Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Abiotic degradation

Air: Based on estimation with the QSAR model AOPWIN, (version 4.10, EpiSuite 2013), Cyclaprop undergoes in air rapid degradation after reaction with hydroxyl radicals or ozone. The DT50 values after reaction with hydroxyl radicals and ozone are 1.9 hours and 1.4 hours respectively. The half-life time of Cyclaprop is < 2 days. Cyclaprop will not reach the stratosphere and is therefore not considered to be 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). Cyclaprop 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 1272/2008 and its amendments).

Water: Based on read-across to a study performed on the structurally related substance Cyclobutanate, the half-life time of Cyclaprop at 25°C is >1 year at pH 4 and 7, whereas the half-life is expected to be 13 days at pH 9. It is concluded that Cyclaprop is hydrolytically stable under environmental conditions.

Biotic degradation:

1) In a screening study according to OECD TG 301F, 15% biodegradation was found after 28 days. This means that Cyclaprop is not readily biodegradable.

2) DT50 -water: For Cyclaprop a half-life of 17 days at 12°C has been derived using read across and QSAR modelling.

Bioaccumulation:

Aquatic organisms

1) The BCF of Cyclaprop is 156 l/kg based on read across from Verdox which is tested in an OECD TG 305 test and has a BCF of 156 l/kg.

2) This BCF is supported with the calculated BCF of 1096 l/kg in aquatic organism using the equation of Veith (1979, included in EUSES) using a log Kow of 4.4.

Terrestrial organisms

The BCF in earthworms was estimated to be 302 l/kg ww with the equation from Jager (1998, included in EUSES), indicating that the potential for bioaccumulation in terrestrial organisms will also be limited.

Transport and distribution:

Koc: The adsorption coefficient (Koc) of Cyclaprop has been established to be 1300, log Koc of 3.1, using the HPLC screening method (OECD121). This indicates that the substance will have a moderate potential to adsorb to sediment/soil (>500 - <5000).

Henry's law constant: To assess the volatilisation potential of the substance a Henry's law constant was calculated which gave a result of 2.432 Pa. m3/mol at 25°C. From the distribution modelling results it can be concluded that volatilisation is of minor importance in the environmental behaviour of Cyclaprop.

Based on Level III distribution modelling using EPISUITE (assuming equal and continuous releases to air, water and soil) using the CAS number 68912-13-0 and the measured physico-chemical parameters as input, it is estimated that the majority of the substance released to the environment will partition mainly into soil (75.4 %) and water (23.5%) with small amounts to sediment and air (1.04% and 0.114% respectively).

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 Kow and (non) ready biodegradability. The model predicts that 84.1% of the substance will partition to water, 13.8% to sewage sludge and 2.11% to air at 15°C.