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Endpoint:
adsorption / desorption: screening
Remarks:
adsorption
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:
For the QMRF, see 'Overall remarks, attachments'.
For the QPRF, see 'Executive summary'.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Calculation using KOCWIN (v2.00) Molecular Connectivity Index (MCI)
GLP compliance:
no
Type of method:
other: QSAR estimation: KOCWIN v2.00: Koc estimate from MCI
Specific details on test material used for the study:
- Substance name (as in EPISuite CAS inventory): 1-Tridecanol
- SMILES: CCCCCCCCCCCCCO
Test temperature:
25 °C
Type:
Koc
Value:
769.6 L/kg
Temp.:
25 °C
Type:
log Koc
Value:
2.886 dimensionless
Temp.:
25 °C

Koc Estimate from MCI:

First Order Molecular Connectivity Index

6.914

Non-Corrected Log Koc (0.5213 MCI + 0.60)

4.2042

Fragment Correction(s):

1 Aliphatic Alcohol (-C-OH)

-1.3179

Corrected Log Koc

2.8863

Estimated Koc

769.6 L/kg

Executive summary:

QPRF: KOCWIN v2.00 (MCI methodology) (18 Nov. 2013)

1.

Substance

See “Test material identity”

2.

General information

 

2.1

Date of QPRF

See “Data Source (Reference)”

2.2

QPRF author and contact details

See “Data Source (Reference)”

3.

Prediction

3.1

Endpoint
(OECD Principle 1)

Endpoint

Adsorption to solid phase of soils etc.

Dependent variable

Organic carbon normalised adsorption coefficient (Koc)

3.2

Algorithm
(OECD Principle 2)

Model or submodel name

KOCWIN

Model version

v. 2.00

Reference to QMRF

QMRF: Estimation of Soil Adsorption Coefficient using KOCWIN v2.00 (EPI Suite v4.11): MCI methodology

Predicted value (model result)

See “Results and discussion”

Input for prediction

- Chemical structure via CAS number or SMILES

Descriptor values

- MCI (first order molecular connectivity index)

- Correction factors

3.3

Applicability domain
(OECD principle 3)

Domains:

1) Molecular weight
(range of test data set: 32.04 to 665.02 g/mol; On-Line KOCWIN User’s Guide, Ch. 6.2.4 Domain)

Substance within range (200.4 g/mol)

2) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line KOCWIN User’s Guide)

Fulfilled.

3.4

The uncertainty of the prediction
(OECD principle 4)

Statistical accuracy for training dataset:

n = 516, r² = 0.916, std. dev. = 0.330, average dev.= 0.263

3.5

The chemical mechanisms according to the model underpinning the predicted result
(OECD principle 5)

Adsorption is caused by temporary (reversible) or permanent bonding between the substance and a surface (e.g. due to van der Waals interactions, hydrogen bonding to hydroxyl groups, ionic interactions, covalent bonding, etc.). The organic carbon normalized adsorption coefficient (Koc) is the ratio of a substance concentration sorbed in the organic matter component of soil or sediment to that in the aqueous phase at equilibrium.

MCI methodology: The first-order molecular connectivity index is a measure to describe a variety of properties of chemicals. According to Sabljic (1984; cited in Meylan et al., 1992), the soil sorption potential is highly correlated with the first order MCI. Therefore, it has been used to derive the adsorption coefficient.

References

- US EPA (2012). On-Line KOCWIN User’s Guide.

- Meylan, W., P.H. Howard and R.S. Boethling. 1992. Molecular topology/fragment contribution method for predicting soil sorption coefficients. Environ. Sci. Technol. 26: 1560-1567.

Assessment of estimation domain (molecular weight, fragments, correction factors):  

Training set: Molecular weights

Training set

Validation set

Minimum

32.04

73.14

Maximum

665.02

504.12

Average

224.4

277.8

Assessment of molecular weight

Molecular weight within range of training set

 

Appendix D. MCI Correction Factors for 447 Compound Training Set

Correction Factor Descriptor

Coefficient for Molecular Connectivity Index (MCI) Regression Methodology

Occurrence

No. of instances

of each bond

found for the

current substance

(new model)

Remark

(number of compounds

(max. per structure)

Aliphatic Alcohol

(-C-OH)

-1.317914

(a)

21

1

1

(a) Counted up to twice per structure, regardless of number of occurrences.

Endpoint:
adsorption / desorption: screening
Remarks:
adsorption
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:
For the QMRF, see 'Overall remarks, attachments'.
For the QPRF, see 'Executive summary'.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Calculation using KOCWIN (v2.00) Molecular Connectivity Index (MCI)
GLP compliance:
no
Type of method:
other: QSAR estimation: KOCWIN v2.00: Koc estimate from MCI
Specific details on test material used for the study:
- Substance name (as in EPISuite CAS inventory): 1-Pentadecanol
- SMILES: CCCCCCCCCCCCCCCO
Test temperature:
25 °C
Type:
Koc
Value:
2 556 L/kg
Temp.:
25 °C
Type:
log Koc
Value:
3.408 dimensionless
Temp.:
25 °C

Koc Estimate from MCI:

First Order Molecular Connectivity Index

7.914

Non-Corrected Log Koc (0.5213 MCI + 0.60)

4.7255

Fragment Correction(s):

1 Aliphatic Alcohol (-C-OH)

-1.3179

Corrected Log Koc

3.4076

Estimated Koc

2556 L/kg

Executive summary:

QPRF: KOCWIN v2.00 (MCI methodology) (18 Nov. 2013)

1.

Substance

See “Test material identity”

2.

General information

 

2.1

Date of QPRF

See “Data Source (Reference)”

2.2

QPRF author and contact details

See “Data Source (Reference)”

3.

Prediction

3.1

Endpoint
(OECD Principle 1)

Endpoint

Adsorption to solid phase of soils etc.

Dependent variable

Organic carbon normalised adsorption coefficient (Koc)

3.2

Algorithm
(OECD Principle 2)

Model or submodel name

KOCWIN

Model version

v. 2.00

Reference to QMRF

QMRF: Estimation of Soil Adsorption Coefficient using KOCWIN v2.00 (EPI Suite v4.11): MCI methodology

Predicted value (model result)

See “Results and discussion”

Input for prediction

- Chemical structure via CAS number or SMILES

Descriptor values

- MCI (first order molecular connectivity index)

- Correction factors

3.3

Applicability domain
(OECD principle 3)

Domains:

1) Molecular weight
(range of test data set: 32.04 to 665.02 g/mol; On-Line KOCWIN User’s Guide, Ch. 6.2.4 Domain)

Substance within range (228.4 g/mol)

2) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line KOCWIN User’s Guide)

Fulfilled.

3.4

The uncertainty of the prediction
(OECD principle 4)

Statistical accuracy for training dataset:

n = 516, r² = 0.916, std. dev. = 0.330, average dev.= 0.263

3.5

The chemical mechanisms according to the model underpinning the predicted result
(OECD principle 5)

Adsorption is caused by temporary (reversible) or permanent bonding between the substance and a surface (e.g. due to van der Waals interactions, hydrogen bonding to hydroxyl groups, ionic interactions, covalent bonding, etc.). The organic carbon normalized adsorption coefficient (Koc) is the ratio of a substance concentration sorbed in the organic matter component of soil or sediment to that in the aqueous phase at equilibrium.

MCI methodology: The first-order molecular connectivity index is a measure to describe a variety of properties of chemicals. According to Sabljic (1984; cited in Meylan et al., 1992), the soil sorption potential is highly correlated with the first order MCI. Therefore, it has been used to derive the adsorption coefficient.

References

- US EPA (2012). On-Line KOCWIN User’s Guide.

- Meylan, W., P.H. Howard and R.S. Boethling. 1992. Molecular topology/fragment contribution method for predicting soil sorption coefficients. Environ. Sci. Technol. 26: 1560-1567.

Assessment of estimation domain (molecular weight, fragments, correction factors):  

Training set: Molecular weights

Training set

Validation set

Minimum

32.04

73.14

Maximum

665.02

504.12

Average

224.4

277.8

Assessment of molecular weight

Molecular weight within range of training set

 

Appendix D. MCI Correction Factors for 447 Compound Training Set

Correction Factor Descriptor

Coefficient for Molecular Connectivity Index (MCI) Regression Methodology

Occurrence

No. of instances

of each bond

found for the

current substance

(new model)

Remark

(number of compounds

(max. per structure)

Aliphatic Alcohol

(-C-OH)

-1.317914

(a)

21

1

1

(a) Counted up to twice per structure, regardless of number of occurrences.

Endpoint:
adsorption / desorption: screening
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
See the OECD SIDS (2006) category approach under IUCLID section 13: 'Assessment reports'.
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Key result
Type:
Koc
Value:
>= 770 - <= 2 556 L/kg
Remarks on result:
other: as determined from read-across to C13 alcohol, linear (lower value) and C15 alcohol, linear (higher value).

Description of key information

Adsorption of alcohols, C13 -15 -branched and linear to the solid soil phase is expected.

Key value for chemical safety assessment

Additional information

Experimental data is available only for isotridecanol (CAS 27458 -92 -0) which is one of the components of the alcohol C13 -15 -branched and linear. For this component a log Koc value of 3.05 L/kg was determined in a study according to OECD 121 (HPLC method). Estimation of the Koc value for the same substance by means of the MCI method (as incorporated in EPISuite-KOCWIN) gives a log Koc value of 2.81. The 0.2 log unit difference between measured and predicted data is considered to be to comparable to the experimental error when repeating a test. Therefore, this QSAR is considered to be useful also for estimations of Koc values for the C13 and C15 linear alcohols. The predicted values for the linear variants are slightly higher than predicted values for the branched variants as linear carbon chains have slightly higher first order molecular connectivity index for the same carbon number). Use of data for the C13 and C15 linear alcohols is therefore considered to be slightly worst case (QSARs for branched alcohols are not included in the dossier).

The MCI predicted Koc values for C13 and C15 linear alcohols are 770 and 2556 L/kg, respectively. The value of 2556 L/kg is used for assessment as a worst case approach.

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.

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 the substance (Q)SAR results were used for adsorption / desorption.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.