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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
20 November to 12 December 1989
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Justification for read-across is warranted given the similarities in toxicity profile and physico-chemical properties for silicon dioxide and magnesium silicate.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report date:
1989

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
Plate incorporation assay
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Silicon dioxide
EC Number:
231-545-4
EC Name:
Silicon dioxide
Cas Number:
7631-86-9
Molecular formula:
O2Si
IUPAC Name:
dioxosilane
Details on test material:
- Name of test material (as cited in study report): Cab-O-Sil EH-5:
CAS-Name: Silica, amorphous, fumed, cryst.-free;
CAS-No.: 112945-52-5
- Analytical purity: >99%
- Lot/batch No.: 1H049
- Stability under test conditions: stable
Specific details on test material used for the study:
Name of test material (as cited in study report): Cab-O-Sil EH-5:
CAS-Name: Silica, amorphous, fumed, cryst.-free;
CAS-No.: 112945-52-5
- Analytical purity: >99%
- Lot/batch No.: 1H049
- Stability under test conditions: stable

Method

Target gene:
Histidine
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
Metabolic activation:
with and without
Metabolic activation system:
S9 mix prepared from the livers of Aroclor induced adult male SD rats
Test concentrations with justification for top dose:
667, 1000, 3333, 6667 and 10000 µg/plate
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
not specified
Details on test system and experimental conditions:
Ames test
METHOD OF APPLICATION: in medium; in agar (plate incorporation)

DURATION
- Exposure duration: no data

NUMBER OF REPLICATIONS: 3/concentration

NUMBER OF CELLS EVALUATED: seeded cells 10^8/plate

DETERMINATION OF CYTOTOXICITY
- Background lawn evaluated in pre-tests using TA 100

OTHER EXAMINATIONS:
- Other: Reversion rate
Evaluation criteria:
Standard Ames test criteria looking for doubling ortrebling of mutation rates in test plates
Statistics:
Arithmetic averages with standard deviations.

Results and discussion

Test results
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 information
Remarks on result:
other: strain/cell type: Salmonella typhimurium TA98, TA100, TA1535, TA1537,TA1538
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

No further information

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

No evidence of reverse mutation in five test strains used in the Ames test to determine potential genotoxicity of magnesium silicate
Executive summary:

An Ames bacterial mutation study has been conducted with silicon dioxide in strains TA98, TA100, TA1535, TA1537 and TA1538. Concentrations of 667, 1000, 3333, 6667 and 10000 µg/plate were used.

The test substance showed no evidence of mutagenicity.