4-tert-pentylcyclohexanone

Endpoint summary

Description of key information

Abiotic degradation

Air:No experimental data on the phototransformation of the substance in air are available. Based on estimation with the QSAR model AopWin (v1.92), in air the substance undergoes rapid degradation after reaction with hydroxyl radicals with a DT50-value of 24.149 hours. This indicates that the substance is not a long-range transported chemical in air according to the UNECE criteria (http://www.unece.org/fileadmin/DAM/env/documents/2000/ece/eb/ece%20eb%20air.60.e.pdf). This half-life will not be used for the CSA because these are calculated and not experimental values. The half-life with ozone could not be calculated. Furthermore, the substance does not have an ozone depletion potential because it does not contain halogens and does not have the potential to reach the stratosphere (EU CLP, EC no 1272/2008 and its updates).

Water:The substance is expected to be hydrolytically stable because it does not contain hydrolysable groups such as ester, carbamates, epoxides, halomethanes, acylhalides (see Hydrowin, EpiSuite for all hydrolysable groups). The half-life at 25 °C is >1 year.

Biotic degradation

The biodegradation potential of Orivone in water was determined in a screening study according to OECD TG 301D (Closed Bottle Test) and in compliance with GLP criteria (IFF, 2016). The test was performed according to slightly modified OECD, EU and ISO Test Guidelines: ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification. In this study, 2 mg/L test substance was inoculated with river water for 28 days under aerobic conditions. At regular intervals throughout the incubation period the oxygen consumption was measured and compared to the ThOD as indication of biodegradation. The observed biodegradation percentages did not exceed 3%. Based on these findings the substance is classified as not readily biodegradable.

Bioaccumulation:

Bioaccumulation in aquatic and terrestrial species is based on the available information (log Kow and calculated BCF values). The BCFs for aquatic and terrestrial organisms were calculated using QSARs of Veith et al. (1979) and Jager (1998), both incorporated in the EUSES model, and yielded values of 412 and 96.2 L/kg ww, respectively.

Transport and distribution:

The adsorption coefficient of Orivone has been determined to be 3.74E+02 (log10 Koc 2.57)using the HPLC screening method, designed to be compatible with Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001 Method C.19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008.

The Henry's Law constant is calculated using the equation from EUSES. Using a molecular weight of 168.28 g/mol, and the experimentally determined vapour pressure of 4.2 Pa (at 24 °C) and water solubility of 370.8 mg/L (at 24 °C) the Henry's Law constant at environmental temperature (12 °C) is calculated to be 0.964 Pa·m³/mol.

Based on Level III environmental distribution modelling using EPISUITE (assuming equal and continuous releases to air, water and soil) using the CAS number 16587-71-6 and the measured physicochemical parameters (water solubility and log Kow) as input, it is estimated that the majority of the substance released to the environment will partition mainly into soil (80.5%) and water (17.8%) with minor amounts to air (1.55%) and sediment (0.24%).

The SimpleTreat model, which is incorporated in EUSES, simulates the distribution of the substance in a Sewage Treatment Plant (STP). Model calculations show that 0% of the substance will be degraded and that 93.9%, 4.44% and 1.66% will partition to water, sewage sludge and air, respectively.