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Partition coefficient

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Description of key information

log Pow - experimental value (slow-stirring method - OECD 123): 4.2 at 24 °C, pH = 5.8 - 6.0 
log Pow - calculated from weight-averaged log Koc value: 5.17
log Pow - calculated using KOWWIN v1.68 (weight-averaged value): 5.14
log Pow - calculated using KOWWIN v1.67 (individual constituents): 2.03 - 7.72

Key value for chemical safety assessment

Log Kow (Log Pow):
5.16
at the temperature of:
25 °C

Additional information

The log Pow of the substance Alcohols, C12 -18, ethoxylated, <2.5EO was determined in the weight of evidence approach from various calculated and experimental log Pow values. The log Pow of 4.2 was determined experimentally using the slow stirring method according to OECD Guideline 123.

Additionally the following calculations were applied:

1. based on weight-averaged log Koc values using the TGD equation for predominantly hydrophobic substances: log Koc = 0.81 log Pow + 0.10 thus log Pow = (log Koc – 0.10)/0.81) (2003 EU Technical Guidance Document on Risk Assessment Part III, Chapter 4, Section 4.3 (pp 24 – 27)

2. based on EPIsuite v 4.10, KOWWIN v 1.68 log Pow values for (possible) individual constituents of the substance; a weighting based on normalized composition was applied to derive a log Pow value for the whole substance.

3. based on KOWWIN v1.67 logPow values for individual components of the substance with ethoxylation degree nEO=0 to nEO=10

Due to the fact that the substance is a surfactant, for which none of the experimental method is well suited, the key value for chemical safety assessment is derived in a weight-of-evidence approach from the two calculated log Pow values (average of values: 5.14 and 5.17) for the substance Alcohols, C12-18, ethoxylated, < 2.5 EO.

 

The experimental value was not considered in developing of key value for chemical safety assessment due to the fact that the substance is a surfactant and note of the experimental method is well suited for surfactants. Also the experimental logKow is lower than both log Kow calculated from Koc and KOWWIN and therefore the latter conservative values were chosen for development of the key value for CSA. The experimental value confirms however the hydrophobicity of the substance (log Pow > 4). Other available KOWWIN v1.67 calculations (log Pow = 2.03 - 7.72) for individual components of the substance were not considered in calculation of the key value for CAS because the values log Pow < 4 refer to the estimations for higher ethoxylated alcohols nEO = 10.