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Environmental fate & pathways

Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption, other
Remarks:
QSAR
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR study, acceptable with restrictions
Justification for type of information:
QSAR prediction
The justification for read across is provided as an attachment in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across: supporting information
Principles of method if other than guideline:
QSAR: KOCWIN (Kow method). A training set of 516 substances was used to derive a regression based estimate of Koc based on log Kow. Equations were tested with a validation data set consisting of 158 compounds.
GLP compliance:
no
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not applicable
SMILES: c1ccccc1COC(=O)C2CCCCC2C(=O)OC(C(C)C)C(C)(C)COC(=O)C(C)(C)
Test temperature:
not applicable
Details on study design: HPLC method:
not applicable
Details on sampling:
not applicable
Details on matrix:
not applicable
Details on test conditions:
not applicable
Computational methods:
not applicable
Key result
Type:
log Koc
Value:
4.915 dimensionless
Type:
Koc
Value:
82 170 dimensionless
Details on results (HPLC method):
not applicable
Adsorption and desorption constants:
not applicable
Recovery of test material:
not applicable
Concentration of test substance at end of adsorption equilibration period:
not applicable
Concentration of test substance at end of desorption equilibration period:
not applicable
Details on results (Batch equilibrium method):
No further details - QSAR calculation
Statistics:
not applicable

Based on Kow value from KOWWIN

Conclusions:
The calculated log Koc of P1700 is 4.915
Executive summary:

Experimental data for this endpoint is not available for Santicizer P1700. Instead, a standard QSAR that has been used previously in regulatory risk assessment has been used to calculate a log Koc, and is considered appropriate as the key study for this endpoint.

Description of key information

This data is read across from the source dossier that tested Santicizer S278 (benzyl 3-(isobutyryloxy)-1-isopropyl-2,2-dimethylpropyl phthalate) based on analogue read across. A discussion and report on the read across strategy is provided as an attachment in Section 13 of the dossier.

The mean estimated log Koc for Santicizer P1700 is 4.915.

Key value for chemical safety assessment

Koc at 20 °C:
16 218

Additional information

Experimental adsorption/desorption data is not available for Santicizer P1700.As the log Kow is >3 the adsorption/desorption endpoint cannot be waived. However, ECHA's Guidance on Information Requirements and Chemical Safety Assessment R7a Endpoint Specific Guidance (2008) indicates that before commissioning a new study alternative sources of data (e.g. QSAR) on the adsorption/desorption potential of a chemical should be used.

Soil sorption of non-ionic substances can be estimated from their log Kow. Several QSAR have been developed that calculate the Koc of non-polar hydrocarbons on the basis of their log Kow. Two QSARs (the two methods of KOCWIN, USEPA 2008) have been used to calculate the log Koc of structural analogue Santicizer 278. The estimated log Koc are 6.099 and 4.666, and the mean of these values will be used in the risk assessment.