Copper sulphide

Additional physico-chemical information

Administrative data

Endpoint:

other: Transformation/Dissolution

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This is a well designed and reported study conducted in accordance with sound scientific principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2012

Materials and methods

Principles of method if other than guideline:

The report aims to describe the 28 days transformation/dissolution behavior of copper minerals in powder form (less than 60µm) in OECD medium pH 6, through an experimental design that follows the recommendations of the United Nations (GHS 2011) and the standard operating procedures
(SOP) proposed by CANMET and LISEC for the transformation / dissolution (T/D) protocol to the ad hoc OECD Validation Management Group (VMG). The developed procedure, called SOP, provide a detailed methodology for T/D that includes instrumentation requirements, reagents quality, procedures for the 7-day and 28-days full test, chemical analyses and a quality assurance program (QA/QC standards). The results of T/D protocol can be used to compare with the existing eco-toxicity reference values to establish the aquatic hazard classification of the tested substances.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Covellite (CuS)

IUPAC Name:

Covellite (CuS)

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Mineral samples were received from “La CorporacionNacional del Cobre de Chile (Codelco)”during 2009. The minerals were crashed and sieved to less than 60 µm. Although several different minerals were evaluated, only results relating to Covellite (CuS) are reported in this summary.
Composition of Covellite: Cu 66.46%; S 33.54%.

Results and discussion

Results:

The solubility values as copper for 7 (Acute) and 28 days (Chronic) T/D tests are as follows:
7days mean: 5.7 µg/L (Coefficient of Variation 5%). 7 days solubility: 0.9%.
28 days mean: 14.5 µg/L (Coefficient of Variation 12%). 28 days solubility: 2.2%.

Any other information on results incl. tables

Detailed results obtained for the period 0 - 28 days are shown in attached Table 1 and Figure 1.

Applicant's summary and conclusion

Conclusions:

The mean solubility values as copper for 7 (Acute) and 28 days (Chronic) T/D tests were 5.7 µg/L and 14.5 µg/L, respectively.

Executive summary:

A study was conducted to determine the transformation/dissolution behavior over a period of 28 days of several copper minerals in powder form (less than 60µm) in OECD medium at pH 6. For the purpose of this summary, only information related directly to the Covellite (CuS) sample are considered. The experimental design followed recommendations of the United Nations (GHS 2011) and the standard operating procedures (SOP) proposed by CANMET and LISEC to the ad hoc OECD Validation Management Group. The SOP provides a detailed methodology for T/D that includes instrumentation requirements, reagents quality, procedures for the 7-day and 28-days full test, chemical analyses and a quality assurance program. The results can be compared with eco-toxicity reference values to establish the aquatic hazard classification of the tested substances.

The twenty eight day tests were performed using a sample loading of 1 mg/L. The tests were carried out at 22 ± 2 °C and a stirring rate of 100 rpm. The OECD medium was buffered with CO2, in order to achieve the desired pH value. Laboratory setup involved the use of an orbital shaker with capacity for 16 vessels. Each sample analysis required 3 vessels (replicas) and one set of blanks, 3 more vessels under the same atmosphere. To avoid metal contamination from the pH electrodes an additional vessel with test media was added as a control. The pH and O2 were measured in this proxy vessel that contained the test media without sample.

Three sample replicates were taken from each test vessel at predetermined times and passed through 0.2µm PTFE pore size filters and acidified to a pH below 2 with nitric acid. Dissolved copper concentration was measured using an ICP-MS Perkin Elmer model 9000 instrument. A pre concentration protocol based on USEPA method 200.10 was used to achieve better sensitivity in metal determinations. Detection limits, quality assurance and quality control measurements were performed.

The solubility values for Covellite as Cu were as follows:
Mean for 7days (acute): 5.7 µg/L (Coefficient of Variation 5%). 7 days solubility: 0.9%.
Mean for 28 days (chronic): 14.5 µg/L (Coefficient of Variation 12%). 28 days solubility: 2.2%.