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Adsorption / desorption

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Description of key information

For 2 -(2 -hexyloxyethoxy)ethanol Koc values were calculated to be ca. 10 L/kg (log Koc = 1) and 18.74 L/kg (log Koc = ca. 1.28) when based on the MCI method and the log Kow method, respectively. The value of 18.74 L/kg is used for calculation of PNECs for sediments and soil (based on equilibrium partitioning method (EPM)).

Based on a log Koc of <3 adsorption to solid soil phase is not expected.

Key value for chemical safety assessment

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 -(2 -hexyloxyethoxy)ethanol (Q)SAR results were used for adsorption / desorption. 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.


 


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 (> 90% in 15 d, BASF AG, 1999, report no. 98/0899/21/1; see IUCLID Ch. 5.2.1). In addition, the substance has a log Kow of 1.7 (see IUCLID Ch. 4.7). Therefore, a study does not need to be conducted.


 


In order to assess the adsorption potential of the substance, the Koc value was estimated using QSAR models. According to the MCI method of the KOCWIN v2.00 module of EPI Suite v4.11 the substance has a log Koc of 1.27 (Koc = 18.7 L/kg). 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. The latter method resulted in a log Koc of 1 (Koc = 10 L/kg). The substance is within the applicability domain of the estimation models.


Based on the estimated adsorption coefficient it can be concluded that adsorption to the solid soil is not to be expected.