Naphthenic acids, cobalt salts

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

other: OECD guideline for testing of chemicals - draft proposal - February 2001. Transformation dissolution of metals and metal compounds in aqueous media.

Qualifier:

according to guideline

Guideline:

other: The standard procedure for the transformation/dissolution of metals and sparingly soluble metal compounds, version February 2004.

GLP compliance:

no

Remarks:

The tests were following as close as possible the GLP guidelines proposed by OECD

Type of method:

flask method

Temp.:

20.6 °C

pH:

6.07

Remarks on result:

other: Cobalt naphthenate concentration at 0 hour sampling time at 1 mg/L loading was below detection limit. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

9.9 µg/L

Temp.:

21.7 °C

pH:

6.03

Remarks on result:

other: Cobalt naphthenate concentration at 24 hour sampling time at 1 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

14 µg/L

Temp.:

21.2 °C

pH:

6

Remarks on result:

other: Cobalt naphthenate concentration at 48 hour sampling time at 1 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

18.3 µg/L

Temp.:

21.4 °C

pH:

5.98

Remarks on result:

other: Cobalt naphthenate concentration at 96 hour sampling time at 1 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

19 µg/L

Temp.:

21.8 °C

pH:

6

Remarks on result:

other: Cobalt naphthenate concentration at 168 hour sampling time at 1 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

23.5 µg/L

Temp.:

21.7 °C

pH:

6.02

Remarks on result:

other: Cobalt naphthenate concentration at 672 hour sampling time at 1 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

1.5 µg/L

Temp.:

21.7 °C

pH:

5.9

Remarks on result:

other: Cobalt naphthenate concentration at 0 hour sampling time at 10 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

134.5 µg/L

Temp.:

21.2 °C

pH:

6.07

Remarks on result:

other: Cobalt naphthenate concentration at 24 hour sampling time at 10 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

165.4 µg/L

Temp.:

21.3 °C

pH:

6.06

Remarks on result:

other: Cobalt naphthenate concentration at 48 hour sampling time at 10 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

263.6 µg/L

Temp.:

21.3 °C

pH:

6.1

Remarks on result:

other: Cobalt naphthenate concentration at 168 hour sampling time at 10 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

6.9 µg/L

Temp.:

22.2 °C

pH:

5.96

Remarks on result:

other: Cobalt naphthenate concentration at 0 hour sampling time at 100 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Water solubility:

2 433.5 µg/L

Temp.:

21.5 °C

pH:

5.95

Remarks on result:

other: Cobalt naphthenate concentration at 168 hour sampling time at 100 mg/L loading. Sample analysis was conducted in triplicate per test vessel (3 test vessels per loading). Average value from the tests is given.

Conclusions:

Under the conditions of the transformation/dissolution test,
the dissolution of cobalt naphthenate is 23.5 µg/L at 1 mg/L loading for the 28-day endpoint.
The dissolution of cobalt naphthenate is 263.6 µg/L at 10 mg/L loading for the 7-day endpoint.
The dissolution of cobalt naphthenate is 2433.5 µg/L at 100 mg/L loading for the 7-day endpoint.

Executive summary:

A seven day transformation/dissolution test according to the OECD guideline 29 and the GHS (Annex 10) protocol was run on cobalt naphthenate at a mass loading of 10 and 100 mg/L, at a pH of 6.0. Also a 28 day transformation/dissolution was run on cobalt naphthenate at a mass loading of 1 mg/L and at a pH of 6.0. Under the conditions of this test, the dissolution of cobalt naphthenate is 23.5 µg/L for the 28 -day endpoint (1 mg/L loading), 263.6 µg/L for the 7-day endpoint (10 mg/L loading) and 2433.5 µg/L for the 7-day endpoint (100 mg/L loading).

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-09-28 to 2009-12-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

2008-04-30

Type of method:

flask method

Water solubility:

293 mg/L

Temp.:

20 °C

pH:

>= 5.7 - <= 6.52

Remarks on result:

other: Based on a determined concentration of 26.07 mg Co/L

Water solubility:

356 mg/L

Temp.:

37 °C

pH:

>= 5.91 - <= 6.48

Remarks on result:

other: Based on a determined concentration of 31.69 mg Co/L

Details on results:

After shaking times of 72, 96 and 120 hours at 30 °C and at 47 °C, respectively, the samples were equilibrated for another 24 hours at 20 °C and 37 °C, respectively. Afterwards, the samples were centrifuged, filtered, diluted and analyzed by AAS. The water solubility of Cobalt Naphthenate at 20 °C was determined to be 293 mg/L and at 37 °C 356 mg/L. The measured results at 96 hours and 120 hours differ by less than 15%. Therefore, the study is considered to be valid.

Sample No.	Shaking Time [h] at 30°C/47°C	Concentration Analyzed [mg Co/L]	Concentration Calculated [mg Co/L]	Concentration Calculated [mg test item/L]	Water Solubility Calculated (Rounded) [mg test item/L]
Test at 20 °C (Shaking at 30 °C)
1	120	3.802	38.02*	426.71*	293
2		2.882	28.82	323.46
3		2.267	22.67	254.43
4	96	2.400	24.00	269.36
5		2.442	24.42	274.07
6		2.923	29.23	328.06
7	72	2.347	23.47	263.41
8		2.947	29.47	330.75
9		2.650	26.50	297.42
Mean			26.07	292.62
SD			2.79	31.35
SD rel.			10.71%	10.71%
Test at 37 °C (Shaking at 47 °C)
1	120	2.914	29.14	327.05	356
2		3.263	32.63	366.22
3	96	3.197	31.97	358.81
4		3.302	33.02	370.59
5	72	2.814	28.14**	315.82**
6		2.867	28.67**	321.77**
Mean			31.69	355.67
SD			1.75	19.69
SD rel.			5.54%	5.54%

*outlier, not used for further calculations

** Not used for calculation of mean, because the mean value at 72 hours differs by more than 15% from the mean value at 96 hours.SD = Standard Deviation

SD rel. = Relative Standard Deviation

The water solubility of the test item was calculated with a cobalt content of 14.69% as given by the Sponsor.

Conclusions:

Interpretation of results (migrated information): moderately soluble (100-1000 mg/L)
According to OECD Guideline for Testing of Chemicals, No. 105, “Water solubility”; adopted July 27, 1995 and Council Regulation (EC) No. 440/2008, 30 May 2008, Part A, Methods for the determination of physico-chemical properties, A.6 “Water solubility” the water solubility of the test item at 20 °C and at 37 °C was determined using the flask method and was found to be 293 mg/L at 20 °C (based on a determined concentration of 26.07 mg Co/L) and 356 mg/L at 37 °C (based on a determined concentration of 31.69 mg Co/L).

Description of key information

Cobalt naphthenate has a water solubility of 293 mg/L at 20 °C and 356 mg/L at 37 °C.

Key value for chemical safety assessment

Water solubility:

293 mg/L

at the temperature of:

20 °C