Iron cobalt black spinel

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and OECD guideline compliant study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

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 the individual inorganic building blocks of this substance (i.e., the element Co) were estimated according to OECD 29.

GLP compliance:

yes (incl. QA statement)

Type of method:

other: OECD 29

Test material

Test material information

Constituent 1

Reference substance name:

Iron cobalt black spinel

EC Number:

269-102-2

EC Name:

Iron cobalt black spinel

Cas Number:

68187-50-8

Molecular formula:

CoFe2O4

IUPAC Name:

Iron cobalt spinel

Results and discussion

Water solubility

Remarks on result:

other: not a standard test. Thus detailed results are shown below.

Any other information on results incl. tables

According to OECD guidance document 29, a screening test with a loading of 100 mg test item/L over 1 d was performed at pH 6 and 8.5 to cover acidic as well as basic conditions in

environment. The sampling was conducted after 1 d and the amount of dissolved Co was quantified by ICP-OES. The results presented as arithmetic mean value are given in following:

Co pH 8.5: 11.18 μg/L

Co pH 6: 62.47 μg/L

The screening test indicated that the transformation/dissolution of cobalt at acidic conditions is significantly higher compared to alkaline conditions. Therefore, the full test was performed at

pH 6 over up to 28 days.

All tests were performed in triplicate vessels per concentration (agitation at 100 rpm, 21.5 ±1.5 °C) and duplicate samples per vessel, this includes method blanks (same procedure but

without test item). All dissolved concentrations of Co were quantified by ICP-OES.

Slight cobalt background concentrations were measured to be in the range of 1 mg test/L loaded vessels at the beginning of the full test. Therefore, the dissolved Co concentrations of

the loading of 1 mg/L are reported with background correction in the summary.

Loading 1 mg/L

Co 7 d: 4.384 μg/L

Co 28 d: 5.072 μg/L

Loading 10 mg/L

Co 7 d: 31.498 μg/L

Loading 100 mg/L

Co 7 d: 103.731 μg/L

The results in detail are presented in following tables:

Sample time [h]	Metal average concentration at a loading rate of 1 mg/L
	Co [ µg/L]
2	0.484
6	0.648
24	1.298
96	3.693
168	4.384
336	5.128
504	5.256
672	5.072

 

 

Sample time [h]	Metal average concentration at a loading rate of 10 mg/L
	Co [µg/L ]
2	7.889
6	11.016
24	20.776
96	28.988
168	31.498

 

 

Sample time [h]	Metal average concentration at a loading rate of 100 mg/L
	Co [µg/L]
2	55.387
6	66.610
24	76.585
96	86.500
168	103.731