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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Adsorption to solid soil phase is not to be expected under environmentally relevant conditions.

Key value for chemical safety assessment

Koc at 20 °C:
71

Additional information

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.

 

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 -aminoethyldiethylamine (CAS 100 -36 -7) (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.

 

Assessment

According to Regulation (EC) No 1907/2006, Annex VIII, Section 9.3.1, Column 2, the study on adsorption/desorption screening 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. The substance is readily biodegradable according to OECD criteria (read-across to the structurally similar substance 3-Diethylaminopropylamine CAS 104-78-9, OECD 301A, BASF SE, 2005; see IUCLID Ch. 5.2.1). In addition, the substance has a log Kow of 0.10 (at pH 11, 25 °C; BASF AG, 1999, see IUCLID Ch. 4.7). Therefore, a study does not need to be conducted.

To assess the adsorption potential of 2 -aminoethyldiethylamine no experimental data exist. Therefore, the Koc value was estimated using QSAR models. According to the MCI method of the KOCWIN v2.00 module of EPI Suite v4.11,

2 -Aminoethyldiethylamine has a Koc of 56.7 L/kg and a log Koc of 1.75 (BASF SE 2019). The MCI module is more reliable than the log Kow method of KOCWIN v2.00, which estimates the Koc based on the n-octanol/water partition coefficient (log Kow of 0.1 @23°C, pH 11; BASF AG, 1999, report no.: 98L00765, see IUCLID Ch. 4.7). The latter method resulted in a Koc of 7.82 L/kg and a log Koc of 0.89. These estimates are representative for uncharged molecules. The substance was within the applicability domain of the models.

 

At environmentally relevant conditions, 2 -aminoethyldiethylamine will be present in its ionised form (pKa = 9.91; at 23°C, BASF AG 1999, report no.: 98L00765, see IUCLID Ch. 4.21). Therefore, the adsorption coefficient was calculated according to Franco & Trapp (2008, 2009, 2010) to correct for the charged molecule at pH 5, 7, and 8. This pH range is representative for 98% of the European soils. 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 molecule. The resulting Koc at pH 5 to 8 is 71 L/kg and the log Koc is 1.85, respectively.

 

It can be concluded that adsorption to the solid soil phase is not expected under environmentally relevant conditions