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Physical & Chemical properties

Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)
GLP compliance:
yes
Type of method:
other: syringe method
Partition coefficient type:
octanol-water
Analytical method:
other: GC-MS
Type:
log Pow
Partition coefficient:
8.023
Temp.:
25.3 °C
Remarks on result:
other: pH not stated

Tabulated results for Test Vessel A

Sampling Time, h

Average concentration D5(oct)μg/ml

Replicate difference D5(oct)μg/ml

Average concentration D5(aq)ng/ml

Replicate difference D5(aq)ng/ml

Log Kow

27.6

4740

392

0.04084

0.00010

8.0647

52.3

4572

50

0.03924

0.00034

8.0663

 73.5

 4606

 42

 0.04419

0.00024

8.0180

98.5

4707

197

0.04700

0.00079

8.0006

Average

4656

0.04282

 

8.0374

 Std Dev

 80

157 

 0.00347

0.00032

0.0332

abulated results for Test Vessel B

Sampling Time, h

Average concentration D5(oct)μg/ml

Replicate difference D5(oct)μg/ml

Average concentration D5(aq)ng/ml

Replicate difference D5(aq)ng/ml

Log Kow

28.1

4568

145

0.04288

0.00029

8.0275

51.1

4584

270

0.04379

0.00290

8.0198

72.7

4654

160

0.04798

0.0095

7.9868

99.5

4714

29

0.04459

0.00104

8.0241

Average

4630

0.04481

 

8.0145

Std Dev

67

123

0.00222

0.00151

0.0188

Tabulated results for Test Vessel C

Sampling Time, h

Average concentration D5(oct)μg/ml

Replicate difference D5(oct)μg/ml

Average concentration D5(aq)ng/ml

Replicate difference D5(aq)ng/ml

Log Kow

28.7

4518

30

0.04185

0.00768

8.0332

51.2

4478

80

0.03943

0.00141

8.0553

74.1

4556

238

0.04323

0.00072

8.0228

97.3

4496

179

0.04486

0.00105

8.0010

Average

4512

0.0423

 

8.0280

Std Dev

33

109

0.00230

0.00185

0.0226

Conclusions:
A partition coefficient value of 8.023 ±0.006 was determined at 25.3°C in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Description of key information

Partition coefficient: (log Kow) 8.02 at 25.3 °C

Key value for chemical safety assessment

Log Kow (Log Pow):
8.02
at the temperature of:
25.3 °C

Additional information

Two reliable studies are available for the n-octanol-water partition coefficient of D5; a syringe method gave a Log Kow of 8.07 at 24.6°C (SEHSC 2007) and a slow-stirring method gave a Log Kow of 8.02 at 25.3°C (DCC 2007). The slow-stirring method is selected as key because it is a guideline study conducted in accordance with GLP. The two results are very similar.

Earlier measurements gave Log Kow values in the range 4.8 to 5.2. However, it is likely that in all cases the methodology was not appropriate for the substance.

A log Koa value of 4.96 was determined in a reliable study conducted according to scientifically sound methods, and in compliance with GLP.

A Log Kaw value of 3.13 has been determined in a reliable study (presented in Section 5.4.2).