In vitro genotoxicity of dyes present in colored smoke munitions

Area of Science:

• Toxicology
• Genetics
• Chemical Safety

Background:

• Organic dyes are used in colored smoke munitions.
• Assessing the genotoxicity of these dyes is crucial for safety evaluations.

Purpose of the Study:

• To evaluate the genotoxic potential of specific organic dyes and a dye mixture used in colored smoke munitions.
• To determine mutagenicity, cytotoxicity, sister chromatid exchanges (SCE), and chromosome aberrations in bacterial and mammalian cell systems.

Main Methods:

• Standard Ames assay using Salmonella strains (TA1535, TA100, TA98, TA1538) with and without metabolic activation (S-9).
• In vitro assays in Chinese hamster ovary (CHO) cells, including mutation assays (HGPRT), cytotoxicity, SCE induction, and chromosome aberration tests.
• Pre-incubation assay for azo dye reduction to free amines.

Main Results:

• No dyes were genotoxic in the standard Ames assay or in CHO cells for mutagenicity or clastogenicity.
• Disperse Red 11 (Lot 2) exhibited weak mutagenic activity in bacterial strains TA98 and TA1538 with S-9 activation.
• Solvent Red 1 was cytotoxic and increased SCE in CHO cells but was not mutagenic or clastogenic.
• Disperse Red 11 (Lot 1 and Lot 2) increased cell cycle time and SCE frequency but were not cytotoxic or clastogenic.
• A contaminant in Disperse Red 11 (Lot 2) is suspected as the cause of weak mutagenic activity.

Conclusions:

• The tested organic dyes and dye mixture are not genotoxic or clastogenic.
• A contaminant in Disperse Red 11 (Lot 2) likely accounts for the observed weak mutagenic activity in bacterial and mammalian cells.
• Further investigation into the contaminant is warranted to fully understand the toxicological profile.