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Toxicological information

Genetic toxicity: in vitro

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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline study, limitations in design and reporting but otherwise adequate for assessment.

Data source

Reference
Reference Type:
publication
Title:
Conditions affecting the mutagenicity of trichloroethylene in Salmonella.
Author:
McGregor DB, Reynolds DM, Zeiger E.
Year:
1989
Bibliographic source:
Environ Mol Mutagen. 1989;13(3):197-202.

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
TCE ("Hi-Tri", manufactured by Dow Chemical Co., Richmond, VA) was obtained from the National Institute of Environmental Health Sciences (NIEHS), National Toxicology Program Chemical Repository, and supplied by Radian Corporation (Austin, TX). The TCE samples were analysed for purity and identity of contaminants at the Research Triangle Institute (Research Triangle Park, NC). Unstabilised TCE (purity > 99%) contained 0.74% water and 0.6 ppm epichlorohydrin.

Method

Target gene:
his
Species / strain
Species / strain / cell type:
other: S. typhimurium TA98 and TA100
Metabolic activation:
with
Metabolic activation system:
liver homogenates (S9) prepared from Aroclor 1254-induced adult male Fischer 344 rats and Syrian hamsters. Cofactors were added to prepare S9 mix according to the method described by Ames et al. (1973).
Test concentrations with justification for top dose:
0, 1.25, 2.5, 5.0, 10.0 and 20.0% in air
Vehicle / solvent:
none
Controls
Untreated negative controls:
yes
Remarks:
air
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: dichloromethane
Details on test system and experimental conditions:
METHOD OF APPLICATION: The vapor exposure protocol required the petri dishes with bacteria, S9 mix (if used), and top agar to be prepared without TCE. The dishes were then placed in jars of known volume fitted with tapped, ground-glass lids. On the assumptions that the test liquid completely vaporises at 37 degrees Celsius and that the ideal gas laws are approximated, the quantities of test liquid required to produce the desired vapor concentrations were added. The test liquid was weighed into glass vials and frozen in liquid nitrogen. For some experiments with very small volumes of test compound, acetone was used as a vehicle. The vials were introduced to the jars containing the petri dishes. The jars were closed, partially evacuated and permitted to warm to 37 degrees Celsius over 3 hours, after which taps were opened to equilibrate with atmospheric pressure. As soon as atmospheric pressure was regained, the taps were closed and incubation continued for 2 days after which the colonies were counted.

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
Toxicity was judged to have occurred if there were reduction in colony number and/or clear reductions in microcolony number, as subjectively assessed with the aid of a low power microscope.
Evaluation criteria:
Not specified.
Statistics:
Not specified.

Results and discussion

Test results
Species / strain:
other: S. typhimurium TA98 and TA100
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not applicable
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
Trichloroethylene without stabilisers was not toxic or mutagenic in the vapor exposure assay at atmospheric concentrations nominaly up to 20% in the presence of S9.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion