摘要：Within recent years, concern over contamination with organic compounds in aquatic environment has risen. But due to the extremely low levels and many kinds of organics present, it is difficult to get sufficient information about all compounds. Therefore mutagenicity is studied on tap water, river water and river sediment. This report is on mutagenicity of dichloromethane (DCM) extracts from the sediments which were collected at 7 points in the Nakatsu river during 1987. The Nakatsu river is a branch of the Sagami river used for drinking water supply in Kanagawa prefecture and has the best quality of water among branches. However, it is obvious that those sediments show mutagenicity (2-20 times as many as spontaneous revertants per 5 g dry weight) by using the strain TA98 of Salmonella typhimurium with S9mix. Certain sediment also shows mutagenicity without S9mix. DCM extract of some sediments are separated to acidic, neutral and basic portions, and the neutral portion is fractionated to three fractions on a silicagel column (Fr. 1, Fr. 2 and Fr. 3). Futhermore Fr. 3 is fractionated to three sub-fractions with HPLC (sub-fr. 1, sub-fr. 2 and sub-fr. 3). Each fraction is surveyed with both the Ames test and GC-MS analysis. As the result it is confirmed that Fr. 2 gives 10-26% of the total mutagenicity observed in the sediment and contains many kinds of mutagenic polynuclear aromatic hydrocarbons. It is also found that Fr. 3 gives the residual mutagenicity which mainly depends on sub-fr. 2. But the mutagenicity in Fr. 3 is not able to be explained because of the existence of unidentified peaks on GC-MS. We are investigating these unknown compounds which cause the mutagenicity of the Nakatsu river sediments.
关键词：mutagenicity;Nakatsu river;sediment;dichrolomethane extract;silicagel column chromatography;HPLC;GC-MS;Ames test
