Fumes, silica

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Link to relevant study records

Reference

Endpoint:

in vitro transformation study in mammalian cells

Remarks:

Type of genotoxicity: genome mutation

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.21 (In Vitro Mammalian Cell Transformation Test)

Principles of method if other than guideline:

Evaluation of cytotoxic and cell transforming effects of various crystalline (quartz, cristobalite) and amorphous forms of silica (biogenic, synthetic) in Syrian hamster embryo cells was performed.

GLP compliance:

not specified

Type of assay:

in vitro mammalian cell transformation assay

Species / strain / cell type:

mammalian cell line, other: Syrian hamster embryo cells

Metabolic activation:

without

Test concentrations with justification for top dose:

3, 8, 25 and 30 microg/cm2 (estimated on the basis of figures in study report)

Vehicle / solvent:

sterile tridistilled water

Untreated negative controls:

no

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

no

Positive control substance:

other: 2158

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium
DURATION
- Preincubation period: 24 h
- Exposure duration: 7 days
- Expression time (cells in growth medium): -
- Selection time (if incubation with a selection agent): -
- Fixation time (start of exposure up to fixation or harvest of cells): 7 days
DETERMINATION OF CYTOTOXICITY
- Method: Inhibition of cell growth.

Evaluation criteria:

The criteria decribed by DiPaolo (Journal Natl Cancer Inst, 42, 867-876, 1969) and Pienta et al. (Short term tests for Chemical carcinogens, ed. H.F. Stick and R.H.C. San, Springer-Verlag, NY, p. 323-337, 1981) was used to define the colony as morphologically transformed

Statistics:

The relation between the transformation induced by a sample and the treatment concentrations was indicated by the significance of the correlation coefficient (r). No further information on statistical methods was given.

Species / strain:

other: Syrian hamster ovarian cells

Metabolic activation:

not applicable

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

not specified

Positive controls validity:

not examined

Additional information on results:

Comparison to diacemateous earth and crystalline silica was made. Hydrophilic pyrogenic silica (Aerosil® OX50) was neither cytotoxic nor transforming whereas some quartz and cristobalite samples and 3 differant diatomaceous earths induced cytotoxicity and morphological colony transformation in a dose-dependent manner. Surface properties (distribution of silanol groups and trace amounts of iron) appeared to be important in the induction of cytotoxicity.

Remarks on result:

other: strain/cell type: Syrian hamster ovarian cells

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

Hydrophilic pyrogenic silica (Aerosil® OX50) was neither cytotoxic nor transforming.

Executive summary:

Elias et al. (2000) evaluated cytotoxic and cell transforming effects of various crystalline (quartz, cristobalite) and amorphous forms of silica (biogenic, synthetic) in Syrian hamster embryo cells. Hydrophilic pyrogenic silica (Aerosil® OX50) was neither cytotoxic nor transforming.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

Justification for selection of genetic toxicity endpoint
Evaluation of cytotoxic and cell transforming effects of various crystalline (quartz, cristobalite) and amorphous forms of silica (biogenic, synthetic) in Syrian hamster embryo cells was performed.