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Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

experimental dates: 05-11 March 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method with no deviation, and under GLP. The substance is considered to be adequately characterised, with isomers composition. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

Version / remarks:

11 July 2006

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.23 Partition Coefficient (1-Octanol/Water): Slow-Stirring Method

Version / remarks:

2014
(Commission Regulation No 440/2008, method last updated by Regulation (EU) No 260/2014)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed on 15 Nov. 2018

Type of method:

slow-stirring method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

Storage conditions of test material: Stored refrigerated (2-8°C) in aluminium bottle. An injection of nitrogen gas is performed into the bottle after each sampling to keep the test item under nitrogen atmosphere during the storage period.

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

3.89

Temp.:

25 °C

pH:

5

Experimental results

The log Pow, corresponding to concentrations obtained in both phases, are presented as a function of time during the three independent slow-stirring experiments in the following table:

Sampling date (m/d/y, h)	Vessel 1	Vessel 2	Vessel 3
03/06/2019 09:10	3.95	---	---
03/06/2019 14:30	3.89	---	---
03/07/2019 08:50	3.85	3.82	3.89
03/07/2019 14:00	3.85	3.87	3.85
03/08/2019 08:55	3.83	3.90	3.88
03/08/2019 14:10	3.89	3.89	3.91
03/11/2019 10:10	3.89	3.90	3.91

The pH values measured in the three systems were 5 in the three vessels at the beginning and at the end of the experiment.

Demonstration of the chemical equilibrium

The equilibrium state was verified for all the vessels between 7 March at 14:00 to 11 March at 10:10.

log Pow calculation

The following table presents the log Pow for each vessel and their corresponding statistical weights (w_i):

	log Powi	wi
Vessel 1	3.87	1111
Vessel 2	3.89	5000
Vessel 3	3.89	1212

 

The average log Pow is 3.89 ± 0.01.

Demonstration of mass balance

The mass balance in each system can be calculated knowing the measured concentration in both phases at the equilibrium state and the introduced amount of test item.

The average mass balances between7 March at 14:00 and 11 March at 10:10for each vessel are presented below:

Time	Vessel 1	Vessel 2	Vessel 3
03/07/2019 14:00	98.9%	98.1%	95.1%
03/08/2019 8:55	91.9%	91.7%	92.0%
03/08/2019 14:10	95.0%	100.9%	101.2%
03/11/2019 10:10	105.0%	101.8%	98.7%
Average	97.7%	98.1%	96.7%

 

All the mass balances are close to 100 %, indicating that no significant loss or degradation of the test item occurred during the study.

Conclusions:

The substance has low potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow <4).

Executive summary:

The partition coefficient of the test substance was measured under GLP according OECD 123 guideline, slow-stirring method.

Three vessels were prepared, at 25°C. Each phase was analysed with a validated HPLC-DAD method. After equilibrium was achieved, four samples were taken in each phase. The overall average was calculated weighted for the variance. Mass balance was demonstrated >96%.

Log Kow = 3.89 (at 25°C, pH=5).

Description of key information

The substance has low potential for bioaccumulation, according to CLP classification criteria for aquatic chronic toxicity (log Kow <4).

It should also be of no concern for PBT assessment.

Key value for chemical safety assessment

Log Kow (Log Pow):

3.89

at the temperature of:

25 °C

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EC method and under GLP, is available. Therefore, it is considered as a key study, and the result is retained as key value.