In Japan, musty odor produced by cyanobacteria are major problems for comfortability in drinking water.Available information on morphological characteristics and gene information of musty odor producing cyanobacteria in Japan is limited. In this study, musty odor producing cyanobacteria in nationwide water sources were surveyed by optical microscope and gene analysis and collected their characteristics and gene information. Aphanizomenon spp., Dolichospermum spp. and Phormidium spp. were found as geosmin producing cyanobacteria. And, Microcoleus spp., Phormidium spp., Planktothricoides spp. and Pseudanabaena spp. were found as 2-methylisoborneol (2-MIB) producing cyanobacteria. As results of morphological characteristics and 16S rRNA gene analysis, some parts of musty odor producing cyanobacteria were unable to identified by only morphological characteristics or gene analysis. Combination between morphological characteristics and gene analysis is important to identify these cyanobacteria. In gene detection of geosmin biosynthesis gene (geoA gene) and 2-MIB biosynthesis gene by PCR, targeted gene were detected from 18 of 19 water sources. PCR targeting biosynthesis gene related to musty odor is a useful tool for survey of musty odor producing cyanobacteria in water sources as a monitoring system.

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We investigated the occurrence in its water resource and the behavior of tefuryltrione and ipfencarbazone in drinking water purification system especially by coagulation sedimentation, sand filtration, ozonation, granular activated carbon (GAC) adsorption, chlorination and powdered activated carbon (PAC) adsorption. We confirmed that tefuryltrione and ipfencarbazone flow into the water source. Coagulation sedimentation and sand filtration were not applicable for tefuryltrione, but ozonation and chlorination were much effective and GAC adsorption was also effective, although the degree varied depending on the conditions such as water temperature and aging. Coagulation sedimentation, sand filtration, ozonation, chlorination were not applicable for ipfencarbazone, but GAC adsorption was much effective for it regardless of water temperature and space velocity. PAC adsorption was effective for tefuryltrione and ipfencarbazone regard injection rate. We confirmed that tefuryltrione and ipfencarbazone can be effectively removed by PAC adsorption or combination with ozonation and GAC adsorption.

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[in Japanese]

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