Biological and Chemical Characterization of Organic Substances in Water Purification Pond at Sea-Based Solid Waste Disposal Site

The biological and chemical properties of organic substances in the water purification pond at a sea-based solid waste disposal site, in Osaka City, have been investigated. The mutagenic activities in the extract of water and benthal mud were detected by the Ames Salmonella typhimurium TA98/microsome assay. The extracts of water and sediments of the disposal site showed a weak mutagenic activity to TA98 with S9 mix. The levels of mutagenic activity in water were almost the same as those of the Yodo river. Dichloromethane (DCM) extracts of sediments were separated into acidic, basic and neutral fractions. The neutral fraction was further fractionated on a silica-gel column chromatography and tested for mutagenicity in the Ames assay. The mutagenic subfractions were analyzed by capillary column gas chromatography-mass spectrometory (GC-MS) and 20 kinds of polynuclear aromatic hydrocarbon (PAHs) were detected. These results indicate that the PAH-containing fractions account for most of the genotoxic activity observed in this reservoir sediment.