Flow cytometric measurement of micronuclei induced in a permanent fish cell line as a possible screening test for the genotoxicity of industrial waste waters

An in vitro micronucleus assay using the permanent fish cell line RTG-2 (rainbow trout gonads) was developed to test industrial waste waters for their genotoxic potential. Comparison of flow cytometric measurement and microscopic scoring of micronucleus frequency with the reference chemicals 1,4-butane sultone (0.2–1 mM), ethylmethane sulphonate (2–10 mM), potassium dichromate (20–100 μM) and benzo[a]pyrene (5–25 μM) showed similar dose–effect relationships. Thirty-eight industrial waste waters from 11 different branches of industry obtained from the Bavarian state office for water research were tested using the flow cytometric method (18 from metal processing, 10 from combined waste water, two from synthetic fibre production, one sample each from settlement wastes, non-iron metal manufacturing, leather production, sulphuric acid production, ore processing, graphite film production, cellulose production and flue gas washing). Fourteen of them showed a significant increase in micronucleus frequency.