ｉｎ ｖｉｔｒｏ小核試験とコロニー形成阻害試験を用いた多摩川河川水の遺伝・細胞毒性評価

Abstract

Genotoxicity and cytotoxicity of Tama river water was determined with micronucleus in vitro test and colony formation inhibition test, using a human cultured cell line. River water samples were taken from 5 stations of Tama River ; Hamuraseki, Hinobashi, Sekidobashi, Toumeishita and Marukobashi, and 1 station of its main tributary, Asakawa ; Araibashi. The organic substances in water were once recovered with solid phase adsorbent and then eluted with dichloromethane and methanol in this order. After evaporating, the residues were dissolved in DMSO and used for the assays. The dichloromethane fractions from Sekidobashi and Marukobashi strongly inhibited colony formation but micronucleus formation was not increased by any of them except Araibashi station, suggesting the occurrence of cytotoxic substances in river water from these stations. The methanol fractions from Toumeishita and Marukobashi strongly increased micronucleus formation but colony formation inhibition was not observed with the fractions, indicating the occurrence of genotoxic substances. The results suggest that Tama river water is polluted with genotoxic and cytotoxic substances and that the genotoxic substances have more polarity than cytotoxic ones.in vitro micronucleus test and colony formation inhibition test using cultured cells are simple and effective methods for evaluating both genotoxicity and cytotoxicity of environmental water.