(4E)-4-(3,3,4-trimethylcyclopentylidene)butanal

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: October 14, 2019 to August 5, 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method, and under GLP. The substance is adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Council Regulation (EC) No 440/2008 (as amended by Regulation (EU) No 260/2014)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

11 July 2006

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:

Actual storage conditions: Ambient temperature in the dark, original glass bottle.

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

4.3

Temp.:

25 °C

pH:

5

Experimental data from main test
The log Pow are presented as a function of time during the three independent slow-stirring experiments from the main test in the following table. The mass balance in each system was calculated knowing the measured concentration in both phases and the introduced amount of test item.

Sampling date (m/d/y)	Resting time	Vessel 1		Vessel 2		Vessel 3
		log Pow	Mass balance	log Pow	Mass balance	log Pow	Mass balance
10/15/19 8:50	20 min	4.44	58.9%
10/15/19 14:30	15 min	4.32	47.3%
10/16/19 8:55	20 min	4.11	41.5%
10/16/19 15:10	10 min	4.23	44.5%
10/17/19 8:10	10 min	4.29	54.6%	4.29	51.6%	4.25	56.2%
10/17/19 13:50	10 min	4.11	66.9%	4.15	68.7%	4.15	74.2%
10/18/19 8:25	10 min	4.50	77.6%	4.45	69.8%	4.33	71.3%
10/18/19 14:50	15 min	4.45	86.1%	4.44	85.0%	4.45	84.6%
10/21/19 9:05	5 min	4.14	49.9%	4.09	48.9%	4.15	55.3%
10/21/19 15:40	10 min	4.42	75.0%	4.41	74.1%	4.37	71.5%

The temperature variations were included in the range 24.9 °C - 25.3 °C. The pH values measured in the three systems were 5 in the three vessels at the beginning and at the end of the experiment.

Experimental data from additional test
The log Pow and mass balance are presented in the following table for the additional test.

Sampling date (m/d/y)	Resting time	Vessel 4
		log Pow	Mass balance
08/03/20 15:25	0 min	4.01	69.6%
08/03/20 15:40	15 min	4.35	62.9%
08/03/20 15:55	30 min	4.31	72.2%
08/03/20 16:10	45 min	4.29	78.2%
08/03/20 16:25	60 min	4.17	71.2%
08/05/20 10:45	0 min	4.39	63.1%
08/05/20 11:00	15 min	4.18	67.0%
08/05/20 11:15	30 min	4.35	67.1%
08/05/20 11:30	45 min	4.12	67.3%
08/05/20 11:45	60 min	4.15	64.3%

The temperature variations were included in the range 24.8 °C - 25.2 °C.

Demonstration of the chemical equilibrium (main test)

The equilibrium state was verified for the five last sampling times, i.e. from October 17 at 13:50 to October 21 at 15:40. The sampling time on October 21 at 9:05 was discarded because of its mass balance inferior to 60%.

log Pow calculation
The mass balance did not depend on the resting time; therefore, the POW of the test item was calculated as the mean of the log POW of the main test and the additional test.

Main test
The following table presents the log Pow for each vessel from the main test and their corresponding statistical weights (wi):

	log Pow,i	wi
Vessel 1	4.37	32.12
Vessel 2	4.36	49.12
Vessel 3	4.33	62.11

The average log Pow for the main test is: log Pow.mt = 4.35 ± 0.01.

Additional test
The mean of the log Pow values calculated in the additional test is 4.23 with a standard deviation of 0.12.
Thus, the log Pow for the additional test is: log Pow,at = 4.2 ± 0.1.

Test item log Pow
Using results from the main test and the additional test, the average log Pow for the test item is: log Pow = 4.3 ± 0.1.

Conclusions:

The substance has 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.
In the first (main) test, despite equilibrium was achieved, poor mass balance was observed in some samples. An additional test was conducted to investigate the impact of the resting time, but no correlation was evidence. Therefore, the final logPow was calculated as the mean of the two tests (average of four values weighted for the variance for the main test, and mean of the additional test), for samples with mass balance >60%.
Log Pow = 4.3 (at 25°C, pH=5).

Description of key information

The substance has potential for bioaccumulation, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).
It should be of no concern for PBT assessment (logKow <4.5).

Key value for chemical safety assessment

Log Kow (Log Pow):

4.3

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.