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

GLP compliance:

yes (incl. QA statement)

Type of method:

other: transformation/ dissolution

Key result

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 mg/L

Incubation duration:

672 h

Test conditions:

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

Remarks on result:

other:

Key result

Type of test:

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

Mean dissolved conc.:

< 0.02 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 mg/L

Incubation duration:

168 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.:

< 0.004 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

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

Remarks on result:

other:

Key result

Type of test:

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

Mean dissolved conc.:

0.877 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 mg/L

Incubation duration:

672 h

Test conditions:

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

Remarks on result:

other: SD: ± 0.5881 µg/L

Key result

Type of test:

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

Mean dissolved conc.:

0.542 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 mg/L

Incubation duration:

168 h

Test conditions:

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

Remarks on result:

other: SD: ± 0.1923 µg/L

Type of test:

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

Mean dissolved conc.:

0.02 µg/L

Element analysed:

Zr

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

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

Remarks on result:

other: SD: ± 0.0042 µg/L

Key result

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 mg/L

Incubation duration:

672 h

Test conditions:

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

Remarks on result:

other:

Key result

Type of test:

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

Mean dissolved conc.:

0.08 µg/L

Element analysed:

Cd

Loading of aqueous phase:

1 mg/L

Incubation duration:

168 h

Test conditions:

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

Remarks on result:

other: SD: ± 0.0046 µg/L

Type of test:

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

Mean dissolved conc.:

0.023 µg/L

Element analysed:

Cd

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

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

Remarks on result:

other: SD: ± 0.0009 µg/L

Key result

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 mg/L

Incubation duration:

672 h

Test conditions:

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

Remarks on result:

other: Background corrected; SD: ± 0.0993 µg/L

Key result

Type of test:

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

Mean dissolved conc.:

0.113 µg/L

Element analysed:

Cd

Loading of aqueous phase:

1 mg/L

Incubation duration:

168 h

Test conditions:

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

Remarks on result:

other: Background corrected; SD: ± 0.0362 µg/L

Type of test:

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

Mean dissolved conc.:

0.033 µg/L

Element analysed:

Cd

Loading of aqueous phase:

1 mg/L

Incubation duration:

24 h

Test conditions:

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

Remarks on result:

other: SD: ± 0.0046 µg/L

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 ± 0.3 °C during the test with 1 mg/L loading at pH 8. The mean temperature during the test at pH 6 was 20.4 ± 0.3 °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 zirconium at 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 8 were background (means) corrected.

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: 0.0011 – 0.068 µg/L Cd: 0.0025 – 0.0053 µg/L
limit of quantification	Zr: 0.0033– 0.0204 µg/L Cd: 0.0076 – 0.0158 µg/L
accuracy and precision	Mean recovery for TM-25.4 1st series Cd: 106.0 ± 1.5% (n = 5) 2nd series Cd: 103.2 ± 1.2 % (n = 9) 4th series Cd: 99.2 ± 1.8 % (n = 11) 6th series Cd: 103.0 ± 0.6 % (n = 9)	Diluted (5 fold) to 4.7 µg Cd/L
accuracy and precision	Mean recovery for TM-25.4 3rd series 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 5th series Cd: 97.7 ± 1.7 % (n = 7)	Diluted (20 fold) to 1.175 µg Cd/L
accuracy and precision	Mean recovery for TMDA-53.3 1st series Cd: 105.1 ± 1.5 % (n = 5) 2nd series Cd: 100.7 ± 2.9 % (n = 9) 4th series Cd: 99.3 ± 1.2 % (n = 11) 5th series Cd: 99.2 ± 1.1 % (n = 7) 6th series Cd: 103.6 ± 1.4 % (n = 9)	Diluted (10 fold) to 11.8 µg Cd/L
accuracy and precision	Mean recovery for TMDA-53.3 3rd series: Cd: 103.6 ± 1.5 % (n = 11)	Diluted (5 fold) to 23.6 µg Cd/L
accuracy and precision	Mean recovery for QC 1st series Zr: 93.9 ± 1.0 % (n = 5) Cd: 99.6 ± 1.3 % (n = 5) 2nd series Zr: 93.6 ± 0.8 % (n = 9) Cd: 96.0 ± 1.3 % (n = 9)	Diluted to 5 µg Zr/ 5 µg Cd/L
accuracy and precision	Mean recovery for QC1 3rd series Zr: 92.8 ± 1.7 % (n = 11) Cd: 99.7 ± 3.2 % (n = 11) 4th series Zr: 91.3 ± 1.3 % (n = 11) Cd: 95.8 ± 0.8 % (n = 11) 5th series Zr: 90.5 ± 1.8 % (n = 7) Cd: 95.7 ± 0.5 % (n = 7)	Diluted to 5 μg Zr/L 5µg Cd/L
accuracy and precision	Mean recovery for QC1 6th series Zr: 102.5 ± 1.5 % (n = 9) Cd: 101.0 ± 2.1 % (n = 9)	Diluted to 10 µg Zr/L 10 µg Cd/L
accuracy and precision	Mean recovery for recalibration samples 1st series Zr: 95.3 ± 0.8 % (n = 5) Cd: 100.9 ± 1.2 % (n = 5) 2nd series Zr: 93.9 ± 0.7 % (n = 9) Cd: 97.3 ± 1.0 % (n = 9) 3rd series Zr: 96.3 ± 2.9 % (n = 11) Cd: 100.8 ± 4.1 % (n = 11) 4th series Zr: 95.7 ± 1.4 % (n = 11) Cd: 98.3 ± 1.0 % (n = 11) 5th series Zr: 95.1 ± 1.0 % (n = 7) Cd: 100.4 ± 3.1 % (n = 7)	Diluted to 10 μg Zr/L 10 μg Cd/L
accuracy and precision	Mean recovery for recalibration samples 6th series Zr: 102.6 ± 2.4 % (n = 9) Cd: 99.2 ± 1.5 % (n = 9)	Diluted to 0.5 μg Zr/L 0.5 µg Cd/L
trueness	recovery of fortified samples: Zr: 89.4 – 120.1 % (n = 16) Cd: 100.3 – 108.6 % and 464.0 % (n = 16)	One Zr sample (120.1 %) is not within 100 ± 15 % and one Cd sample exhibits a recovery of 464.0 %. However, that is not critical because > 60 % of all QA/QC samples are within 100 ± 15 %.

 

Recoveries of fortified samples Zirconium (M - metal; values were rounded, internal calculations were performed with more digits

measured Zr conc. [μg/L] calculated nominal Zr conc. after addition [μg/L] recovery [μg Zr/L] recovery [%] 1st series 1 mL of sample + 2 mL of 5 μg M/L vessel 1, sample a after 2 h 0.0125 3.3375 3.0783 92.2 vessel 4, sample a after 2 h <LOD 3.3333 3.0535 91.6 2nd series1 mL of sample + 2 mL of 5 μg M/L vessel 1, sample a after 6 h 0.0243 3.3414 3.0399 91.0 vessel 4, sample a after 6 h <LOD 3.3333 3.0024 90.1 vessel 1, sample a after 1 d 0.0442 3.3481 3.0428 90.9 vessel 4, sample a after 1 d <LOD 3.3333 3.0044 90.1 3rd series1 mL of sample + 2 mL of 5 μg M/L vessel 4, sample a after 4 d <LOD 3.3333 3.0403 91.2 4th series1 mL of sample + 2 mL of 5 μg M/L vessel 4, sample a after 7 d <LOD 3.3333 3.1727 95.2 5th series1 mL of sample + 2 mL of 5 μg M/L vessel 4, sample a after 14 d <LOD 3.3333 2.9815 89.4 vessel 4, sample a after 21 d <LOD 3.3333 3.1299 93.9 vessel 4, sample a after 28 d <LOD 3.3333 3.1032 93.1 6th series1 mL of sample + 2 mL of 5 μg M/L vessel 1, sample a after 4 d 0.4899 3.4966 3.7389 106.9 vessel 1, sample a after 7 d 0.9467 3.6489 3.9822 109.1 6th series1 mL of sample + 2 mL of 0.5 μg M/L vessel 4, sample a after 14 d 1.4188 0.8063 0.9685 120.1 vessel 4, sample a after 21 d 1.5496 0.8499 0.9674 113.8 vessel 4, sample a after 28 d 1.8906 0.9635 1.0683 110.9

Recoveries of fortified samples Cadmium (M - metal; values were rounded, internal calculations were performed with more digits)

	measured Cd conc. [μg/L]	calculated nominal Cd conc. after addition [μg/L]	recovery [μg Cd/L]	recovery [%]
1st series 1 mL of sample + 2 mL of 5 μg M/L
vessel 1, sample a after 2 h	<LOQ	3.3333	3.6189	108.6
vessel 4, sample a after 2 h	<LOD	3.3333	3.4817	104.5
2nd series 1 mL of sample + 2 mL of 5 μg M/L
vessel 1, sample a after 6 h	0.0172	3.3391	3.4155	102.3
vessel 4, sample a after 6 h	<LOQ	3.3333	3.3447	100.3
vessel 1, sample a after 1 d	0.0327	3.3442	3.5400	105.9
vessel 4, sample a after 1 d	0.0230	3.3410	3.4834	104.3
3rd series 1 mL of sample + 2 mL of 5 μg M/L
vessel 4, sample a after 4 d	0.1497	3.3832	3.4757	102.7
4th series 1 mL of sample + 2 mL of 5 μg M/L
vessel 4, sample a after 7 d	0.0796	3.3599	3.5652	106.1
5th series 1 mL of sample + 2 mL of 5 μg M/L
vessel 4, sample a after 14 d	0.1035	3.3678	3.4327	101.9
vessel 4, sample a after 21 d	0.1261	3.3754	15.6614	464.0
vessel 4, sample a after 28 d	<LOD	3.3333	3.4016	102.0
6th series 1 mL of sample + 2 mL of 5 μg M/L
vessel 1, sample a after 4 d	0.0948	3.3649	3.5265	104.8
vessel 1, sample a after 7 d	0.1531	3.3844	3.5828	105.9
6th series 1 mL of sample + 2 mL of 0.5 μg M/L
vessel 4, sample a after 14 d	0.2650	0.4217	0.4342	103.0
vessel 4, sample a after 21 d	0.3031	0.4344	0.4384	100.9
vessel 4, sample a after 28 d	0.3143	0.4381	0.4510	102.9

 

Conclusions:

The transformation/dissolution test (OECD Series on Testing and Assessment Number 29, 2001) of "Zircon, cadmium yellow" at a loading of 1 mg/L at pH 6 and 8, resulted after 28 days in maximum quantified Zr concentrations of 0.8796 µg/L (pH = 8), as well as maximum Cd concentrations of 0.1966 µg/L (pH = 8). The solubility of zircon, cadmium yellow is below 1.2 µg/L, referring to a solubility of < 0.12 wt%. Thus, the extent to which "Zircon, cadmium yellow " can produce soluble available ionic and other metal-bearing species in aqueous media is limited.

Description of key information

The solubility of Zirconium zircon with encapsulated cadmium sulphide is < 0.12 wt% at a 1mg/L loading. A GLP-conform transformation/dissolution test with a loading of 1 mg/L at pH6 and ph8 over 28 days, revealed higher dissolution at pH 8. Transformation/dissolution at a loading of 1 mg/L at pH8 after 7 days resulted in dissolved cadmium and zirconium concentrations of 0.12µg/L, and 0.54 µg/L, respectively. The dissolved cadmium and zirconium concentrations after 28 days were of 0.197 µg/L and 0.88 µg/L, respectively (Klawonn, 2018). The particle size of the tested sample (BET surface area 0.9 m2/g) is representative for the particle size on the market. Thus, the extent to which "Zirconium zircon with encapsulated cadmium sulphide" can produce soluble available ionic and other metal-bearing species in aqueous media is limited.