Tetrabismuth triorthosilicate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 May 2016 to 05 July 2016

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

Qualifier:

according to guideline

Guideline:

other: EEC guideline SANCO/3029/99 rev. 4 dated 11/07/00: Working document “Guidance for generating and reporting methods of analysis in support of residue data requirements for Annex II (part A, Section 4) and Annex III (part A, Section 5)

GLP compliance:

yes (incl. QA statement)

Type of method:

other: Transformation / dissolution test

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature without particular precaution to avoid the light exposure
- Stability under test conditions: Stable under test conditions

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: None
- Final preparation of a solid: 1 mg of test item was added to the test medium

Type of test:

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

Mean dissolved conc.:

< 1 µg/L

Element analysed:

Bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

test medium pH 6, room temperature

Type of test:

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

Mean dissolved conc.:

2.35 µg/L

Element analysed:

Bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

7 d

Test conditions:

test medium pH 6, room temperature

Type of test:

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

Mean dissolved conc.:

2.88 µg/L

Element analysed:

Bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

14 d

Test conditions:

test medium pH 6, room temperature

Type of test:

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

Mean dissolved conc.:

3.32 µg/L

Element analysed:

Bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Test medium pH 6, room temperature

Type of test:

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

Mean dissolved conc.:

< 1 µg/L

Element analysed:

Bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

Test medium pH 8, room temperature

Type of test:

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

Mean dissolved conc.:

2.43 µg/L

Element analysed:

Bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

7 d

Test conditions:

Test medium pH 8, room temperature

Type of test:

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

Mean dissolved conc.:

3.44 µg/L

Element analysed:

bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

14 d

Test conditions:

Test medium pH 8, room temperature

Type of test:

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

Mean dissolved conc.:

3.77 µg/L

Element analysed:

bismuth

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Test medium pH 8, room temperature

Details on results:

After 28 days, 3.32 and 3.77 µg/L of bismuth had been released from the test item at pH 6 and pH 8, respectively. Considering an initial Bismuth silicate load of 1 mg and a maximum possible Bismuth release of 748 µg/L (calculated from the test item composition) the test results indicate that the test item is essentially insoluble in both test media.

TABLE 1a  Summary table: Bismuth Silicate 28-day full test with a loading of 1 mg/L at pH6

Full test 28 days at 1 mg/L pH 6 2926586-001		^209Bi (µg/L)	Full test 28 days at 1 mg/L pH 6 2926586-001		^209Bi (µg/L)
Test medium pH 6 T0 hour	Mean	n.d.	Test medium pH 6 T7 days	Mean	2.35
	S.D.	-		S.D.	0.22
	RSD%[SK7] [s8] [SK9]	-		RSD%	9.5
Test medium pH 6 T2 hours	Mean	n.d.	Test medium pH 6 T14 days	Mean	2.88
	S.D.	-		S.D.	0.19
	RSD%	-		RSD%	6.5
Test medium pH 6 T6 hours	Mean	< 1.00	Test medium pH 6 T21 days	Mean	3.11
	S.D.	-		S.D.	0.06
	RSD%	-		RSD%	1.9
Test medium pH 6 T24 hours	Mean	< 1.00	Test medium pH 6 T28 days	Mean	3.32
	S.D.	-		S.D.	0.08
	RSD%	-		RSD%	2.3
Test medium pH 6 T4 days	Mean	1.17	-
	S.D.	0.03
	RSD%	2.7

n.d.: lower than the Limit of Detection (L.O.D. = 0.50 µg/L for Bi).

< 1.00: lower than the Limit of Quantification (L.O.Q. = 1.00 µg/L for Bi) but higher than the Limit of Detection (L.O.D. = 0.50 µg/L for Bi)

The between-vessel variation was less than 20% recommended by OECD Series No. 29.

TABLE 1b  Summary table: Bismuth Silicate 28-day full test with a loading of 1 mg/L at pH8

 

Full test 28 days at 1 mg/L pH 8 2926586-001		^209Bi (µg/L)	Full test 28 days at 1 mg/L pH 8 2926586-001		^209Bi (µg/L)
Test medium pH 8 T0 hour	Mean	n.d.	Test medium pH 8 T7 days	Mean	2.43
	S.D.	-		S.D.	0.22
	RSD%	-		RSD%	9.0
Test medium pH 8 T2 hours	Mean	< 1.00	Test medium pH 8 T14 days	Mean	3.44
	S.D.	-		S.D.	0.33
	RSD%	-		RSD%	9.5
Test medium pH 8 T6 hours	Mean	< 1.00	Test medium pH 8 T21 days	Mean	3.75
	S.D.	-		S.D.	0.20
	RSD%	-		RSD%	5.4
Test medium pH 8 T24 hours	Mean	< 1.00	Test medium pH 8 T28 days	Mean	3.77
	S.D.	-		S.D.	0.09
	RSD%	-		RSD%	2.5
Test medium pH 8 T4 days	Mean	1.57	-
	S.D.	0.10
	RSD%	6.4

n.d.: lower than the Limit of Detection (L.O.D. = 0.50mg/L for Bi).

< 1.00: lower than the Limit of Quantification (L.O.Q. = 1.00mg/L for Bi) but higher than the Limit of Detection (L.O.D. = 0.50mg/L for Bi)

The between-vessel variation was less than 20% recommended by OECD Series No. 29.

 

Conclusions:

After 28 days, 3.32 and 3.77 µg/L of bismuth had been released from the test item at pH 6 and pH 8, respectively. The test item is essentially insoluble in both test media.

Executive summary:

The transformation/dissolution test with bismuth silicate was conducted at a loading rate of 1 mg/L in two aqueous media at pH 6 and pH 8 (Martinez 2016). The study was performed according the OECD 29 guideline and is a GLP-compliant. This study is considered reliable without restrictions (Klimisch 1) and is suitable for use as a key study for this endpoint.

In the 28-day transformation/dissolution test with bismuth silicate, 3.32 and 3.77 µg/L of bismuth had been released after 28 days from the test item at pH 6 and pH 8, respectively. Considering an initial bismuth silicate load of 1 mg and a maximum possible bismuth release of 748 µg/L (calculated from the test item composition) the test results indicate that the test item is essentially insoluble in both test media.

Description of key information

Based on the results of the transformation/dissolution study, bismuth silicate is considered essentially insoluble in the media tested. After 28 days, 3.32 and 3.77 µg/L of bismuth had been released from the test item at pH 6 and pH 8, respectively.

Key value for chemical safety assessment

Water solubility:

3.77 µg/L

at the temperature of:

20 °C

Additional information

The transformation/dissolution test with bismuth silicate was conducted according to the OECD 29 guideline (Martinez 2016). TD tests are a standard method for assessing the solubility of poorly soluble metal substances and provide additional data that cannot be obtained from a standard OECD 105 water solubility study. This is a guideline, GLP-compliant study and is considered reliable without restrictions (Klimisch 1). It is suitable for use as a key study for this endpoint.

The 28 -day test was performed in two aqueous media at pH 6 and pH 8 at a loading rate of 1 mg/L. In the 28-day transformation/dissolution test with Bismuth silicate, 3.32 and 3.77 µg/L of bismuth had been released after 28 days from the test item at pH 6 and pH 8, respectively. Considering an initial bismuth silicate load of 1 mg and a maximum possible bismuth release of 748 µg/L (calculated from the test item composition) the test results indicate that the test item is essentially insoluble in both test media.