Barium zirconium trioxide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data given in this end point relates to barium chloride dihydrate and not to barium zirconate. Both barium salts are soluble, although barium zirconate is only sparingly soluble, and dissociate to the individual ions in solution releasing Ba2+ and the anion. Once in solution, the Ba2+ ions will be equivalent in their behaviour and so it is considered valid for barium chloride to be used as a read-across material for this end point.

Data source

Reference

Reference Type:

review article or handbook

Title:

TOXICOLOGY AND CARCINOGENESIS STUDIES OF BARIUM CHLORIDE DIHYDRATE

Author:

U.S. DEPARTMENT OF HEALTE AND HUMAN SERVICES Public Health Service National Institutes of Health

Year:

1994

Bibliographic source:

NATIONAL TOXICOLOGY PROGRAM Technical Report Series No. 432

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

Principles of method if other than guideline:

Barium chloride was incubated with the Salmonella typhimurium tester strains (TA97, TA98, TA100, TA1535, and TA1537) either in buffer or S9 mix (metabolic activation enzymes and cofactors from Aroclor 1254-induced male Sprague-Dawley rat or Syrian hamster liver) for 20 minutes at 37" C. Top agar supplemented with I-histidine and d-biotin was added, and the contents of the tubes were mixed and poured ontothe surfaces of minimal glucose agar plates. Histidine-independent mutant colonies arising on these plates were counted following incubation for 2 days at 37" C.
Each trial consisted of triplicate plates of concurrent positive and negative controls, and of at least five doses of barium chloride dihydrate. The high dose was limited to 10,000 micrograms per plate

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Barium chloride

EC Number:

233-788-1

EC Name:

Barium chloride

Cas Number:

10361-37-2

Molecular formula:

BaCl2. 2H2O

IUPAC Name:

barium(2+);dichloride;dihydrate

Specific details on test material used for the study:

Barium chloride dihydrate was sent to the laboratory as a coded aliquot from Radian Corporation (Austin, "X).

Method

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 97

Metabolic activation:

with and without

Vehicle / solvent:

either in buffer or S9 mix

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

not specified

Details on test system and experimental conditions:

Each trial consisted of triplicate plates of concurrent positive and negative controls, and of at least five doses of barium chloride dihydrate

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

In this test, a positive response was defined as a reproducible, dose-related increase in histidineindependent (revertant) colonies in any one strain / activation combination. An equivocal response was defined as an increase in revertants that was not dose related, not reproducible, nor was of sufficient magnitude to support a determination of mutagenicity. A negative response was obtained when no increase in revertant colonies was observed following chemical treatment. There was no minimum percentage or fold increase required for a chemical to be judged positive or weakly positive

Applicant's summary and conclusion

Conclusions:

Barium chloride dihydrate was not mutagenic in Salmonella typhimurium strains TA97, TA98, TA100, TA1535, or TA1537,with or without exogenous metabolic activation (S9).