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Environmental fate & pathways

Adsorption / desorption

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Description of key information

This endpoint is not expected to be an importent environmental fate for N-Methylethanolamine. Two different calculation methods were used to estimate the logPow and Pow value of the substance. KOCWIN will only take the uncharged molecule into account, whereby the calculation method according to Franco and Trapp considers the ionic structure at different pH values.  

Key value for chemical safety assessment

Koc at 20 °C:
1.303

Additional information

Considering the low logPow (-0.91) the adsorption / desorption won´t be an important environmental fate for the substance N-Methylethanolamine. In additon, the chemical is readily biodegradable. Due to this assumption, experimental data are not necessary for this endpoint. A calculation was performed with the help of the US-EPA computer tool EPIWIN (software KOCWINv2.00) to receive a first indication for the adsorption / desorption properties of N-Methylethanolamine. The MCI method gives a Koc value of 1.303 L/kg, whereby the traditional method shows a value of 0.8915 L/kg. The MCI method is taken more seriously into account, due to the fact that it uses correction factors. The traditional method is estimation from the logPow value. The data of this calculation tool refer to the uncharged molecule. Since N-Methylethanolamine possess a pKa value of 9.95, it will exist almost completely as a cation in the environment. Cations generally adsorb stronger to soil containing organic carbon and clay than their neutral counterparts. Hence, the KOCWIN model may underestimeate adsorption to organic carbon since it does not consider the ionic structure of the molecule.

For this reason another calculation approach was used: according to Franco and Trapp the logKoc (as well as the Koc) value will not change at a range from pH 5 to pH 9. This indicates that for the substance N-Methylethanolamine the surrounding pH will not have a great influence on its adsorption coefficients.