Phenol, 3-bromo-5-chloro-

Genetic toxicity: in vitro

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:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Version / remarks:

2000

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3-bromo-5-chlorophenol

EC Number:

611-435-6

Cas Number:

56962-04-0

Molecular formula:

C6H4BrClO

IUPAC Name:

3-bromo-5-chlorophenol

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 102

Metabolic activation:

with and without

Metabolic activation system:

Arochlor 1254-induced rat liver

Test concentrations with justification for top dose:

1.0, 3.16, 10 31.6 and 100 µg/plate

Vehicle / solvent:

dimethylsulfoxide (DMSO)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: Cyclophosphamide and 2-Amino-anthracene

Details on test system and experimental conditions:

A preliminary cytotoxicity test without metabolic activation in test strain TA 100 employing a plate incorporation test was performed. Ten concentra-
tions ranging from 0.316 to 5000 μg 3-Bromo-5-chlorophenol/plate were tested.

Main study: 3 per concentration and experiment; 2 independent experiments without and with metabolic activation. The vehicle DMSO served as the
negative control.
2 independent experiments have been performed: 1st independent experiment - Plate Incorporation Method; 2nd independent experiment - Prein-
cubation Method

Evaluation criteria:

see below

Statistics:

In this study a test item is considered to show a positive response if
- the number of revertants is significantly increased (p ≤ 0.05, U-test according to MANN and WHITNEY, see section 6, reference 3) compared with the solvent control to at least 2-fold of the solvent control for TA 98, TA 100 and TA 102 and 3-fold of the solvent control for TA 1535 and TA 1537 in both independent experiments;
- in addition, a significant (p ≤ 0.05) concentration (log value)-related effect (Spearman’s rank correlation coefficient, see section 6, reference 3) is observed;
- positive results have to be reproducible and the histidine independence of the revertants has to be confirmed by streaking random samples on histidine-free agar plates.

Cytotoxicity is defined as a reduction in the number of colonies by more than 50 % compared with the solvent control and/or a scarce background lawn.

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Cytotoxicity was observed at the highest test concentration of 100 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

Under the present test conditions the test substance tested up to a cytotoxic concentration caused no mutagenic effect in the Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 neither in the plate ineorporation test nor in the preincubation test each carried out without and with metabolic activation.

Executive summary:

The test substance was examined in the 5 Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 in two independent experiments, each carried out without and with metabolic activation (a microsomal preparation derived from Aroclor 1254-induced rat liver). The first experiment was carried out as a plate incorporation test and the second as a preincubation test.

Preliminary test

The test substance was examined in a preliminary cytotoxicity test without metabolic activation in test strain TA 100 employing a plate incorporation test. The test substance was dissolved in dimethylsulfoxide (DMSO). The concentrations refer to the test substance, a correction factor of 1.12 was employed. Ten concentrations ranging from 0.316 to 5000 μg/plate were tested. Pronounced cytotoxicity (scarce background lawn and reduction of the number of revertants) was noted from concentrations of 100 μg/plate onwards.

Hence, 100 μg/plate was chosen as the top concentration for the main study.

Main study

Five concentrations ranging from 1.0 to 100 μg/plate were employed in independent experiments each carried out without and with metabolic activation.

Cytotoxicity

Cytotoxicity (scarce background lawn and/or reduction of the number of revertants) was observed in the plate incorporation test and in the preincubation test, both carried out without and with metabolic activation, at the top concentration of 100 μg/plate in all test strains.

Mutagenicity

No mutagenic effect (no increase in revertant colony numbers as compared with control counts) was observed for the test substance tested up to a cytotoxic concentration of 100 μg/plate in any of the 5 test strains in two independent experiments without and with metabolic activation (plate incorporation and preincubation test, respectively).