We estimated carbon fluxes associated with primary production and respiration by micro- and meiosized benthic organisms in tidal flats to examine how those biological processes were affected by sediment organic matter. The area-based respiration flux was not clearly related to organic content level. Particularly in the sandy sediments, the ratio of algal-originated carbon to total sediment carbon was relatively high, and showed active respiration despite the relatively low organic content and bacterial density. Hence, we should consider algal-origin material which is biologically easily degradable as a significant descriptor for benthic metabolism in tidal flats.

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The highly toxic tributyltin (TBT) compounds used as biocides in ship antifouling paints have been released to aquatic environments. Because TBT has low solubility and high hydrophobicity, it is easy to be accumulated in the harbor sediments.
In this study, we investigated the distribution characteristics of TBT, dibutyltin (DBT) and monobutyltin (MBT) in sediments and in sea water column at Nagoya port. As a result, the concentration of TBT in seawater was found to be lower than those of DBT and MBT. However, TBT in sediments was still high concentration. The release flux of TBT from sediments to the water column was calculated to be about 2 to 13 g-Sn/day in all over the port. Good correlation between distribution coefficient Kd (=q/Cp) and amount of the organic matter in the sediment particle (TOC) was found. We suggested that Kd was affected by organic carbon mineralization processes. Finally, we estimated the behavior of three tin compounds at the entrance and the inner part of the harbor, and demonstrated that TBT in sediments was the main pollution source in the marine ecosystems.

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The importance of effective recycling technology for the bottom ash increases more and more because the construction of the disposal of reclamation is difficult. Therefore, facilities such as the melting and the Eco-cement of the incineration ash are spreading. However, it is difficult for the municipality of the scale of the medium-small business to construct these because the cost of construction and the maintenance expense of these facilities are large amount of cost. Then, this research reports the cheap effective use of bottom ash. The bottom ash leaches comparatively little heavy metal, and the bottom ash leaches comparatively little heavy metal, and the majority of the portion of incineration ash that go through in a 2mm sieve is the ash. Therefore, authors research for the bottom ash of 2mm or less. The solidification material which mixed the solidification assistance materials such as the coal ash and quicklime with the sample which crushed this bottom ash of 2mm or less was able to be developed. This solidification material can manufacture the high strength solidification which has arbitrary shape by mixing with water and placing in the mold and compacting by vibration. In addition, the lead concentration in the leachate of this solidity is below the quantitative limit value of environmental quality Standards for Soil Contamination.

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In this study, to investigate zoeal characteristics of D.japonicus on special distribution and movement, field observations in the Kita River in Miyazaki, Japan and laboratory experiments were carried out. Then, the movement of zoeae after hatched in the upper end of the tide area was simulated by using a 3-D tidal current and Lagragean model newly developed.
Zoeae of D.japonicus prefer high salinity concentration, more than 30, and range almost inside the salt water wedge. Computation results of movement of the zoeae indicated that they are able to easily come back to the parental area by preferring high salinity.

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Bisphenol A (BPA) is a chemical organic compound that is used as the material of plastic products and is suspected endocrine disruptors action (environmental hormones action). This study aimed to clarify the source and path of BPA discharged from a housing development through domestic wastewater. The mean concentrations of BPA in inflow investigated by 1-week research and 24 hours research at wastewater treatment facility of A-housing development in Hiroshima Prefecture were in the range of 0.12 - 0.22 μg/L. The particulate fraction accounted for approximate half of total BPA in the wastewater. The discharge load of BPA from A-housing development was calculated to be 189 - 333 mg/day. On the other hand, BPA discharge load from several kinds of domestic wastewater in home such as the effluents from a washing machine and a dishwasher were studied and it was estimated that the sum of the investigated individual BPA discharge was equivalent to 15 % of the inflow load to the wastewater treatment facility mentioned above. Therefore, it was suggested that the investigations of the nonpoint emission source of BPA such as the inside of drainpipe were necessary.

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This paper evaluates ecological functions of TWA (Temporary Water Area), by which better diversity of fish community can be supported, and physical environment which influences the functions. We have indicated that relatively low velocity area where fishes can use appear in and around TWA during floods form field fish surveys. This implies that fishes can avoid to be flushed away during floods by migrating between main stream and TWA using the area.
Several researches have indicated that the connection frequency of main channel to TWA, Area, and the duration of inundation are major parameters to explain the ecological function of TWAs. In addition to these parameters, our research showed that the spatial and temporal velocity distribution during floods can influence the constitution of fish community in TWAs. This result is interesting and this is an important perspective when we evaluate the function of TWAs.

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The target of soil washing is to separate and densificate fine soil particles by sieving, cycloning and floatation, since the heavy metal and the oil pollution exist in the fine soil particles. The fine soil particles separated from polluted soil are flocculated and densificated to be conveyed to the controlled waste deposit. It is necessary to conduct the rapid flocculation and the large dehydration to create the efficient and economic soil washing system. The proper selection of flocculant type and its concentration is essential for the rapid flocculation and large dehydration. In this paper, the experimental investigation on the proper flocculants concentration criterion for the rapid flocculation and large dehydration is conducted using soil plasticity index and its pH value. The criterion was validated by the actual flocculants usage in the soil washing plant.

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This paper proposes a prioritization method using hierarchical network model to capture the complexity in the multi-criteria evaluation of remedial countermeasures. Such complexity arises from the complex interdependencies in the decision structure, as well as, from the inherent subjectivity of the decision maker. The proposed method which was built from the Analytic Network Process (ANP) uses the eigenvector approach to derive the local relative priorities and the overall relative priorities from the pairwise comparison matrix and supermatrix, respectively. The processes involved are illustrated using a decision problem drawn from real-life case study of a contaminated site caused by uncontrolled landfill in Japan.

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