Caesium iodide

Endpoint summary

Additional information

Short-term toxicity to fish

The acute toxicity to fish was assessed with cesium iodide under static conditions according to OECD guideline 203 and EU-method C.1 to a nominal concentration of 100 mg/L. The 96h-LC50 was calculated to be > 100 mg/L. The observed end points were the followings: 96h NOEC value: ≥ 100 mg test item/L; 96h LOEC value: > 100 mg test item/L; 96h LC50 value: > 100 mg test item/L.

Long-term toxicity to fish

A long-term toxicity test in fish with cesium iodide is not available. Consequently, read-across was applied using study results from the structural analogue cesium hydroxide monohydrate. In an early life stage toxicity study (FELS, OECD guideline 210, EU method) in Zebrafish (Danio rerio) with cesium hydroxide monohydrate, no significant lethal or sub-lethal effects were observed. The calculated endpoints (35 days LOEC and NOEC) obtained were > 43 mg cesium hydroxide monohydrate/L and 43.0 mg cesium hydroxide monohydrate/L respectively. Based on these data, the calculated NOEC (35 d) for cesium iodide was 66.5 mg/L and the LOEC (35 d) was greater than 66.5 mg/L.

Short-term toxicity to aquatic invertebrates

In the 48-hour static acute toxicity test to Daphnia magna according to OECD guideline 202 and EU C.2 method with cesium iodide the 48-hour EC50 value was determined as 0.51 mg/L (Probit analysis). The overall NOEC was determined to be 0.175 mg/L.

Long-term toxicity to aquatic invertebrates

For the endpoint long-term toxicity to invertebrates no study on cesium iodide was performed since the data base on the cesium as well as on the iodide ion is sufficient. On the one hand, read-across data on thestructural analogue cesium hydroxide monohydrate were used to fill the data gap. In addition, iodine and iodine compounds are considered to have a significant toxicity towards the aquatic compartment. However, iodine and iodine compounds, are omnipresent distributed in the environment, created by the natural cycle of iodine species in the environment. A lot of reasearch hasbeen made on the environmental fate and distribution of iodine and iodine compounds.The Swedish competent authority published

an evaluation report on iodine. In this report, which refers to open literature data, e.g. overview articles, data on environmental background concentration of iodine are available. For the freshwater compartment (river and lake) a background concentration of iodine up to 20 μg/L is reported. This concentration corresponds to 40.94 μg/L for CsI. Therefore, for the PNEC derivation the worst-case approachusing these iodine background data was applied (see IUCLID summary section “Ecotoxicological Information”).

A chronic daphnia toxicity study with cesium iodide is not available. Consequently, read-across was applied using study results from the structural analogue cesium hydroxide monohydrate. Under the conditions of this chronic daphnia toxicity study according to OECD guideline 211 and EU method C.20 the observed endpoints related to reproduction for the effect of cesium hydroxide monohydrate were the following: 21-day NOEC: 15.8 mg/L; 2-day LOEC: 30.0 mg/L; 21-day EC50: > 15.8 mg/L. All reported biological results are related to the nominal concentrations. Based on these data, the calculated 21-day NOEC for cesium iodide was 24.5 mg/L, the 21-day EC50 > 24.5 mg/L and the LOEC = 46.4 mg/L.

Toxicity to Algae

In the 72-h algal growth inhibition test on Pseudokirchneriella subcapitata according to OECD guideline 201 and EU method C.3 with cesium iodide the observed endpoints based on the growth rate were the following: 72-h EC50 > 100 mg/L (635.75 mg/L); NOEC = 6.25 mg/L; LOEC = 12.5 mg/L.

Toxicity to microorganisms

The toxicity to microorganisms was assessed with cesium iodide according to OECD guideline 209 and EU method C.11.

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 and the NOEC can be statistically determined as 1000 mg/L. Please refer to IUCLID section 13 for read-across justification.

For detailed information on the read-across strategy please refer to the read-across justification in IUCLID section 13.