Application of micronucleus in vitro assay to micropollutants in river water

To determine the genotoxicity of river water towards mammalian cells, we applied Micronucleus in vitro test using mammalian cells to the samples taken from river Tamagawa located between Tokyo and Kanagawa prefecture. Water samples were condensed by Sep-pak cartridges and extracted by dichloromethane and methanol. Positive genotoxicity was observed in methanol extracts from sampling stations of Hinobashi and Marukobashi, while no dichloromethane extracts showed genotoxicity, suggesting that polar genotoxic micropollutants may be contained in the water of Tamagawa, at least in its down-stream. Significantly high mutagenicity also detected from Hinobashi and Marukobashi by Ames mutagenicity test using Salmonella Typhimurium, and some difference was obtained in sensitivity between the two methods. This may arise from the difference in species used, that is, mammalian cells in micronucleus test and bacteria in Ames mutagenicity test.