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Endpoint:
water solubility
Type of information:
(Q)SAR
Adequacy of study:
supporting 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:
See attached QMRF/QPRF
Principles of method if other than guideline:
The model is based on fragment values. That is, the chemical structure is broken down into its constituent functional groups, and the contribution of each group toward the overall solubility is calculated. Certain correction factors may also apply.
Water solubility:
>= 0 - <= 0.004 mg/L
Temp.:
20 °C
Remarks on result:
other: The water solubility of the individual constituents of the substance is in the range 8.8E-06 - 4.3E-03 mg/l at 20°C

Table 1: Predicted water solubility for the individual constituents for linear and branched alkanes of C14-C16.

Carbon Number

CH3

CH2

branched

log Kow1

 

SMILEs2

log WS mmol/l

WS mg/l

13

2

11

0

6.73

CCCCCCCCCCCCC

-4.79

3.0E-03

13

3

9

1

6.65

CCCCCC(C)CCCCCC

-4.71

3.6E-03

13

4

7

2

6.58

CCC(CC(C)C)CCCCCC

-4.63

4.3E-03

14

2

12

0

7.22

CCCCCCCCCCCCCC

-5.34

9.0E-04

14

3

10

1

7.14

CCCCCC(C)CCCCCCC

-5.26

1.1E-03

14

4

8

2

7.07

CCC(CC(C)C)CCCCCCC

-5.18

1.3E-03

15

2

13

0

7.71

CCCCCCCCCCCCCCC

-5.89

2.7E-04

15

3

11

1

7.63

CCCCCC(C)CCCCCCCC

-5.81

3.3E-04

15

4

9

2

7.56

CCC(CC(C)C)CCCCCCCC

-5.73

4.0E-04

16

2

14

0

8.20

CCCCCCCCCCCCCCCC

-6.44

8.2E-05

16

3

12

1

8.13

CCCCCC(C)CCCCCCCCC

-6.36

9.9E-05

16

4

10

2

8.05

CCC(CC(C)C)CCCCCCCCC

-6.28

1.2E-04

17

2

15

0

8.69

CCCCCCCCCCCCCCCCC

-6.99

2.4E-05

17

3

13

1

8.62

CCCCCC(C)CCCCCCCCCC

-6.91

2.9E-05

17

4

11

2

8.54

CCC(CC(C)C)CCCCCCCCCC

-6.83

3.6E-05

 18  3  14  1 9.11   CCCCCC(C)CCCCCCCCCCC -7.46  8.8E-06 

 

1The Kow is not dependent of the location of any branch point in the molecule.

2Only a single possible isomer is represented for branched compounds

Conclusions:
The individual constituents of the substance have predicted water solubility values of 8.8E-06 - 4.3E-03 mg/l using a validated QSAR estimation method. The result is considered reliable.
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Experimental Starting Date: 10 July 2014 Experimental Completion Date: 17 October 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EU Method A.6 (Water Solubility)
Version / remarks:
slow stir adaptation of the standard method
Deviations:
no
Principles of method if other than guideline:
The water solubility of Shell GTL Solvent GS250 at 20.0 ± 0.5 °C was evaluated using a slow stir adaptation of the standard test method, based on the findings of Letinski, D.J., Connolly, M.J., Peterson, D.R. and Parkerton, T.F. (2002) “Slow-stir water solubility measurements of selected alcohols and diesters”, Chemosphere 48, 257-265. The method employed was designed to be compatible with the data endpoint requirements of Method A6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995.
GLP compliance:
yes
Type of method:
other: slow-stir adaptation of standard method
Key result
Water solubility:
< 0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 100 mg/L
Key result
Water solubility:
< 0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 10 mg/L

Results

Main Test

The mean peak area ratios relating to the standard, sample and blank solutions are shown in the following tables:

 

Table 3.1– Nominal 100 mg/L Loading Rate

Solution

Mean Peak Area Ratio

Standard 13.1 mg/L

1.2455

Standard 11.9 mg/L

1.1236

Vessel 1 Sample 1

0.025338

Vessel 2 Sample 1

0.018761

Vessel 3 Sample 1

0.014080

Sample Blank

0.014589

Standard 11.8 mg/L

1.1496

Standard 11.0 mg/L

0.97343

Vessel 1 Sample 2

0.034150

Vessel 1 Sample 3

0.015391

Vessel 2 Sample 2

0.011149

Vessel 2 Sample 3

0.14443

Vessel 3 Sample 2

0.018739

Vessel 3 Sample 3

0.013605

Sample Blank

0.0098544

Standard 11.6 mg/L

1.0472

Standard 11.6 mg/L

1.0394

Vessel 1 Sample 4

0.012603

Vessel 1 Sample 5

0.014919

Vessel 2 Sample 4

0.013304

Vessel 2 Sample 5

0.089442

Vessel 3 Sample 4

0.012701

Vessel 3 Sample 5

0.018584

Sample Blank

0.011041

 

Table 3.1– Nominal 100 mg/L Loading Rate - Continued

Solution

Mean Peak Area Ratio

Standard 12.0 mg/L

1.0897

Standard 14.2 mg/L

1.3738

Vessel 1 Sample 6

0.012388

Vessel 2 Sample 6

0.013000

Vessel 3 Sample 6

0.012906

Sample Blank

0.0088541

 

Table 3.2– Nominal 10 mg/L Loading Rate

Solution

Mean Peak Area Ratio

Standard 13.1 mg/L

1.2455

Standard 11.9 mg/L

1.1236

Vessel 1 Sample 1

0.036757

Vessel 2 Sample 1

0.015738

Vessel 3 Sample 1

0.014172

Sample Blank

0.014589

Standard 11.8 mg/L

1.1401

Standard 11.0 mg/L

0.96982

Vessel 1 Sample 2

0.024546

Vessel 1 Sample 3

0.015647

Vessel 2 Sample 2

0.028618

Vessel 2 Sample 3

0.0170820

Vessel 3 Sample 2

0.0099977

Vessel 3 Sample 3

0.033146

Sample Blank

0.0098544

 

 

 

Table 3.2– Nominal 10 mg/L Loading Rate - Continued

Solution

Mean Peak Area Ratio

Standard 11.6 mg/L

1.0383

Standard 11.6 mg/L

1.0401

Vessel 1 Sample 4

0.011069

Vessel 1 Sample 5

0.011206

Vessel 2 Sample 4

0.022098

Vessel 2 Sample 5

0.014229

Vessel 3 Sample 4

0.013482

Vessel 3 Sample 5

0.012506

Sample Blank

0.011041

Standard 12.0 mg/L

1.0897

Standard 14.2 mg/L

1.3738

Vessel 1 Sample 6

0.0056822

Vessel 2 Sample 6

0.0080248

Vessel 3 Sample 6

0.010143

Sample Blank

0.0088541

 

As the test item peaks covered a wide retention time range and there were peaks observed in the blank solutions over the same range, the concentration attributed to the blank was subtracted from the sample concentrations. 

 

The concentration (g/L) of test item in the sample solutions corrected for blank response is shown in the following tables:

 

Table3.3– Nominal 100 mg/L Loading Rate, Vessel 1

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.3

1.13 x 10-6

6.95

2

47.2

2.60 x 10-6

6.78

3

54.5

5.94 x 10-7

7.00

4

71.1

1.74 x 10-7

6.78

5

76.7

4.31 x 10-7

6.79

6

95.1

3.77 x 10-7

6.62

 

A variable, negligible quantity was detected in the retention time range of the test item in both samples and sample blank. The amount detected was well below the range investigated for the analysis. The result is therefore taken as less than the level at which successful detection of the test item was achieved. See validation and discussion within overall remarks and attachments section below.

 

Table 3.4– Nominal 100 mg/L Loading Rate, Vessel 2

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.3

4.40 x 10-7

7.00

2

47.2

1.39 x 10-7

6.66

3

54.5

1.44 x 10-5

6.91

4

71.1

2.52 x 10-7

6.91

5

76.7

8.72 x 10-6

6.88

6

95.1

4.43 x 10-7

6.63

 

A variable, negligible quantity was detected in the retention time range of the test item in both samples and sample blank. The amount detected was well below the range investigated for the analysis. The result is therefore taken as less than the level at which successful detection of the test item was achieved. See validation and discussion within overall remarks and attachments section below.

 

 

Table3.5– Nominal 100 mg/L Loading Rate, Vessel 3

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.3

-5.37 x 10-8

6.89

2

47.2

9.53 x 10-7

6.94

3

54.5

4.02 x 10-7

6.89

4

71.1

1.85 x 10-7

7.09

5

76.7

8.39 x 10-7

6.88

6

95.1

4.33 x 10-7

6.71

 

A variable, negligible quantity was detected in the retention time range of the test item in both samples and sample blank. The amount detected was well below the range investigated for the analysis. The result is therefore taken as less than the level at which successful detection of the test item was achieved. See validation and discussion within overall remarks and attachments section below.

 

Table3.6– Nominal 10 mg/L Loading Rate, Vessel 1

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.3

2.34 x 10-6

6.84

2

47.2

1.59 x 10-6

7.10

3

54.5

6.31 x 10-7

6.90

4

71.1

8.00 x 10-9

7.15

5

76.7

2.32 x 10-8

6.94

6

95.1

-3.39 x 10-7

6.77

 

A variable, negligible quantity was detected in the retention time range of the test item in both samples and sample blank. The amount detected was well below the range investigated for the analysis. The result is therefore taken as less than the level at which successful detection of the test item was achieved. See validation and discussion within overall remarks and attachments section below.

 

 

Table 3.7– Nominal 10 mg/L Loading Rate, Vessel 2

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.3

1.21 x 10-7

6.79

2

47.2

2.03 x 10-6

6.91

3

54.5

9.99 x 10-8

6.97

4

71.1

1.24 x 10-6

6.66

5

76.7

3.61 x 10-7

7.02

6

95.1

-8.86 x 10-8

6.90

 

A variable, negligible quantity was detected in the retention time range of the test item in both samples and sample blank. The amount detected was well below the range investigated for the analysis. The result is therefore taken as less than the level at which successful detection of the test item was achieved. See validation and discussion within overall remarks and attachments section below.

 

Table 3.8– Nominal 10 mg/L Loading Rate, Vessel 3

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.3

-4.40 x 10-8

6.87

2

47.2

2.20 x 10-8

6.99

3

54.5

2.52 x 10-6

6.66

4

71.1

2.77 x 10-7

6.90

5

76.7

1.68 x 10-7

6.98

6

95.1

1.38 x 10-7

6.79

 

A variable, negligible quantity was detected in the retention time range of the test item in both samples and sample blank. The amount detected was well below the range investigated for the analysis. The result is therefore taken as less than the level at which successful detection of the test item was achieved. See validation and discussion within overall remarks and attachments section below.

 

 

The overall water solubility results for the two different loading rates evaluated are summarized in the following tables:

 

Table 3.9– Nominal 100 mg/L Loading Rate

Vessel

1

2

3

Mean Water Solubility (g/L at 20.0 ± 0.5 ºC)

< 1.01 x 10-4

< 1.01 x 10-4

< 1.01 x 10-4

Standard Deviation

not applicable

not applicable

not applicable

Relative Standard Deviation

not applicable

not applicable

not applicable

 

Overall water solubility                             :         less than 1.01x 10-4g/L at 20.0 ± 0.5 ºC

 

Table 3.10– Nominal 10 mg/L Loading Rate

Vessel

1

2

3

Mean Water Solubility (g/L at 20.0 ± 0.5 ºC)

< 1.01 x 10-4

< 1.01 x 10-4

< 1.01 x 10-4

Standard Deviation

not applicable

not applicable

not applicable

Relative Standard Deviation

not applicable

not applicable

not applicable

 

Overall water solubility                             :         less than 1.01x 10-4g/L at 20.0 ± 0.5 ºC

 

 

Conclusions:
Please see the Conclusion within the Executive Summary Section below.
Executive summary:

The determination was carried out using a slow stiradaptation of the standard test method, based on thefindings of Letinski, D.J., Connolly, M.J., Peterson, D.R. and Parkerton, T.F. (2002) “Slow-stir water solubility measurements of selected alcohols and diesters”, Chemosphere 48, 257-265. The method employed was designedto be compatible with the data endpoint requirements of Method A6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995.

 

The slow-stir procedure was used as during a previous study (Harlan Study Number 41304206) using the flask method, it was identified that excess, undissolved test item could not be successfully excluded from the saturated solutions. The slow stir method eliminated dispersion of the test item throughout the solution and thus allowed isolation of saturated solutions free from excess, undissolved test item suitable for analysis.

 

Slow-stirring therefore enables the solubilisation of the test item without the formation of potentially problematic micro-droplets. The alternative column elution method proposed by the guidelines for addressing substances of low solubility is poorly suited to liquid test items.

 

As the test item is a UVCB substance, the effect of initial loading rate was also evaluated during the definitive determination of water solubility, using initial nominal loading rates of 100 mg/L and 10 mg/L, in order to assess if this affected either the resulting aqueous concentration or the composition of the dissolved fraction.

 

Conclusion

The water solubility of the test item at 20.0 ± 0.5 °C was evaluated using a slow stiradaptation of the standard test method. The results are summarized in the following table:

 

Table 3.11

Initial Nominal Loading Rate

Water Solubility
 (g/L of solution at 20.0 ± 0.5 °C)

100 mg/L

< 1.01x 10-4

10 mg/L

< 1.01x 10-4

Description of key information

Water solubility (whole substance): <0.1 mg/l at 20±0.5°C (measured).  

Water solubility (individual constituents): <1E-04 - 4.3E-03 mg/l at 20°C (QSAR)

Key value for chemical safety assessment

Additional information

The substance is a hydrocarbon UVCB and the constituent hydrocarbons will exhibit a wide range of water solubility.

The "whole substance" water solubility of Hydrocarbons, C14 -C16, n-alkanes, isoalkanes, <2% aromatics was evaluated using a slow-stir method (Tarran 2015). The method was designed to be compatible with EU Method A.6 and OECD 105. Since the submission substance is a UVCB, the effect of initial loading rate was also evaluated during the definitive study using initial nominal loading rates of 100 mg/l and 10 mg/l to assess if resulting aqueous concentration or composition of the dissolved fraction were affected. The water solubility of Hydrocarbons, C14-C16, n-alkanes, isoalkanes 2% aromatics was determined to be <0.1 mg/l at 20±0.5°C in both the 100 mg/l and 10 mg/l loading rates.

As supporting information, the water solubility of each constituent has also been predicted using a separately validated QSAR estimation method. The prediction method uses a fragment method and water solubility decreases with increasing carbon number. The prediction domain covers carbon chain length in the range C2-C15 carbon atoms, it is therefore expected that water solubility for longer chain length (i.e. greater than C15) compounds will be lower than the predicted value for C15 atom. Thus the water solubility of the individual constituents is in the range <1E-04 mg/l - 4.3 E-03 mg/l at 20°C.