Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

The general principles applied for read across between metal substances are that ecotoxicity and the potential for adverse environmental effects are based on the metal ion in cases where the counter ions can reasonably be expected to be non-toxic, as is the case for many simple metals salts (e.g. anions such as SO42-, NO3-, OH-). For diammonium hexachloroplatinate it was considered that the counter ion may potentially contribute to adverse effects. Therefore, for this substance limited testing was conducted on the substance itself (acute Daphnia study). The results from this study indicated that the counter ion does not lead to increased toxicity and therefore this is considered to support the assumption that toxicity is driven by the metal ion, and read across from another soluble form of the metal, in the same oxidation state, is justified for other ecotoxicity endpoints.

 

When reading across between different metal substances, the oxidation state of the metal ion needs to be carefully considered. For metals, chemical speciation can affect both the fate of the substance in the environment and its toxicity. For some metals (e.g. chromium and arsenic), large differences in environmental toxicity between difference oxidation states have been observed. For platinum substances, the database of ecotoxicity data is not as extensive as for other metal substances, but there may be a difference in toxicity between platinum (II) and platinum (IV) substances. For this reason, read-across between different substances is limited to metal compounds in which the metal exists in the same oxidation state.

 

Based on the available ecotoxicity data for platinum substances, it is evident that the ecotoxicity of platinum substances is not controlled by the concentration of platinum in the substance alone. It would appear that there may be a similar situation as has been observed for palladium, in that the chloride complexes may exhibit greater toxicity than complexes with other ligands. It is not, however, currently possible to identify a clear cut-off between chloro-platinum compounds and other platinum complexes, or to provide a mechanistic explanation of the effect. However, due to the observed differences in toxicity between chloride complexes and substances without chloride ligands, for platinum substances with a chloro ligand data are read across from other substances that also contain a chloro ligand.

 

For diammonium hexachloroplatinate, ecotoxicity data are available for the substance itself and are read across from other platinum(IV) substances that also contain a chloro ligand, hexachloroplatinic acid and platinum(IV) chloride.