2,6-dichlorobenzaldehyde

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Only 4 Strains tested

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Materials and methods

Test guideline

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:

2,6-dichlorobenzaldehyde

EC Number:

201-472-2

EC Name:

2,6-dichlorobenzaldehyde

Cas Number:

83-38-5

Molecular formula:

C7H4Cl2O

IUPAC Name:

2,6-dichlorobenzaldehyde

impurity 1

Reference substance name:

2,6-dichlorobenzoic acid

EC Number:

200-025-9

EC Name:

2,6-dichlorobenzoic acid

Cas Number:

50-30-6

Molecular formula:

C7H4Cl2O2

IUPAC Name:

2,6-dichlorobenzoic acid

Method

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9-Mix

Test concentrations with justification for top dose:

8, 40, 200, 1000, 5000 µg/Plate

Vehicle / solvent:

Ethylene glycol dimethylether

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

other: Nitrofurantoin, 4-nitro-1,2-phenylene diamine, 2-aminoanthracene

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Up to 20 µg per plate no bacteriotoxic effects. At higher doses, the substance had a strong, strain-specific bacterio-toxic effect, so that this range could only be used to a limited extent up to 320 µg per plate for assessment purposes.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

2,6-Dichlorobenzaldehyde was investigated using the Salmonel-la/microsome test for point mutagenic effects in doses up to 5000 µg per plate on four Salmonella typhimurium LT2 mutants. These comprised the histidine-auxotrophic strains TA 1535, TA 100, TA 1537 and TA 98.

Doses up to and including 20 µg per plate did not cause any bacteriotoxic effects: Total bacteria counts remained unchanged and no inhibition of growth was observed. At higher doses, the substance had a strong, strain-specific bacterio-toxic effect, so that this range could only be used to a limited extent up to 320 µg per plate for assessment purposes. Substance precipitation occurred at the dose 5000 µg per plate.
Evidence of mutagenic activity of 2,6-dichlorobenzaldehyde was not seen. No biologically relevant increase in the mutant count, in comparison with the negative controls, was ob-served. Therefore, 2,6-dichlorobenzaldehyde was considered to be non-mutagenic without and with S9 mix in the Salmonella/ microsome test.

The positive controls sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine and 2-aminoanthracene had a marked mutagenic effect, as was seen by a biologically relevant in-crease in mutant colonies compared to the corresponding nega-tive controls.