Registration Dossier
Registration Dossier
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EC number: 232-146-8 | CAS number: 7789-18-6
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
Based on a read-across toxicity to microorganisms study with cesium hydroxide monohydrate according to OECD guideline 209 and EU method C.11 the observed endpoints, EC10 and EC50, were determined to be greater than 1000 mg/L.
Based on these data, the calculated EC10 and EC50 values of cesium nitrate were greater than 1160.66 mg/L and the NOEC was 1160.66 mg/L. In addition to these data, the calculated EC10 and EC50 values of cesium were greater than 791.43 mg/L and the NOEC was 791.43 mg/L.
Key value for chemical safety assessment
- EC10 or NOEC for microorganisms:
- 1 160.66 mg/L
Additional information
A toxicity test to microorganisms with cesium nitrate is not available. Consequently, read-across was applied using results from a study with cesium hydroxide monohydrate.
The purpose of the 3-hour test was to evaluate the influence of the test item cesium hydroxide monohydrate on the activity of activated sludge by measuring the respiration rate under defined conditions. The respiration rates (total, heterotrophic and nitrification oxygen uptake rates) of samples of activated sludge fed with synthetic sewage were measured in an enclosed cell containing an oxygen electrode after a contact time of 3 hours. The test item was investigated at one (limit) concentration level of 1000 mg/L. The observed oxygen consumption rates consequently the specific respiration rates were in the range of the blank controls, no inhibitory effect of the test item was observed. Based on measured oxygen consumption values and calculated specific respiration rates it can be stated that the 3-hour EC10 and EC50 values of the test item are higher than 1000 mg/L.
Based on these data, the calculated EC10 and EC50 values of cesium nitrate were greater than 1160.66 mg/L and the NOEC was 1160.66 mg/L. In addition to these data, the calculated EC10 and EC50 values of cesium were greater than 791.43 mg/L and the NOEC was 791.43 mg/L.
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