Dipotassium hexacyanocobalt(II)-ferrate(II)

Surface tension

Administrative data

Endpoint:

surface tension

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because water solubility is below 1 mg/L at 20°C

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with column 2 of REACH Annex VII, the surface tension study (required in section 7.6) does not need to be conducted if the water solubility is below 1 mg/L at 20 °C. The substance's water solubility is less than or equal to 0.89 mg/L at 20 °C as determined in the Water Solubility test.

Furthermore, in accordance with the test guidelines
- Method A5 Surface Tension of Commission Regulation (EC) No 440/2008 of 30 May 2008
- Method 115 of the OECD Guidelines for Testing of Chemicals, 27 July 1995,
the surface tension of substances with a water solubility of less than 1 mg/L need not be tested for surface tension.

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24.5.-11.9.2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was performed by following the recommended methods (Method A6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995) and GLP.

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

The flask method was used even though the method recommends the column elution method for test items with a solubility < 10 mg/L.

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

The flask method was used even though the method recommends the column elution method for test items with a solubility < 10 mg/L.

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate is included in the study report

Type of method:

flask method

Water solubility:

<= 0.89 mg/L

Temp.:

20 °C

pH:

>= 6.32 - <= 6.48

Remarks on result:

other: T = 20.0 ± 0.5 °C

Details on results:

The final concentration was calculated based on the iron and cobalt concentrations in the samples:
Concentration Range:
- 4.35 x 10^-4 to 8.90 x 10^-4 g/L based on cobalt solubility
- 1.93 x 10^-4 to 5.32 x 10^-4 g/L based on iron solubility.
Overall Result : ≤ 8.90 x 10^-4 g/L at 20.0 ± 0.5 ºC

The cobalt concentration (g/L) in the sample solutions is shown in the following table:

Sample Number	Time Shaken at ~ 30 ⁰C (hours)	Time Equilibrated at 20 ⁰C (hours)	Concentration (g/L)	Mean Concentration (g/L)	Test Item Mean Concentration (g/L)	Solution pH
1A	24	24	8.87 x 10^-5	8.90 x 10^-5	5.27 x 10^-4	6.32
1B	24	24	8.93 x 10^-5
2A	48	24	1.49 x 10^-4	1.50 x 10^-4	8.90 x 10^-4	6.48
2B	48	24	1.51 x 10^-4
3A 3B	72 72	24 24	7.34 x 10^-5 7.34 x 10^-5	7.34 x 10^-5	4.35 x 10^-4	6.33

The iron concentration (g/L) in the sample solutions is shown in the following table:

Sample Number	Time Shaken at ~ 30 ⁰C (hours)	Time Equilibrated at 20 ⁰C (hours)	Concentration (g/L)	Mean Concentration (g/L)	Test Item Mean Concentration (g/L)	Solution pH
1A	24	24	4.83 x 10^-5	4.83 x 10^-5	3.02 x 10^-4	6.32
1B	24	24	4.83 x 10^-5
2A	48	24	8.46 x 10^-4	8.52 x 10^-4	5.32 x 10^-4	6.48
2B	48	24	8.58 x 10^-4
3A 3B	72 72	24 24	3.03 x 10^-5 3.15 x 10^-5	3.09 x 10^-5	1.93 x 10^-4	6.33

Conclusions:

During the preliminary study the water solubility of the test item was estimated to be 0.558 mg/L. Method A6 Water solubility (440/2008/EC) recommends that the column elution method should be used if the water solubility is < 1x10^-2 g/L. However, since the substance is insoluble in organic solvents, the column elution method could not be applied.

Using the flask method, the water solubility of the test item has been determined to be less than or equal to 8.90 x 10-4 g/L of solution at 20.0 ± 0.5 °C. The substance is therefore poorly soluble in water.

Executive summary:

The water solubility of the substance was determined to be less than or equal to 8.90 x 10^-4 g/L of solution at 20.0 ± 0.5 °C, using the flask method, designed to be compatible with Method A6 Water Solubility of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 105 of the OECD Guidelines for Testing of Chemicals, 27 July 1995.