Caesium carbonate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

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:

21 d

Dose descriptor:

EC50

Effect conc.:

> 13 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

24 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

13 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

> 15 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs2CO3

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

29 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs2CO3

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

15 mg/L

Nominal / measured:

nominal

Conc. based on:

other: calculated for Cs2CO3

Basis for effect:

reproduction

Description of key information

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. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

15 mg/L

Additional information

A long-term toxicity study to aquatic invertebrates with cesium carbonate is not available. Consequently, read-across was applied using data from cesium hydroxide monohydrate.

A semi-static Daphnia magna reproduction test was performed according to OECD Guideline 211 and EU Method C.20. At this method Daphnia magna, aged lower or equal 24 h at the beginning of the test, are exposed to a range of cesium hydroxide monohydrate under defined conditions over a period of 21 days. In the definitive test the nominal concentrations were as follows: 2.3, 4.4, 8.3, 15.8 and 30 mg/L. The performed parallel running analytical determinations confirmed that the test item concentrations remained within the range of ±20 % of the nominal and of the initial concentrations (varied between 93 and 109 per cent of the nominal concentration); therefore all of the results are based on the nominal test item concentrations. In the main test the mean number of offspring produced per animal was slightly lower (100.1, 106.5 and 109.1) in concentrations of 2.3, 4.4 and 8.3 mg/L and somewhat higher (124.2) at the concentrations of 15.8 mg/L. Due to the 100 % mortality in parent animals at the highest concentration of 30 mg/L, results of this concentration is excluded from data analysis. Correspondingly the 21-day NOEC related to reproduction was determined to be 15.8 mg/L and the LOEC as 30 mg/L. At the highest tested concentration of 30 mg/L the produced offspring were excluded from data analysis (because all of parent animals were died by the end of the experiment) and the mean number of offspring produced in the next lower concentration (15.8 mg/L) was higher than produced in the control (i.e. NOEC), therefore the obtained results were not sufficient for an exact EC50 value estimation. A Probit analysis was not performed from the available data. The 21-day EC50 was determined to be higher than 15.8 mg/L. 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.