Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

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Additional information

Short-term toxicity to fish

The acute toxicity to fish was assessed with cesium hyroxide monohydrate under static conditions according to OECD guideline 203 and EU-method C.1 to a nominal concentration of 100 mg/L. The 96h-LC50 was calculated to be > 100 mg/L. Based on these data the calculated 96 h-LC50 for cesium hydroxide anhydrous is > 89.3 mg/L.  

Long-term toxicity to fish

The long term toxicity to fish was assessed with cesium hydroxide monohydrate under semi-static conditions according to OECD Guideline 210. The calculated 35d-LOEC and 35d-NOEC obtained were > 43 mg test item/L and 43.0 mg test item/L respectively. Based on these data, the calculated 35d-NOEC for cesium hydroxide anhydrous was 38.38 mg/L and the 35d-LOEC was greater than 38.38 mg/L

Short-term toxicity to aquatic invertebrates

The acute toxicity to invertebrates was assessed with cesium hydroxide monohydrate under static conditions according to OECD guideline 202 and EU-method C.2. In this 48-hour acute toxicity test with daphnia, the EC50 value was 94.44 mg/L, the LOEC was 50 mg/L and the NOEC was 25 mg/L (nominal concentration). Based on these data, the calculated 48h-EC50 for cesium hydroxide anhydrous was 84.3 mg/L, the 48h-LOEC was 44,6 mg/L and the 48h-NOEC was 22.3 mg/L.

Long-term toxicity to aquatic invertebrates

The long term toxicity to aquatic invertebrates was assessed with cesium hyroxide monohydrate under semi-static conditions over a period of 21 days according to OECD guideline 211 and EU-method C.20. The overall NOEC was determined to be 15.8 mg/L (nominal concentration) and the LOEC was determined to be 30 mg/L. Based on these data, the calculated NOEC for cesium hydroxide anhydrous was 14.1 mg/L and the LOEC 26.8 mg/L.  

Toxicity to Algae

The toxicity to algae was assessed with cesium hydroxide monohydrate under static conditions according to OECD guideline 201 and EU-method C.3. In this 72 -hour toxicity test with green algae, the EC50 value was 133.9 mg/L (nominal concentration). The no-observed-effect concentration (NOEC) was 12.5 mg/L (nominal concentration). Based on these data the EC50 calculated for cesium hydroxide anhydrous was 119.62 mg/L and the NOEC was 11.2 mg/L. All reported biological results are related to the nominal concentrations.

Toxicity to microorganisms

The toxicity to microorganisms was assessed with cesium hydroxide monohydrate according to OECD guideline 209, EU-method C.11. After 3 hours of exposure the EC10 and EC50 values of the test item were determined to be higher than 1000 mg/L (nominal concentration) and the NOEC was determined to be 1000 mg/L. Based on these data, the calculated EC10 and EC50 values of cesium hydroxide anhydrous was greater than 892.8 mg/L and the NOEC was 892.8 mg/L