Alkaline co-precipitation products of soluble cobalt, manganese and nickel salts

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

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

GLP compliance:

yes (incl. QA statement)

Type of method:

other: transformation/dissolution

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

45.9 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

42.7 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 6.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

14.2 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1.27 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

86 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

76.3 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 6.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

45.5 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

12 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

2 444 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

2 215 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 6.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1 480 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

541 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.5

Key result

Type of test:

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

Mean dissolved conc.:

14.1 µg/L

Element analysed:

Mn

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

32.4 µg/L

Element analysed:

Mn

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

193 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

15.4 µg/L

Element analysed:

Co

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

44.3 µg/L

Element analysed:

Co

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

377 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

310 µg/L

Element analysed:

Ni

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

951 µg/L

Element analysed:

Ni

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

8 314 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Results

Observations
In vessels loaded with 1 mg/L after 14 days it cannot be clearly seen, if the material is completely dissolved, due to the low loading.

 

Temperature
The temperature of the thermostatically controlled room was monitored inside an extra vessel filled with ultrapure water by thermo data loggers (Testo 175-T2, Testo AG, Germany). Two data loggers were applied to have a backup in case of malfunction.

lt can be clearly seen that the temperatures were always in the range of 21.5 ± 1.5 °C (upper limit at 23.0 °C and lower at
20.0 °C) for both data loggers in all tiers of the test.

 

Solution pH and dissolved oxygen concentrations

In the following chapters the measured pH values and oxygen concentration in the pH optimum screening test as well as in the full test are given.

 

Screening test for optimum pH

At target pH 5.5 the pH value in method blanks over the 1 d were in the range of 5.35 - 5.67. In test item loaded vessels the pH value increased from 5.35 to 7.08.

At target pH 6.0 the pH value in method blanks was in the range of 5.94 to 6.04. In test item loaded vessels the pH value increased from 5.95 to 7.00.

lncreasing of pH values in media at target pH values of 5.5 and 6.0 is probably due to the test item properties.

At target pH 8.0 the pH value in method blanks was in the range of 7.72 to 8.21. In test item loaded vessels the pH value increased slightly from 7.83 to 8.03.

At target pH 8.5 the pH value in method blanks was in the range of 8.38 to 8.48. In test item loaded vessels the pH value increased slightly from 8.39 to 8.45.

 

Media pH values at target pH of 5.5, 6, 8 and 8.5 in all vessels of the one day test with loadlng of 100 mg/L (K1, K2, K3- triplicate vessels, BW - method blank): The dissolved oxygen concentration in the screening test is in accordance with the guidance document [4] of at least 70 % of 8.5 ppm = 6.0 ppm. All measured values are above 6.0 ppm.

 

Results of measured Mn, Ni and Co concentration in 0.2 µm filtrates from the screening test for the optimum pH for the method blanks:

Mn concentrations in method blanks in 1 d test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]
5.5	0.051	0.153	1	0.051	0.000
6.0	0.051	0.153	1	0.051	0.000
8.0	0.051	0.153	1	0.055	0.010
8.5	0.051	0.153	1	0.051	0.000

 

Co concentratlons in method blanks In 1 d test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]
5.5	0.484	1.45	1	0.484	n.a.
6.0	0.484	1.45	1	0.484	n.a.
8.0	0.484	1.45	1	0.484	n.a.
8.5	0.484	1.45	1	0.484	n.a.

 

Ni concentrations in method blanks in 1 d test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels ± SD [µg/L]
5.5	0.594	1.78	1	0.792±0.171
6.0	0.594	1.78	1	0.643 ± 0.086
8.0	0.594	1.78	1	0.792 ± 0.086
8.5	0.594	1.78	1	1.23 ± 0.85

 

The results of measured Mn, Ni and Co concentration in 0.2 µm filtrates from the screening test for the optimum pH are for test item loaded samples:

Mn concentrations in test item loaded samples 100 mg/L in 1d test (1. 2. 3- triplicate vessels, a, b -duplicate samples)

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Dilution factor	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [µg/L]
5.5	0.051	0.153	1	3	45.9	1.0	2.2
6.0	0.051	0.153	1	3	42.7	2.9	6.8
8.0	0.051	0.153	1	3	14.2	0.5	3.5
8.5	0.051	0.153	1	3	1.27	0.14	10.9

 

Co concentrations in test item loaded samples 100 mg/L in 1d test (1. 2. 3- triplicate vessels, a, b -duplicate samples)

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Dilution factor	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [µg/L]
5.5	0.484	1.45	1	3	86.0	3.1	3.6
6.0	0.484	1.45	1	3	76.3	7.8	10.2
8.0	0.484	1.45	1	3	45.5	1.9	4.3
8.5	0.484	1.45	1	3	12.0	0.2	1.7

 

Ni concentrations in test item loaded samples 100 mg/L in 1d test (1. 2. 3- triplicate vessels, a, b -duplicate samples)

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Dilution factor	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [µg/L]
5.5	0.594	1.78	1	3	2444	94	3.9
6.0	0.594	1.78	1	3	2215	209	9.5
8.0	0.594	1.78	1	3	1480	66	4.5
8.5	0.594	1.78	1	3	541	20	3.7

 

Analytical measurements

According to the measured concentrations the simulated environmental water which maximizes dissolution in the 1 day test is the medium at target pH 5.5. Therefor this medium was used in full tests.

 

Full test

The pH in method blank media was in the range of 5.27 - 5. 72 over 7 days of testing and 5.34 -5.79 from day 14 to day 28.

The pH value for the loading of 1 mg/L increased from 5.37 - 5.52 (prior to test start) to 5. 76 -5.83 on day seven. On day 28 pH values of 6.03 - 6.13 were recorded. The maximum pH was measured on day 21 (value of 6.16).

In media with the loading of 10 mg/L the pH value increased from 5.36 - 5.61 to 6.34 - 6.36.

In media with the loading of 100 mg/L the pH value increased from 5.35 - 5.58 to 7.32 - 7.33.

Due to the fact that the pH values in the method blanks were mainly in a constant range (5.5 ± 0.3) in contrast to the test item loaded media (1 mg: 5.5 ± 0.7; 10 mg: 5.5 ± 0.9; 100 mg: 5.5 ± 1.8) the increase is probably due to the test item properties.

 

 

Mn concentratlons in method blanks in 28 d full test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]
0.058	0.175	0.083	0.068	0.008
0.058	0.175	0.25	0.068	0.008
0.058	0.175	1	0.063	0.008
0.112	0.336	4	0.112	0.000
0.112	0.336	7	0.112	0.000
0.139	0.418	14	0.197	0.020
0.139	0.418	21	0.209	0.000
0.139	0.418	28	0.334	0.217

 

Mn concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L with all vessels (1, 2, 3- triplicate vessels, a, b- duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [%]	Mn background conc. [µg/L]	Mean Mn conc. vessels-background corrected [µg/L]
0.058	0.175	0.083	0.124	0.032	26.0	0.068	0.056
0.058	0.175	0.25	0.294	0.035	11.9	0.068	0.226
0.058	0.175	1	0.831	0.147	17.7	0.063	0.768
0.112	0.336	4	2.92	0.59	20.1	0.112	2.81
0.112	0.336	7	5.68	0.40	7.0	0.112	5.57
0.139	0.418	14	10.4	0.5	5.2	0.197	10.2
0.139	0.418	21	12.8	0.9	7.2	0.209	12.6
0.139	0.418	28	14.4	0.9	6.3	0.334	14.1

 

Mn concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L without vessel 1 (1,2, 3- triplicate vessels, a, b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [%]	Mn background conc. [µg/L]	Mean Mn conc. vessels-background corrected [µg/L]
0.058	0.175	0.083	0.113	0.036	31.8	0.068	0.045
0.058	0.175	0.25	0.275	0.017	6.1	0.068	0.207
0.058	0.175	1	0.787	0.177	22.5	0.063	0.724
0.112	0.336	4	2.92	0.83	28.4	0.112	2.81
0.112	0.336	7	5.90	0.11	1.9	0.112	5.79
0.139	0.418	14	10.6	0.5	5.0	0.197	10.4
0.139	0.418	21	13.1	1.2	8.9	0.209	12.8
0.139	0.418	28	14.4	1.3	8.9	0.334	14.1

 

Mn concentrations in test item loaded samples in 7 d test with the loading of 10 mg/L (1, 2, 3- tripllcate vessels, a, b - duplicate samples)

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [%]	Mn background conc. [µg/L]	Mean Mn conc. vessels-background corrected [µg/L]
0.058	0.164	0.083	0.701	0.015	2.2	0.068	0.633
0.058	0.164	0.25	1.43	0.06	4.3	0.068	1.36
0.058	0.255	1	5.01	0.18	3.6	0.063	4.95
0.112	0.255	4	16.4	1.1	6.6	0.112	16.3
0.112	0.336	7	32.5	2.6	8.1	0.112	32.4

 

Mn concentrations in test item loaded samples in 7 d test with the loading of 100 mg/L (1, 2, 3- triplicate vessels, a,b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [%]	Mn background conc. [µg/L]	Mean Mn conc. vessels-background corrected [µg/L]
0.058	0.175	0.083	5.50	0.71	12.9	0.068	5.44
0.058	0.175	0.25	12.1	0.6	5.1	0.068	12.0
0.058	0.175	1	53.1	1.8	3.3	0.063	53.0
0.112	0.366	4	162	3	1.7	0.112	162
0.112	0.366	7	193	7	3.9	0.112	193

 

Co concentratlons in method blanks in 28 d full test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]
0.215	0.646	0.083	0.323	0.000
0.215	0.646	0.25	0.323	0.000
0.215	0.646	1	0.323	0.000
0.053	0.159	4	0.219	0.098
0.053	0.159	7	0.328	0.149
0.781	2.34	14	0.781	0.000
0.781	2.34	21	0.846	0.113
0.781	2.34	28	0.846	0.113

 

Co concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L with all vessels (1, 2, 3- triplicate vessels, a, b- duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [%]	Co background conc. [µg/L]	Mean Co conc. vessels-background corrected [µg/L]
0.215	0.646	0.083	0.323	0.000	0.0	0.323	0.000
0.215	0.646	0.25	0.667	0.127	19.0	0.323	0.344
0.215	0.646	1	1.14	0.259	22.8	0.323	0.813
0.053	0.159	4	4.14	0.704	17.0	0.219	3.93
0.053	0.159	7	7.30	0.356	4.9	0.328	6.97
0.781	2.34	14	12.5	0.763	6.1	0.781	11.7
0.781	2.34	21	14.6	0.777	5.3	0.846	13.8
0.781	2.34	28	16.3	0.810	5.0	0.846	15.4

 

Co concentrations in test item loaded samples in 28 d test with theloading of 1 mg/L without vessel 1 (1, 2, 3- triplicate vessels, a, b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [%]	Co background conc. [µg/L]	Mean Co conc. vessels-background corrected [µg/L]
0.215	0.646	0.083	0.323	0.000	0.0	0.323	0.000
0.215	0.646	0.25	0.609	0.107	17.7	0.323	0.286
0.215	0.646	1	1.05	0.297	28.3	0.323	0.726
0.053	0.159	4	4.09	0.986	24.1	0.219	3.87
0.053	0.159	7	7.50	0.081	1.1	0.328	7.17
0.781	2.34	14	12.8	0.791	6.2	0.781	12.0
0.781	2.34	21	14.7	1.070	7.3	0.846	13.9
0.781	2.34	28	16.3	1.145	7.0	0.846	15.4

 

Co concentrations in test item loaded samples in 7 d test with the loading of 10 mg/L (1, 2, 3- tripllcate vessels, a, b - duplicate samples)

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [%]	Co background conc. [µg/L]	Mean Co conc. vessels-background corrected [µg/L]
0.215	0.646	0.083	1.39	0.21	15.4	0.323	1.07
0.215	0.646	0.25	2.27	0.25	10.9	0.323	1.95
0.215	0.646	1	6.86	0.28	4.0	0.323	6.54
0.053	0.159	4	22.3	1.2	5.2	0.219	22.1
0.053	0.159	7	44.7	3.8	8.5	0.328	44.3

 

Co concentrations in test item loaded samples in 7 d test with the loading of 100 mg/L (1, 2, 3- triplicate vessels, a,b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [%]	Co background conc. [µg/L]	Mean Co conc. vessels-background corrected [µg/L]
0.215	0.646	0.083	10.6	1.3	12.4	0.323	10.2
0.215	0.646	0.25	22.7	1.3	5.7	0.323	22.3
0.215	0.646	1	95.7	2.6	2.7	0.323	95.4
0.053	0.159	4	294	3	0.9	0.219	293
0.053	0.159	7	377	12	3.2	0.328	377

 

Ni concentratlons in method blanks in 28 d full test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]
0.947	2.84	0.083	0.947	0.000
0.947	2.84	0.25	0.947	0.000
0.947	2.84	1	0.947	0.000
0.736	2.21	4	0.858	0.106
0.736	2.21	7	0.919	0.000
0.575	1.73	14	0.623	0.083
0.575	1.73	21	0.623	0.083
0.575	1.73	28	0.623	0.083

 

Ni concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L with all vessels (1, 2, 3- triplicate vessels, a, b- duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [%]	Ni background conc. [µg/L]	Mean Ni conc. vessels-background corrected [µg/L]
0.947	2.84	0.083	6.35	0.45	7.1	0.947	5.40
0.947	2.84	0.25	11.2	0.8	7.1	0.947	10.2
0.947	2.84	1	30.8	4.0	13.1	0.947	29.8
0.736	2.21	4	84.7	14.4	17.0	0.858	83.8
0.736	2.21	7	146	7	4.6	0.919	145
0.575	1.73	14	237	10	4.2	0.623	236
0.575	1.73	21	282	16	5.7	0.623	282
0.575	1.73	28	309	18	5.8	0.623	308

 

Ni concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L without vessel 1 (1, 2, 3- triplicate vessels, a, b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [%]	Ni background conc. [µg/L]	Mean Ni conc. vessels-background corrected [µg/L]
0.947	2.84	0.083	6.39	0.63	9.8	0.947	5.44
0.947	2.84	0.25	11.2	1.1	10.1	0.947	10.2
0.947	2.84	1	30.3	5.6	18.5	0.947	29.4
0.736	2.21	4	83.7	20.0	24.2	0.858	82.8
0.736	2.21	7	150	1	1.0	0.919	149
0.575	1.73	14	240	11	4.4	0.623	240
0.575	1.73	21	285	21	7.5	0.623	285
0.575	1.73	28	310	25	8.0	0.623	310

 

Ni concentrations in test item loaded samples in 7 d test with the loading of 10 mg/L (1, 2, 3- tripllcate vessels, a, b - duplicate samples)

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [%]	Ni background conc. [µg/L]	Mean Ni conc. vessels-background corrected [µg/L]
0.947	2.84	0.083	50.4	1.2	2.4	0.947	49.4
0.947	2.84	0.25	86.9	3.5	4.1	0.947	85.9
0.947	2.84	1	207	5	2.4	0.947	206
0.736	2.21	4	503	27.5	5.5	0.858	503
0.736	2.21	7	952	80	8.4	0.919	951

 

Ni concentrations in test item loaded samples in 7 d test with the loading of 100 mg/L (1, 2, 3- triplicate vessels, a,b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [%]	Ni background conc. [µg/L]	Mean Ni conc. vessels-background corrected [µg/L]
0.947	2.84	0.083	479	43	9.0	0.947	478
0.947	2.84	0.25	888	49	5.6	0.947	887
0.947	2.84	1	2762	62	2.2	0.947	2761
0.736	2.21	4	6644	120	1.8	0.858	643
0.736	2.21	7	8315	194	2.3	0.919	8314

 

 

 

Reference 2

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

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

GLP compliance:

yes (incl. QA statement)

Type of method:

other: transformation/dissolution

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

981 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

956 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 6.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

844 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

305 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1 371 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1 343 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 6.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1 165 mg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

495 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1 472 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1 442 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 6.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

1 028 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.0

Key result

Type of test:

screening transformation/dissolution test - sparingly soluble metal compounds

Mean dissolved conc.:

375 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

1 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 8.5

Key result

Type of test:

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

Mean dissolved conc.:

70.3 µg/L

Element analysed:

Mn

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

103 µg/L

Element analysed:

Mn

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

857 µg/L

Element analysed:

Mn

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

78.2 µg/L

Element analysed:

Co

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 wk

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

161 µg/L

Element analysed:

Co

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

2 128 µg/L

Element analysed:

Co

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

76.9 µg/L

Element analysed:

Ni

Loading of aqueous phase:

1 mg/L

Incubation duration:

28 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

218 µg/L

Element analysed:

Ni

Loading of aqueous phase:

10 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Key result

Type of test:

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

Mean dissolved conc.:

3 629 µg/L

Element analysed:

Ni

Loading of aqueous phase:

100 mg/L

Incubation duration:

7 d

Test conditions:

Temperature: 21.5 ± 1.5 °C
pH value: 5.5

Results

Visual Observations
Some black substance is floating on top of medium surface and further material is found at the bottom of test item loaded flasks for the loadings of 10 mg/L and 100 mg/L. Moreover, on the inner glass wall of test item loaded flasks a black ring consisting out of the substance was
observed. In vessels loaded with 1 mg/L after 14 days it cannot be clearly seen, if the material is completely dissolved, due to the low loading.

 

Temperature
The temperature of the thermostatically controlled room was monitored inside an extra vessel filled with ultrapure water by thermo data loggers (Testo 175-T2, Testo AG, Germany). Two data loggers were applied to have a backup in case of malfunction.
lt can be observed that the temperatures were always in the range of 21.5 ± 1.5 °C (upper limit at 23.0 °C and lower at 20.0 °C) for both data loggers in all tiers of the test.

 

Solution pH and dissolved oxygen concentrations

Screening test for optimum pH

At target pH 5.5 the pH value in method blanks over the 1 d were in the range of 5.43 - 5. 72. In test item loaded vessels the pH value increased from 5.48 to 7.02.

At target pH 6.0 the pH values in method blanks were in the range of 5.95 to 6.23. In test item loaded vessels the pH values increased from 6.01 to 6.92 - 6.96.

The increase of pH values in media at target pH values of 5.5 and 6.0 is probably due to the test item properties.

At target pH 8.0 the pH values in method blanks and in test item loaded samples were in the range of 7.86 - 7.92. An increase of the pH values was not observable.

In medium at target pH 8.5 the pH values in method blanks were in the range 8.36 - 8.40. In test item loaded media the pH values were in the range of 8.29 - 8.38. As for the pH 8.0 an increase of the pH was not observable.

Media pH values at target pH of 5.5, 6, 8 and 8.5 in all vessels of the one day test with loadlng of 100 mg/L (K1, K2, K3- triplicate vessels, BW - method blank): The dissolved oxygen concentration in the screening test is in accordance with the guidance document [4] of at least 70 % of 8.5 ppm = 6.0 ppm. All measured values are above 6.0 ppm.

 

Results of measured Mn, Ni and Co concentration in 0.2 µm filtrates from the screening test for the optimum pH for the method blanks:

Mn concentrations in method blanks in 1 d test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]
5.5	0.154	0.462	1	0.180	0.022
6.0	0.154	0.462	1	0.167	0.022
8.0	0.154	0.462	1	0.167	0.022
8.5	0.154	0.462	1	0.205	0.022

 

Co concentratlons in method blanks In 1 d test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]
5.5	0.573	1.72	1	0.859	0.000
6.0	0.573	1.72	1	0.859	0.000
8.0	0.573	1.72	1	0.764	0.165
8.5	0.573	1.72	1	0.859	0.000

 

Ni concentrations in method blanks in 1 d test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]
5.5	0.446	1.34	1	0.446	0.000
6.0	0.446	1.34	1	0.446	0.000
8.0	0.446	1.34	1	0.446	0.000
8.5	0.446	1.34	1	0.483	0.064

 

The results of measured Mn, Ni and Co concentration in 0.2 µm filtrates from the screening test for the optimum pH are for test item loaded samples:

Mn concentrations in test item loaded samples 100 mg/L in 1d test (1. 2. 3- triplicate vessels, a, b -duplicate samples)

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Dilution factor	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [µg/L]
5.5	0.154	0.462	1	2	981	36	3.6
6.0	0.154	0.462	1	2	956	6	0.6
8.0	0.154	0.462	1	2	844	4	0.5
8.5	0.154	0.462	1	2	305	4	1.4

 

Co concentrations in test item loaded samples 100 mg/L in 1d test (1. 2. 3- triplicate vessels, a, b -duplicate samples)

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Dilution factor	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [µg/L]
5.5	0.573	1.72	1	2	1371	46	3.3
6.0	0.573	1.72	1	2	1343	11	0.8
8.0	0.573	1.72	1	2	1165	11	0.9
8.5	0.573	1.72	1	2	495	7	1.4

 

Ni concentrations in test item loaded samples 100 mg/L in 1d test (1. 2. 3- triplicate vessels, a, b -duplicate samples)

Target pH	LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Dilution factor	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [µg/L]
5.5	0.446	1.34	1	2	1472	49	3.3
6.0	0.446	1.34	1	2	1442	12	0.9
8.0	0.446	1.34	1	2	1028	12	1.2
8.5	0.446	1.34	1	2	375	4	1.0

 

Analytical measurements

According to the measured concentrations the simulated environmental water which maximizes dissolution in the 1 day test is the medium at target pH 5.5. Therefor this medium was used in full tests.

 

Full test

The pH values in method blank media were in the range of 5.37 - 5. 73 over 7 days of testing and 5.47 - 5.75 from day 14 to day 28.

The pH values for the loading of 1 mg/L were in the range of 5.35 (prior to test start) to 6.06 over the whole period of testing. Over the period of sampling an increase of the pH was observable with a maximum of 6.06 on day 14.

In media with a loading of 10 mg/L the pH values ranged from 5.47 to 6.25 andin media with a loading of 100 mg/L the pH value from 5.33 to 7.19. In both loadings an increase of the pH was observable as for the 1 mg/L loading.

 

The dissolved oxygen concentrations in vessels of the full test are in accordance with the guidance document [4] of at least 70 % of 8.5 ppm = 6.0 ppm. All measured values are above 6.0 ppm.

 

Mn concentratlons in method blanks in 28 d full test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]
0.055	0.164	0.083	0.055	0.000
0.055	0.164	0.25	0.068	0.000
0.085	0.255	1	0.135	0.050
0.085	0.255	4	0.113	0.012
0.085	0.255	7	0.113	0.012
0.166	0.498	14	0.166	0.000
0.166	0.498	21	0.180	0.024
0.166	0.498	28	0.166	0.00

 

Mn concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L with all vessels (1, 2, 3- triplicate vessels, a, b- duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [%]	Mn background conc. [µg/L]	Mean Mn conc. vessels-background corrected [µg/L]
0.055	0.164	0.083	1.46	0.50	34.4	0.055	1.40
0.055	0.164	0.25	3.55	1.97	55.6	0.068	3.48
0.085	0.255	1	10.3	9.71	94.6	0.135	10.1
0.085	0.255	4	24.0	20.2	84.0	0.113	23.9
0.085	0.255	7	39.7	14.9	37.6	0.113	39.8
0.166	0.498	14	53.5	9.70	18.1	0.166	53.4
0.166	0.498	21	63.2	9.19	14.5	0.180	63.0
0.166	0.498	28	70.3	9.69	13.8	0.166	70.2

 

Mn concentrations in test item loaded samples in 7 d test with the loading of 10 mg/L (1, 2, 3- tripllcate vessels, a, b - duplicate samples)

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [%]	Mn background conc. [µg/L]	Mean Mn conc. vessels-background corrected [µg/L]
0.055	0.164	0.083	8.11	0.63	7.8	0.055	8.06
0.055	0.164	0.25	18.8	0.8	4.4	0.068	18.8
0.085	0.255	1	33.7	1.9	5.5	0.135	33.6
0.085	0.255	4	63.0	8.8	14.0	0.113	62.8
0.085	0.255	7	103	27.4	26.7	0.113	103

 

Mn concentrations in test item loaded samples in 7 d test with the loading of 100 mg/L (1, 2, 3- triplicate vessels, a,b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Mn conc. all vessels [µg/L]	SD Mn conc. all vessels [µg/L]	Between vessel variation [%]	Mn background conc. [µg/L]	Mean Mn conc. vessels-background corrected [µg/L]
0.055	0.164	0.083	94.8	19.2	20.3	0.055	94.8
0.055	0.164	0.25	209	19	9.2	0.068	209
0.085	0.255	1	425	16	3.7	0.135	425
0.085	0.255	4	814	10	1.2	0.113	814
0.085	0.255	7	857	12	1.4	0.113	857

 

Co concentratlons in method blanks in 28 d full test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]
0.069	0.208	0.083	0.213	0.051
0.069	0.208	0.25	0.226	0.026
0.142	0.427	1	0.580	0.104
0.142	0.427	4	0.498	0.150
0.142	0.427	7	0.436	0.207
0.422	1.26	14	0.422	0.000
0.422	1.26	21	0.422	0.000
0.422	1.26	28	0.422	0.000

 

Co concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L with all vessels (1, 2, 3- triplicate vessels, a, b- duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [%]	Co background conc. [µg/L]	Mean Co conc. vessels-background corrected [µg/L]
0.069	0.208	0.083	1.70	0.50	29.6	0.213	1.49
0.069	0.208	0.25	4.01	1.95	48.5	0.226	3.79
0.142	0.427	1	11.8	9.13	77.4	0.580	11.2
0.142	0.427	4	27.4	18.2	66.3	0.498	26.9
0.142	0.427	7	45.2	12.1	26.7	0.436	44.7
0.422	1.26	14	61.6	7.17	11.6	0.422	61.2
0.422	1.26	21	70.7	6.72	9.5	0.422	70.3
0.422	1.26	28	78.2	7.36	9.4	0.422	77.8

 

Co concentrations in test item loaded samples in 7 d test with the loading of 10 mg/L (1, 2, 3- tripllcate vessels, a, b - duplicate samples)

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [%]	Co background conc. [µg/L]	Mean Co conc. vessels-background corrected [µg/L]
0.069	0.208	0.083	10.6	0.87	8.2	0.231	10.4
0.069	0.208	0.25	25.8	1.28	5.0	0.226	25.6
0.142	0.427	1	49.3	2.6	5.2	0.580	48.7
0.142	0.427	4	95.5	9.8	10.3	0.498	95.0
0.142	0.427	7	161	38	23.3	0.436	161

 

Co concentrations in test item loaded samples in 7 d test with the loading of 100 mg/L (1, 2, 3- triplicate vessels, a,b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Co conc. all vessels [µg/L]	SD Co conc. all vessels [µg/L]	Between vessel variation [%]	Co background conc. [µg/L]	Mean Co conc. vessels-background corrected [µg/L]
0.069	0.208	0.083	133	24	17.8	0.231	133
0.069	0.208	0.25	319	25	7.9	0.226	319
0.142	0.427	1	804	25	3.2	0.580	803
0.142	0.427	4	1861	11	0.6	0.498	1861
0.142	0.427	7	2128	12	0.6	0.436	2128

 

 

Ni concentratlons in method blanks in 28 d full test (1, 2, 3- triplicate vessels, a, b - duplicate samples, BW - method blank).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]
0.541	1.62	0.083	0.631	0.078
0.541	1.62	0.25	0.722	0.078
0.130	0.390	1	0.130	0.000
0.130	0.390	4	0.152	0.037
0.130	0.390	7	0.152	0.019
0.386	1.16	14	0.515	0.112
0.386	1.16	21	0.700	0.296
0.386	1.16	28	0.580	0.000

 

Ni concentrations in test item loaded samples in 28 d test with the loading of 1 mg/L with all vessels (1, 2, 3- triplicate vessels, a, b- duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [%]	Ni background conc. [µg/L]	Mean Ni conc. vessels-background corrected [µg/L]
0.541	1.62	0.083	2.64	0.10	3.9	0.631	2.01
0.541	1.62	0.25	5.34	1.48	27.7	0.722	4.61
0.130	0.390	1	12.2	7.3	59.9	0.130	12.1
0.130	0.390	4	2.75	13.0	47.4	0.152	27.4
0.130	0.390	7	46.3	6.1	13.2	0.152	46.2
0.386	1.16	14	61.2	1.9	3.1	0.515	60.7
0.386	1.16	21	70.3	2.1	2.9	0.700	69.6
0.386	1.16	28	76.9	4.0	5.3	0.580	76.3

 

Ni concentrations in test item loaded samples in 7 d test with the loading of 10 mg/L (1, 2, 3- tripllcate vessels, a, b - duplicate samples)

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [%]	Ni background conc. [µg/L]	Mean Ni conc. vessels-background corrected [µg/L]
0.541	1.62	0.083	16.7	1.2	7.0	0.631	1.61
0.541	1.62	0.25	35.2	1.6	4.5	0.722	34.5
0.130	0.390	1	64.8	2.4	3.7	0.130	64.7
0.130	0.390	4	127	11	8.5	0.152	124
0.130	0.390	7	218	55.2	25.3	0.152	218

 

Ni concentrations in test item loaded samples in 7 d test with the loading of 100 mg/L (1, 2, 3- triplicate vessels, a,b - duplicate samples).

LOD   [µg/L]	LOQ   [µg/L]	Sampling   [d]	Mean Ni conc. all vessels [µg/L]	SD Ni conc. all vessels [µg/L]	Between vessel variation [%]	Ni background conc. [µg/L]	Mean Ni conc. vessels-background corrected [µg/L]
0.541	1.62	0.083	194	23	11.9	0.631	194
0.541	1.62	0.25	443	21	4.6	0.722	442
0.130	0.390	1	1196	30	2.5	0.130	1196
0.130	0.390	4	3033	17	0.6	0.152	3033
0.130	0.390	7	3629	22	0.6	0.152	3629

 

 

 

 

 

 

 

 

 

Description of key information

Information obtained in a Transformation/dissolution test was used in estimate the water solubility of the substance.

Water solubility of the individual elements contained in the substance (Mn, Co and Ni) were determined (at pH 5.5, 100 mg/l loading rate and after 7 days stirring) as:

	Form 1	Form 4
Mn	857 µg/l	193 µg/l
Co	2128 µg/l	377 µg/l
Ni	3629 µg/l	8314 µg/l

 

 

Additional information

The water solubility of the substance was estimated from data obtained from a Transformation/dissolution test, which was conducted in preference to the standard ecotoxicological studies.

 

The Transformation/dissolution test is designed to determine the rate and extent to which metals and sparingly soluble metal compounds can produce soluble available ionic and other metal-bearing species in aqueous media under a set of standard laboratory conditions representative of those generally occurring in the environment.

 

Based on the chemical composition of the test material, monitoring of the individual metallic elements was considered the most scientifically correct method of analysis and calculation.

 

It was considered that the data relating to water solubility from this study would provide a level of information equivalent to that which would be produced from a standard water solubility study (such as EU Method A6/OECD method 105) and as such it was considered unnecessary to conduct a standard water solubility study. The transformation/dissolution test was carried out through an experimental design that follows the recommendations of the OECD guidance document on transformation/dissolution (T/D) (OECD 2001).

 

One day test for identification of optimum pH value that maximizes dissolution
The 1 d test was performed in test media at pH values of 5.5, 6.0, 8 and 8.5 with a loading of 100 mg/L test item each and one sampling after 1 d. This step was conducted in triplicate test item loaded vessels and triplicate method blanks at 21.5 ± 1.5 ° C to determine the pH which maximizes dissolution in the full test. "With reference to the conditions generally found in the environment a pH range of 6 to 8.5 must be used, except for the 28 day full test where the pH range of 5.5 to 8.5 should be used in order to take into consideration possible long term effects on acidic lakes".

 

According to the results of this test a pH of 5.5 was defined as the pH with the highest dissolution. Therefore the medium with a pH of 5.5 was used for the full test for all loadings.

 

Full test: pH 5.5, loading of 1 mg/L 28 days of testing.
The full test was performed in triplicate test item loaded vessels and triplicate method blanks at 21.5 ± 1.5 °C. Duplicate samples were taken after 2 h, 6 h, 1 d, 4 d, 7 d, 14 d, 21d and 28 d for the loading of 1 mg/L.
The amount of dissolved manganese, cobalt and nickel at target pH value of 5.5 was quantified by ICP-OES .

 

Full test: pH 5.5, loading of 10, 100 mg/L 7 days of testing.
The full test was performed in triplicate test item loaded vessels and triplicate method blanks at 21.5 ± 1.5 °C. Duplicate samples were taken after 2 h, 6 h, 1 d, 4 d, and 7 dfor the loading of 10 mg/L.
The amount of dissolved manganese, cobalt and nickel at target pH value of 5.5 was quantified by ICP-OES ..

 

Results

Water solubility of the individual elements contained in the substance (Mn, Co and Ni) were determined (at pH 5.5, 100 mg/l loading rate and after 7 days stirring) as:

	Form 1	Form 4
Mn	857 µg/l	193 µg/l
Co	2128 µg/l	377 µg/l
Ni	3629 µg/l	8314 µg/l

 

The results show that each individual component has a water solubility below 10 mg/l and therefore conclude that the substance is slightly soluble in water.

 

In addition the above results are a worst case scenario as the results were obtained from the test with the highest loading rate (100 mg/L) and the pH (pH 5.5) of maximum solubilisation and maximum release of the most eco-toxicological relevant metals.

 

Please refer to the Transformation/dissolution tests (additional ecotoxicological information) for further details on the study.