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Endpoint:
adsorption / desorption
Remarks:
adsorption
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Accepted calculation method. Molecular weight within range of training and validation set. LogKow within range of training and validation set. The number of instances of each bond found for the current substance was exceeded in one case.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Principles of method if other than guideline:
KOCWIN (v2.00): estimation using estimated or experimentally derived log Kow
GLP compliance:
no
Type of method:
other: QSAR estimation: KOCWIN v2.00: Koc estimate from log Kow
Test temperature:
25 °C
Computational methods:
- Other: log Kow used for estimation: 2.65 (estimated by KOCWIN)
Type:
Koc
Value:
1 953
Temp.:
25 °C
Remarks on result:
other: Molecular weight within range of training and validation set. LogKow within range of training and validation set. The number of instances of each bond found for the current substance was exceeded in one case.
Type:
log Koc
Value:
3.291
Temp.:
25 °C
Remarks on result:
other: Molecular weight within range of training and validation set. LogKow within range of training and validation set. The number of instances of each bond found for the current substance was exceeded in one case.

KOCWIN Program (v2.00) Results:

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

SMILES : c1ccc2C(=O)C(CL)=C(CL)C(=O)c2c1

CHEM  : 1,4-Naphthalenedione, 2,3-dichloro-

MOL FOR: C10 H4 CL2 O2

MOL WT : 227.05

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

 

Koc Estimate from Log Kow:

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

Log Kow (Kowwin estimate) ......................... : 2.65

Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 2.3909

Fragment Correction(s):

2  Ketone (-C-CO-C-) ................... : 0.3912

*  Quinone (diketone) ring ............... : 0.5086

Corrected Log Koc .................................. : 3.2907

 

Estimated Koc: 1953 L/kg  <===========

Executive summary:

QPRF: KOCWIN v2.00 (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): Estimation using log Kow

Predicted value (model result)

See “Results and discussion”

Input for prediction

- Chemical structure via CAS number or SMILES

- log Kow (for log Kow method; optional)

Descriptor values

- Chemical structure

- 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 (227.05 g/mol)

2) log Kow (range of test data set: -2.11 to 8.12; On-Line KOCWIN User’s Guide, Appendices E & F)

Substance within range (2.65)

3) 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)

Not fulfilled.

3.4

The uncertainty of the prediction
(OECD principle 4)

Nonpolar compounds: n = 68; r2=0.478, average dev. = 0.371

Polar compounds: n = 447, r²=0.855, std. dev. = 0.396, average dev. = 0.307

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.

Estimation using log Kow: The model is based on the high correlation of log Kow and the adsorption potential.

 

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):

 

  Molecular weight (g/mol)   log Kow
Minimum Maximum Average   Minimum Maximum
Training set 32.04 665.02 224.4   -2.11 8.12
Validation set 73.14 504.12 277.8   -5.98 8.68
Assessment of molecular weight Molecular weight within range of training and validation set.
 
             
Assessment of log Kow (only relevant for log Kow method) Log Kow within range of training and validation set.
             
Appendix D. MCI & Log Kow Correction Factors for 447 Compound Training Set    
Correction Factor Descriptor Coefficient for Molecular Connectivity Index (MCI) Regression Methodology Coefficient for log Kow Regression Methodology Occurrence No. of instances
of each bond
found for the
current substance
(new model)  Remark (number of compounds (max per structure)  
Ketone (-C-CO-C-) -1.129027 (a) 0.195596 7 1 2
.
(a) Counted up to twice per structure, regardless of number of occurrences. .
(b) Either one or both carbons aromatic; if both carbons aromatic, can not be cyclic. .
(c) Any nitrogen attached to double bond isnotcounted; also, carbonyl and thiocarbonyl arenotcounted as carbons. .
(d) This is theonlyfragment counted, even if other fragments occur. .
(e) Not included in regression derivation; estimated from other carbonyl fragments. .
(f) Counted only once per structure, regardless of number of occurrences. .

 

Endpoint:
adsorption / desorption
Remarks:
adsorption
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Accepted calculation method. Molecular weight of the compound within range of training and validation set. The number of instances of each bond found for the current substance was exceeded in one case.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Principles of method if other than guideline:
KOCWIN (v2.00): estimation using first-order Molecular Connectivity Index (MCI)
GLP compliance:
no
Type of method:
other: QSAR estimation: KOCWIN v2.00: Koc estimate from MCI
Test temperature:
25 °C
Type:
Koc
Value:
1 243
Temp.:
25 °C
Remarks on result:
other: Molecular weight of the compound within range of training and validation set. The number of instances of each bond found for the current substance was exceeded in one case.
Type:
log Koc
Value:
3.094
Temp.:
25 °C
Remarks on result:
other: Molecular weight of the compound within range of training and validation set. The number of instances of each bond found for the current substance was exceeded in one case.

KOCWIN Program (v2.00) Results:

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

SMILES : c1ccc2C(=O)C(CL)=C(CL)C(=O)c2c1

CHEM  : 1,4-Naphthalenedione, 2,3-dichloro-

MOL FOR: C10 H4 CL2 O2

MOL WT : 227.05

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

 

Koc Estimate from MCI:

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

First Order Molecular Connectivity Index ........... : 6.626

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 4.0539

Fragment Correction(s):

2  Ketone (-C-CO-C-) ................... : -2.2581

*  Quinone (diketone) ring ............... : 1.2986

Corrected Log Koc .................................. : 3.0944

 

Estimated Koc: 1243 L/kg  <===========

Executive summary:

QPRF: KOCWIN v2.00 (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 (227.05 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)

Not 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):

 

  Molecular weight (g/mol)   log Kow
Minimum Maximum Average   Minimum Maximum
Training set 32.04 665.02 224.4   -2.11 8.12
Validation set 73.14 504.12 277.8   -5.98 8.68
Assessment of molecular weight Molecular weight within range of training and validation set.
 
             
Appendix D. MCI & Log Kow Correction Factors for 447 Compound Training Set    
Correction Factor Descriptor Coefficient for Molecular Connectivity Index (MCI) Regression Methodology Coefficient for log Kow Regression Methodology Occurrence No. of instances
of each bond
found for the
current substance
(new model)  Remark (number of compounds (max per structure)  
Ketone (-C-CO-C-) -1.129027 (a) 0.195596 7 1 2
.
(a) Counted up to twice per structure, regardless of number of occurrences. .
(b) Either one or both carbons aromatic; if both carbons aromatic, can not be cyclic. .
(c) Any nitrogen attached to double bond isnotcounted; also, carbonyl and thiocarbonyl arenotcounted as carbons. .
(d) This is theonlyfragment counted, even if other fragments occur. .
(e) Not included in regression derivation; estimated from other carbonyl fragments. .
(f) Counted only once per structure, regardless of number of occurrences. .

 

Description of key information

Adsorption to solid soil phase is expected. 

Key value for chemical safety assessment

Additional information

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. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 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 CAS 117 -80 -6 (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.

Therefore, further experimental studies on adsorption/desorption are not provided.

The adsorption/desortpion potential of the substance was assessed with two QSAR calculation methods integrated in the EPISuite v4.11 (KOCWIN v2.00; MCI and logKow-method). Both the molecular weight and the logKow of the substance are within the respective training set ranges. The number of instances of each bond found for the current substance was exceeded in one case. However, this is not expected to have a significant influence on the result. In conclusion, the QSAR calculations are regarded as reliable. The MCI method determined a logKoc of 3.0944 and the estimate from the logKow a logKoc of 3.2907. Adsosorption to the solid soil phase is expected.