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Environmental fate & pathways

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Adsorption / desorption

Reaction mass of disodium N,N'-[(2-hydroxy-5-nonylphen-1,3-ylene)bis(methylene)]bis[N-methylaminoacetate] and sodium N-[(2-hydroxy-5-nonylphenyl)methyl]-N-methylaminoacetate was shown to be a surface active material, therefore (as stated in the OECD 121 Guideline for estimation of the adsorption coefficient (Koc)) an experimental HPLC method to determine the Koc is not applicable. Therefore, a Koc value was estimated based on the weighted averages of components using the (Q)SAR model KOCWIN v2.01 integrated in the EPISuite 4.11 software. In order to perform estimations via the Molecular Connectivity Index (MCI) method, KOCWIN removed Na, hence such Koc estimations represent a worst-case with respect to adsorption capacity.

Based on the MCI method, a weighted average Koc of 56600.23 L/kg was estimated, whereas based on the Kow method a weighted average Koc of 629.30 L/kg was estimated. Based on these two weighted averages, an overall Koc value of 28614.76 was derived and the substance is therefore considered to have strong adsorption capacity and thus low mobility in soils.

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