Methoxycarbonyloxycyclooct-4-ene

Endpoint summary

Description of key information

Abiotic 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 1.7 hours. Ozone reaction estimate is 1.4 hours. 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: The substance has a half-life at 25 °C of >1 year at pH 4 and pH 7, and 30 days at pH 9.

 

Biotic degradation

In a biodegradation screening study(OECD TG 301D) activated sewage sludge from an STP treating predominantly domestic sewage was exposed to ca 2 mg/L substance for 28 days. In this test 67% biodegradation was observed at day 28. Although due to study design the 14 -day window criterion could not be assessed, based on the fact that >60% biodegradation was achieved within 15 days, the substance is concluded to be 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 58.2 and 10.4 L/kg ww, respectively, using a log Kow of 2.9.

 

Transport and distribution

The adsorption potential of the test substance was determined in a HPLC screening test according to EU Method C.19 and in compliance with GLP criteria. Solutions of reference substances with known log Koc values based on soil adsorption data and the test substance were analysed by HPLC using a Hypersil H5CPS column. The log k’ values of reference substances were plotted against the known log Koc values. The log Koc value for the test substance was calculated by substituting its mean log k’ in the calibration curve. Under the conditions of the test, the log Koc of the test substance was determined to be 3.16, which is equivalent to a Koc value of 1445 L/kg.

A Henry's law constant of 0.85 Pa·m³/mol (at 12°C) was calculated in EUSES (184.2 g/mol molecular weight, vapour pressure 4.02 Pa (25°C), and 415 mg/L water solubility (18°C)). Based on this value the substance has no 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 SMILES notation O=C(OC1CCC=CCCC1)OC and the measured physico-chemical parameters (water solubility (at 25 °C) and log Kow) as input, it is estimated that the majority of the substance released to the environment will partition mainly into soil (66.7%) and water (32.5%) with small amounts to air (0.5%) and sediment (0.3%).

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 77% of the substance will be degraded, and that 11.5 %, 11.3%, and 0.3% will partition to sludge, water, and air, respectively.