Indeno[4,3a-b]furan, decahydro-2,2,7,7,8,9,9-heptamethyl-

Endpoint summary

Description of key information

Abiotic degradation

Air: No experimental data on the photo-transformation of the substance in the air is available. Based on estimation with the QSAR model AopWin (v1.93), the substance using its SMILES notation CC1C(C)(C)C2CCC3CC(C)(C)OC3C2C1(C)C undergoes in air rapid degradation after reaction with hydroxyl radicals (ozone could not be estimated). The DT50 value after reaction with hydroxyl radicals is 4.675 hours (based on 12-hour time frame and 1.5E+06 OH radicals/cm3; AOPWIN default settings). Based on the half-life, the substance will not reach the stratosphere and is not a long-range transported chemical in the air. 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 amendments). The half-life in the air is not used in the risk characterisation because it is not an experimental value.

Water: The substance is hydrolytically stable in an OECD TG 111 study at pH 4, 7 and 9 at 25°C (DT50 > 1 year).

Biotic degradation

Substance is not readily biodegradable and shows 2% degradation after 28 days in an OECD TG 301B test.

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 1140 and 316 L/kg ww, respectively, using a log Kow of 4.42.

Transport and distribution

The adsorption potential of the substance was determined with the HPLC screening study according to OECD TG 121. The retention time of the substance could not be determined because it was much higher than the reference substance DDT (RT was 67 minutes), which may partly be due to the substance viscosity, though information on this is not available. For the risk assessment, a point value is needed to estimate the partitioning between sludge and water, sediment and water and soil in water. In addition, the Koc value is needed for the PNEC derivation for sediment and soil. In this case, the following QSAR equation can be used: log Koc = 0.81 log Kow + 0.10, according to Sablic et al. (1995) on hydrophobics. This results in a Koc = 4790 L/kg and log Koc = 3.68 L/kg. The QSAR is scientifically valid. The test substance can be considered a hydrophobic substance because it mainly consists of hydrocarbons and only one oxygen. Therefore the substance is in the applicability domain of the QSAR.

A Henry's law constant of 222 Pa·m³/mol (at 12 °C) was calculated in EUSES (Vapour pressure 0.38 Pa (at 25°C), 264 g/mol molecular weight and 0.202 mg/L water solubility (at 20 °C).

Based on Level III environmental distribution modelling using EPISUITE (assuming equal and continuous releases to air, water and soil) using the Smiles CC1C(C)(C)C2CCC3CC(C)(C)OC3C2C1(C)C and the measured physico-chemical parameters (0.202 mg/L water solubility and 4.42 log Kow) as input, it is estimated that the majority of the substance released to the environment will partition mainly into soil (85.2%), water (6.47%) and sediment (7.76%) with small amounts to air (0.53%).

The SimpleTreat model, which is incorporated in EUSES, simulates the distribution of the substance in a Sewage Treatment Plant (STP) based on vapour pressure, water solubility, log Koc and ready biodegradability. Model calculations show that none of the substance will be degraded and that 54.7%, 16.4% and 28.9% will partition to air, water and sewage sludge, respectively.