Gallium arsenide

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:

no data available

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP toxicity study conducted under the US National Toxicology Program (NTP). Tested with 5 strains of salmonella, TA100, TA 98, TA 1535, TA 97 and TA102.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Salmonella Mutagenicity Tests: V. Results from the Testing of 311 Chemicals

Author:

Zeiger, E., Anderson, B., Haworth, S., Lawlor, T. & Mortelmans, K.

Year:

1992

Bibliographic source:

Environmental and Molecular Mutagenesis Volume 19, Supplement 21:2 - 141.

Reference 2

Reference Type:

publication

Title:

Unnamed

Year:

2000

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:

gallium arsenide (Mechanically destroyed material not marketed. Particle size is fundamentally different from the coarser particles measured at the workplace.)

IUPAC Name:

gallium arsenide (Mechanically destroyed material not marketed. Particle size is fundamentally different from the coarser particles measured at the workplace.)

Details on test material:

- Name/CAS number of test material (as cited in study report): gallium arsenide/ 1303-00-0
- Physical state: solid
- vendor: Johnson Mattey
- Analytical purity: (vendors purity: 99.99%, analyzed purity at Midwest Research Institute, Kansas, City, MO: 99%)
No further details are given.

Method

Target gene:

not applicable

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 102

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 100

Additional strain / cell type characteristics:

not specified

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 1535

Additional strain / cell type characteristics:

not specified

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 97

Additional strain / cell type characteristics:

not specified

Species / strain 5

Species / strain / cell type:

S. typhimurium TA 98

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9-mix (metabolic activation enzymes and cofactors from Aroclor 1254-induced male Sprague-Dawley rat or Syrian hamster)

Test concentrations with justification for top dose:

0.0, 10, 33, 100, 333, 1000, 1666, 3333 and 10000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: no data

Controls

Controls 1

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

Controls 2

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 TA 1535 and TA 100

Controls 3

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; strain TA 97

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylenediamine

Remarks:

without metabolic activation; strain TA98

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

without metabolic activation; strain TA102

Details on test system and experimental conditions:

Cultures were grown overnight at 37°C in defined minimal medium supplemented with biotin (0.8 µg/mL) and histidine (40 µg/mL). The phenotypes of the strains were analysed at the time of their use in mutagenicity assay.

METHOD OF APPLICATION: in agar; preincubation;

DURATION
- Preincubation period: 20 minutes at 37°C
- Exposure duration: 48 hours at 37°C

NUMBER OF REPLICATIONS: 3

EVALUATION: Histidine-independent (his+) colonies arising on the plates were counted. Plates were machine counted unless precipitate was present which interfered with the count.

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth:
A toxicity assay was run initially to determine the appropriate dose range for the mutagenicity assay. The toxicity assay was performed using TA 100 . Toxic concentrations were defined as those that produced a decrease in the number of his+ colonies, or a clearing in the density of the background lawn, or both.
The test substance was initially tested in the preincubation test at half-log dose intervals up to a dose that elicited toxicity. If the test substance was not toxic, it was tested to a maximum dose of 10 mg/plate or up to the dose defined by its solubility. At least five doses were tested in triplicate, and repeat experiments were performed at least one week following the initial trial.

Evaluation criteria:

A chemical was judged mutagenic (+) or weakly mutagenic (+W) if it produced a reproducible, dose-related response over the solvent control, under a single metabolic activation condition, in replicate trials.
A chemical was judged questionable (?) if the results of individual trials were not reproducible, if increases in his+ revertants did not meet the criteria for a “+W” response, or if only single doses produced increases in hisf revertants in repeat trials.
Chemicals were judged nonmutagenic (-) if they did not meet the criteria for a mutagenic or questionable response.

Statistics:

not mandatory for this test system

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

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:

No further details are reported.

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

According to the study, gallium arsenide gave a non-mutagenic response.

Executive summary:

The purpose of the study was to present the results and data from the testing of gallium arsenide for its ability to induce mutations in tester strains of Salmonella typhimurium.The test substance was suspended in DMSO and tested at following concentrations in the preincubation method in the presence and absence of metabolic activation: 0.0, 10, 33, 100, 333, 1000, 1666, 3333 and 10000 µg/plate.

Toxicity was determined with TA 97, TA 98, TA 100, TA 102 and TA 1535. Concurrent solvent and positive controls were run with each trial.

According to the results, gallium arsenide is not mutagenic in the Ames test.