Chromium

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro transformation study in mammalian cells

Remarks:

Type of genotoxicity: genome mutation

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable publication which meets basic scientific principles; however all details of the study are not presented.

Data source

Reference

Reference Type:

publication

Title:

Welding fumes and chromium compounds in cell transformation assays.

Author:

Hansen, K. and R. M. Stern

Year:

1985

Bibliographic source:

J Appl Toxicol.5(5): 306-14.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

lack of positive controls, no metabolic activation

GLP compliance:

not specified

Type of assay:

in vitro mammalian cell transformation assay

Test material

Test material information

Constituent 1

Reference substance name:

Chromium(III) oxide

IUPAC Name:

Chromium(III) oxide

Constituent 2

Reference substance name:

metallic chromium

IUPAC Name:

metallic chromium

Details on test material:

Metallic chromium (Cr) ; Merck analytical grade.
Chromic oxide (Cr2O3) Merck analytical grade.
No other details given.

Method

Species / strain

Species / strain / cell type:

other: Syrian hamster BHK cells

Details on mammalian cell type (if applicable):

- Type and identity of media: Dulbecco's modified Eagle's medium supplemented with 20% newborn calf serum.
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: no data
- Periodically checked for karyotype stability: no data
- Periodically "cleansed" against high spontaneous background: no data

Additional strain / cell type characteristics:

not specified

Metabolic activation:

without

Test concentrations with justification for top dose:

Metallic chromium: no concentrations given.
Cr2O3: 100, 400, 1600 µg/ml (68,5, 274, 1095 µg Cr(III)/ml).

Vehicle / solvent:

Water

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

no details given; obviously water

True negative controls:

no

Positive controls:

no

Positive control substance:

no

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: cells were grown until the monolayer was approx 70% confluent
- Exposure duration: 7 h for transformation test, 8 days for toxicity test

Transformation test: After exposure cells were plated in 0.3% agar solution to allow transformed cells to grow into large (>400 µm) colonies during 3 weeks.



SELECTION AGENT (mutation assays):
SPINDLE INHIBITOR (cytogenetic assays):
STAIN (toxicity test): crystal violet


NUMBER OF REPLICATIONS: no data


NUMBER OF CELLS EVALUATED: 2*5*10(exp-5) (minus 2*1250 removed for tox determination). BHK cells were evaluated using a haemocytometer.


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth


OTHER EXAMINATIONS:
- Determination of polyploidy:
- Determination of endoreplication:
- Other:


OTHER:

Evaluation criteria:

- Number of transformations per 500000 cells / per 500000 survivors (absolute and specific transformation frequency)
- relative survival

Statistics:

No data

Results and discussion

Test results

Test results 1

Species / strain:

other: Syrian hamster BHK cells

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

not examined

Test results 2

Species / strain:

other: Syrian hamster BHK cells

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

not examined

Additional information on results:

No transforming effects of metal chromium or Cr2O3 on BHK cells (no values presented)



ADDITIONAL INFORMATION ON CYTOTOXICITY: slight toxic effects of Cr2O3; however the authors concluded that it may be related to contamination. No toxic effects of Cr metal.

Remarks on result:

other: strain/cell type: BHK, Cr metal exposure

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative Cr metal
negative Cr2O3

Metallic chromium and Cr2O3 did not have a transforming effect on cells. Cr metal was not toxic. Cr2O3 showed some signs of toxicity, however the authors mentioned that it may be due to contamination.

Executive summary:

The genotoxic potential of chromium metal and chromium(III) oxide was tested in Syrian hamster BHK cells, using an in vitro mammalian cell transformation test. Metallic chromium and Cr2O3 did not have a transforming effect on cells. Cr metal was not toxic. Cr2O3 showed some signs of toxicity, however the authors mentioned that it may be due to contamination. It should be noted that all details were not presented in the publication, for example the test concentrations of chromium metal remained unclear.