Distribution of ampicillin-resistant E. coli was investigated in the Tama River, Tokyo, municipal wastewater treatment plants in the basin and in other five prefectures, and septic tanks at the upper reaches. Although the bacterial count in the Tama River significantly increased downstream, the percentage of resistance was not significantly different. The statistical test for all wastewater treatment plants showed that there was no regional difference in the percentage, while the bacterial count was significantly different. In these plants, no significant change in the percentage was observed through the treatment. From the septic tank study, the percentages were widely different among the households. The examinations on coliform group and Enterobacteriaceae revealed that the percentages of resistance increased through the treatment possibly due to change in composition of species.

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This study focused on the succession of botanical communities after reed plantation and also on the identification of the ground level that promotes reeds to grow well. Findings are as follows: (1) After reed plantation, the number of species was increased with elapsed years and the percentage of annual plants was decreased so that the stabilization of the botanical communities was confirmed, (2) Submersion from 94 to 192 days per a year promoted reeds growth, (3) The analysis of variance suggested that planting position increased its effect, while reducing the effect of planting methods with elapsed time. Where Paspalum distichum was dominant, Phragmites australis (reed) was declined. The effect of the competition of niche was suggested.

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The objective of this study is to identify the controlling factors to construct tidal flat ecosystem having similar characteristics to natural ones. The change of soil structure at constructed tidal flats that were restored was investigated. Furthermore, annual change of soil structure at 3 natural and 7 constructed tidal flats in Hiroshima Bay was studied. When the slope of the restored tidal flat was small and soil with high content of silt and bacterial population was used, constructed tidal flat similar to natural tidal flat was temporarily created. However, the slope of the tidal flat increased again and the silt content and bacterial population also decreased after two years of the restoration. It is important to make a slope of the tidal flat gradual for the construction of the tidal flat with a similar soil structure to that in a natural tidal flat. Then, the outflow of silt which exists in the soil decreases and the silt subsides easily. It is supposed that if techniques for the maintenance and management like making a breakwater are not applied to the restored tidal flat, washout of tidal flat soil occurs gradually because of daily seawater flow even if a constructed tidal flat similar to the nature was created.

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The characteristics of organic matter degradation under high ammonia concentration was investigated by continuous experiments. The carbohydrate removal rate significantly decreased as HRT decreased at the ammonia nitrogen concentration of near 4000mg-N/L. On the other hand, protein removal rate decreased in almost same proportion as HRT decreased, regardless of ammonia nitrogen concentration. Furthermore it seemed that increase in protein concentration of substrate restricted carbohydrate degradation at high ammonia concentration. In conclusion, it was appeared that preference of organic matter utilization were affected by condition at high ammonia concentration.

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Methodology to set remediation goals of chemical mixtures in contaminated soil and groundwater was proposed based on risk assessment for human health. The methodology can calculate the remediation goals based on conditions of each individual site, the correlation of concentrations of chemicals in soil-groundwater-surface water, and total toxicity of chemical mixtures. The remediation goals of chlorinated organic compounds were calculated; the goals for residents who drink groundwater were same levels as Japanese environmental standards. Drinking groundwater made the goals several 10 times higher. The goals for industrial area were several times higher than for residential area.

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This study is to examine quantitative relationships between physical indices of basins or rivers and the number of fish species using the National Census on Environments. A summary of this study is given as follows. (1) We determined the distribution characteristics of the fish species found in 109 class A rivers. Among the class A rivers studied, the Yodo River is characterized by the largest diversity with 61 fish species. The Honmyo River exhibits the smallest diversity with 15 fish species. Mean of the fish species in 109 class A rivers is 37.8. (2) The regression analysis of the data revealed that the number offish species has strong relationships to the parameters, including basin area, latitude of river-mouth, river density, flow variation, the number of shrimp, crab, shellfish species, and the number of plant species. (3) A multiple regression model was developed to estimate the number of fish species from the physical indices of river (or basins) and the number of aquatic biota (except for fish). The model was shown to predict the change in the number of fish species resulting from the physical impacts.

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The CVM (Contingent Valuation Method) and the TCM (Travel Cost Method) are commonly used to estimate the value of environment, but both of them have some drawbacks yet to be solved. In this paper, the value of water environment in the Suwa Lake was estimated at four levels of improvement by both CVM and TCM under stated preference. The results suggest that the estimated values by the CVM include a certain amount of overestimation caused by the embedding effect. On the other hand, the relative values among the four levels by the TCM are reliable, though the absolute values are not reliable. A novel method was proposed to eliminate this overestimation by the embedding effect in the CVM using the estimated values by the TCM, and to provide more reliable estimation.

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In this study, DTA (Differential Thermal Analysis) method was applied to classify the fusion patterns of bottom ash and fly ash from municipal solid waste incinerators and sewage sludge incinerators. 41 samples were classified into 5 patterns according to the shapes of DTA curves. 577 data on a DTA curve from 900 to 1450°C were compressed to av. 19 data by a feature extraction method. The common temperatures were selected to determine the typical patterns of DTA curves in each class by the optimization using pattern recognition. Based on above procedures, we developed a model to distinguish DTA curves of unknown samples and found that the fusion characteristics were classified by measuring the DTA curve.

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In order to estimate hemisphere temperatures of bottom ash and fly ash from municipal solid waste incinerators and sewage sludge incinerators, multiple regression analysis was conducted using the ash compositions and differential thermal analysis (DTA) data processed by principal component analysis. The hemisphere temperatures of 41 samples were measured by Japan Industry Standard method (K 2151) and used as criterion variable. When the second principal component of DTA data was used as a predictor variable, the more useful equations with higher contribution ratio adjusted for degrees of freedom were obtained in three of five groups.

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Estrogens are deemed to be important substances that may give estrogenic effects on fish in the water environment due to their occurrence in river water and wastewater. Therefore, we developed a novel analysis method for natural estrogens (E2, E1) and synthetic estrogen (EE2) in wastewater by LC/MS/MS. Detection limit and recovery ratio of the estrogens in this method ranged 0.12-0.24ng/l and 90-105% respectively.
We measured estrogens concentration in the sewage treatment process by using this method. The results suggest that E2 is dehydrated in sewage treatment process, and is changed into E1. Such a dehydration was remarkablely observed in the aeration tank.

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In order to understand unsaturated hydraulic characteristics of various residues from intermediate waste treatment process, measurement of specific weight, particle size distribution, saturated hydraulic conductivity, and water characteristic curve had been done. In addition one- and two- dimensional unsaturated water movement experiments had been conducted. Every residue has high hydraulic conductivity and peculiar water characteristic curve which doesn't have clear capillary fringe. One dimensional vertical water movement in those residues was dominated by rapid gravity flow because of macro pores which they contain. Vertical water movement formula was derived from the relation between water content and flux, which is obtained by flux control method.

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