Zircon, cadmium yellow

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:

2015-05-06 to 2015-06-15

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

Version / remarks:

2001

Deviations:

yes

Remarks:

Determination at pH 6 and 8 instead of 5.5 and 8.5

GLP compliance:

yes (incl. QA statement)

Type of method:

other: transformation/ dissolution

Type of test:

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

Mean dissolved conc.:

< 0.002 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 other: mg test item/L

Incubation duration:

672 h

Test conditions:

pH 6, agitation at 100 rpm, 21.5 ± 1.5 °C

Remarks on result:

other:

Type of test:

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

Mean dissolved conc.:

0.924 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 other: mg test item/L

Incubation duration:

672 h

Test conditions:

pH 8, agitation at 100 rpm, 21.5 ± 1.5 °C

Remarks on result:

other: SD: ± 0.4349 µg/L

Type of test:

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

Mean dissolved conc.:

0.82 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 other: mg test item/L

Incubation duration:

672 h

Test conditions:

pH 8, agitation at 100 rpm, 21.5 ± 1.5 °C

Remarks on result:

other: SD: ± 0.4349 µg/L

Remarks:

background (means) corrected

Type of test:

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

Mean dissolved conc.:

< 0.005 µg/L

Element analysed:

Cd

Loading of aqueous phase:

1 other: mg test item/L

Incubation duration:

672 h

Test conditions:

pH 6, agitation at 100 rpm, 21.5 ± 1.5 °C

Remarks on result:

other:

Type of test:

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

Mean dissolved conc.:

0.208 µg/L

Element analysed:

Cd

Loading of aqueous phase:

1 other: mg test item/L

Incubation duration:

672 h

Test conditions:

pH 8, agitation at 100 rpm, 21.5 ± 1.5 °C

Remarks on result:

other: SD: ± 0.0993 µg/L

Type of test:

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

Mean dissolved conc.:

0.197 µg/L

Element analysed:

Cd

Loading of aqueous phase:

1 other: mg test item/L

Incubation duration:

672 h

Test conditions:

pH 8, agitation at 100 rpm, 21.5 ± 1.5 °C

Remarks on result:

other: SD: ± 0.0993 µg/L

Remarks:

background (means) corrected

Details on results:

Temperature
The temperature of the thermostatically controlled room was recorded with a Testo 175-T2 data logger. The mean temperature was 20.4 ± 0.2 °C during the test with 1 mg/L loading at pH 8. The mean temperature during the test at pH 6 was 20.4 ± 0.2 °C. Therefore, the mean temperature is in agreement with the OECD guidance document 29.

Solution pH and oxygen concentrations
In solutions containing 1 mg/L of the test item at pH 6 and pH 8 as well as in method blanks (BW), the pHs in the range of 5.8 – 6.5 and 7.6 – 8.2, respectively.

Mass balance
The measured vanadium concentrations in samples from rinsed filters and vessels from pH 6 all were below LODs/LOQs (pH 6: 0.2033/0.6098). Therefore, the mass balance was not calculated for pH 6.
The measured concentrations for mass balance samples from pH 8 were above respective limits. However, the recovery of vanadium was 20.8 – 24.1%. This is clearly below 100 ± 15 %, indicating that aqua regia is not sufficient for a complete dissolution of the test item. The latter fact is expected for inorganic pigments.

Within-vessel variation and between-vessel variation
According to the guidance, “[…]it is reasonable to anticipate that for a constant loading of a substance, tested in a narrow particle size (e.g. 37 - 44 μm) and total surface area range, the within-vessel variation in transformation data should be less than 10 % and the between-vessel variation should be less than 20 %”.
The particle size distribution of each loading replicate may differ and thus resulting in different overall total surface areas per vessel. Since the exposed surface area is affecting the rate of transformation and dissolution of sparingly soluble metal compounds, increases in vessel variations may be observed in tests of materials with wider particle size distributions.
For the measured metals these variations are not always within the limits.
Background concentrations for antimony and vanadium at pH 6 and pH 8 were measured to be in the range of test item loaded samples. Therefore, the measured concentrations from test item loaded vessels at pH 6 and 8 were background (means) corrected. The background concentration of tin was below the LOD.

Method validation summary

Validation parameter	Results	Comment
selectivity	selective wavelength and isotopes for detection and evaluation of Cd and Zr
linearity	applied calibration functions were linear	correlation factor at least 0.9998
limit of detection	Zr: ICP-MS: 0.0011 – 0.068 µg/L ICP-OES (mass balance): 0.1773 µg/L Cd: ICP-MS: 0.0025 – 0.0053 µg/L
limit of quantification	Zr: ICP-MS: 0.0033– 0.0204 µg/L ICP-OES (mass balance): 0.5318 µg/L Cd: ICP-MS: 0.0076 – 0.0158 µg/L
accuracy and precision; repeatability	Mean recovery for TM-25.4 Cd: 102.3 ± 2.7 % (n = 34)	Diluted (5 fold) to 4.7 µg Cd/L
accuracy and precision	Mean recovery for TM-25.4 Cd: 102.3 ± 1.9 % (n = 11)	Diluted (10 fold) to 2.35 µg Cd/L
accuracy and precision	Mean recovery for TM-25.4 Cd: 97.7 ± 1.7 % (n = 7)	Diluted (20 fold) to 1.175 µg Cd/L
accuracy and precision; repeatability	Mean recovery for TMDA-53.3 Cd: 101.2 ± 2.8 % (n = 41)	Diluted (10 fold) to 11.8 µg Cd/L
accuracy and precision	Mean recovery for TMDA-53.3 Cd: 103.6 ± 1.5 % (n = 11)	Diluted (5 fold) to 23.6 µg Cd/L
accuracy and precision; repeatability	Mean recovery for quality control standard QC: Zr: 92.3 ± 1.8 % (n = 43) Cd: 97.3 ± 2.6 % (n = 43)	Diluted to 5 µg Cd, Zr/L
accuracy and precision	Mean recovery for quality control standard QC: Zr: 99.3 ± 1.9 % (n = 9) Mass balance (Zr): 92.9 ± 1.8 (n= 2) Cd: 101.0 ± 2.1 % (n = 9)	Diluted to 10 µg Cd, Zr/L
accuracy and precision; repeatability	Mean recovery for recalibration standard: Zr: 95.3 ± 1.9 % (n = 43) Cd: 99.4 ± 2.8 % (n = 43)	Diluted to 10 µg Cd, Zr/L
accuracy and precision	Mean recovery for recalibration standard: Zr: 94.7 ± 1.4 % (n = 9) Cd: 99.2 ± 1.5 % (n = 9)	Diluted to 0.5 µg Cd, Zr/L
accuracy and precision; repeatability	mean recovery for CRM TMDA-53.3 52Cr[2]: 105.8 ± 6.0 % (n = 31) 118Sn[3]: 103.0 ± 3.1 % (n = 24) Cr 205.560nm: 101.4 ± 1.1 % (n = 7)	Diluted (10 fold) to 34.1 µg Cr/L 1.84 µg Sn/L
trueness	recovery of fortified samples: ICP-MS Zr: 89.4 – 113.9 % (n = 13) Cd: 91.5 – 108.4 % (n = 13) ICP-OES (mass balance) Zr: 100.2 %

Recoveries of fortified samples (values were rounded, internal calculations were performed with more digits)

sample	measured concentration [µg Zr/L]	calculated level after addition [µg Zr/L]	recovery [µg Zr/L] / [%]	measured concentration [µg Cd/L]	calculated level after addition [µg Cd/L]	recovery [µg Cd/L] / [%]
1 mL of sample + 2 mL of 5 µg M/L
Sample a from vessel 1 after 2h	0.013	3.34	3.08 /92.3	0.012	3.34	3.62 / 108.4
Sample a from vessel 4 after 2h	0.002	3.33	3.48 / 104.4	<LOD	3.33	3.05 / 91.5
Sample a from vessel 1 after 6h	0.024	3.34	3.04 / 91.0	0.017	3.34	3.42 / 102.4
Sample a from vessel 4 after 6h	<LOD	3.33	3.33 / 99.9	0.007	3.34	3.34 / 100.1
Sample a from vessel 1 after 24h	0.044	3.35	3.04 / 90.8	0.033	3.34	3.34 / 99.9
Sample a from vessel 4 after 24h	<LOD	3.33	3.33 / 99.9	0.023	3.34	3.34 / 100.0
Sample a from vessel 4 after 96h	<LOD	3.33	3.04 / 91.2	0.150	3.38	3.48 / 102.7
Sample a from vessel 4 after 168h	0.005	3.34	3.17 / 95.1	0.080	3.36	3.57 / 106.1
Sample a from vessel 4 after 336h	<LOD	3.33	2.98 / 89.4	0.103	3.37	3.43 / 101.9
Sample a from vessel 4 after 672h	<LOD	3.33	3.10 / 93.1	<LOD	3.33	3.40 / 102.0
Sample a from vessel 1 after 96h	0.306	3.44	3.39 / 98.8	0.095	3.36	3.53 / 104.8
Sample a from vessel 1 after 168h	0.654	3.55	3.80 / 107.0	0.153	3.38	3.58 / 105.9
1 mL of sample + 2 mL of 0.5 µg M/L
Sample a from vessel 1 after 672h	1.428	0.81	0.92 / 113.9	0.314	0.438	0.451 / 102.9
0.5 mL of sample from mass balance + 4.5 mL of 2.5 µg M/L
Sample from rinsed filter 1 (mass balance)	<LOD	2.25	2.25 / 100.2

Conclusions:

According to the OECD Series on Testing and Assessment Number 29 (2001), dissolved mean Zr and Cd concentrations were determined in a transformation/dissolution test with a loading of 1 mg test item (zircon, cadmium yellow) /L media (agitation at 100 rpm, 21.5 ± 1.5 °C) over 672 hours with samplings after 2 h, 6 h, 24 h, 96 h, 168 h, 332 h, 504 h and 672 h. Following conecntrations were determined after 672 h:
pH 6 pH 8
Zr [µg/L] Cd [µg/L] Zr [µg/L] background (means) corrected 0.8195 ± 0.4349
Cd [µg/L] background (means) corrected 0.1973 ± 0.0993

Description of key information

Transformation/ dissolution of zircon, cadmium yellow with a loading of 1 mg/L at 21.5 ± 1.5 °C after 672 hours at pH 8:

- Zr [µg/L] background (means) corrected: 0.8195 ± 0.4349

- Cd [µg/L] background (means) corrected: 0.1973 ± 0.0993

Additional information

According to the OECD Series on Testing and Assessment Number 29 (2001), dissolved mean Zr and Cd concentrations were determined in a transformation/dissolution test with a loading of 1 mg test item (zircon, cadmium yellow) /L media (agitation at 100 rpm, 21.5 ± 1.5 °C) over 672 hours with samplings after 2 h, 6 h, 24 h, 96 h, 168 h, 332 h, 504 h and 672 h. Following conecntrations were determined after 672 h:

	pH 6	pH 8
Zr [µg/L]	<LOD (<0.0017)	0.9241 ± 0.4349
Cd [µg/L]	<LOD (<0.0048)	0.2077 ± 0.0993
Zr [µg/L] background (means) corrected		0.8195 ± 0.4349
Cd [µg/L] background (means) corrected		0.1973 ± 0.0993