Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

This multi-constituent substance is a mixture of molecules with 4 or 5 ethylene oxide 'monomer' units with a methoxy terminal function at one end of the molecule and a hydroxyl function group at the other end. Impurities are primarily the higher molecular weight members of the family present in diminishing amounts as the number of EO units increases, although some n=3 substance is also present. The assessment of the environmental fate of the substance is therefore based on an assessment of its main components, as shown below:

The components of this substance, if present in ambient air, are expected to exist almost entirely in the vapour phase. This substance is not expected to absorb UV light in the environmentally significant range of >290 nm and is not therefore expected to undergo direct photolysis on sunlit soil surfaces, in the atmosphere or in aquatic environments. However, modelling predicts that it is likely to undergo indirect photolysis through hydroxyl radical reaction at a fast rate, with an estimated half life of no more than 2.4 hours (0.2 days) at an OH concentration of 1.5million OH/cm3 and a 12 hour day). Atmospheric degradation can therefore be considered rapid. Based on its chemical structure, the substance and its homologues are expected to be hydrolytically stable under normal environmental conditions. This data is considered to be representative of the substance that is the subject of this dossier.

No biodegradation data is available on the multi-constituent substance itself. Experimental data is available on one major components however and a closely related member of the homologous series. In a guideline study, the substance 2-(2-(2-methoxyethoxy)ethoxy)ethanol was found to be readily biodegradable and met the 10 day window. Full degradation occured within 13 days. In a guideline study, the substance 3, 6, 9, 12-tetraoxotridecanol was found to be readily biodegradable but did not meet the 10 day window. A QSAR suggests that both of these substances and PentaEGME are readily biodegradable, but that there is a slight trend towards slower degradation with increasing molecular weight. A conservative conclusion therefore, based on the experimental data available and the trends seen with the QSAR, is that the multi-constituent substance is readily biodegradable but may not meet the 10 day window.