Development of Micronuclei test with gills of Medaka, Oryzias latipes and its application to the various effluents

Abstract

The micronuclei test with gills of Japanese medaka (Oryzias latipes) was developed by modification of the traditional method. The effectiveness of this assay was confirmed with medaka exposed to Benzo[a] pyren, and the time course and concentration-dependent patterns of micronuclei induction were discussed. Finally, this new method was applied to effluent samples from 3 landfill sites and 1 chemical factory. All of raw leachate samples induced micronuclei significantly, which were reduced through treatments. The fact that the significant induction of micronucleated cells was observed when fishes were exposed to lower concentration of effluents than that of LC50 suggests the importance of genotoxicity monitoring with this test.