The characteristics of soil erosion was investigated in a part of the Loess Plateau, in China. The rainfall erosivity factor (R) of the USLE was 41.85 (m²βtf/ha·h) on the average of 3 years, 198890. The soil erodibility factor (K) was the relatively largevalue of 0.43(th/m²·tf). As a result of observation on the Huangjiahe River, the relationship between discharge, Q (m³/s), and suspended sediment concentration, C (mg/l), was expressed as followslog C=2.757+4.208 Q, (r=0.815**)The concentration was about 1, 000 times higher than that of the observed cases in Hokkaido. The heavy soil erosion in the Loess Plateau was attributed to the loess soil properties and land use rather than the conditions of rainfall. Interception of raindrops and control of surface runoff by the replanting will conserve the whole watershed. A furthermore important management, however, is the improvement of drainage system to prevent the surface runoff erosion.

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We develop the knowledge-based system RARCOM (Risk Assessment and Risk COMmunication support system), which deals with risk problems of carcinogenic chemicals contained in drinking water of Tokyo metropolitan area. The system has a model of growth and propagation of risks in urban water network. Functions of the system include executing the klowledge-based simulation, displaying information about estimated risks, and explaining the interdisciplinary knowledge about urban network and water pollution problems. The framework of "Composite Object Model" is developed to help constructing knowledge-bases to deal with such interdisciplinary problems as environmental risks. The framework consists of three kinds of knowledge: (1)independent domain knowledge, (2)relationship between model components, and (3)bridging rules over gaps among multiple domain knowledge.

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The municipal refuse collection by source separation is an effective way to reduce and recycle the refuse. This method needs residents' active cooperation to separate recyclable refuse. But it is not easy to set their cooperation. The paper aims to clarify the consciousness and behavior of residents on the municipal refuse collection by source separation and grasp the impacts of diffusion and enlightenment activities for this policy. In order to clarify these, we constructed a hypothetical model of the behavior of source separation based on the residential environmental management models . The method of the municipal refuse collection by source separation in Meguro-ku, Tokyo, was selected for the case study and a questionnaire sheet survey was conducted there . As a result, the following were concluded. 1) the level of behavior were related to the level of cognition of the refuse problems. 2) the level of behavior were related to the motive of the evasion of the complaints of neighbors. 3) most residents think local governmental reports, the neighbor's autonomous organization and mass communication media are important sources for getting informations on the refuse problems. 4) the interest on refuse problems were related to the valuation on a mass communication media, and the cognition of refuse problems were related to the valuation on local governmental reports. 5) the motive of evasion of the complaints of neighbors were related to the valuation on local governmental reports . Considering the results of the survey, it is concluded that there are two behavioral patterns, voluntary and compulsory. The diffusion and enlightenment activities through local governmental reports are very important to give the refuse problems' information to the residents of voluntary behavior

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The rain and snow samples were collected at the summit (3776m) and Tarobo (1300m) of Mt. Fuji from Aug., 1990 to July, 1992 in order to evaluate the ion concentrations of chemical species in precipitation. Generally, the concentrations of all the chemical species were lower at the summit than at Tarobo. The following relations were found between the ion concentrations and the pressure patterns. At the summit, the concentrations of nssSO₄^2- and NO₄^- were very low for the precipitations caused from low passings along coast of Japan and Typhoons when air mass above the Pacific Oecean would be brought to Mt. Fuji. At Tarobeo, however, the ion concentrations were above 6 μeq 1^-1 for nssSO₃^2- and above 5 μeq1^-1 for NONO₃^- in most cases of these pressure patterns. This result indicates that precipitation collected at the elevaiton of 1300m would be affected by short-distance transport from urban regions. The ion concentration of NO₃^- was high at Tarobo in the case of northeasterly type of pressure pattern, suggesting advection of pollutants originated from the metropolitan area. Precipitations at Baiu showed markedly high values of nssSO₄^2- and NO₃^- concentra tions at both elevations.

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Various kinds of methods are available in the study of bacteria in environments, but most of them rely on cultivation, which leads to difficulty in the research on nonculturable bacteria dominated in aquatic environments. We applied flow cytometer to analyze bacterial sizes and nucleic acid contents. We could distinguish E. coil from Bacillus megaterium on the strength of their forward scatter and measured their DNA contents by fluorescence signals. Flow cytometric analysis of natural bacterial population in river water exhibited that we could detect bacteria smaller than E, coli, and the diversity of bacterial size reflected the pollution level in the aquatic environment.

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The survery was carried out during September 1991 and February 1992 to esimate the effects of acid rain precipitates on the Yamato River water quality in Nara Prefecture, which runs in the Nara Basin and through southern part of Osaka Prefecture. The main ionic species were sulfate in the rain fall and bicarbonate in the river water, and their percentage were 40.6% and 42.3%, respectively. The each contribution of ions in the rain fall to the river water was calculated. Although the contributions of ammonium, nitrate and sulfate were 19.3%, 13.9% and 11.4%, respectively, other ionic species were only a few percentage.

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Fundamental changes in the public's awareness and attitudes toward the environment are required for solving environmental problems which have become more and more globalized. People's awareness and attitudes are influenced by various factors such as interaction among members of the group ("internal interaction") and forces exerted from the outside to the group ("external forces"), etc. In this study, a mathematical model to describe such processes of changing public opinion and attitudes is presented based on a cell dynamical systems model. Here, the characteristics of the society under consideration are described by three parameters, i. e., self-assurance parameter a, mutual interaction parameterβ, and the responsiveness parameter y. Simulation analysis is conducted by changing the parameter values. In the case where members have a strong tendency of self-assurance, the distribution of individual opinions will be in a widely disposed multi-modal situation. On the other hand, when such tendency is weak, it is sharply peaked at a pro-environmental point. The interaction parameter governs the correlation among individual opinions in the group. If individual members are responsive to external forces, then the distribution of individual opinions tends to be biassed.

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Water qualities of 221 domestic wells were analyzed during February 1990 and December 1991. Ten items of sodium, potassium, calcium, magnesium, chloride, nitrate, sulfate, bicarbonate, pH, and conductivity were measured. Predominant cation and anion species were calcium and bicarbonate and their concentration ranged between 75.0mg/1-0.7mg/l and 6.1-0.lmeq/l, respectively. Groundwater quality was evaluated on the basis of the idea of SCORE and was worse in almost central area of the Nara Basin compared to the neighboring area of the Basin.

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The aim of this study is to clarify the pollution-economy relationships by means of a new pollution model. We established a new pollution model from some environmental economic factors ; output, energy, pollutants, and costs of pollution abatement. This model explains how Japan could sustain a high economic growth under the strict pollution regulation. The results of this study showed a negative relation ships between the cost of pollution abatements and the amount of pollutant in Japan. This pollution model reveals that the experience of Japan, which has developed and anti-pollution technology and has created very economical use of energy, would be very useful to the environmental pollicies of the developing countries having serious environmental problems, and this wise Japan's role could be seen as becoming increasingly important in tackling the global environmental problems.

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[in Japanese]

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