Registration Dossier

Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Testing was conducted between 16 May 2008 and 13 June 2008.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
The work described was performed in compliance with UK GLP standards (Schedule 1, Good Laboratory Practice Regulations 1999 (SI 1999/3106 as amended by SI 2004/0994)).
Type of method:
shake-flask method to: flask method
Partition coefficient type:
octanol-water

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Analytical method:
photometric method

Results and discussion

Partition coefficient
Type:
log Pow
Partition coefficient:
-1.49
Temp.:
22.2 °C
pH:
ca. 7

Any other information on results incl. tables

Preliminary estimate

Approximate solubility in n-octanol: 7.4 x 10-2 g/l
Approximate solubility in water:       > 26.2 g/l
Approximate Pow:   2.82 x 10-3
Log10 Pow:   -2.55

               Definitive test

The absorbances obtained for the standard, stock and sample solutions are shown in the following two tables:

Organic Phase

Solution

Absorbance

Standard 26.3 mg/l

0.48243

Standard 25.4 mg/l

0.49886

Organic phase matrix blank

None detected

Sample 1

0.30913

Sample 2

0.30069

Sample 3

0.36801

Sample 4

0.33432

Sample 5

0.43799

Sample 6

0.39313

Aqueous Phase

Solution

Absorbance

Standard 26.3 mg/l

0.51781

Standard 25.4 mg/l

0.58801

Aqueous phase matrix blank

None detected

Sample 1

0.50465

Sample 2

0.49188

Sample 3

0.49135

Sample 4

0.49643

Sample 5

0.50327

Sample 6

0.50906

Stock solution A

0.50507

Stock solution B

0.51063

The total weights (mg) and analysed concentration (mg/l) of the respective phases are shown in the following table:

Sample Number

Volume of water saturated

n-octanol (ml)

Volume of stock solution (ml)

Total Weight (mg)*

Organic Phase

Aqueous Phase

Analysed Concentration (mg/l)

Weight (mg)†

Analysed Concentration (mg/l)

Weight (mg)†

pH

1

120

30

35.6

32.6

3.91

1.18 x 103

35.4

8.0

2

120

30

35.6

31.7

3.80

1.15 x 103

34.5

8.3

3

100

50

59.3

38.8

3.88

1.15 x 103

57.4

8.5

4

96

48

57.0

35.2

3.38

1.16 x 103

55.7

8.5

5

65

65

77.1

46.2

3.00

1.18 x 103

76.4

8.2

6

70

70

83.1

41.4

2.90

1.19 x 103

83.3

8.5

* From analysis of the stock solution

† From analysis of the respective phase

pH of n-octanol saturated water:           7.7
pH of stock solution:                             7.9
Temperature:                                        22.2 ± 0.5°C

The partition coefficient determined for each sample is shown in the following table:

Sample Number

n-Octanol/Water Volume Ratio

Partition Coefficient

Log10 Pow

Mean Partition Coefficient

1

4:1

2.76 x 10-2

-1.56

2.76 x 10-2

2

2.76 x 10-2

-1.56

3

2:1

3.38 x 10-2

-1.47

3.21x 10-2

4

3.04 x 10-2

-1.52

5

1:1

3.93 x 10-2

-1.41

3.71 x 10-2

6

3.48 x 10-2

-1.46

Mean Pow  : 3.23 x 10-2 log10 Pow : -1.49                        Pow standard deviation : 4.58 x 10-3

  Validation

Linearities of the detector response with respect to concentration were assessed over the nominal concentration range of 0 to 50 mg/l, for both the organic phase and the aqueous phase. These were found to be satisfactory, with a correlation coefficient of 1.00 being obtained for both phases.

Discussion

Substances having a log10 Powof greater than 3 are regarded as having the potential to bioaccumulate in the environment.

The test was carried out using unadjusted n-octanol saturated water, at ~ pH 7 (as recommended for salts).

Conclusion

The partition coefficient of the test material has been determined to be 3.23 x 10-2 at 22.2 ± 0.5°C, log10Pow -1.49.


Applicant's summary and conclusion

Conclusions:
The partition coefficient of the test material has been determined to be 3.23 x 10-2 at 22.2 ± 0.5°C, log10 Pow -1.49
Executive summary:

For substance Na-Na in project number 1307 - 0436 the determination was carried out using the shake-flask method, Method A8 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC). The partition coefficient of the test material has been determined to be 3.23 x 10-2 at 22.2 ± 0.5°C, log10 Pow -1.49.