Naphthenic acids, zinc salts

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

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

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

Water Solubility. July 27, 1995.

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

Water Solubility. March 04, 2016.

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Version / remarks:

Water Solubility: Column Elution Method; Shake Flask Method. March 1998.

Deviations:

no

GLP compliance:

yes

Type of method:

column elution method

Specific details on test material used for the study:

- Batch: A036/99 (Supplier batch number: SCC-1709-0300)
- Expiration date: 31 August 2018
- Storage condition of test material: Room temperature, protected from light

Water solubility:

< 10 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

10 mg/L

Incubation duration:

48 h

Temp.:

25 °C

pH:

7

Details on results:

- Conclusion: The flask method was applied for the determination of the water solubility of Naphthenic acids, zinc salts. Because of the observed spread, no mean value and therefore no maximum difference could be calculated. It is not expected that more accurate results can be obtained.
- pH: The pH of the aqueous samples was between 6.4 and 7.1.
- Analytical results: the analytical method was validated for the analysis of Naphthenic acids, zinc salts in water for the following parameters: Specificity; Calibration curve; Accuracy and Repeatability; Limit of quantification; Stability analytical system and end solutions. Samples in water have to be analysed freshly.

Preliminary test: Water solubility of the test item after stirring for 48 hours

Loading rate [mg test item/L]	Concentration dissolved Zn analyzed [mg Zn/L]	Equivalent concentration test item^1 [mg test item/L]	pH
10	1.06	7.42	6.7
100	8.89	62.2	6.4
1000	32.7	229	6.2
10000	57.8	404	6.1

¹          Content Zn in test item: 14.3%.

           
Preliminary test: Water solubility of the test item after stirring for 49 hours

Loading rate [mg test item/L]	Analyzed TOC concentration [mg C/L]	Analyzed TOC concentration corrected for blank [mg C/L]	pH
blank	0.129	n.a.
10	3.89	3.76	6.7
100	28.7	28.5	6.5
1000	134	134	6.2
10000	289	289	6.1

 

Main study - water solubility of the test item at a loading rate of 100 mg/L

Stirring time [hours]	Concentration dissolved Zn analyzed [mg Zn/L]	Equivalent concentration test item^1 [mg test item/L]	pH
24	6.35	44.4	7.1
48	8.05	56.3	6.8
72	4.48	31.4	7.0

¹  Content Zn in test item: 14.3%.

 

Main study - water solubility of the test item at a loading rate of 1000 mg/L

Stirring time [hours]	Concentration dissolved Zn analyzed [mg Zn/L]	Equivalent concentration  test item^1 [mg test item/L]	pH
24	28.3	198	6.4
48	22.6	158	6.4
72	19.1	134	6.4

¹  Content Zn in test item: 14.3%.

           
Main study - water solubility of the test item at a loading rate of 100 mg/L

Stirring time [hours]	Analyzed TOC concentration^1 [mg C/L]	pH
24	15.2	7.0
48	28.6	6.8
72	21.4	7.1

¹   Corrected for response in the blank.

    
Main study - water solubility of the test item at a loading rate of 1000 mg/L

Stirring time [hours]	Analyzed TOC concentration^1 [mg C/L]	pH
24	69.6	7.0
48	82.9	6.8
72	103	7.1

¹   Corrected for response in the blank.

Water solubility results

Loading rate [mg test item/L]	Stirring time [hours]	Equivalent test item concentration^1 [mg test item/L]	Analyzed TOC concentration^2 [mg C/L]
100	24	44.4	15.2
	48	56.3	28.6
	72	31.4	21.4
1000	24	198	69.6
	48	158	82.9
	72	134	103

¹   Based on dissolved zinc concentration analyzed and the information supplied by the sponsor that the test
     item contains 14.3% zinc.

²   Corrected for the response in the blank.

Conclusions:

The water solubility of naphthenic acids, zinc salts was 31.4-56.3 mg/L at a loading rate of 100 mg/L and 134-198 mg/L at a loading rate of 1000 mg/L. Because of the observed spread, no mean value and therefore no maximum difference could be calculated. It is not expected that more accurate results can be obtained.

Executive summary:

Charles River (2018) is a GLP-compliant study following OECD guideline 105 and is considered reliable without restrictions (Klimisch 1). The flask method was applied for the determination of the water solubility of Naphthenic acids, zinc salts. Because of the observed spread, no mean value and therefore no maximum difference could be calculated. It is not expected that more accurate results can be obtained. 

Description of key information

The water solubility of naphthenic acids, zinc salts was 31.4-56.3 mg/L at a loading rate of 100 mg/L and 134-198 mg/L at a loading rate of 1000 mg/L. Because of the observed spread, no mean value and therefore no maximum difference could be calculated. It is not expected that more accurate results can be obtained.

Additional information

Charles River (2018) is a GLP-compliant study following OECD guideline 105 and is considered reliable without restrictions (Klimisch 1). The flask method was applied for the determination of the water solubility of Naphthenic acids, zinc salts. Because of the observed spread, no mean value and therefore no maximum difference could be calculated. It is not expected that more accurate results can be obtained. 

Under standard test conditions, it was not feasible to derive a water solubility value. Naphthenic acids, zinc salts is a UVCB consisting of a large number of different constituents. Water solubility values have been predicted for representative structures within the UVCB. The QSAR model WSKOWWIN v 1.42 was used and the study was assigned a reliability score of 2 (Reliable with restrictions) as it is an accepted calculated method. The water solubility predictions of the representative structures of zinc naphthenate were 9.367 E-07 to 979.20 mg/L. The QSAR model WATERNT v 1.01 was also used and the study was assigned a reliability score of 2 (Reliable with restrictions) as it is an accepted calculated method. The water solubility predictions of the representative constituents of zinc naphthenate are in the range of 3.1 E-7 - 2645 mg/L.