Dibismuth trioxide

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

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

Adequacy of study:

key study

Study period:

Experimental work started on 17 March 2010 and was completed on 31 May 2010.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study. Rated as Klimisch 2 because it is a read-across study.

Justification for type of information:

Please see read-across justification attached below.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

no

GLP compliance:

yes

Type of assay:

mammalian cell gene mutation assay

Target gene:

hprt locus

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

- Type and identity of media: RPMI 1640 media supplemented with 100 units/mL Penicillin, 100 µg/mL Streptomycin, 2.5 µg/mL Amphotericin B, 0.5 mg/mL Pluronic (except for RPMI 20 medium) and with 0%, 10% and 20% v/v heat inactivated horse serum for RPMI A, RPMI 10 and RPMI 20, respectively.

The master stock of L5178Y tk+/- mouse lymphoma cells originated from Dr Donald Clive, Burroughs Wellcome Co. Cells supplied to Covance Laboratories Ltd. were stored as frozen stocks in liquid nitrogen.
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes; each batch of frozen cells was purged of HPRT- mutants, checked for spontaneous mutant frequency and confirmed to be mycoplasma free.
- Periodically checked for karyotype stability: yes
- Periodically "cleansed" against high spontaneous background: yes
For each experiment, at least one vial was thawed rapidly, the cells diluted in RPMI 10 and incubated in a humidified atmosphere of 5% v/v CO2 in air.

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

Range-finder (with and without S9-mix): 3.125, 6.25, 12.5, 25, 50 and 100 µg/mL;
Experiment I (with and without S9-mix): 20, 40, 60, 80, 100, 110, 120, 130 and 140 µg/mL;
Experiment II (with and without S9-mix): 10, 20, 40, 60, 80, 100, 110, 120, 130 and 140 µg/mL.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: purified water
- Justification for choice of solvent/vehicle: Initial solubility tests with the test item in purified water.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

purified water diluted 10-fold in the treatment medium

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitroquinoline 1 oxide; 0.1 and 0.15 µg/mL (dissolved in DMSO)

Remarks:

without metabolic activation

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

purified water diluted 10-fold in the treatment medium

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

with metabolic activation Migrated to IUCLID6: 2 and 3 µg/mL (dissolved in DMSO)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 3 hours at 37°C with gentle agitation
- Expression time (cells in growth medium): 7 days; cultures were maintained in flasks for a period of 7 days during which the hprt- mutation would be expressed. At the end of the expression period, cell cultures were plated for 6TG resistance.
- Selection time (if incubation with a selection agent): 12 days; cells were placed into 96 well microtitre plates that were incubated at 37ºC in a humidified incubator gassed with 5% v/v CO2 in air until scoreable and wells containing clones were identified and counted.

SELECTION AGENT (mutation assays): 6-thioguanine (6TG)

NUMBER OF REPLICATIONS: Each treatment, in the absence or presence of S9-mix, was in duplicate (single cultures only used for positive control treatments).

DETERMINATION OF CYTOTOXICITY
- Method: relative survival:
Treatment of cell cultures for the cytotoxicity Range Finder Experiment was as described for the Mutation Experiments. However, single cultures only were used and positive controls were not included. Following treatment, cells were centrifuged, washed with tissue culture medium and resuspended in 20 mL RPMI 10. Cells were plated into each well of a 96 well microtitre plate for determination of relative survival. The plates were incubated at 37ºC in a humidified incubator gassed with 5% v/v CO2 in air for 7 days. Wells containing viable clones were identified by eye using background illumination and counted.

OTHER: From observations on recovery and growth of the cultures during the expression period, the following cultures were selected to be plated for viability and 6TG resistance:
Experiment I (with and without S9-mix): 0, 40, 80, 100, 110, 120, 130 and 140 µg/mL;
Experiment II (with and without S9-mix): 0, 20, 40, 60, 80, 100, 120, 130 and 140 µg/mL.

Analysis of results:
- Plating efficiency (PE) = P/No of cells plated per well;
- Percentage relative survival (% RS) = [PE (test)/PE (control)] x 100;
- Mutant frequency (MF) = [PE (mutant)/PE (viable)] x 10^6

Evaluation criteria:

For valid data, the test article was considered to induce forward mutation at the hprt locus in mouse lymphoma L5178Y cells if:
1. The mutant frequency at one or more concentrations was significantly greater than that of the negative control (p<0.05).
2. There was a significant concentration relationship as indicated by the linear trend analysis (p<0.05).
3. The effects described above were reproducible.
Results that only partially satisfied the assessment criteria described above were considered on a case-by-case basis.

Statistics:

Statistical significance of mutant frequencies was carried out according to the UKEMS guidelines. The control log mutant frequency (LMF) was compared with the LMF from each treatment concentration and the data were checked for a linear trend in mutant frequency with test article treatment. These tests require the calculation of the heterogeneity factor to obtain a modified estimate of variance.

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

No statistically significant increases in mutant frequency were observed following treatment with bismuth hydroxide nitrate oxide at any concentration tested.

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
Osmolality and pH measurements on post-treatment media were taken in the cytotoxicity Range-Finder Experiment and Experiment I.
- Effects of pH and osmolality: No marked changes in osmolality or pH were observed in the Range Finder Experiment and Experiment I at the highest concentrations tested (100 and 140 µg/mL, respectively), compared to the concurrent vehicle controls (individual data not reported).
- Water solubility: Initial solubility data indicated that bismuth hydroxide nitrate oxide was soluble in water at a concentration of 1 mg/mL. The maximum practicable concentration was 100 µg/mL, based on 10% v/v additions of the test article stock solution into culture medium. A maximum concentration of 100 µg/mL was therefore selected for the cytotoxicity Range-Finder Experiment in order that treatments were performed up to the maximum practicable concentration. However, prior to the Mutation Experiments, further solubility measurements indicated that the test item was soluble in purified water at an increased solubility level of 1.4 mg/mL. The maximum concentration selected for the Mutation Experiments was therefore 140 µg/mL, based on these additional data.

RANGE-FINDING/SCREENING STUDIES: In the cytotoxicity Range-Finder Experiment, 6 concentrations were tested in the (with and without S9-mix) The highest concentration tested was 100 µg/mL, which gave 135% (without S9-mix) and 106% RS (with S9-mix).

COMPARISON WITH HISTORICAL CONTROL DATA: Comparison of controls with historical means.

ADDITIONAL INFORMATION ON CYTOTOXICITY: In Experiment I concentrations, ranging from 20 to 140 µg/mL, were tested in the absence and presence of S9. Seven days after treatment, concentrations of 20 and 60 µg/mL in the absence and presence of S9 were not selected to determine viability and 6TG resistance as there were sufficient non-toxic concentrations. The highest concentration analysed was 140 µg/mL in the absence and presence of S9, which gave 97% and 74% RS, respectively.
In Experiment II concentrations, ranging from 10 to 140 µg/mL, were tested in the absence and presence of S9. Seven days after treatment, concentrations of 10 and 110 µg/mL were not selected to determine viability and 6TG resistance as there were sufficient non-toxic concentrations. The highest concentration selected was 140 µg/mL in the absence and presence of S9, which gave 96% and 82% RS, respectively.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

It is concluded that bismuth hydroxide nitrate oxide did not induce mutation at the hprt locus of L5178Y mouse lymphoma cells when tested under the conditions employed in this study. These conditions included treatments up to the maximum practicable concentration, 140 µg/mL (limited by solubility in the primary vehicle), in two independent experiments in the absence and presence of a rat liver metabolic activation system (S9).

Executive summary:

Bismuth hydroxide nitrate oxide was assayed for the ability to induce mutation at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus (6-thioguanine [6TG] resistance) in mouse lymphoma cells using a fluctuation protocol. The study consisted of a cytotoxicity Range-Finder Experiment followed by two independent experiments, each conducted in the absence and presence of metabolic activation (S9). A 3-hour treatment incubation period was used for all experiments.

In the cytotoxicity Range-Finder Experiment, 6 concentrations were tested in the absence and presence of S9, ranging from 3.125 to 100 µg/mL (limited by solubility in the primary vehicle, purified water). The highest concentration tested, 100 µg/mL in the absence and presence of S9, gave 135% and 106% RS, respectively.

Prior to the Mutation Experiments, further solubility measurements gave an increased solubility of bismuth hydroxide nitrate oxide in purified water at 1.4 mg/mL. Accordingly, for Experiment I 9 concentrations, ranging from 20 to 140 µg/mL, were tested in the absence and presence of S9. 7 days after treatment, the highest concentration analysed to determine viability and 6TG resistance was 140 µg/mL in the absence and presence of S9, which gave 97% and 74% RS, respectively.

In Experiment II, 10 concentrations, ranging from 10 to 140 µg/mL, were tested in the absence and presence of S9. 7 days after treatment, the highest concentrations selected to determine viability and 6TG resistance was 140 µg/mL in the absence and presence of S9, which gave 96% and 82% RS, respectively.

Negative (vehicle) and positive control treatments were included in each Mutation Experiment. Mutant frequencies in negative control cultures fell within acceptable ranges and clear increases in mutation were induced by the positive control chemicals.

In Experiments I and II, no statistically significant increases in mutant frequency were observed following treatment with bismuth hydroxide nitrate oxideat any concentration tested in the absence and presence of S9 and there were no significant linear trends.

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

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

Adequacy of study:

key study

Study period:

no data available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented publication.

Justification for type of information:

Please see read-across justification attached below.

Reason / purpose for cross-reference:

read-across source

Qualifier:

no guideline followed

Principles of method if other than guideline:

Investigation of the cyto- and genotoxic effects of the test item to investigate the toxic potential.

GLP compliance:

no

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

lymphocytes: from humans

Details on mammalian cell type (if applicable):

Cells were obtained from one voluntary female blood donor and were processed immediately after collection to start the lymphocyte culture. Human lymphocytes were cultivated in McCoy's 5A medium, supplemented with 20% blood for 20 hours at 37°C.

Additional strain / cell type characteristics:

not specified

Metabolic activation:

without

Test concentrations with justification for top dose:

Concentration of Bi in exposure medium: 0, 2.5, 5.0, 25, 50, 250 µM.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: no data

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

(0.05 to 500 µM)

Positive control substance:

other: monomethylarsonous acid (0.5 µM)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 1 hour
- Expression time (cells in growth medium): Following the incubation, cells were washed twice and resuspended in 5 mL of McCoy's 5A medium.
For the evaluation of first post-treatment metaphases with chromosomal aberrations, cells were pre-labelled with 20 µM BrdU. Thereafter, cells were cultivated for additional 44 hours.
- Fixation time: Cell growth was stopped by treatment of lymphocytes with 0.08 µg/mL colcemid solution for a further 4-hour period.

STAIN (for cytogenetic assays): Metaphases were stained with Höchst-Giemsa solution.

NUMBER OF REPLICATIONS: All experiments were performed in duplicate.

NUMBER OF CELLS EVALUATED: At least 100 uniformly stained first post-treatment metaphases were analysed.

DETERMINATION OF CYTOTOXICITY
Human lymphocytes were treated with different concentrations of the test item (0.5 to 500 µM) for 1 and 24 hours. Cell viability was evaluated immediately after exposure. Cell counting under the light microscope was performed following trypan blue staining. The membrane of dead cells was permeable to trypan blue (blue stained cells), whereas living cells remained unstained. Cell viability was expressed as a percentage of surviving cells as compared to the total number of cells. The experiments were performed in duplicate. Significance was tested by using the Student's t test.

No further details are given.

Evaluation criteria:

No criteria are reported.

Statistics:

The chi square test was used for the statistical analysis of CA results. A p value of 0.05 and 0.01 was considered as stastistically relevant.

Species / strain:

lymphocytes: from humans

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

Bismuth citrate did not show any toxic effect: The cytotoxicity of the test item was <5% up to a tested concentration of 500µM after 1 hour exposure.

Vehicle controls validity:

not specified

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

Bismuth citrate did not induce chromosomal aberrations up to the highest tested concentration of 250 µM.
MMA(III) was used as a positive control and induced 9% CA in lymphocytes (p<0.05).

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

Colloidal bismuth subcitrate did not induce chromosomal aberrations up to the highest tested concentration of 250 µM.

Reference 3

Endpoint:

in vitro DNA damage and/or repair study

Type of information:

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

Adequacy of study:

key study

Study period:

no data available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented publication.

Justification for type of information:

Please see read-across justification attached below.

Reason / purpose for cross-reference:

read-across source

Qualifier:

no guideline followed

Principles of method if other than guideline:

Investigation of the cyto- and genotoxic effects of the test item to investigate the toxic potential.

GLP compliance:

no

Type of assay:

sister chromatid exchange assay in mammalian cells

Target gene:

not applicable

Species / strain / cell type:

lymphocytes: from humans

Details on mammalian cell type (if applicable):

Cells were obtained from one voluntary female blood donor and were processed immediately after collection to start the lymphocyte culture. Human lymphocytes were cultivated in McCoy's 5A medium, supplemented with 20% blood for 20 hours at 37°C.

Additional strain / cell type characteristics:

not specified

Metabolic activation:

without

Test concentrations with justification for top dose:

Concentration of Bi in exposure medium: 0, 2.5, 5.0, 25, 50, 250 µM.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: no data

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

(0.05 to 500 µM)

Positive control substance:

other: monomethylarsonous acid (0.5 µM)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 1 hour
- Expression time (cells in growth medium): Following the incubation, cells were washed twice and resuspended in 5 mL of McCoy's 5A medium.
For the analysisof sister chromatid exchanges (SCE), cells were prelabeled with 20 µM BrdU. Thereafter, cells were cultivated for additional 68 hours.
- Fixation time: Cell growth was stopped by treatment of lymphocytes with 0.08 µg/mL colcemid solution for a further 4-hour period.

STAIN (for cytogenetic assays): Mataphases were stained with Höchst-Giemsa solution.

NUMBER OF REPLICATIONS: All experiments were performed in duplicate.

NUMBER OF CELLS EVALUATED: 50 differentially stained second post-treated metaphases were evaluated for SCE.

DETERMINATION OF CYTOTOXICITY
Human lymphocytes were treated with different concentrations of the test item (0.5 to 500 µM) for 1 and 24 hours. Cell viability was evaluated immediately after exposure. Cell counting under the light microscope was performed following trypan blue staining. The membrane of dead cells was permeable to trypan blue (blue stained cells), whereas living cells remained unstained. Cell viability was expressed as a percentage of surviving cells as compared to the total number of cells. The experiments were performed in duplicate. Significance was tested by using the Student's t test.

No further details are given.

Evaluation criteria:

No criteria are reported.

Statistics:

The ANOVE test was used for evaluating the data from the SCE experiments.

Species / strain:

lymphocytes: from humans

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

Bismuth citrate did not show any toxic effect: The cytotoxicity of the test item was <5% up to a tested concentration of 500µM after 1 hour exposure.

Vehicle controls validity:

not specified

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

Colloidal bismuth subcitrate did not induce SCEs up to the highest tested concentration of 250 µM.
MMA(III) was used as a positive control and induced 9% CA in lymphocytes (p<0.05).

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

Colloidal bismuth subcitrate did not induce sister chromatid exchanges up to the highest tested concentration of 250 µM.

Reference 4

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

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

Adequacy of study:

key study

Study period:

no data available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented publication.

Justification for type of information:

Please see read-across justification attached below.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

The test substance was tested initially at half-log doses up to a dose that elicited toxicity.
Doses: 0, 3.3, 10, 33, 100, 333, 666 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
A maximum of 0.05 mL solvent was added to each plate.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without metabolic activation; strains TA1535 and TA100

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

without metabolic activation; strains TA97 and TA1537)

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylendiamine

Remarks:

without metabolic activation; strain TA98

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with metabolic activation; all strains

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 minutes at 37°C
- Expression time: The histidine-revertant (his+) colonies arising on these plates were counted following 2 days incubation at 37°C.

NUMBER OF REPLICATIONS: At least 5 doses were tested in triplicate. Experiments were repeated at least 1 week following the initial trial.

EVALUATION: The plates were hand-counted when a precipitate was present; otherwise automatic colony counters were used.

DETERMINATION OF CYTOTOXICITY
- Method: The test substance was tested initially in a toxicity assay to determine the appropriate dose range. The toxicity assay was performed by using TA 100. Toxic concentrations were those at which a decrease in the number of his+ colonies was seen or at which there was a clearing in the density of the background lawn.

No further details are given.

Evaluation criteria:

An individual trial was judged mutagenic (+) if a dose-related increase over the corresponding solvent control was seen, and it was judged weekly mutagenic (+W) if a low-level dose response was seen. A trial was considered questionable if a dose-related increase was judged insufficiently high to justify a call of "+W", if only a single dose was elevated over the control, or if a non-dose-related increase was seen.
A chemical was judged to be mutagenic, or weakly mutagenic, if it produced a reproducible, dose-related increase in his+ revertants over the corresponding solvent controls in replicate trials. A chemical was considered to be questionable if a reproducible increase of his+ revertants did not meet the criteria for either a mutagenic or weakly mutagenic, or if only single doses produced an increase in his+ revertants in repeat trials.

Statistics:

According to the guideline for a bacterial reverse mutation assay (e.g. Ames test), statistical analysis is not mandatory.

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

No further details are reported.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

Bismuth subsalicylate is non mutagenic in the reverse mutation assay with Salmonella typhimurium, tested with doses up to 666µg/plate.

Reference 5

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

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

Adequacy of study:

supporting study

Study period:

no data available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented publication.

Justification for type of information:

Please see read-across justification attached below.

Reason / purpose for cross-reference:

read-across source

Qualifier:

no guideline followed

Principles of method if other than guideline:

After incubation of bacteria with the test substance for 2 hours at 37 °C, the cells were lysed and the activity of the ß galactose enzymes and the phosphatase alkaline enzymes were determined.

GLP compliance:

no

Type of assay:

bacterial gene mutation assay

Target gene:

not applicable

Species / strain / cell type:

E. coli, other: K12

Details on mammalian cell type (if applicable):

not applicable

Additional strain / cell type characteristics:

other: Lac Z gene

Metabolic activation:

not specified

Test concentrations with justification for top dose:

0.03 - 100 nmol/tube

Vehicle / solvent:

no data

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 2 hours at 37°C

NUMBER OF REPLICATIONS: no data

EVALUATION: After incubation the bacteria were lysed and the activity of the ß galactose enzymes and the phosphatase alkaline enzymes were determined.

DETERMINATION OF CYTOTOXICITY
no data

Evaluation criteria:

no data

Statistics:

no data

Species / strain:

E. coli, other: K12

Metabolic activation:

not specified

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

toxic dose: 3 nmol/tube

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

No further details are given.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

According to the reference, bismuth (III) trinitrate is not mutagenic in an in vitro mutation test in E. coli bacteria, tested up to 100 nmol/tube.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

According to Annexes VII and VIII, point 8.4 of Regulation No 1907/2006 information on mutagenicity of substances shall be provided.

No published data or studies for determination the mutagenicity of dibismuth trioxide is available. A new study with this substance can hardly be conducted in accordance with the guidelines, since the substance is only slightly soluble in water.

However, there are publications available in which soluble bismuth salts were tested. Colloidal bismuth subcitrate was tested to induce sister chromatid exchanges or chromosome aberrations and bismuth subsalicylate and bismuth nitrate were both tested to induce gene mutation in bacterial cells. There is no indication for genotoxic/mutagenic effects of either colloidal bismuth subcitrate, bismuth subsalicylate or bismuth nitrate in these available publications.

In addition, in an available guideline study with the soluble bismuth hydroxide nitrate oxide the gene mutation potential was determined in the hprt locus of L5178Y mouse lymphoma cells. The study included treatments up to the maximum practicable concentration, 140 µg/mL (limited by solubility in the primary vehicle), in two independent experiments in the absence and presence of a rat liver metabolic activation system (S9).

Results show that bismuth hydroxide nitrate oxide does not induce gene mutation in mouse lymphoma cells.

Due to the fact, that soluble bismuth compounds are not mutagenic, it can be considered that dibismuth trioxide as a poorly soluble substance (resulting in a lower bioavailability) is not mutagenic or genotoxic and should not be classified as such.

Justification for selection of genetic toxicity endpoint
It is not possible to select one study as all studies are read-across, Klimisch 2 studies.

Short description of key information:
Dibismuth trioxide is not genotoxic by read across.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

No data about genetic toxicity of dibismuth trioxide are available. There are publications available in which soluble bismuth salts were tested. There is no indication for genotoxic/mutagenic effects of either colloidal bismuth subcitrate, bismuth subsalicylate or bismuth nitrate in these available publications. In addition, in an available guideline study with the soluble bismuth hydroxide nitrate oxide no gene mutation potential was determined in the hprt locus of mouse lymphoma cells. Bismuth hydroxide nitrate oxide should not be classified and labelled according to regulation (EC) No.: 1272/2008.

Due to the fact, that soluble bismuth compounds are not mutagenic, it can be considered that dibismuth trioxide as a poorly soluble substance (resulting in a lower bioavailability) is not mutagenic or genotoxic and should not be classified as such.

Based on available data from publications and on experimental results with bismuth hydroxide nitrate oxide, dibismuth trioxide does not need to be classified for genetic toxicity by read across.