Chrome antimony titanium buff rutile

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:

2017-03-21 to 2017-07-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and OECD guideline compliant 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

Principles of method if other than guideline:

The transformation/dilution of chrome antimony titanium buff rutile (Sicotan Yellow K 2011) in environmentally relevant test medium were estimated according to the OECD Series on Testing and Assessment 29: Guidance document on transformation/dissolution of metals and metal compounds in aqueous media ENV/JM/MONO(2001)9. The transformed/dissolved amount of the test item was quantified by assessing the elemental chromium and antimony concentrations in the test media.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Type of test:

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

Mean dissolved conc.:

0.071 µg/L

Element analysed:

Cr

Loading of aqueous phase:

1 mg/L

Incubation duration:

7 d

Test conditions:

pH 8.5, 0.2 µm filtration

Key result

Type of test:

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

Mean dissolved conc.:

0.05 µg/L

Element analysed:

Cr

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

pH 8.5, 0.2 µm filtration

Key result

Type of test:

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

Mean dissolved conc.:

0.766 µg/L

Element analysed:

Sb

Loading of aqueous phase:

1 mg/L

Incubation duration:

7 d

Test conditions:

pH 8.5, 0.2 µm filtration

Key result

Type of test:

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

Mean dissolved conc.:

1.027 µg/L

Element analysed:

Sb

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

pH 8.5, 0.2 µm filtration

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

0.073 µg/L

Element analysed:

Cr

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

pH 8.5, 0.2 µm filtration

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

0.029 µg/L

Element analysed:

Cr

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 6, 0.2 µm filtration

Remarks on result:

other: Concentrations below the LOD (5 out of 6 samples) were estimated as follows in order to allow for the calculation of a mean Cr concentration: LOD > x = LOD / √(2) = 0.0065 µg/L.

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

0.193 µg/L

Element analysed:

Cr

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 8.5, 0.2 µm filtration

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

0.253 µg/L

Element analysed:

Sb

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

pH 8.5, 0.2 µm filtration

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1.859 µg/L

Element analysed:

Sb

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 6, 0.2 µm filtration

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

2.139 µg/L

Element analysed:

Sb

Loading of aqueous phase:

100 mg/L

Incubation duration:

24 h

Test conditions:

pH 8.5, 0.2 µm filtration

Key result

Type of test:

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

Mean dissolved conc.:

0.13 µg/L

Element analysed:

Cr

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

pH 8.5, 0.2 µm filtration

Key result

Type of test:

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

Mean dissolved conc.:

0.277 µg/L

Element analysed:

Cr

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

pH 8.5, 0.2 µm filtration

Key result

Type of test:

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

Mean dissolved conc.:

2.246 µg/L

Element analysed:

Sb

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

pH 8.5, 0.2 µm filtration

Key result

Type of test:

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

Mean dissolved conc.:

7.731 µg/L

Element analysed:

Sb

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

pH 8.5, 0.2 µm filtration

Details on results:

All data presented above including the screening test ("solubility of metal ions in aqueous media") are corrected for background if practical (i.e. measured mean elemental concentrations in method blanks > LOQ). Blank concentrations below the LOD or LOQ were estimated as follows in order to allow for the calculation of a mean Cr blank value: LOD > x = LOD / √(2) and/or LOQ > x > LOD = LOD + 0.5 x (LOQ – LOD). For Cr and Sb background levels used for correction in the full test, please refer to "any other information on results incl. tables, Table 4: Relevant dissolved (0.2 µm filtration) Cr and Sb concentrations in method blanks".

Solution pH, oxygen concentrations, temperature:
Mean temperature was 22.7 ± 0.1 °C during the screening test at pH 6 and 21.5 ± 0.1 °C during the screening test at pH 8.5. Mean temperatures during the full test were 21.4 ± 0.1 °C (loadings of 10 and 100 mg/L) and 21.5 ± 0.3 °C (1 mg/L loading).
In the 100 mg/L screening tests, pH values at pH 6 and pH 8.5 (target pH) in sample and blank vessels were in the range of 5.9 – 6.1 and 8.7, respectively.
In the 1, 10 and 100 mg/L full tests, pH values at pH 8 (target pH) in sample and blank vessels were in the range of pH 8.3 – 8.8.
Oxygen levels of all test solutions were in the range recommended by the OECD Test Guidance 29 during the test (> 70 % of oxygen saturation at 8.5 mg/L (70 % of 8.5 mg/L = 6 mg/L).

Within and between vessel variations in titanium and antimony concentrations
At some samples, the within-vessel variation in transformation data and the between vessel variation exceeded 10 and 20 %, respectively. This can be explained by formation of particles which have passed the filter membrane. However, these variations have no impact on the overall results.

The 24 h screening measurements were performed with a concentration of the test item of 100 mg/l. At pH = 6.0, the concentrations of Cr were mainly below LOD (0.009 µg/L) and 1.9 µg/L Sb were found in the solution, after 24 hours of leaching time. The same procedure was performed at pH = 8.5 and the concentration of Cr and Sb were found to be 0.2 and 2.2 µg/L, respectively. Therefore, the full tests were conducted at the most relevant pH with respect to ecotoxicology, i.e. at pH 8.5. Slight chromium and antimony background concentrations were measured. If dissolved metal amounts of test item loaded samples were in the range of background levels, the mean background concentrations per day were additionally subtracted.

The results are presented in following tables:

Table 1: Mean chromium and antimony concentrations at a loading rate of 1 mg/L

Sample time [h]	Metal average concentration at a loading rate of 1 mg/L
	Cr [µg/L]	Sb [µg/L]
2	0.0046*	<LOQ
6	0.0058*	0.0494*
24	0.0728*	0.2527*
96	0.1053*	0.5842*
168	0.0710*	0.7662*
336	0.0500*	0.8611*
504	0.0594*	0.9832*
672	0.0495*	1.0274*

 *data corrected for elemental background in method blanks

 

Table 2: Mean chromium and antimony concentrations at a loading rate of 10 mg/L

Sample time [h]	Metal average concentration at a loading rate of 10 mg/L
	Cr [µg/L]	Sb [µg/L]
2	0.0127*	0.0694
6	0.0209*	0.1843
24	0.1124*	0.9451
96	0.1849*	2.1535
168	0.1299*	2.2573

 *data corrected for elemental background in method blanks

Table 3: Mean chromium and antimony concentrations at a loading rate of 100 mg/L

Sample time [h]	Metal average concentration at a loading rate of 100 mg/L
	Cr [µg/L]	Sb [µg/L]
2	0.0532*	0.3914
6	0.0318*	0.6850
24	0.0872*	2.2094
96	0.2416*	5.8518
168	0.2771*	7.7426

 *data corrected for elemental background in method blanks

 

Table 4: Full test - Relevant dissolved (0.2 µm filtration) Sb concentrations in method blanks

Sample time [h]	pH	Sb [µg/L]
7 d	8.5	0.0110

Conclusions:

The transformation/dissolution test (OECD Series on Testing and Assessment Number 29, 2001) of chrome antimony titanium buff rutile (Sicotan Yellow K 2011) at a loading of 1 mg/L at pH 8.5, i.e. the pH that maximizes the dissolution, resulted after 1, 7 and 28 days in dissolved chromium concentrations (0.2 µm filtration) of 0.0728, 0.0710 and 0.0495 µg Cr/L, respectively. In addition, dissolved antimony concentrations after 1, 7 and 28 days at pH 8.5 were determined with 0.2527, 0.7662 and 1.0274 µg Sb/L, respectively. At loadings of 10 and 100 mg/L test item, dissolved chromium concentrations after 7 days amounted to 0.1299 and 0.2771 µg Cr/L whereas dissolved antimony concentrations were determined with 2.2456 and 7.7309 µg Sb/L, respectively. Thus, the extent to which chrome antimony titanium buff rutile (Sicotan Yellow K 2011) can produce soluble available ionic and other metal-bearing species in aqueous media is limited.

Description of key information

Chrome antimony titanium buff rutile (Sicotan Yellow K 2011) is practically insoluble in water (<0.1 mg/L at 20 °C). In addition, the extent to which chrome antimony titanium buff rutile can produce soluble available ionic and other metal-bearing species in aqueous media is limited. According to a transformation/dissolution test (OECD Series on Testing and Assessment Number 29, 2001), measured dissolved antimony and chromium concentrations (0.2 µm fraction) after 7 and 28 days at a loading of 1 mg/L at pH 8.5 (i.e. the pH which maximizes dissolution) amount for 0.07 and 0.05 µg/L chromium as well as 0.76 and 1.03 µg Sb/L antimony, respectively. At loadings of 10 and 100 mg/L test item, dissolved chromium concentrations after 7 days amounted to 0.13 and 0.28 µg Cr/L whereas dissolved antimony concentrations were determined with 2.25 and 7.73 µg Sb/L, respectively. Thus, the dissolution of chrome antimony titanium buff rutile in relevant environmental media is limited.

Additional information

The substance is insoluble in water.

Transformation/dissolution of the substance according to OECD 29:

(i): 24 h, loading 100 mg/L: 0.029 µg/L for Cr and 1.86 µg/L Sb at pH 6 and 0.19 µg/L Cr and 2.14 µg/L Sb at pH 8.5

(ii): 7 d, loading 1, 10 and 100 mg/L at pH 8.5: 0.07, 0.13 and 0.28 µg/L for Cr and 0.76, 2.25 and 7.73 µg/L for Sb

(iii): 28 d, loading 1 mg/L at pH 8.5: 0.05 µg/L for Cr and 1.03 µg/L for Sb