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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
Standard Partition Coefficient studies for this endpoint are intended for monoconstituent substances and are not appropriate for petroleum UVCB substances. In accordance with Annex XI Section 1.3 the endpoint has been fulfilled using QSAR calculations for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see the representative structures from the PETRORISK Product Library in the spreadsheet attached in IUCLID section 13.2). As such, testing is not scientifically necessary.

Full justifications for these QSAR are presented in 'Attached justification' within the associated endpoint records, but in brief these are justified because:
-the results are obtained from a QSAR model whose scientific validity has been established
-petroleum substances fall within the applicability domain of the QSAR model
-results are adequate for the purposes of risk assessment
-adequate and reliable documentation is provided
Qualifier:
no guideline required
Principles of method if other than guideline:
- Software and model(s) used: PETRORISK v7.04, which incorporates the model USEPA KOWWIN v1.68 (September 2010)
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Attached justification'
Key result
Type:
log Pow
Partition coefficient:
>= 4.35 - <= 9.18
Temp.:
20 °C
pH:
ca. 7
Remarks on result:
other: See Remarks
Remarks:
Multiple results Calculated log Pow for constituents of this substance have been reported as a range. It should be borne in mind that this is the full range of predicted values, and that this may be misleading or unrepresentative of the properties of the UVCB substance as a whole. The range should therefore be treated with caution and not taken out of context. The substance is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is characterised using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see Product Library in PETRORISK spreadsheet attached in IUCLID section 13).
Conclusions:
Partition coefficient has been predicted using PETRORISK, which uses the USEPA KOWWIN model to calculate the log Kow of the representative constituents of this substance identified in the PETRORISK Product Library. The predicted log Kow for this substance ranges from 4.35 - 9.18.
Executive summary:

Standard Partition Coefficient studies for this endpoint are intended for monoconstituent substances and are not appropriate for petroleum UVCB substances. In accordance with Annex XI Section 1.3 the endpoint has been fulfilled using QSAR calculations for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see the representative structures from the PETRORISK Product Library in the spreadsheet attached in IUCLID section 13.2). As such, testing is not scientifically necessary.

Full justifications for these QSAR are presented in 'Attached justification' within the associated endpoint records, but in brief these are justified because:

-the results are obtained from a QSAR model whose scientific validity has been established

-petroleum substances fall within the applicability domain of the QSAR model

-results are adequate for the purposes of risk assessment

-adequate and reliable documentation is provided

The predicted log Kow for this substance ranges from 4.35 - 9.18.

Description of key information

Standard Partition Coefficient studies for this endpoint are intended for monoconstituent substances and are not appropriate for petroleum UVCB substances. In accordance with Annex XI Section 1.3, the endpoint has been fulfilled using QSAR calculations for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see the representative structures from the PETRORISK Product Library in the spreadsheet attached in IUCLID section 13.2). As such, testing is not scientifically necessary.

Full justifications for these QSAR are presented in 'Attached justification' within the associated endpoint records, but in brief these are justified because:

-the results are obtained from a QSAR model whose scientific validity has been established

-petroleum substances fall within the applicability domain of the QSAR model

-results are adequate for the purposes of risk assessment

-adequate and reliable documentation is provided

Key value for chemical safety assessment

Additional information

For the purpose of PBT assessment (Annex XIII), a combination of QSAR models and experimental data for both screening and assessment level information are utilized, in accordance with REACh Annex XI and ECHA Guidance on integrated testing and evaluation strategies (R.11). As a result, single values or ranges of values reported for individual endpoints within the substance registration should be considered within this weight of evidence context and not applied individually for the purpose of PBT assessments. A complete, integrated PBT assessment for the range of relevant constituents within petroleum hydrocarbon UVCB substances is attached to this dossier (section 13.2).