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Endpoint:
adsorption / desorption, other
Remarks:
adsorption
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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:
1. SOFTWARE
ChemProp(TM) Main Module 6.4, Helmholtz Centre for Environmental Research - UFZ Department for Ecological chemistry, Public OSIRIS Edition, EU Integrated Project

2. MODEL (incl. version number)
Franco, Fu & Trapp (Partitioning, soil soprtion coefficient, Koc), ionizable substances, acids

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached information on the model provided by the developer. Further information on the OECD criteria as outlined by the applicant is provided below under "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See attached information and information as provided in "Any other information on results incl. tables".

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.
Qualifier:
according to
Version / remarks:
REACH Guidance on QSARs R.6
Principles of method if other than guideline:
- Software tool(s) used including version: ChemProp v6.4
- Model(s) used: Franco, Fu, Trapp, 2009, Koc calculation for ionizable substances (acid)
Full reference and details of the used formulas can be found in:
1. Franco A, Fu W, Trapp S 2009. Influence of soil pH on the sorption of ionizable chemicals: Modeling advances. Environ. Toxicol. Chem. 28: 458-464.
2. Franco A, Trapp S 2008. Estimation of the soil-water partition coefficient normalized to organic carbon for ionizable organic chemicals. Environ. Toxicol. Chem. 27: 1995-2004.
- Model description: see field 'Justification for non-standard information', 'Attached justification' and 'any other information on Material and methods'
- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'overall remarks'
GLP compliance:
no
Type of method:
other:
Media:
soil
Details on test conditions:
BASIS FOR CALCULATION OF Koc:
- Estimation software: ChemProp v6.4, Franco,Fu and Trapp model for acids
- Log Kow: 3.05
- pKa: 5.3
- pH: 7
Type:
Koc
Value:
111.6 L/kg
pH:
7
% Org. carbon:
5
Remarks on result:
other: from eq. 2
Type:
log Koc
Value:
2.05 dimensionless
pH:
7
% Org. carbon:
5
Remarks on result:
other: from eq. 2
Endpoint:
adsorption / desorption, other
Remarks:
adsorption
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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:
1. SOFTWARE
EPI Suite v4.11 Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
KOCWIN v2.00

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached information on the model provided by the developer. Further information on the OECD criteria as outlined by the applicant is provided below under "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See attached information and information as provided in "Any other information on results incl. tables".

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.
Qualifier:
according to
Guideline:
other: REACH Guidance on QSARs R.6
Principles of method if other than guideline:
- Software tool(s) used including version: EPISuite v4.11
- Model(s) used: KOCWIN v2.00, MCI based method
Full reference and details of the used formulas can be found in:
Meylan, W., P.H. Howard and R.S. Boethling, "Molecular Topology/Fragment Contribution Method for Predicting Soil Sorption Coefficients", Environ. Sci. Technol. 26: 1560-7 (1992)
- Model description: see field 'Justification for non-standard information', 'Attached justification' and 'any other information on Material and methods'
- Justification of QSAR prediction: see field 'Justific ation for type of information', 'Attached justification' and/or 'overall remarks'
GLP compliance:
no
Type of method:
other: calculation
Media:
soil
Details on test conditions:
BASIS FOR CALCULATION OF Koc:
- Estimation software: EPISuite v 4.11, KOCWIN v2.00, MCI based method

Type:
Koc
Value:
28.94 L/kg
Temp.:
25 °C
Remarks on result:
other: MCI based method
Type:
log Koc
Value:
1.462 dimensionless
Temp.:
25 °C
Remarks on result:
other: MCI based method

KOCWIN Program (v2.00) Results:

==============================

SMILES : O=C(O)CCCCCCC

CHEM : Octanoic acid

MOL FOR: C8 H16 O2

MOL WT : 144.22

Koc may be sensitive to pH!

--------------------------- KOCWIN v2.00 Results ---------------------------

Koc Estimate from MCI:

---------------------

First Order Molecular Connectivity Index ........... : 4.770

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 3.0864

Fragment Correction(s):

* Organic Acid (-CO-OH) ............... : -1.6249

Corrected Log Koc .................................. : 1.4616

Estimated Koc: 28.94 L/kg <===========

Description of key information

Log Koc = 2.05 (ChemProp, Franco, Fu & Trapp model)

Koc = 111.61 L/Kg (ChemProp, Franco, Fu & Trapp model)

Key value for chemical safety assessment

Koc at 20 °C:
111.61

Additional information

The adsorption potential of the substance, was predicted using the established calculation interfaces EPISuite v4.11 and ChemProp v6.4.

The Koc was predicted with the KOCWIN v. 2.00 calculation tool according to the MCI method (US EPA EPISuite v4.11). Based on the neutral chemical form of octanoic acid, the estimated Koc value was 28.94 L/Kg.

However, since octanoic acid is a weak acid with a pKa of 5.3 and occurs in its ionisable form in the environment, the Koc was additionally estimated based on the soil-water partitioning coefficient calculation method for ionizable substances developed by Franco, Fu & Trapp (2009). Considering the speciation of the molecule in the calculation the Koc value amounts 111.61 L/Kg. This value was used for further assessment.

[LogKoc: 2.05]