Dicerium tricarbonate

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:

from 25-OCT-2005 to 13-JAN-2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to EU / OECD guidelines and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Cited as Directive 2000/32/EC, B.13/14

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:

Dicerium tricarbonate

EC Number:

208-655-6

EC Name:

Dicerium tricarbonate

Cas Number:

537-01-9

Molecular formula:

CH2O3.2/3Ce

IUPAC Name:

dicerium tricarbonate

Method

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100, TA 102

Metabolic activation:

with and without

Metabolic activation system:

Liver S9 fraction of rats induced with Phenobarbital/beta-naphthoflavone

Test concentrations with justification for top dose:

Pre-experiment (Experiment I): 3, 10, 33, 100, 333, 1000, 2500, and 5000 µg/plate
Experiment II: 33, 100, 333, 1000, 2500, and 5000 µg/plate
See table 1 below

Vehicle / solvent:

- VEHICLE: DMSO (100 µL/2600 µL medium)
- Justification for choice of solvent/vehicle: the solvent was chosen because of its solubility properties and its relative non-toxicity to bacteria

Controls

Controls 1

Untreated negative controls:

yes

Remarks:

concurrent untreatment and solvent controls

Negative solvent / vehicle controls:

yes

Remarks:

medium with solvent or vehicle alone

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

Migrated to IUCLID6: (NaN3, 10 µg/pl) in TA1535 and TA100 without S9 mix

Controls 2

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylene-diamine (4-NOPD), 10 µg/pl in TA98 and 50 µg/pl in TA1537 without S9 mix

Controls 3

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

Migrated to IUCLID6: (MMS, 4 µg/pl) in TA 102 without S9 mix

Controls 4

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (2-AA, 2.5 µg/pl) in TA1535, TA1537, TA98, TA100 and TA102 with S9 mix

Details on test system and experimental conditions:

- METHOD OF APPLICATION: in agar (plate incorporation) in experiment I; preincubation in experiment II
- DURATION:
> Preincubation period: 60 minutes
> Exposure duration: 48 hours
- NUMBER OF REPLICATIONS: 3

OTHER: the colonies were counted using a Petri Viewer Mk2. Due to precipitation of the test item the colonies were partly counted manually.

Evaluation criteria:

A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, and TA 102) or thrice (strains TA 1535 and TA 1537) the colony count of the corresponding solvent control is observed.
A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration.
An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment.
A dose dependent increase in the number of revertant colonies below the threshold is regarded as an indication of a mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative and solvent controls such an increase is not considered biologically relevant.

Statistics:

not mandatory

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

- TEST-SPECIFIC CONFOUNDING FACTORS:
> Precipitation: precipitation was observed from 333 µg/plate in experiment I, and from 1000 µg/plate in experiment II

SEE DETAILED RESULTS BELOW IN TABLES 2 AND 3

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 2: Number of revertants per plate in experiment I (mean of 3 plates)

	TA 1535				TA 1537				TA 98				TA 100				TA 102
Conc. [µg/plate]	-MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)
0*	21	25	no	no	13	19	no	no	21	38	no	no	126	147	no	no	430	530	no	no
Untreated	20	20	no	no	7	22	no	no	25	46	no	no	132	153	no	no	398	555	no	no
3	22	22	no	no	9	19	no	no	24	33	no	no	120	133	no	no	434	546	no	no
10	19	18	no	no	10	15	no	no	21	37	no	no	117	133	no	no	462	520	no	no
33	20	33	no	no	10	19	no	no	27	41	no	no	125	155	no	no	456	581	no	no
100	20	27	no	no	10	18	no	no	26	36	no	no	116	157	no	no	412	488	no	no
333	13	23	yes	no	8	22	yes	no	22	37	yes	no	121	126	yes	no	419	566	yes	no
1000	14	27	yes	no	8	17	yes	no	24	38	yes	no	122	146	yes	no	424	557	yes	no
2500	11	23	yes	no	11	20	yes	no	18	35	yes	no	107	151	yes	no	428	463	yes	no
5000	16	18	yes	no	7	9	yes	no	20	26	yes	no	97	115	yes	no	304	333	yes	no
NaN3	1315												2055
4-NOPD					90				354
MMS																	5178
2-AA		291				195				1710				1992				2338

*solvent control with DMSO

MA: metabolic activation

Table 3: Number of revertants per plate in experiment II (mean of 3 plates)

	TA 1535				TA 1537				TA 98				TA 100				TA 102
Conc. [µg/plate]	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)	- MA	+ MA	Precipit. (yes/no)	Cytotox (yes/no)
0*	21	31	no	no	9	13	no	no	28	31	no	no	114	175	no	no	513	599	no	no
Untreated	23	36	no	no	10	19	no	no	27	36	no	no	161	195	no	no	514	661	no	no
33	26	30	no	no	9	13	no	no	24	38	no	no	131	166	no	no	482	611	no	no
100	20	26	no	no	11	12	no	no	24	31	no	no	130	148	no	no	486	632	no	no
333	19	28	no	no	13	14	no	no	25	31	no	no	127	145	no	no	468	627	no	no
1000	20	29	yes	no	8	11	yes	no	30	28	yes	no	136	154	yes	no	455	610	yes	no
2500	21	27	yes	no	12	12	yes	no	27	33	yes	no	116	158	yes	no	482	616	yes	no
5000	19	23	yes	no	7	7	yes	no	21	30	yes	no	115	148	yes	no	451	473	yes	no
NaN3	1579												2202
4-NOPD					83				416
MMS																	2278
2-AA		248				206				1435				1305				2725

*solvent control with DMSO

MA: metabolic activation

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.

Executive summary:

In a reverse gene mutation assay in bacteria (Wollny HE, 2006), strains TA1535, 1537, 98, 100 and 102 of S. typhimurium were exposed to cerium carbonate, (65.62 % a.i.), at concentrations of 3 to 5000 µg/plate in the presence and absence of mammalian metabolic activation.

Cerium carbonate was tested up to precipitating concentrations. The positive controls induced the appropriate responses in the corresponding strains. There was no evidence of induced mutant colonies over background. Therefore, CERIUM CARBONATE is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.