4-(1,1-dimethylethyl)cyclohexyl acrylate

Endpoint summary

Description of key information

Hydrolysis:

The calculated half-lifes at pH 8 and pH 7 of the test substance are 3.609 and 36.090 years, respectively (QSAR, HYDROWIN v.2.00).

Biodegradation:

The substance was not readily biodegradable under the conditions of a modified MITI test according to OECD guideline 301 C (BASF, 09G0580/09G205, 2016).

Adsorption:

The measured log Koc of the test substance is 3.96 using the Kow method (QSAR, KOCWIN v.2.00). Thus, adsorption to the solid phase is expected.

Additional information

Hydrolysis:

The half-life of the test substance was calculated using EPI Suite HYDROWIN program. The calculation revealed a half-life of 3.609 years at pH 8 and a half-life of 36.090 years at pH 7 for the test substance. Thus, in contact with water the substance will hydrolyse slowly at pH 7. At pH 8 the substance will hydrolyse rapidly.

Biodegradation:

For the determination of the aerobic biodegradability of the test substance in water a modified MITI test according to OECD guideline 301 C was conducted (BASF, 09G0580/09G205, 2016). Mixtures of the test substance, a defined mineral medium and non-adapted, aerobic sludge from several samples were incubated and aerated under static conditions in a respirometer for 28 days. The mean degree of biodegradation of the test substance was 4% BOD/ThOD after an exposure period of 28 days. The results derived from specific analysis show that the test substance had a dissipation degree at the end of exposure of 25% releated to the test substance content in the blank control and 98.0% related to the test substance concent in the blank control at the start of exposure. Thus, the test substance is not readily biodegradable under the conditions of this test.

Degradation pathway:

Two models of the OASIS Catalogic tool (v5.11.19) were used to assess the degradation pathway and to identify potential metabolites of the registration item.

CATALOGIC 301C v.10.14 predicted a total of 76 metabolites. 11 out of those exceeding a quantity of 0.1 % [mol/mol parent], which therefore are considered relevant for the PBT assessment. Four metabolites were estimated to be readily biodegradable (between 69% and 90% after 28 days, based on BOD), the remaining degradation products were calculated to be not readily biodegradable (<60% after 28d, based on BOD). All of the relevant metabolites have log POWs below 4.5 and are therefore not fulfilling the B criterion under REACH.

CATALOGIC 301F v.5.12.1 identified a total of 24 metabolites with 4 of them having PBT relevance (quantity >= 0.1 % [mol/mol parent]). Two out of those were estimated to readily biodegrade (73% and 77% after 28 days, based on BOD), two were predicted to degrade moderately (49% and 50% after 28 days, based on BOD). Based on the calculated log POWs of these relevant metabolites, significant bioaccumulation is not to be expected.

Adsorption:

The soil adsorption coefficient (Koc) was calculated using EPI Suite KOCWIN program. Using the molecular connectivity index (MCI) method the Koc was calculated to be 824 L/kg (log Koc: 2.92). Using the Kow method the Koc was calculated to be 9058 L/kg (log Koc: 3.96). Because the Kow method is based on an experimental determined log Kow value of 5.6, this value is considered to be more accurate and is therefore chosen as key value. The Kow method showed a log Koc >3. Thus, adsorption to the solid soil phase is expected.