Divanadium trioxide

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)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

See "Principles of method if other than guideline"

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

See "Principles of method if other than guideline"

Principles of method if other than guideline:

The test was performed according to the OECD-Guideline for Testing of Chemicals No. 105, Water Solubility, flask method with the following modifications.
- Based on experience and in view of the poor solubility of other metal substances, it was considered to conduct the test under exclusion of atmospheric carbon dioxide and oxygen.
- Two vessels were set up in a parallel design at 20.5 ± 0.5°C (According to the study plan a temperature of 20.0 ± 0.5°C was anticipated). However this deviation is not considered to be critical. Each vessel was sampled several times instead of sampling one vessel at every point in time. This modification helped avoiding weighing errors and enables sampling up to 7 times.

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2007-03-21

Type of method:

flask method

Key result

Water solubility:

335 mg/L

Conc. based on:

test mat. (dissolved fraction)

Loading of aqueous phase:

500 mg/L

Incubation duration:

264 h

Temp.:

20.5 °C

pH:

4.2

Remarks on result:

other: mean dissolved concentration: 335 ± 40 mg/L

Water solubility:

228 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

Vanadium

Loading of aqueous phase:

500 mg/L

Incubation duration:

264 h

Temp.:

20.5 °C

pH:

4.2

Remarks on result:

other: mean dissolved concentration: 228 ± 27 mg V/L

Details on results:

Mean vanadium concentrations (vessels A and B)

stirring time mean V conc. vessel mean dissolved V2O3 variation [%]
[h] A and B [mg/L] vessel A and B [mg/L]

24 16.2 ± 0.7 23.7 ± 1.0 
48 23.9 ± 2.9 35.0 ± 4.3 + 47.8
72 35.2 ± 4.9 51.5 ± 7.2 + 47.0
96 53.9 ± 10 79.0 ± 15 + 53.3
216 178 ± 32 261 ± 46 + 230
240 203 ± 27 298 ± 39 + 14.0
264 228 ± 27 334 ± 40 + 12.2

Method validation summary

Validation parameter	results	comment
selectivity	similar data with three different wavelengths for ICP-OES method	no interferences observed
linearity	applied calibration functions were linear	correlation coefficient at least 0.9999
limits of detection	4.6 - 14 µg/L
limits of quantification	15 - 46 µg/L
method blanks	at least below < LOQ = < 15 - < 46 µg/L ; n = 42	-
accuracy and precision	mean recovery for TMDA-70: 101 ± 1.3 % (n = 30)	corresponds to concentration range of diluted samples (312 µg/L)
accuracy and precision	mean recovery for quality control standard: 98.5 ± 2.1 % (n = 30)	corresponds to concentration range of diluted samples (100 µg/L)
accuracy and precision	mean recovery for recalibration: 102 ± 2.2 % (n = 15)	corresponds to concentration range of diluted samples (100 µg/L)
accuracy and precision	recovery from fortification of samples: 99.0 - 99.5 % (n = 4)	corresponds to concentration range of diluted samples
reproducibility	mean recovery for TMDA-70: 101 ± 1.3 % (n = 30)	for concentration range of diluted samples (312 µg/L)
reproducibility	mean recovery for quality control standard: 98.5 ± 2.1 % (n = 30)	for concentration range of diluted samples (CPI standard diluted to 100 µg/L V)
reproducibility	mean recovery for recalibration: 102 ± 2.2 % (n = 15)	for concentration range of diluted samples

Test conditions:

- temperature: 20.2 -20.7°C

- pH: 4.0 - 4.3

Mean vanadium concentrations (vessels A and B)

stirring time [h]	mean V conc. vessel A and B [mg/L]	mean dissolved V2O3 vessel A and B [mg/L]	variation [%]
24	16.2 ± 0.7	23.7 ± 1.0
48	23.9 ± 2.9	35.0 ± 4.3	+ 47.8
72	35.2 ± 4.9	51.5 ± 7.2	+ 47.0
96	53.9 ± 10	79.0 ± 15	+ 53.3
216	178 ± 32	261 ± 46	+ 230
240	203 ± 27	298 ± 39	+ 14.0
264	228 ± 27	334 ± 40	+ 12.2

The amount of divanadium trioxide dissolved was calculated by:

= mean of measured values / 50.94 g/mol (V) * 149.88 g/mol [V2O3]/2

Conclusions:

Under the conditions of this test (under exclusion of CO2 and O2 under inert argon gas; flask method; loadings of 512 mg/L and 500 mg/L in vessel A and B, respectively), the solubility equilibrium was not reached. Not reaching a solubility equilibrium may be explained by reactions of the test item during the test, and/or a slow but consistent dissolution and transformation. The mean maximum of dissolved divanadium trioxide after 264 h at 20.5 ± 0.5 °C is 335 ± 40 mg/L (determined as dissolved V, separated by filtration from undissolved test item). The resulting solution pH was measured to be approximately 4.2. Hence, divanadium trioxide may considered as moderately soluble (100-1000 mg/L)

Reference 2

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-07-28 to 2011-11-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Series on Testing and Assessment No. 29 (23-Jul-2001): Guidance document on transformation/dissolution of metals and metal compounds in aqueous media

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed on 2011-02-07

Type of method:

flask method

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

86 µg/L

Element analysed:

Vanadium

Loading of aqueous phase:

1 mg/L

Incubation duration:

1 d

Test conditions:

21 °C, pH 8

Remarks on result:

other: mean dissolved concentration: 86 ± 7 µg V/L

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

94 µg/L

Element analysed:

Vanadium

Loading of aqueous phase:

1 mg/L

Incubation duration:

1 d

Test conditions:

21 °C, pH 6

Remarks on result:

other: mean dissolved concentration: 94 ± 3 μg V/L

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

85 µg/L

Element analysed:

Vanadium

Loading of aqueous phase:

1 mg/L

Incubation duration:

7 d

Test conditions:

21 °C, pH 8

Remarks on result:

other: mean dissolved concentration: 85 ± 7 µg V/L

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

106 µg/L

Element analysed:

Vanadium

Loading of aqueous phase:

1 mg/L

Incubation duration:

7 d

Test conditions:

21 °C, pH 6

Remarks on result:

other: mean dissolved concentration: 106 ± 10 µg V/L

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

100 µg/L

Element analysed:

Vanadium

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

21 °C, pH 8

Remarks on result:

other: mean dissolved concentration: 100 ± 12 μg V/L

Key result

Type of test:

full transformation/dissolution test - metals and sparingly soluble metal compounds

Mean dissolved conc.:

105 µg/L

Element analysed:

Vanadium

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

21 °C, pH 6

Remarks on result:

other: mean dissolved concentration: 105 ± 9 μg V/L

Details on results:

Under the described conditions of this test with divanadium trioxide at a loading of 1 mg/L, dissolved vanadium concentrations after 28 days were 100 ± 12 μg/L and 105 ± 9 μg/L and after 24h were 86 ± 7 μg V/L and 94 ± 3 μg V/L at pH 8 and 6, respectively. Recoveries of fortified test samples were in the range of 100 -101 %.
After 96h, the within (except for one sample (# 6) after 168h) and between vessel variation, and the variation of mean V concentrations between sampling intervals meet the requirements of the OECD-Guidance document 29. Measured pH, temperature and oxygen levels also comply with OECD specifications.

Conclusions:

Dissolved vanadium concentrations at a loading of 1 mg/L amount to 85 and 106 µg/L after 7 days and 100 μg/L and 105 μg/L after 28 days at pH 8 and pH 6, respectively, in the transformation/dissolution test (OECD Series No 29) with the finest representative divanadium trioxide powder marketed (BET specific surface area: 2.649 m2/g).

Reference 3

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-09-01 to 2011-10-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

,1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Water Solubility: Column Elution Method; Shake Flask Method, 1998

Deviations:

not specified

GLP compliance:

no

Type of method:

flask method

Water solubility:

471 mg/L

Temp.:

20 °C

pH:

>= 3 - <= 4.5

Remarks on result:

other: 1:100 + nitric acid – clear

Details on results:

The soluble vanadium appeared to be continuing to increase after the 3 day. Therefore additional times of 7 and 9 days equilibration at 30°C followed by 24 hr at 20°C were analyzed. These additional time did not met the criteria for < 15% difference: the triplicates of the V2O3 samples at 7 days, in which one sample was much lower than the other two (meeting the criterion for a statistical outlier using Grubb’s test). To assess whether there was an error at the point of either the dilution into water or in the analysis, the original supernatants of these samples (7 and 9 day samples for V2O3), which had been held at room temperature (approximately 22° ± 2°C) for approximately 1 week, were re-diluted and acidified, and these replicates were analyzed for vanadium content. The unexpected result was a more homogeneous set of values for the 7 day time, but an extremely low value for one of the 9 day replicates (again, a true statistical outlier by Grubb’s test). After consultation with the sponsor, the data are being reported as the average of 5 values: the two outliers being omitted from the reported data.

Conclusions:

Interpretation of results (migrated information): moderately soluble (100-1000 mg/L)
A water solubility of 471mg/L divanadium trioxide was determined after 9 days at 20°C and pH 3-4.5.

Description of key information

Water solubility:

The water solubility of divanadium trioxide at a loading of ~ 500 mg/L is estimated with 334 mg/L at 20.5 °C and pH 4.2 after 11 days under O2 and CO2 exclusion. However, a solubility equilibrium was not reached (Klawonn, 2010). In a further test, a water solubility of 471 mg/L was determined at 20 °C and pH 3-4.5 after 9 days (Seagrave, 2012).

 

Transformation/dissolution in environmental medium:

Dissolved vanadium concentrations at a loading of 1 mg/L amount to 85 and 106 µg/L after 7 days and 100μg/L and 105μg/L after 28 days at pH 8 and pH 6, respectively, in the transformation/dissolution test (OECD Series No 29) with divanadium trioxide powder (Klawonn, 2012). The tested V2O3 powder with a BET specific surface area of 2.649 m2/g represents the smallest material on the market.

Key value for chemical safety assessment

Water solubility:

471 mg/L

at the temperature of:

20 °C