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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Adsorption to solid soil phase is not expected.

Key value for chemical safety assessment

Additional information

In accordance with column 2 of REACH Annexes VIII and IX, the study does not need to be conducted if based on the physicochemical properties the substance can be expected to have a low potential for adsorption (e.g. the substance has a low octanol water partition coefficient), or the substance and its relevant degradation products decompose rapidly. 2-(2-Aminoethylamino)ethanol (CAS 111-41-1) has a log Kow of -1.46 (@ 25°C, pH 11; BASF AG, 1989; BRU 89.025) and is readily biodegradable in freshwater.

Estimates by the MCI method and the log-Kow method of KOCWIN v2.00 (EPISuite v4.11; BASF SE 2015) calculated for 2-(2-Aminoethylamino)ethanol log Koc values of 2.65 (MCI) and 0.44 (log Kow).

 

However, pKa values of 6.83 and 9.82 indicate that the molecule will primarily exist as a cation in the environment. Cations generally adsorb stronger to soils containing organic carbon and clay than their neutral counterparts. Therefore, the KOCWIN-model may underestimate adsorption to organic carbon, as it does not consider the ionic structure of the molecule. In a calculation conducted according to Franco & Trapp (2008, 2009 & 2010), pH-corrected log Koc values of 1.34 and 0.92 (at pH 7) were calculated respectively. The model is not yet validated; in addition, the applicability domain is not clearly defined. Nevertheless, the Koc values of the Franco & Trapp method give a good indication on the adsorption potential of a substance depending on the pH conditions of soil. The method is based on the dissociation constant pKa and the log Kow for the uncharged moelcule.

Referring to the charged molecule at pH 7, the substance is not expected to adsorb to the solid soil phase.

 

QSAR-disclaimer:

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

 

For the assessment of 2-(2-Aminoethylamino)ethanol (Q)SAR results were used for the estimation of the adsorption potential. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

 

Therefore, further experimental studies on the adsorption potential are not provided.