Chloroacetonitrile

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1995

Materials and methods

Principles of method if other than guideline:

The Ames fluctuation test, an in vitro test detecting point mutation on Salmonella typhimurium. This assay is the modification, in liquid medium, of the widely used Ames/Salmonella assay. Thanks to its better sensitivity, the fluctuation test is very well suited to the search for mutagenicity in water samples (Wilcox and Denny, 1985; Monarca et al., 1985).

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Chloroacetonitrile

EC Number:

203-467-0

EC Name:

Chloroacetonitrile

Cas Number:

107-14-2

Molecular formula:

C2H2ClN

IUPAC Name:

2-chloroacetonitrile

Test material form:

liquid

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 100

Details on mammalian cell type (if applicable):

Source of cells: B.N. Ames (University of California, Berkeley, USA)

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 (rat)

Test concentrations with justification for top dose:

3-300 µg/ml without metabolic activation, 1-1000 µg/ml with metabolic activation

Vehicle / solvent:

DMSO

Controls

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Remarks:

1 ng/ml 4-NQO without the metabolic system and 60 µg/ml CPA with metabolic activation

Details on test system and experimental conditions:

The Ames-fluctuation test was performed as described by Hubbard et al. (1984). This assay is a modification of the Ames test: the compound under study is exposed to bacteria in a liquid medium in many replicate cultures (96-well microplate) instead of the agar plate used in the Ames assay.
After the 3-day incubation, bromothymol blue (600 µg/ml) was added. Positive wells (containing prototrophic mutants) turned yellow whereas negative wells remained green. For each experiment, spontaneous reversion in response to the solvent used (DMSO) was included. Compounds were tested at least twice (two independent assays) using 3 experimental points for each concentration.

Rationale for test conditions:

Strain TA100 was used during all the experiment because it is considered as the most sensitive strain to water mutagens and particularly to chlorinated by-products (Loper, 1980; Forster et al., 1983; Harrington et al., 1983; Vartiainen and Liimatainen, 1986; Fielding and Horth, 1987; Meier, 1988).

Evaluation criteria:

A chemical is considered as toxic when it produces a significant decrease in the number of positive wells compared to the solvent control.
A compound is considered as mutagenic:
(1) if it induces a statistically significant increase in the number of positive wells compared to the solvent control,
(2) if a dose-effect relationship is noticeable and
(3) if the result is reproducible.

Statistics:

The statistical significance of the results was assessed with the X2 test: p < 0.05 for X2 > 3.84 and p < 0.01 for X2 > 6.63 (Green et al., 1976).

Results and discussion

Test results

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

30 µg/ml (in the presence of S9-mix only)

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

300 µg/ml (threshold toxic concentration)