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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Adsorption to the solid soil phase is not expected.

Key value for chemical safety assessment

Additional information

The log Koc for the uncharged mole was calculated to be 1.73 (MCI method) using SRC PCKOC v2.0 (BASF SE, 2013). The dissociation constant (pKa) of the test substance was experimentally determined to be 7.63 (BASF AG 96L00234, 1996). This pKa value indicates that the molecule will partly exist as a cation in the environment and cations generally adsorb stronger to soils containing organic carbon and clay than their neutral counterparts. Hence, the PCKOC-model may underestimate adsorption to organic carbon since it does not consider the ionic structure of the molecule. Under environmentally relevant conditions (pH from 5 to 9) the test substance is partly present in its charged forms (approx. 100% at a pH of 5, 70% at a pH of 7 and 2% at pH 9). In a calculation conducted according to a publication by Franco & Trapp, 2008 using the parameters pKa = 7.63 and log Pow = 0.11 a log Koc range of 1.96 at pH 9 and 2.98 at pH 5 was determined.