Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

The standard approach for assessing the toxicity of metals is based on read across between soluble metal substances in the same oxidation state, taking into account any potential toxicity from ligands or counter ions. For palladium substances, the available ecotoxicity data indicate that substances with a chloro ligand are more toxic than those without a chloro ligand. For tetraammine palladium dichloride the chloride ions are present as counter ions rather than ligands with the metal centre, which is coordinated to the four ammine ligands. Due to the differences in bonding for this substance it is expected to be less toxic than other substances containing a chloro group. Ecotoxicity data for this substance is therefore read across from tetraammine palladium hydrogen carbonate, a palladium(II) substance that does not contain a chloro group.

For risk assessment purposes, many sites produce and use different palladium substances, and when monitoring site emissions only the concentration of palladium is monitored. For this reason, although a specific read across approach is followed for the environmental classification of each palladium substance, a single PNEC is derived covering all palladium substances, for each environmental compartment. This allows a site to conduct a risk assessment for total emissions of palladium, rather than attempting to link a proportion of the site emissions to each palladium substance that is used. As a single palladium PNEC is derived, the PNEC is determined based on a worst case approach, using data for the most toxic palladium substance, diamminedichloropalladium.