Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

A calculated logKoc of 1.56 is available (BASF AG, SRC PCKOC v1.66, 2007). This value refers to the uncharged molecule (pKa value: 10.45 - 10.86). This pKa value indicates that the molecule will exist primarily 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 environmental conditions (pH from 5 to 9) the test substance is almost completely present in its charged form (as calculated by the formula % ionised = 100/(1+10(pKa - pH)): 97% at a pH of 9, 100% at lower pH values). In a calculation conducted according to a publication by Franco & Trapp, 2008 using the parameters pKa = 10.45 and log Pow = 0.4 a log Koc value of 4.39 was determined.

If the substance is exposed to water, it will slowly evaporate into the atmosphere from the water surface because of the Henry's Law Constant for the uncharged molecule of 1.79 Pa m³/mol. However, volatilization is expected to be negligible due to the ionic structure of the molecule at environmental conditions.

Due to the results of the Mackay LEVEL 1 calculation, over time the uncharged substance will preferentially distribute into air (55.5%) and water (44.5%). This calculation does not consider the ionic character of the molecule and hence the model may underestimate the distribution into water.