Cesium bicarbonate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006-04-14 to 2006-04-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and Guideline compliant study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted 1997

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Caesium carbonate

EC Number:

208-591-9

EC Name:

Caesium carbonate

Cas Number:

534-17-8

Molecular formula:

CH2O3.2Cs

IUPAC Name:

Cesium carbonate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Method

Target gene:

The Salmonella typhimurium strains are constructed to differentiate between base pair (TA 1535, TA 100) and frameshift (TA 1537, TA 98) mutations. The Escherichia coli WP2 uvrA detect mutagens that cause other base-pair substitutions.

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital (PB) and ß-naphthoflavone (BNF) induced rat liver S 9-mix

Test concentrations with justification for top dose:

3, 10 33, 11, 333, 1000, 3330, 5000 µg/plate

Vehicle / solvent:

Milli-Q water

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

2-nitrofluorene

sodium azide

benzo(a)pyrene

methylmethanesulfonate

Details on test system and experimental conditions:

An initial mutation test was performed. Bacteria were exposed to the test item, both in the presence and absence of an appropriate metabolic activation system. Freshly grown cultures were used. It were used Agarplates with 25 ml glucose agar medium. Agar plates for test with Salmonella typhimurium strains also con tained 12.5µg/plate biotin and 15µg/plate tryptophan.

The entire test consisted of non-activated and activated test conditions (without S9 Mix and with addition of S9 Mix) and each of them with the addition of negative and positive controls.
Top agar in top agar tubes was molten and heated to 45°C. Following solutions were addet to 3 ml top agar: 0.1 ml bacterial culture of one of the tester strains, 0.1 ml of a dilution (tests substance in Milli-Q-water and either 0.5 ml S9 mix (for activation assay) or 0.5 ml 0.1 M phosphate buffer (for non activation assay). Ingrdients were mixed and poured onto a selective agar plate.
After solidification the plates were inverted and incubated at 37 °C for at least 48 hours in the dark and revertante colonies (Histidin independent for Salmonella typhimurium and tryptophan independet for Escherichia coli) were counted manually or with a Protos model 50000 counter.
The colony numbers on the control, positive control and the test plates were determined, the mean values, standard deviations and the mutation rates were calculated.

Evaluation criteria:

Cesium Carbonat is considered negativ (not mutagenic) if the total number of revertants in tester strain TA 100 is no greater than two times in the concurrent control, in tester strain TA 1535, TA1537, TA 98 or WP2uvrA is not greater than 3 times in concurrent control. Negative response shold be reproducible in one independentliy repeated experiment.
Cesium Carbonat is considered positve (mutagenic) if the total number of revertants in tester strain TA 100 is greater than two times in the concurrent control, in tester strain TA 1535, TA1537, TA 98 or WP2uvrA is not greater than 3 times in concurrent control. Positive response will be repeated, and reproducible in one independentliy repeated experiment.

Statistics:

not applicable

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Dose range finding test was reported as a part of the first experiment of the muation assay.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The test item was investigated for its mutagenic potential in vitro via an Ames assay with and without metabolic activation. Based on the results, Cesium carbonate is considered to be non-mutagenic.

Executive summary:

The mutagenic potential of cesium carbonat was investigated in five bacterial strains: Salmonella typhimurium (TA 98, TA 100, TA 1535, TA1537 and Escherichia coli WP2 uvrA), according to OECD Guideline No. 471 and EU Method B 13/14. The test item was investigated in vitro via an Ames assay with and without metabolic activation. Therefor concentrations up to 5000 µg Cesium carbonate/plate were tested in two independent experiments in absence and presence of S9 -mix.

Based on the results, the test item is considered to be non-mutagenic.The bacterial background lawn was not reduced at any tested concentration and no increase in the number of revertants was observed up on treatment with Cesium Carbonate. Negativ and the strain-specific positiv control values indicate that test conditions were adequate.