Barium oxide, obtained by calcining witherite

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

BaO rapidly hydrolyzes to Ba(OH)2, a strongly alkaline substance, upon contact with water. Barium chloride dihydrate as well soluble barium salt was used to assess the potential of BaO to cause barium toxicity. The study was performed similar to OECD TG 471 and a detailed study report is available.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

10326-27-9

EC Number:

600-412-6

Cas Number:

10326-27-9

IUPAC Name:

10326-27-9

Constituent 2

Reference substance name:

Barium Chloride Dihydrate

IUPAC Name:

Barium Chloride Dihydrate

Details on test material:

- Name of test material (as cited in study report): Barium chloride dihydrate
- Molecular formula (if other than submission substance): BaCl2*2H2O
- Molecular weight (if other than submission substance): 244.28 g/mol

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 97

Species / strain 2

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:

0, 100, 333, 1000, 3333 and 10000 µg/plate

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene was used on all strains in the presence of S9. The positive controls in the absence of metabolic activation were sodium azide (TA1535 and TA100), 9-aminoacridine (TA97 and TA1537), 4-nitro-o-phenylenediamine (TA98).

Details on test system and experimental conditions:

Testing was performed as reported by Zeiger et al. (1992). Barium chloride dihydrate 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 l-histidine and d-biotin was added, and the contents of the tubes were mixed and poured onto the 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 µg/plate.

Evaluation criteria:

A positive response was defined as a reproducible dose-related increase in revertant (histidine-independent) colonies.
An equivocal response was defined as an increase in mutant colonies that was not dose-responsive, not reproducible or not of sufficient magnitude to be clearly due to mutagenic activity of the compound.

Results and discussion

Test results

Test results 1

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:

cytotoxicity

Remarks:

slight toxicity at concentration from 333 to 10000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

slight toxicity at concentration from 333 to 10000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid