Caesium carbonate

Endpoint summary

Additional information

A short-term toxicity study to fish with cesium carbonate is not available. Consequently, read-across was applied using data from cesium hydroxide monohydrate. Under the conditions of this acute fish toxicity study the observed endpoints for the effect of cesium hydroxide monohydrate were the followings: 96h NOEC value: ≥ 100 mg test item/L; 96h LOEC value: > 100 mg test item/L and 96h LC50 value: > 100 mg test item/L. Based on these data the calculated values of 96h-LC50, 96h-LOEC and 96h-NOEC for cesium are greater/equal or greater than 79 mg/L and for cesium carbonate are greater/equal or greater than 97 mg/L.

Due to the ratio of the molecular weight of cesium atoms and counter ion the values for cesium carbonate are slightly below 100 mg/L. It can be assumed that the test result does not result in classification and labelling of the substance.

 

A long-term toxicity study to fish with cesium carbonate is not available. Consequently, read-across was applied using data from cesium hydroxide monohydrate. Under the conditions of this early life stage toxicity study, the test item had no significant lethal or sub-lethal effects on early life stages of Zebrafish (Danio rerio). The calculated endpoints (35 days LOEC and NOEC) were the following in this test:

The 35 d LOEC> 43 mg test item/L

The 35 d NOEC = 43 mg test item/L

Based on these data, the calculated NOEC for cesium was 34 mg/L and the LOEC was greater than 34 mg/L and for cesium carbonate the calculated NOEC was 42 mg/L and the LOEC was greater than 42 mg/L.

 

A short-term toxicity study to aquatic invertebrates with cesium carbonate is not available. Consequently, read-across was applied using data from cesium hydroxide monohydrate. Under the conditions of this acute daphnia toxicity study the observed endpoints for the effect of cesium hydroxide monohydrate were the following: 48h NOEC value: 25 mg test item/L; 48h LOEC value: > 50 mg test item/L and 48h EC50 value: 94.44 mg test item/L. All reported biological results are related to the nominal concentrations. Based on these data, the calculated 48h-EC50 for cesium carbonate was 92 mg/L, the 48h-LOEC was greater than 49 mg/L and the 48h-NOEC was 24 mg/L.

 

A long-term toxicity study to aquatic invertebrates with cesium carbonate is not available. Consequently, read-across was applied using study from cesium hydroxide monohydrate. Under the conditions of this chronic daphnia toxicity study the observed endpoints related to reproduction for the effect of cesium hydroxide monohydrate were the following: 21d NOEC: 15.8 mg/L; 21d LOEC: 30.0 mg/L; 21d EC50: > 15.8 mg/L. All reported biological results are related to the nominal concentration.

Based on these data, the calculated 21d-NOEC for cesium was 13 mg/L, the 21d-EC50 > 13 mg/L and the LOEC > 24 mg/L and for cesium carbonate the calculated 21d-NOEC was 15 mg/L, the 21d-EC50 > 15 mg/L and the LOEC = 29 mg/L.

 

A toxicity study to aquatic algae and cyanobacteria with cesium carbonate is not available. Consequently, read-across was applied using data from cesium hydroxide monohydrate. 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 was 107 mg/L, the 72h-LOEC was 20 mg/L and the 72h NOEC was 10 mg/L and for cesium carbonate the calculated 72h-EC50 value was 131 mg/L, the 72h-LOEC was 24 mg/L and the 72h NOEC was 12 mg/L. All reported biological results are related to the nominal concentrations.

 

A toxicity study to microorganisms with cesium carbonate is not available. Consequently, read-across was applied using data from cesium hydroxide monohydrate. Under the conditions of the performed Activated Sludge Respiration Inhibition Test, the EC10 and EC50 values of cesium hydroxide monohydrate were determined as higher than 1000 mg/L. Based on the statistical evaluation in this test the NOEC was 1000 mg/L for cesium hydroxide monohydrate.

Based on these data, the calculated EC10 and EC50 values of cesium were greater than 792 mg/L and the NOEC was 792 mg/L and for cesium carbonate the calculated values were as follows: EC10 and EC 50 >974 mg/L and NOEC 974 mg/L.

Due to the ratio of the molecular weight of cesium atoms and counter ion the values for cesium carbonate are slightly below the limit dose of 1000 mg/L. However, it is assumed that this has no impact on the regulatory assessment of the test result.