In many wastes acid digestable copper concentrations appear to trigger an ecotoxic classification. However, the toxicity of copper is dependent on the chemical form (species) in which it is present. To date there are no sufficiently sensitive routine analytical chemical techniques that can distinguish between the non-ecotoxic species, such as copper metal as used in wiring, or ecotoxic species, such as the oxide.
WRc has undertaken numerous studies to determine the form of the copper in wastes, such as:
- verification of compounds from the Approved Supply List, Classification Labelling and Packaging Regulation and REACH dossiers to discount compounds technically not able to be present in waste
- XAFS assessments (‘Diamond Light Synchotron’)
- geochemical fingerprint speciation modelling
- development of a selective extraction technique.
The waste stream-specific data generated by these techniques can be used to establish the proportion of the total copper concentration to be assessed for waste classification purposes.