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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Adsorption to the solid phase is not expected.

Key value for chemical safety assessment

Additional information

In accordance with column 2 of REACH Annexes VIII and IX, a study on the adsorption potential 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. At environmentally relevant conditions 2'-hydroxyacetophenone (CAS 118 -93 -4) has a measured log Kow of 1.92 (Hansch, C. et al., 1995). In addition, 2'-hydroxyacetophenone is assessed to be readily biodegradable (according to OECD criteria; see IUCLID chapter 5.2).

However, in order to assess the adsorption potential of the 2'-hydroxyacetophenone, 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 Koc of 67.95 (log Koc = 1.83). 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 (measured log Kow: 1.92; Hansch, C. et al., 1995). The latter method resulted in a Koc of 223.6 (log Koc = 2.34). These estimates are representative for uncharged molecule; the substance is within the applicability domain of the estimation models.

In conclusion, adsorption of the substance to the solid soil phase is not to be expected.

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'-hydroxyacetophenone (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.