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Adsorption / desorption

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Description of key information

After exposure to soil, significant adsorption to solid soil phase (e.g. clay) is not expected.

Key value for chemical safety assessment

Additional information


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 phthalonitrile (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.



 The adsorption potential of phthalonitrile was assessed using the MCI and the log Kow method of the KOCWIN v2.00 module of EPI Suite v4.11 (BASF SE, 2021). The MCI method, which is more reliable than the log Kow method of KOCWIN v2.00, estimates a Koc of phthalonitrile of 64.4 L/kg (log Koc = 1.81) based on the n-octanol/water partition coefficient (log Kow = 0.58, Tonogai, 1982, see IUCLID Ch. 4.7). The log Kow method resulted in a Koc of 107.5 L/kg (log Koc = 2.03). The substance is within the applicability domain of both methods. These estimates are representative for the uncharged molecule.