Induction of sister-chromatid exchanges in fish exposed to Rhine water.

The induction was studied of sister-chromatid exchanges in gill and testis of fish exposed to Rhine water. The eastern mudminnow, Umbra pygmaea, was chosen because the usefulness of this species with a karyotype of 22 large chromosomes had been demonstrated in cytogenetic mutagenicity testing. Fish exposed to Rhine water for 3 and 11 days showed a 2-fold and 3-fold higher SCE rate resp., compared with fish exposed to ground water of drinking water quality. There was no difference in SCE rate between gill and testicular cells before and after exposure. GLC/MS analysis indicated that different classes of chemical compounds may be involved in the cytogenetic effects found in fish. The mudminnow has proved to be a useful fish species for biological monitoring of mutagens in polluted waters. The SCE test may be a suitable test system to prescreen their mutagenic potential.