6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde

Endpoint summary

Description of key information

Degradation

Air: Based on estimation with the QSAR model Aopwin the substance undergoes in air rapid degradation after reaction with hydroxyl radicals and ozone. The DT50-value after reaction with hydroxyl radicals is 1.108 hours (rate constant is 115.88 E-12 cm3/molecule-sec). For reaction with Ozone, the atmospheric half -lifetime is 0.027 days (rate constant is 43 E-17 cm3/molecule-sec). Based on these half-lives, the substance will not reach the stratosphere and is therefore not considered to be a long-range transported chemical in 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).

Water: Examination of the substance's chemical structure shows that it contains no hydrolysable groups (such as e.g. ester, carbamates, epoxides, halomethanes, acylhalides (see Hydrowin, EpiSuite for all hydrolysable groups)). The half-life at 25 °C is > 1 year.

Biotic degradation of the substance was determined by the Closed Bottle test according to OECD TG 301D under GLP. The substance was degraded by 14% at day 28. In the prolonged Closed Bottle test, the test item was biodegraded by 72 % at day 60 (enhanced biodegradability testing). The substance should be regarded as not readily biodegradable according to this test, but is not expected to be persistent in the environment based on the 60 and 70 day results.

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 902 and 240 L/kg ww, respectively, using a log Kow of 4.3.

Transport and distribution

The adsorption potential of the substance was determined in a study according to OECD TG 121 (HPLC method). Under the conditions of the test, the log Koc of the substance was determined at 3.19 (equivalent Koc = 1.5E3 L/kg) based on the main peak (98 area%). Based on this value the substance has potential for adsorption to solid surfaces and soil.

A Henry's law constant of 6.52 Pa·m³/mol (at 12°C) was calculated in EUSES (Vapour pressure 4.71 Pa (25°C), 178.75 g/mol molecular weight and 61.7 mg/l water solubility (25°C). Based on this value the substance has potential to partition from water to air under environmental conditions (12°C). 

Based on Level III environmental distribution modelling using EPISUITE (assuming equal and continuous releases to air, water and soil) using the CAS number 33885-51-7 and the measured physico-chemical 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 (79.8%) and water (19.9%) with small amounts to air (0.0698%) and sediment (0.194%).

The SimpleTreat model, which is incorporated in EUSES simulates the distribution of the substance in a Sewage Treatment Plant based on vapour pressure, water solubility, log Koc and ready biodegradability. Model calculations show that 0% of the substance will be degraded, and that 75.5%, 15.7%, and 8.8% will partition to water, sludge and air, respectively.