slag, copper smelting

Carcinogenicity

Description of key information

complex metal containing substance

classification made based on CLP rules for mixtures

solubility of metal constituents is poor

in vitro bio-accessability tests, mimicking gastric fluids

Justification for classification or non-classification

Copper final slag contains constituents classified as category 1 carcinogens. At typical metal equivalent levels of 0.05% these constituents do not trigger classification for carcinogenicity.

At maximum actual levels up to 0.35%, Co constituents trigger classification of the substance as cat. 1B above the generic classification limit of 0.1%.To further refine the classification in vitro measurements of bio-accessibility in solvent that resembles gastric fluid performed according to ASTM D5517.07 have been completed. The fraction of metals that solubilize under these conditions can be considered as worst case determinant of bio-accessibility of metals contained in the slag. Results demonstrate the reduced relative bio-accessibility of metals in gastric fluids. Absolutebioaccessible concentrations of Co in two final copper slag samples concerned are 0.003% to 0.004 % thus below the concentration limit of 0.1% for carcinogenicity (Carc. 1B).

This assessment was conducted assuming exposure via the oral route. The inhalation route can be considered in general as not relevant for the classification of copper final slags. Copper slag in massive and granular form cannot be inhaled. In the case of fines, and where powder, dust or fumes formed during production and professional uses of copper final slags, the respirable particle content is typically below 22%. Risk management measures are adopted to keep airborne levels of metals below exposure limits. Respiratory protection is required in case respirable dust or fumes are formed.

A separate assessment report on the Human health classification of copper final slag is attached in IUCLID section 13.

 

Additional information

The copper slag is a complex metal containing substance. It mainly contains iron silicate and silicates of aluminum and calcium . Traces of metals exist in metal, mineral form or included in silicate phases.

Classification derived based on rules for mixtures:

Carcinogenicity: Not classified

Results from calculated classification are further supported (WoE) by consideration of physical chemical properties of the UVCB substance.

Chemistry and mineralogy of the slag (see IUCLID section 4.23 chemical and mineralogical characterization) were taken into account.

Water solubility (IUCLID section 4.8) and Sequential dissolutions (IUCLID 4.23 Chemical assays) furthermore confirmed species present and their solubility behavior.

Copper slag contains As and Co constituents classified as cat. 1A (As) and cat. 1B (Co) carcinogens. At typical metal equivalent levels of 0.05% these constituents do not trigger classification for carcinogenicity.

In vitro measurements of bio-accessibility in solvent that resembles gastric fluid performed according to ASTM D5517.07. The fraction of metals that solubilize under these conditions can be considered as worst case determinant of bio-associability of metals contained in the slag. Results demonstrate the reduced relative bio-accessibility of metals thus further confirm the classification.