Caesium carbonate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

HYPOTHESIS FOR THE ANALOGUE APPROACH
Cesium carbonate completely dissociates in water forming cesium cation and the corresponding carbonate anion. Thus, cesium salts with different anion moieties were found to be suitable candidates for read-across. (Eco)toxicological properties were extrapolated to different endpoints by using the lowest effect concentration.
For further information, please refer to the read-across justification in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 97 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs2CO3

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 97 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs2CO3

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 79 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 79 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs

Basis for effect:

mortality (fish)

Description of key 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.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

> 97 mg/L

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.

Acute toxicity of the test item was assessed with acute fish toxicity test on Zebrafish (Danio rerio) over an exposure period of 96 hours in a static system. The recorded effects were mortality and symptoms of intoxication of the fish. Based on the results of a preliminary range finding test, a limit test was performed: one control and the concentration of 100 mg/L of the test item were tested according to the relevant guideline (OECD 203). Both test groups comprised seven zebrafish and 5 L test solution. No replicates were tested. The test was considered to be valid because assay acceptance criteria were fulfilled. Analytical determination of the test concentration was performed by flame photometry.

Based on the analytical results, the test concentration did not differ from the nominal concentration significantly, hence the biological results based on the nominal concentration of 100 mg/L. No mortality or clinical symptoms were observed in the control. Clinical symptoms (increased motility of operculum, unbalanced swimming, localisation under the water surface, thrashing toward the bottom) was observed on 1 fish from the 7 in the 100 mg/L test item treated group at the 24 hours observation time. Although mortality (1/7 fish) was observed on the subsequent day (at the 48 hours observation time) in this group, this was within the assay acceptance criteria (one animal can die in the control group). Hence the test was considered to be valid and the mortality observed was not taken into consideration during evaluation of the results.

Under the conditions of this acute fish toxicity study the observed endpoints for the effect of cesium hydroxide monohydrate were the following: 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.