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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Link to relevant study record(s)

Description of key information

The key study of Hefner (2014), in which Daphnia magna was exposed for 48 h to Ce(NO3)3, yielded a 48-h EC50 of 6.9 mg Ce/L. This value corresponds to 12 mg CeCl3/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
6.9 mg/L

Additional information

Three studies were included in this dossier as containing relevant information on this endpoint. However, two of these studies were disregarded in the evaluation because the results were not in agreement with those of the key study. This was most likely due to the fact that test concentrations were not analytically verified and effect concentrations were based on nominal concentrations. Therefore, toxicity may have been substantially underestimated.

The first disregarded study was that of Bringmann and Kühn (1959), reporting a 48-h EC50 of > 1000 mg Ce/L after exposing Daphnia magna for 48 h to CeCl3. Cerium concentrations were not analytically verified during the test. The second disregarded study was that of Bazin (1995). This study reported a 48-h EC50 of > 100 mg Ce(NO3)3/L (corresponding to a value > 42.96 mg Ce/L). Cerium disappeared from solution, with concentrations <= 3 mg Ce/L after 24 h of exposure. Data for recalculation of the EC50 value based on measured concentrations was not available.

The third study (Hefner, 2014) was also a 48-h study with Daphnia magna in which the read across substance Ce(NO3)3 was used as test item and dissolved cerium concentrations were analytically monitored during the test. The 48-h EC50 was calculated based on mean measured concentrations and was 6.9 mg Ce/L (corresponding to 16 mg Ce(NO3)3/L or, when re-calculated to CeCl3, 12 mg CeCl3/L). These results are considered as the key values for this endpoint.

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