Registration Dossier
Registration Dossier
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EC number: 244-344-1 | CAS number: 21351-79-1
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
The toxicity to microorganisms of cesium hydroxide monohydrate was tested according to OECD guideline 209 and EU method C.11. Activated sludge was exposed at a nominal concentration of 1000 mg /L (limit test). The EC10 and EC50 value was determined to be greater than 1000 mg/L.
Based on these data, the calculated EC10 and EC50 values of cesium hydroxide anhydrous were greater than 892.8 mg/L and the NOEC was 892.8 mg/L
Key value for chemical safety assessment
Additional information
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 hydroxide anhydrous were greater than 892.8 mg/L and the NOEC was 892.8 mg/L
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