Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Tests have been conducted with diammonium sodium hexakis(nitrito-N)rhodate for acute Daphnia, algae and toxicity to microorganisms endpoints. As Daphnia and algal results are similar for the two substances, and as algae are the most sensitive trophic level and will drive classification, it is considered appropriate to read across data for acute toxicity to fish from another rhodium(III) substance, rhodium trinitrate (hydrate).

The most sensitive trophic level is algae, with an ErC50 of 4.5 mg test item L-1 and an ErC10 of 0.313 mg L-1, for diammonium sodium hexakis(nitrito-N)rhodate and these values are used for classification purposes.

For PNEC derivation all data for rhodium(III) substances has been pooled and the PNEC values derived based on the most sensitive result. In the risk assessment, emissions of different rhodium substances are not analysed separately and therefore measured environmental concentrations are available based on total rhodium concentrations. As the measured emissions data is not apportioned to a particular rhodium(III) substance, a single set of PNECs covering all rhodium substances in the same oxidation state is considered to be the most appropriate approach for conducting the risk assessment. For aquatic PNECs the lowest EC50 value is for the rhodium(III) substance rhodium(III) chloride. There is some indication that rhodium substances containing a chloro ligand may be more toxic than those without, and therefore using the value for rhodium trichloride as the key value for PNEC derivation for all rhodium(III) substances is likely to be worst case.