Caesium fluoride

Endpoint summary

Description of key information

Based on an WoE evaluation of available data with other cesium as well as fluoride salts, the registered substance is considered to be no skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation, other

Remarks:

in vivo data from read-across to LLNA and non-LLNA studies

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

Please refer to read-across justification attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reading:

1st reading

Hours after challenge:

72

Group:

test chemical

Dose level:

0.1

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

other: CsOH

Parameter:

SI

Value:

1.05

Test group / Remarks:

Test item 2.5 %

Parameter:

SI

Value:

0.91

Test group / Remarks:

Test item 25 %

Parameter:

SI

Value:

0.72

Test group / Remarks:

Test item 10 %

Parameter:

SI

Value:

0.97

Test group / Remarks:

Test item 5 %

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

No data are available for the target substance.
Therefore, read-across data from representative Cs+ as well as F- salts are taken into account in a weight of evidence approach. For detailed read-across justification please refer to IUCLID section 13.

 

key LLNA study with CsNO3

The skin sensitisation potential of cesium nitrate was determined in the Local Lymph Node Assay (LLNA) according to the OECD Guideline 429 and EU Method B.42. The individual approach was used in this test whereby the lymph nodes of each animal were evaluated individually (in comparison to a pooled test group approach). The maximum attainable test item concentration, resulting in a homogenous formulation in an appropriate vehicle, was examined.

Each substance was applied on the external surface of each ear (25 μL/ear) of the animals for three consecutive days (Day 1, 2 and 3). No mortality was observed during the test. No local effects at the application sites (ears) were observed in any treatment group. Larger lymph nodes than the control were observed in the positive control group only. No statistically significant lymphoproliferation was observed in any group treated with the test item. The obtained SI values for the test item were 0.91, 0.72, 0.97 and 1.05 at concentrations of 25 %, 10 %, 5 % and 2.5 %, respectively. No dose-related response was observed. The positive control item induced the appropriate stimulation (SI = 11.82), thus confirming the validity of the assay. Since the mean SI value was below 3 at the maximum attainable test concentration of 25 % and at concentrations of 10 %, 5 % and 2.5 % and no dose-related response was observed, the test item was considered to be a nonsensitiser in the LLNA.

 

supporting non-LLNA study with CsOH

In a dermal sensitization study with cesium hydroxide (0.1 %) in water, young adult male albino guinea pigs (in total 15 animals) were tested using the method of Landsteiner and Jacobs (1935). The test compound was administered intradermally three times a week, for a total of nine treatments. Following a two-week period with no further injections a challenge of 0.1% was administered the same way. There was no evidence of erythema, swelling or dicolorartion of the test sites after each of the nine sensitizing cutaneous injections or after the challenge dose. These results indicate that cesium hydroxide did not induce cutaneous sensitisation in guinea pigs.

 

NaF

According to publicly available data, NaF does not require classification as skin sensitiser (ECHA, 2021).

 

Taken together, there is no indication for neither Cs+ nor F- ion to induce skin sensitisation.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The registered substance does not require classification as skin sensitiser according to criteria of EU CLP.