Natural clay mineral, allophane, was tried to be used for removal of cesium ion from aqueous solution. The removal performance of allophane was evaluated by atomic absorption spectrometry in batch test and flow test compared to that of the other clay minerals, such as zeolite, montmorillonite, and kaolinite. The adsorption ability of the allophane for cesium ion was significantly lower than that of zeolite due to its lower cation exchange capacity. On the other hand, water quickly passed though the funnel filled with allophane compared to the other clay minerals. Allophane has somewhat adsorption ability for cesium ion and appropriate water-permeability. The allophane can be an excellent adsorbent when it is appropriately filled in the funnel or column. Furthermore, elusion of cesium ion from the allophane to water was inhibited when the allophane absorbing cesium ion was dispersed in silica gel by the sol-gel method. The same effect was observed for ion of lead used for radiation shielding. This can be a first step toward the development of the disposal of radioactive wastes.

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Perfluorinated compounds (PFCs) that are widely used as surfactants and coatings were determined in muscles of crucian carp (Carassius auratus (gibelio) langsdorfii) taken from 14 freshwater areas throughout Japan during 2003-2005.The sampling sites comprised 10 rivers and 4 ponds and were categorized into 4 groups based on local circumstances: large cities, small cities, agricultural　areas and remote areas. PFCs were detected in all samples analyzed, and total PFCs concentrations ranged from 1.60 to 30.1 (average: 9.54, median: 8.80) ng/g wet wt. and 167 to 3496 (average: 914, median:645) ng/g lipid wt. The highest concentrations of PFCs were found in fish caught at sites in large cities. Fish in the remote area's had low PFCs concentrations. Branched chain PFC isomers were also detected, although the relative ratios of the straight chains to the branch isomers were different between sampling sites. To obtain maternal transfer rates for the PFCs, female fish were collected from the Murasaki River during the spawning season and their muscles and eggs were analyzed. The maternal transfer rate of PFCs was 9.1%, which is lower than those of hydrophobic substances such as dioxins, organochlorine pesticides and hexabromocyclododecanes. As a result, sexual differences between male and female fish were not found.

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Nearly 950 semi-volatile organic compounds (SVOCs) have been investigated in river water from the mouth of the Yangtze River to assess their pollution status and to estimate the amount of chemicals discharged to the East China Sea.The survey was carried out by a combination of screening analysis (GC-MS in Scan mode and an automated identification and quantification system with a database) and targeted analysis (GC-MS in Selected Ion Monitoring mode and GC-MS/MS in Selected Reaction Monitoring mode). The number of SVOCs detected was 143 out of 947 chemicals in the database; the total concentrations of the chemicals detected ranged from 0.78-4.34 µg/L and 0.26-2.48 µg/L in the rainy season and the dry season, respectively. An estimated 3600-10000 tons of these chemicals are discharged to the East China Sea annually.From pollution profiles obtained in this study, the main pollution sources are industrial activities and domestic activities.Since ratios of the detected concentrations (PEC: Predicted environmental concentration) to their predicted no-effect concentrations (PNEC) of 6 compounds such as fenobucarb, 4-chloroaniline, and aniline were larger than one, indicating that these chemicals may cause adverse effects on aquatic organisms living in the Yangtze River. The concentration of chemicals at the point in the East China Sea that is the most affected by water from the Yangtze River is 1/11 of concentrations in the river water. However, considering that the PEC/PNEC of some chemicals are over one and amounts discharged from the river will likely increase with a rapid growth of Chinese economy, continuous surveying is needed to elucidate the transboundary pollution of chemicals transported from China to Japan by ocean currents.

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