Copper dichromium tetraoxide

Additional physico-chemical information

Administrative data

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental work was started on 04 June 2017 and completed on 20 June 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Environmental Health and Safety Publications. Series on Testing and Assessment No.29. Guidance Document on Transformation/Dissolution of Metals and Metal Compounds in Aqueous Media. July 2001.

GLP compliance:

yes (incl. QA statement)

Remarks:

yes Study performed to GLP by ECTX. Analytical phase delegated to WLN Business B.V.

Other quality assurance:

ISO/IEC 17025 (General requirements for the competence of testing and calibration laboratories)

Remarks:

Anaytical phase performed to ISO 17025 by WLN Business B.V.

Test material

Test material information

Constituent 1

Reference substance name:

Copper dichromium tetraoxide

EC Number:

234-634-6

EC Name:

Copper dichromium tetraoxide

Cas Number:

12018-10-9

Molecular formula:

Cr2CuO4

IUPAC Name:

dichromium(3+) copper(2+) tetraoxidandiide

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Test item name: Copper dichromium tetraoxide
Sample name: CuCr2O4
Formula: CuCr2O4
Manufacturer/supplier: Clariant Produkte GmbH, BU Catalysts, Waldheimer Strasse 13-15, D-83052
Bruckmühl, Germany
Batch no.: EX 14502.6
ECTX no.: T0247/01
Elements(s) of interest: Chromium and copper
Composition/purity:
Components:
1. 88.5 % CuCr2O4
2. 8.8 % CuCrO2
3. 2.0 % CuO [1317-38-0]
4. 0.7 % Cr2O3 [1308-38-9]
Element content: Chromium: 43.2%, Copper: 28.0%
Physical form: Solid, (in the powder form)
Molar mass: 231.55g/mol
Colour: Black
Specific surface area: 0.766m2/g
Homogeneous: Yes
Storage conditions: Room temperature, in the dark
Expiry date: 01/01/2023

Results and discussion

Results:

The temperature of the test solutions fluctuated between 21.9 °C and 22.5 °C, which was in line with the test conditions of 20 °C - 23 °C.
The pH measured in the blank and test item vessels at pH 6 varied from 5.99 to 6.02. All measured data were within the specifications of pH 6.0 ± 0.2.
The dissolved oxygen concentration measured in the blank and test item vessels at pH 6 varied from 8.33 to 8.46 mg/L O2 . These values were higher than the required value of ± 6 mg/L O2 at 22 °C corresponding with a minimal saturation level in the air of 70 %.
The raw data of the total organic carbon content (TOC) and of the chromium and copper concentrations dissolved in the test medium, measured by the Test Site with the TOC analyser and the ICP–MS respectively, are presented in Annex 6.
The measured TOC of the medium was <1.0 mg/L C, and below the required level of 2.0 mg/L C as laid down in the OECD Test Guidance no.29 (Annex 6).
The test medium at the start of the test and the blank control vessel during the test showed no concentrations above the detection limit of chromium (0.02 µg/L Cr) and copper (0.2 µg/L Cu) (Annex 2a and 3a, respectively). The detection limit was determined as three times the standard deviation of the chromium and copper measurements of all blank control samples in this study rounded up to one significant figure.

The following observations could be made in the test vessels:

- with a loading of 1 mg/L of Copper dichromium tetraoxide, following amounts of chromium were measured during the test:
The results for dissolved chromium as a function of time are shown in Annex 2b and plotted in corresponding Figure 1. An average dissolved chromium concentration of 0.90 ± 0.02 µg/L µg/L Cr at the 7 day sampling point was measured with a between-vessel variation of 2 % which met the 20 % quality criteria at the 7 days endpoint. The within-vessel coefficients of variation met the <10 % quality criteria for all test vessels. Based on the specific surface area of Copper dichromium tetraoxide (i.e. 0.77 m²/g test item), a chromium release per surface of 0.12 µg/cm² was calculated at the 7 days endpoint. Based on the average chromium content in the test item (43.2 %) and the average dissolved chromium concentration in the test solutions, a chromium release of 0.21 % could be calculated at the 7 days extraction endpoint.

- with a loading of 1 mg/L of Copper dichromium tetraoxide, following amounts of copper were measured during the test:
The results for dissolved copper as a function of time are shown in Annex 3b. An average dissolved copper concentration of 0.2 ± <0.05 µg/L Cu at the 7 day sampling point was measured with a between-vessel variation of 20 % which met the 20 % quality criteria at the 7 days endpoint. The within-vessel coefficients of variation met the <10 % quality criteria for all test vessels. Based on the specific surface area of Copper dichromium tetraoxide (i.e. 0.77 m²/g test item), a copper release per surface of 0.026 µg/cm² was calculated at the 7 days endpoint. Based on the average copper content in the test item (28.0 % and the average dissolved copper concentration in the test solutions, a copper release of 0.071 % could be calculated at the 7 days extraction endpoints.

Applicant's summary and conclusion

Conclusions:

During this transformation/dissolution study on Copper dichromium tetraoxide at a loading of 1 mg/L, it was shown that for chromium, 0.90 µg/L Cr (CV = 2 %) was found after 7 days of exposure to the standard medium at pH 6. The 7 days dissolution results at the 1 mg/L loading corresponded with a chromium release of 0.21% (or 0.12 µg/cm²). For copper, a concentration with average value of 0.2 µg/L Cu (CV = 19 %) was found after 7 days of exposure. The 7 days dissolution results at the 1 mg/L loading corresponded with a copper release of 0.71 % (or 0.026 µg/cm²).
The results can be assumed reliable since the test conditions stayed constant during the experiment.

Executive summary:

The study was performed to GLP by ECTX.  The analytical phase was delegated to WLN Business B.V.. Analysis was conducted to ISO/IEC 17025 (General requirements for the competence of testing and calibration laboratories).

The conduct of the study was based on the OECD Environmental Health and Safety Publications. Series on Testing and Assessment No.29. Guidance Document on Transformation/Dissolution of Metals and Metal Compounds in Aqueous Media. July 2001.

During this transformation/dissolution study on Copper dichromium tetraoxide at a loading of 1 mg/L, it was shown that for chromium, 0.90 µg/L Cr (CV = 2 %) was found after 7 days of exposure to the standard medium at pH 6. The 7 days dissolution results at the 1 mg/L loading corresponded with a chromium release of 0.21 %  (or 0.12 µg/cm²).  For copper, a concentration with average value of 0.2 µg/L Cu (CV = 19 %) was found after 7 days of exposure.  The 7 days dissolution results at the 1 mg/L loading corresponded with a copper release of 0.71 % (or 0.026 µg/cm²). The results can be assumed reliable since the test conditions stayed constant during the experiment.