slag, copper smelting

Endpoint summary

Additional information

Approach for Environmental Classification

The copper slag is considered as complex massive sparingly soluble metal bearing material. It mainly represents of inert matrix (iron silicate and silicates of aluminum and calcium). Traces of metals exist in metal, mineral form or included in silicate phases. In other words the trace metals are firmly built in and bonded into the glass/crystal structures of the silicate and oxide mineral phases, which are characterized by high bonding stability and low water solubility.

Therefore in accordance to the EU hazard classification system, the evaluation of the short term and long term aquatic toxicity of the copper slag is accomplished by comparison of (a) the concentrations of the metal ions in solution, produced during transformation /dissolution in a standard aqueous medium with (b) the appropriate standard eco toxicity data as determined from tests carried out with the soluble metal species (acute and chronic values).

Transformation/dissolution tests (T/DP) (OECD, 2001) of copper slag were carried out to study its potential to release soluble available ionic and other metal-bearing species to the environment ( Rodriges, 2010). Given that copper slag contains different trace elements, broad range of metals were assessed during the T/D test.

To derive the aquatic hazard classification a Toxic Unit (TU) approach was applied assuming additive metal toxicity (in accordance to the CLP guidance for mixtures).

Reliable acute/short term toxicity data are available for the three trophic levels (algae, Daphnia and fish). These studies are further used to confirm the classification.

 

A detailed summary of the classification and the ARCHE software used for the translation of the classification to all samples is attached

 

 Approach for PNEC derivation 

The freshwater PNEC for slag, copper smelting is based on an outdoor aquatic mesocosm study with slag, copper smelting stones produced by a European producer  (Hommen et al., 2010). 

To allow bridging of the results to other slag materials produced by the European copper industry, additional mesososms enclosures were set up using crushed stones (1-2 mm). The study evaluated effects of copper slag crushed stone fines and stones on algae, macrophytes, zooplankton and benthic macroinvertebrates in outdoor mesocosms for one year.

To enable extrapolation from the slag material used in the mesocosm study to other slag materials, 5 selected materials (including the material used in the mesocosm test) were assessed with regards to metal release rates and ecotoxicity profiles in the following bridging studies:

-         Schaefers, 2010, OECD 29 GLP tests, metal release from different slags, copper smelting

-         Wenzel, 2010, OECD 201 GLP-tests withPseudokirchneriella subcapitata(green algae, ECI-001/4-30A)

-         Wenzel, 2010, OECD 201 GLP-tests withNavicula pelliculosa(diatom, ECI-001/4-30D)

-         Simon, 2010, OECD 202 GLP-tests withDaphnia magna(water flea, ECI-001/4-20/G)

-         Non-GLP tests withBrachionus calyciflorus(rotifer, University of Ghent)

 

The bridging studies were interpreted and evaluated by Schaefers, 2010. Report is attached.