Magnesium metaborate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-07-29 - 2017-09-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

30 May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

27 July 1995

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of method:

flask method

Water solubility:

< 0 g/L

Conc. based on:

other: Magnesium

Loading of aqueous phase:

0.1 mg/L

Incubation duration:

72 h

Temp.:

20 °C

pH:

7.1

Water solubility:

< 0 g/L

Conc. based on:

other: Boron

Loading of aqueous phase:

0.1 g/L

Incubation duration:

72 h

Temp.:

20 °C

pH:

7.1

Water solubility:

< 0.001 g/L

Conc. based on:

other: TOC

Loading of aqueous phase:

0.1 g/L

Incubation duration:

72 h

Temp.:

20 °C

pH:

7.1

Preliminary Test

The estimates of water solubility at 20.0 ± 0.5 °C are shown in the following table:

Loading Rate (g/L)	Concentration			pH
	Magnesium	Boron	TOC
0.1	< 1 x 10E-4	< 1 x 10E-4	< 1 x 10E-3	7.1
1	2.2 x 10E-3	5.2 x 10E-4	3.0 x 10E-3	7.8

Definitive Test

The counts per second relating to the standard and sample solutions were detected for creating a calibration curve from which the sample concentrations were interpolated.

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

Sample number	Concentration			Solution pH
	Magnesium	Boron	TOC
1	< 1 x 10E-4	< 1 x 10E-4	< 1 x 10E-3	7.1
2	< 1 x 10E-4	< 1 x 10E-4	< 1 x 10E-3	7.0
3	< 1 x 10E-4	< 1 x 10E-4	< 1 x 10E-3	7.0

Overall results at 20.0 ± 0.5 ºC:

magnesium: < 1 x 10E-4 g Mg / L

boron: < 1 x 10E-4 g B / L

TOC: < 1 x 10E-3 g TOC / L

Discussion:

On completion of the equilibration period, the definitive test samples were clear, colorless solutions with excess, undissolved test item present. After filtration, the samples were observed to be visually clear, colorless solutions but with a possible Tyndall beam effect.

Magnesium and boron were analysed for as the Sponsor had requested testing was to be based on active ingredient of the test item. Total organic carbon was also measured to provide additional information.

It was observed that there was a possible increase in concentration from Sample 1 to Samples 2 and 3 for the ICP and TOC result. This may have been due to the test item being slightly viscous and the analytes requiring longer than 24 hours for equilibrium to be reached.

For the magnesium and boron results of the definitive samples and 0.1 g/L loading rate preliminary samples, they were taken as limit values based on the concentration of the lowest calibration standard as a worst case scenario. Extrapolating from the calibration curve becomes inaccurate at low concentrations.

During the preliminary test, samples using the mineral oil were also prepared and analysed to help assess if any of the test results were derived from the mineral oil. The loading rate of the samples were based on the preliminary test loading rates but compensated for the percentage of mineral oil in the test item. The results are as follows:

Equivalent Loading rate (g/L)	Concentration			Solution pH
	Magnesium	Boron	TOC
0.1	< 1 x 10E-4	< 1 x 10E-4	< 1 x 10E-3	6.9
1	< 1 x 10E-4	< 1 x 10E-4	< 1 x 10E-3	6.4

These results showed there was no significant contribution to the test results from the mineral oil.

Conclusions:

The water solubility of the test item has been determined at 20.0 ± 0.5 °C and a nominal loading rate of 0.1 g/L as shown below:

magnesium: < 1 x 10E-4 g Mg / L
boron: < 1 x 10E-4 g B / L
TOC: < 1 x 10E-3 g TOC / L

Executive summary:

The water solubility was determined at 20.0 ± 0.5 °C and a nominal loading rate of 0.1 g/L using the flask method, designed to be compatible with Method A.6 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 the results are as follows:

Analyte	Concentration
Magnesium	< 1 x 10E-4 g Mg /L
Boron	< 1 x 10E-4 g B /L
TOC	< 1 x 10E-3 g TOC /L

Description of key information

The water solubility was determined at 20.0 ± 0.5 °C and a nominal loading rate of 0.1 g/L using the flask method, designed to be compatible with Method A.6 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 the results are as follows:

Analyte	Concentration
Magnesium	< 1 x 10E-4 g Mg /L
Boron	< 1 x 10E-4 g B /L
TOC	< 1 x 10E-3 g TOC /L

Key value for chemical safety assessment

Water solubility:

0 g/L

at the temperature of:

20 °C