68 was experimentally derived for 2,5-bis(1,1-dimethylpropyl)-1,4-diol.In an OECD 106 study, no adsorption equilibrium could be reached for all soils due to the continuous transfer of test item into a more volatile transformation product not retained in the soil. For both sludges an adsorption equilibrium was reached after 24 hours contact time. Desorption equilibrium was reached after 24 hours contact time in the presence of both soil and sludge. The test item was shown to be unstable during the time frame of the experiment for all soils and sludges.

Freundlich Adsorption and Desorption Coefficients were determined as follows

Test system	Texture [USDA]	Organic carbon [%]	KF^ads [mL/g]	KF,oc^ads [mL/g]	KF,oc^des [mL/g]
Tilburg	Clay	33.6	2791.43	8308	11183
Aa & Maas	Clay	35.6	3716.98	10441	13566