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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Under the conditions of this acute algal growth inhibition test on Pseudokirchneriella subcapitata the observed endpoints for the effect of cesium hydroxide monohydrate based on the growth rate were the following: 72h EC50 value: 133.99 mg test item/L; 72h NOEC value: 12.5 mg test item/L and 72h LOEC value: 25 mg test item/L.
Based on these data the 72h-EC50 calculated for cesium hydroxide anhydrous was 119.62 mg/L, the 72h-LOEC was 22.3 mg/L and the 72h NOEC was 11.2 mg/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
133.99 mg/L

Additional information

An acute growth inhibition test of cesium hydroxide monohydrate on Algae (Pseudokirchneriella subcapitata) over an exposure period of 72 hours in a static system was assessed according to OECD Guideline 201 and EU method C.3. Five different concentrations arranged in a geometric series and an untreated control group were tested in the main study. The highest concentration was 100 mg/L. The following concentrations were used in the main study: 6.25; 12.5; 25, 50 and 100 mg/L. The shape of the algal cells growing was obviously not affected.

Under the conditions of this acute algal growth inhibition test on Pseudokirchneriella subcapitata the observed endpoints for the effect of cesium hydroxide monohydrate based on the growth rate were the followings: 72h EC50 value: 133.99 mg test item/L; 72h NOEC value: 12.5 mg test item/L and 72h LOEC value: 25 mg test item/L.

Based on these data the 72h-EC50 calculated for cesium hydroxide anhydrous was 119.62 mg/L., the 72h-LOEC was 22.3 mg/L and the 72h NOEC was 11.2 mg/L.