Slags, precious metal refining

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: follows standard guideline, acceptable without restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Test Guideline No 29 (2001)

Deviations:

no

GLP compliance:

no

Remarks:

according to the principles of GLP

Type of study / information:

24-h transformation dissolution pre-test

Test material

Test material information

Constituent 1

Reference substance name:

Slags, precious metal refining

EC Number:

308-515-5

EC Name:

Slags, precious metal refining

Cas Number:

98072-60-7

Molecular formula:

Not aplicable (a generic molecural formula cannot be provided for this specific UVCB)

IUPAC Name:

Slags, precious metal refining

Details on test material:

Batch: na (on site intermediate)
Sampling date: 10/02/2010
Manufacturer: Unicore Precious Metals
Active ingredients: silver, arsenic, copper, nickel, lead, antimony, zinc and boron.
Physical form: solid (powder)
Colour: Blue-green
Storage: room temperature; in the dark
Expiry date: 10/02/2011
Safe handling precautions: May cause substances which are carcinogenic through inhalation; Limit dust exposure to the maximal extend and avoid breathing potential dust; Wear gloves when handling to prevent dermal exposure; Eliminate waste which was in contact with the material as hazardous waste and in safe and closed conditions

Results and discussion

Any other information on results incl. tables

The blank values of silver, arsenic, copper, nickel, lead and boron in the test medium at pH 6 and 8 were below the detection limit.For antimony a blank value of 0.05 µg Sb/L was measured in the test medium at pH 6 which was a little bit higher than the detection limit. However, there was a significant blank value for zinc (±2.5 µg/L) for the test medium at pH 6. Taking into account that the test medium at pH 6 and pH 8 are prepared from the same batch of ultra pure water we assume that this blank value for zinc can only come from the buffering system used. This observation does not cause a problem because the results for the blank were consistent and didn’t have an influence on the integrity of the study taking into account that the results for the blank corrected zinc were below the limit of detection of 0.2 µg/L.

pH 6

In the blank control samples 24-h pre-test @ 100rpm at pH 6 no detectable values for silver, arsenic, copper, nickel,lead and boron have been measured. A small amount of 0.04 µg Sb/L was measured for antimony while a blank value of 2.65 µg Zn/L was detected for zinc. This value has been subtracted from the amounts measured in the test item samples of pH 6.

In the blank corrected test item vessels 24-h pre-test @ 100rpm at pH 6 all metals, except zinc, showed a dissolved metal concentration above the limit of detection. An average value of arsenic (1.20 µg As/L), nickel (2.26 µg Ni/L), antimony (4.42 µg Sb/L) and lead (12.0 µg Pb/L) were measured with a between vessel coefficient of variation of respectively 20%, 11%, 2% and 32%. More important amounts of silver (39.3 µg Ag/L), copper (73.7 µg Cu/L) and especially boron (2988 µg B/L) were detected with a between vessel variation of respectively 2%, 23% and 1%. The between vessel variations of arsenic (CV = 20%), lead (CV = 23%) and copper (CV = 32%) fall out of the quality criterion of 20%.

pH 8

In the blank control vessels 24-h pre-test @ 100rpm at pH 8 no detectable values for the 8 elementshave been measured.

In the blank corrected test item vessels 24-h pre-test @ 100rpm at pH 8 all measured elements, except zinc, show dissolution above the detection limit. Detectable amounts of arsenic (2.40 µg As/L), nickel (2.84 µg Ni/L), antimony (3.02 µg Sb/L) and lead (8.71 µg Pb/L) were observed with a between vessel variation of 4%, 1%, 1% and 4%. The more important amounts of metal measured in the test medium at pH 8 aresilver(20.3 µg Ag/L), copper (86.8 µg Cu/L) and especially boron with an average concentration of 2197 µg B/L and a between vessel variation of respectively 2%, 2% and 2%. All the between test item vessel variations fall within the quality criterion of 20%.

Applicant's summary and conclusion

Conclusions:

Except for zinc, all elements have a dissolution concentration above their detection limit in pH 6 and 8. Boron had the highest dissolution concentrations (i.e. 2988 ± 31 µg/L in pH 6 and 2197 ± 39 µg/L in pH 8). For silver, lead, antimony and boron the dissolution concentrations are higher in pH 6 than in pH 8. Arsenic, copper and nickel gave a slight higher dissolution at pH 8. The test conditions stayed constant during the experiment except the pH for both media. The pH shift should be taken into account.

Executive summary:

Except for zinc, all elements have a dissolution concentration above their detection limit in pH 6 and 8. Boron had the highest dissolution concentrations (i.e. 2988 ± 31 µg/L in pH 6 and 2197 ± 39 µg/L in pH 8). For silver, lead, antimony and boron the dissolution concentrations are higher in pH 6 than in pH 8. Arsenic, copper and nickel gave a slight higher dissolution at pH 8. The test conditions stayed constant during the experiment except the pH for both media. The pH shift should be taken into account.

This study is considered reliable an acceptable for use for this endpoint.