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Water solubility

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Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Experimental Starting Date: 06 July 2014 Experimental Completion Date: 30 July 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.
Qualifier:
according to guideline
Guideline:
other: Slow stir adaptation of the standard test method
Deviations:
no
Principles of method if other than guideline:
The water solubility of Shell GTL Solvent GS160 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 the standard test method
Water solubility:
0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 100 mg/L
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 10.6 mg/L

1.3845

Standard 10.4 mg/L

1.3113

Vessel 1 Sample 1

2.9432

Sample Blank

0.11041

Standard 11.7 mg/L

1.8240

Standard 10.7 mg/L

1.7122

Vessel 1 Sample 2

3.8023

Sample Blank

0.39176

Standard 10.2 mg/L

1.5673

Standard 10.4 mg/L

1.6517

Vessel 1 Sample 3

3.8881

Sample Blank

0.37317

Standard 10.7 mg/L

1.6885

Standard 11.0 mg/L

1.7550

Vessel 1 Sample 4

3.6475

Sample Blank

0.45909

Standard 10.8 mg/L

1.6445

Standard 10.0 mg/L

1.5968

Vessel 1 Sample 5

3.5794

Sample Blank

0.39543

 

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

Solution

Mean Peak Area Ratio

Standard 11.1 mg/L

1.7083

Standard 10.8 mg/L

1.6575

Vessel 2 Sample 1

4.1940

Vessel 2 Sample 2

3.9618

Vessel 3 Sample 1

3.6025

Vessel 3 Sample 2

4.1027

Sample Blank

0.42955

Standard 12.7 mg/L

1.9804

Standard 12.1 mg/L

1.8992

Vessel 2 Sample 3

4.2722

Vessel 2 Sample 4

4.0141

Vessel 3 Sample 3

3.3442

Vessel 3 Sample 4

3.7912

Sample Blank

0.42327

 

Table3.2– Nominal 10 mg/L Loading Rate

Solution

Mean Peak Area Ratio

Standard 10.6 mg/L

1.3845

Standard 10.4 mg/L

1.3113

Vessel 1 Sample 1

1.6308

Sample Blank

0.11041

Standard 11.7 mg/L

1.8240

Standard 10.7 mg/L

1.7122

Vessel 1 Sample 2

2.1065

Sample Blank

0.39176

Standard 10.2 mg/L

1.5673

Standard 10.4 mg/L

1.6517

Vessel 1 Sample 3

1.7937

Sample Blank

0.37317

 

 

 

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

Solution

Mean Peak Area Ratio

Standard 10.7 mg/L

1.6885

Standard 11.0 mg/L

1.7550

Vessel 1 Sample 4

1.6142

Sample Blank

0.45909

Standard 10.8 mg/L

1.6445

Standard 10.0 mg/L

1.5968

Vessel 1 Sample 5

1.4515

Sample Blank

0.39543

Standard 11.1 mg/L

1.7083

Standard 10.8 mg/L

1.6575

Vessel 2 Sample 1

2.0642

Vessel 2 Sample 2

28.439

Vessel 3 Sample 1

2.2477

Vessel 3 Sample 2

2.0166

Sample Blank

0.42955

Standard 12.7 mg/L

1.9804

Standard 12.1 mg/L

1.8992

Vessel 2 Sample 3

1.8012

Vessel 2 Sample 4

1.8065

Vessel 3 Sample 3

1.8986

Vessel 3 Sample 4

1.8993

Sample Blank

0.42327

Standard 10.9 mg/L

1.7579

Standard 11.1 mg/L

1.7965

Vessel 2 Sample 5

1.3308

Sample Blank

0.39839

Standard 10.0 mg/L

1.6095

Standard 11.4 mg/L

1.7893

Vessel 2 Sample 6

1.1946

Sample Blank

0.41937

 

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:

 

Table 3.3– Nominal 100 mg/L Loading Rate, Vessel 1

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.9

2.21 x 10-4

6.72

2

42.5

2.77 x 10-4

6.84

3

119.9

2.25 x 10-4

6.80

4

167.7

2.01 x 10-4

6.82

5

188.3

2.04 x 10-4

6.91

 

Equilibrium had been achieved prior to sample 1.

 

Mean concentration               :          2.26 x 10-4 g/L at 20.0 ± 0.5 ºC

Range                                  :          2.01 x 10-4 to 2.77 x 10-4 g/L

Standard deviation                :          3.06 x 10-5

 

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

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

210.0

2.44x 10-4

7.01

2

215.0

2.29x 10-4

6.99

3

233.9

2.46x 10-4

7.01

4

240.8

2.29x 10-4

6.70

 

Equilibrium had been achieved prior to sample 1.

 

Mean concentration               :          2.37 x 10-4 g/L at 20.0 ± 0.5 ºC

Range                                  :          2.29 x 10-4 to 2.46 x 10-4 g/L

Standard deviation                :          9.14 x 10-6

 

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

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

210.0

2.06x 10-4

6.89

2

215.0

2.38x 10-4

7.01

3

233.9

1.87x 10-4

6.89

4

240.8

2.15x 10-4

6.91

 

Equilibrium had been achieved prior to sample 1.

 

Mean concentration               :          2.11 x 10-4 g/L at 20.0 ± 0.5 ºC

Range                                  :          1.87 x 10-4 to 2.38 x 10-4 g/L

Standard deviation                :          2.14 x 10-5

 

 

Table 3.6– Nominal 10 mg/L Loading Rate, Vessel 1

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

24.0

1.19x 10-4

6.82

2

42.6

1.19x 10-4

6.80

3

120.0

9.08x 10-5

6.98

4

167.8

7.28x 10-5

6.79

5

188.4

6.77x 10-5

6.89

 

Equilibrium had been achieved prior to sample 1. The measured concentration began to decrease as headspace in the vessel increased, therefore samples 1 to 3 used for mean.

 

Mean concentration               :          1.10 x 10-4 g/L at 20.0 ± 0.5 ºC

Range                                  :          9.08 x 10-5 to 1.19 x 10-4 g/L

Standard deviation                :          1.63 x 10-5

 

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

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

210.1

1.06x 10-4

6.90

2

215.1

1.82x 10-3

6.79

3

234.0

8.80x 10-5

6.92

4

240.8

8.84x 10-5

7.02

5

288.3

5.76x 10-5

6.98

6

330.0

4.89x 10-5

6.69

 

Equilibrium had been achieved prior to sample 1. Sample 2 contained additional peaks which did not match the profile of the standards and other samples; therefore it was excluded. The measured concentration began to decrease as headspace in the vessel increased, therefore samples 1, 3 and 4 used for mean.

 

Mean concentration               :          9.41 x 10-5 g/L at 20.0 ± 0.5 ºC

Range                                  :          8.80 x 10-5 to 1.06 x 10-4 g/L

Standard deviation                :          1.03 x 10-5

 

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

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

210.1

1.18x 10-4

6.91

2

215.1

1.03x 10-4

6.89

3

234.0

9.42x 10-5

6.92

4

240.8

9.43x 10-5

6.92

 

Equilibrium had been achieved prior to sample 1.

 

Mean concentration               :          1.02 x 10-4 g/L at 20.0 ± 0.5 ºC

Range                                  :          9.42 x 10-5 to 1.18 x 10-4 g/L

Standard deviation                :          1.11 x 10-5

 

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)

2.26 x 10-4

2.37 x 10-4

2.11 x 10-4

Standard Deviation

3.06 x 10-5

9.14 x 10-6

2.14 x 10-5

Relative Standard Deviation

13.6

3.85

10.1

 

Overall mean water solubility                :2.25x 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)

1.10 x 10-4

9.41 x 10-5

1.02 x 10-4

Standard Deviation

1.63 x 10-5

1.03 x 10-5

1.11 x 10-5

Relative Standard Deviation

14.8

10.9

10.9

 

Overall mean water solubility                :1.02x 10-4g/L at 20.0 ± 0.5 ºC

Conclusions:
Please see the Conclusion within the Executive Summary 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 41304201) 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

2.25 x 10-4

10 mg/L

1.02 x 10-4

 

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Experimental Starting Date: 06 July 2014 Experimental Completion Date: 10 August 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.
Qualifier:
according to guideline
Guideline:
other: Slow stir adaptation of the standard test method
Deviations:
no
Principles of method if other than guideline:
The water solubility of Shell GTL Solvent GS170 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 the standard test method
Water solubility:
0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 100 mg/L
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 10.7 mg/L

1.8243

Standard 10.1 mg/L

1.7651

Vessel 1 Sample 1

0.75434

Vessel 1 Sample 2

0.87044

Vessel 2 Sample 1

0.76738

Vessel 2 Sample 2

0.98733

Vessel 3 Sample 1

0.76769

Vessel 3 Sample 2

1.0123

Sample Blank

0.44607

Standard 10.8 mg/L

1.8675

Standard 10.4 mg/L

1.7920

Vessel 1 Sample 3

1.2612

Vessel 1 Sample 4

1.2630

Vessel 2 Sample 3

1.4205

Vessel 2 Sample 4

1.3802

Vessel 3 Sample 3

1.4853

Vessel 3 Sample 4

1.4928

Sample Blank

0.43445

 

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

Solution

Mean Peak Area Ratio

Standard 10.1 mg/L

1.7768

Standard 11.2 mg/L

1.9823

Vessel 1 Sample 5

1.3237

Vessel 1 Sample 6

1.2808

Vessel 2 Sample 5

1.5486

Vessel 2 Sample 6

1.5494

Vessel 3 Sample 5

1.5570

Vessel 3 Sample 6

1.5150

Sample Blank

0.45845

 

Table3.2– Nominal 10 mg/L Loading Rate

Solution

Mean Peak Area Ratio

Standard 10.4 mg/L

1.8078

Standard 10.9 mg/L

1.6978

Vessel 1 Sample 1

0.77210

Sample Blank

0.39153

Standard 12.0 mg/L

1.9070

Standard 10.6 mg/L

1.7156

Vessel 1 Sample 2

0.89902

Sample Blank

0.41560

Standard 10.5 mg/L

1.7428

Standard 10.0 mg/L

1.6608

Vessel 1 Sample 3

0.95494

Sample Blank

0.42023

Standard 11.2 mg/L

1.7932

Standard 10.2 mg/L

1.7056

Vessel 1 Sample 4

0.81906

Sample Blank

0.38136

 

 

 

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

Solution

Mean Peak Area Ratio

Standard 10.8 mg/L

1.7368

Standard 11.9 mg/L

1.8918

Vessel 2 Sample 1

1.0251

Vessel 2 Sample 2

1.7170

Vessel 3 Sample 1

0.95162

Vessel 3 Sample 2

1.6942

Sample Blank

0.47586

Standard 10.5 mg/L

1.6578

Standard 10.6 mg/L

1.7095

Vessel 2 Sample 3

0.83778

Vessel 2 Sample 4

0.80647

Vessel 2 Sample 5

0.79586

Vessel 3 Sample 3

0.86029

Vessel 3 Sample 4

0.86224

Vessel 3 Sample 5

0.78493

Sample Blank

0.38827

 

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:

 

Table 3.3– Nominal 100 mg/L Loading Rate, Vessel 1

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.9

1.79 x 10-5

6.74

2

28.9

2.46 x 10-5

6.59

3

47.6

4.78 x 10-5

6.62

4

52.6

4.80 x 10-5

6.91

5

72.6

4.90 x 10-5

6.66

6

77.6

4.66 x 10-5

6.81

 

Equilibrium had not been achieved prior to sample 3 therefore samples 1 and 2 excluded from the mean.

 

Mean concentration               :          4.78 x 10-5 g/L at 20.0 ± 0.5 ºC

Range                                     :          4.66 x 10-5 to 4.90 x 10-5 g/L

Standard deviation                :          9.95 x 10-7

 

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

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.9

1.86 x 10-5

6.69

2

28.9

3.14x 10-5

6.91

3

47.6

5.71x 10-5

6.66

4

52.6

5.47x 10-5

6.78

5

72.6

6.17x 10-5

6.67

6

77.6

6.18x 10-5

6.80

 

Equilibrium had not been achieved prior to sample 3 therefore samples 1 and 2 excluded from the mean.

 

Mean concentration               :          5.88 x 10-5 g/L at 20.0 ± 0.5 ºC

Range                                     :          5.47 x 10-5 to 6.18 x 10-5 g/L

Standard deviation                :          3.51 x 10-6

 

Table 3.5– Nominal 100 mg/L Loading Rate, Vessel 3

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

23.9

1.86x 10-5

6.62

2

28.9

3.28x 10-5

6.70

3

47.6

6.08x 10-5

6.78

4

52.6

6.13x 10-5

6.69

5

72.6

6.22x 10-5

6.81

6

77.6

5.98x 10-5

6.84

 

Equilibrium had not been achieved prior to sample 3 therefore samples 1 and 2 excluded from the mean.

 

Mean concentration               :          6.10 x 10-5 g/L at 20.0 ± 0.5 ºC

Range                                     :          5.98 x 10-5 to 6.22 x 10-5 g/L

Standard deviation                :          9.98 x 10-7

 

 

Table 3.6– Nominal 10 mg/L Loading Rate, Vessel 1

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

24.3

2.31 x 10-5

6.80

2

48.2

3.02 x 10-5

6.50

3

68.8

3.22 x 10-5

6.95

4

90.5

2.68 x 10-5

6.94

 

Equilibrium had been achieved prior to sample 1.

 

Mean concentration               :          2.81 x 10-5 g/L at 20.0 ± 0.5 ºC

Range                                     :          2.31 x 10-5 to 3.22 x 10-5 g/L

Standard deviation                :          4.02 x 10-6

 

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

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

188.8

3.44 x 10-5

6.62

2

193.7

7.77 x 10-5

6.90

3

210.4

2.81 x 10-5

6.91

4

215.7

2.61 x 10-5

6.69

5

220.5

2.55 x 10-5

6.90

 

Equilibrium had been achieved prior to sample 1. Sample 2 contained additional peaks which did not match the profile of the standards and other samples; therefore it was excluded from the mean.

 

Mean concentration               :          2.85 x 10-5 g/L at 20.0 ± 0.5 ºC

Range                                     :          2.55 x 10-5 to 3.44 x 10-5 g/L

Standard deviation                :          4.07 x 10-6

 

Table3.8– Nominal 10 mg/L Loading Rate, Vessel 3

Sample Number

Stirring / Equilibration Time (hours)

Concentration (g/L)

Solution pH

1

188.8

2.98 x 10-5

6.73

2

193.7

7.63 x 10-5

6.91

3

210.4

2.95 x 10-5

6.78

4

215.7

2.96 x 10-5

6.75

5

220.5

2.48 x 10-5

6.90

 

Equilibrium had been achieved prior to sample 1. Sample 2 contained additional peaks which did not match the profile of the standards and other samples; therefore it was excluded from the mean.

 

Mean concentration               :          2.84 x 10-5 g/L at 20.0 ± 0.5 ºC

Range                                     :          2.48 x 10-5 to 2.98 x 10-5 g/L

Standard deviation                :          2.43 x 10-6

 

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

 

Table3.9– Nominal 100 mg/L Loading Rate

Vessel

1

2

3

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

4.78 x 10-5

5.88 x 10-5

6.10 x 10-5

Standard Deviation

9.95 x 10-7

3.51 x 10-6

9.87 x 10-7

Relative Standard Deviation

2.08

5.97

1.62

 

Overall mean water solubility                :5.59x 10-5g/L at 20.0 ± 0.5 ºC

 

Table3.10– Nominal 10 mg/L Loading Rate

Vessel

1

2

3

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

2.81 x 10-5

2.85 x 10-5

2.84 x 10-5

Standard Deviation

4.02 x 10-6

4.07 x 10-6

2.43 x 10-6

Relative Standard Deviation

14.3

14.3

8.54

 

Overall mean water solubility                :2.83x 10-5g/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 41304202) 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

5.59x 10-5

10 mg/L

2.83x 10-5

 

 

Endpoint:
water solubility
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
1. Hypothesis for the analogue approach:
The hypothesis for the analogue approach is that both the registration substance, Hydrocarbons, C9-C11, n-alkanes, isoalkanes, <2% aromatics (target substance), and the test substances, Hydrocarbons, C8-C11, n-alkanes, isoalkanes, <2% aromatics GS 160 (source substance) and Hydrocarbons, C9-C12, n-alkanes, isoalkanes, <2% aromatics GS 170 (source substance), are produced from the same Fischer-Tropsch substance, GTL Gasoil, by fractional distillation. Substances contain the all of the constituents of the target substance. The substances have constituents that are part of the same homologous series and have many constituents in common. The substances therefore have qualitatively similar properties (RAAF Scenario 2 applies).
2. Source and target chemical(s)
The source substance Hydrocarbons, C8-C11, n-alkanes, isoalkanes, <2% aromatics is composed of linear, branched and cyclic hydrocarbons of chain length C8-C11
The source substance Hydrocarbons, C9-C12, n-alkanes, isoalkanes, <2% aromatics, is composed of linear, branched and cyclic hydrocarbons of chain length C9-C12
The target substance, Hydrocarbons, C9-C11, n-alkanes, isoalkanes, <2% aromatics, is composed of linear, branched and cyclic hydrocarbons of chain length C9-C11.
3. Analogue approach justification
The constituents of the source and target substances are all hydrocarbons. Identical constituents have identical physicochemical profiles. The source substances cover the full carbon chain length of the target substance.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Water solubility:
0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 100 mg/L
Water solubility:
0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 10 mg/L
Water solubility:
0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 100 mg/L
Water solubility:
0 g/L
Temp.:
20 °C
Remarks on result:
other: Initial Nominal Loading Rate of 10 mg/L
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 41304202) 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.

Description of key information

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

Key value for chemical safety assessment

Additional information

There are no reliable measured relative density data for the submission substance. However, reliable data are available for related substances in the relevant carbon number range, including other Fischer-Tropsch process-derived substances.

The water solubilities of the related substances, Hydrocarbons, C8 -C11, n-alkanes, isoalkanes, <2% aromatics (GTL Solvent GS160) and Hydrocarbons, C9 -C12, n-alkanes, isoalkanes, <2% aromatics (GTL Solvent GS170) were evaluated using a slow-stir method. The method was designed to be compatible with EU Method A.6 and OECD 105. Since the test substances are UVCBs, 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 the resulting aqueous concentration or composition of the dissolved fraction were affected. The water solubility of GS160 and GS170 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. The results are considered to be reliable and are used to read across to the registered substance.