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Environmental fate & pathways

Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption, other
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
September 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
1. SOFTWARE: KOCWIN included in EPSUITE
Sparc

2. MODEL (incl. version number):
KOCWIN v2.00 (EPISUITE v4.1)
Sparc v5.1

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
O=C(CC(=O)CCCCCCC)CCCCCCC
OC(c1ccccc1)C
O=C(c(cccc1)c1)C
O=C(O)CCCCCCC
C(=O)(CC(=O)c1ccccc1)c2ccccc2
O=C(c(cccc1)c1)CC(=O)CCCCCCC
O=C(c2ccccc2)CC(C)c1ccccc1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Log Koc
- Unambiguous algorithm: KOCWIN: Molecular Connectivity Index and Log KOW estimation
Sparc : based on calculation of coefficient activity of molecular species
- Defined domain of applicability:
KOCWINN: yes
Sparc: no information available
- Appropriate measures of goodness-of-fit and robustness and predictivity:
KOCWINN: yes for goodness of fit, no information available for robustness and predictivity
Sparc: no information available
- Mechanistic interpretation:no information available for KOCWIN and Sparc

5. APPLICABILITY DOMAIN
- Descriptor domain: KOCWINN: yes
Sparc: no information available
- Structural and mechanistic domains: no information available for KOCWIN and Sparc
- Similarity with analogues in the training set: no information available for KOCWIN and Sparc

6. ADEQUACY OF THE RESULT
The prediction give information about the potentiel of the test item about its binding capacity to solid surfaces. This information is required for environmental exposure models and is relevant to assess environmental persistence.
Reference:
Composition 0
Principles of method if other than guideline:
Recognised and accepted QSAR wer use to predict the adsorption coefficient of the test item. Two QSAR programs and three models have been used in a weight of evidence approach.
GLP compliance:
no
Type of method:
other: QSAR
Media:
soil
Test material information:
Composition 1
Radiolabelling:
no
Test temperature:
Not specified
Details on study design: HPLC method:
Method not used
Analytical monitoring:
no
Key result
Type:
log Koc
Value:
> 1.15 - < 15.35 dimensionless
Remarks on result:
other:
Remarks:
see 'any other information on results incl. tables" section below

Log Koc of the test item constituents have been estimated with 2 Qsars and 3 models.

For KOCWIN, the estimation was performed with MCI and Log Kow methodology. In this last method, a measured Log Kow can be specified to be used for the calculation. The partition coefficient of the test item has been determined with the HPLC Method (according to the OECD guideline n°117). A range between 1.8 up to 6.5 was obtained. These two values have been used to calculate Log Koc with the Log Kow methodology in KOCWIN.

Sparc estimate Log Koc in function of the pH. That’s why for some components of the test item different value have been obtained depending of the pH.

For 8,10-Heptadecanedione, 1,3-diphenylpropane-1,3-dione and 1-phenyldecane-1,3-dione the data obtained with KOCWIN are out of the applicability domain. Therefore, only the data obtained with Sparc are considered to estimation the Log Koc of these compounds. The values obtained at the two extremes environmental pH value are considered (pH 5 and 9).

Except for these three compounds, the others constituents of the test item are included in the applicability domains of the models used. Due to the deviation observed for all compounds between the Log Koc obtained, we decided to use the highest and lowest value for each compounds to estimate this parameter.

Chemical name (IUPAC)

Lowest value of Log Koc

Highest value of Log Koc

8,​10-​Heptadecanedione

11.88 (pH =5)

15.35 (pH=9)

(R)-(+)-1-phenylethanol

1.3

4.24

Acetophenone

1.54

4.24

Octanoic acid

1.15

7.06

1,3-diphenylpropane-1,3-dione

6.84 (pH=5)

10.33 (pH=9)

1-phenyldecane-1,3-dione

9.36 (pH=5)

12.84 (pH=9)

3-PHENYLBUTYROPHENONE

2.12

4.91

The gaps between these values are higher than more than 1 Log unit (expect for Acetophenone for which the different between the Log Koc value is 0.98). All the results obtained are higher than 1.15.

Validity criteria fulfilled:
yes
Conclusions:
Two Qsar programs and three models were used to assess the adsorption coefficient of the test item.
A range of log Koc have been obtained for the test item: between 1.15 up to 15.35.
Executive summary:

Two commercial Qsar programs (KOCWIN and Sparc) and three models were used to assess the adsorption coefficient of the test item.

The reliability of these models for the prediction have been checked.

A range of log Koc has been obtained for the test item: between 1.15 up to 15.35.

The main consituent of the test item possess a log Koc between 9.36 and 12.84 (at respectively pH 5 and 9). The highest Koc value is considered to be affected by a non negligeable uncertainty. Indeed, this value is higher than 10 which result of a Koc value higher than 10000000000 µg/g (10 kg/g) of organic matter.

Description of key information

Two commercial Qsar programs and three models have been used to determine the key value for chemical safety assessment: KOCWIN with MCI method and Log Kow method and Sparc. The reliability of these models for Log Koc prediction of the test item was checked.

Key value for chemical safety assessment

Koc at 20 °C:
2 290 000 000

Additional information

A range of value was obtained for the test item Log Koc. Indeed, the test item is a mono consituent substances with impurities. For each components, the adosprtion coefficient have been estimated by Qsar.

The key value for chemical safety assessment was based on the values obtained for the main consituent of the test item

The main consituent possess a log Koc between 9.36 and 12.84 (at respectively pH 5 and 9). The highest Koc value is considered to be affected by a non negligeable uncertainty. Indeed, this value is higher than 10 which result of a Koc value higher than 10000000000 µg/g (10 kg/g) of organic matter. Therefore, the lowest Log Koc value was used.

The Log Koc of the test item is considered to 9.36 at pH 5.

[LogKoc: 9.36]