Disasters due to unusual tropical rainfall events subsequently occured in Venezuela and Mekong Delta in December 1999 and 2000. First, this paper briefly shows an aspect of causes and diffrent situations of these disasters taking 1) rainfall event and 2) degree of abnormality into considerations. Then this paper shows some comments on a) what is abnormality for the people in each place and b) what the pople can do, taking “human and field” and “regionallity on globe” into consideration based on feelings that we got through field surveyies.

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Channel network with 1km mesh is developed for the Upper Chang Jiang Basin of 760, 000km² by using DEM and GLOBE. Arrangement of the network to one dimensional array enables runoff computation for the large area with the small mesh. The runoff analysis with kinematic wave approximation and input data from ISLSCP on rainfall and evapotranspiration gives appropriate discharge hydrograph at Yichang.

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The objective of this research is to evaluate investment as a robust adaptation strategy in response to projected climate change in China. Four scenarios combining climate change and investment have been simulated in the model which is established adopting the standard approach of modern optimal economic growth theory and includes two discount factors from the climate sector, i. e., flood damage from climate variability and climate change. Relationships between flood sectors are established from historical data and applied to estimate the benefit of investment to mitigate flood damage from climate variability. By assuming that the marginal adaptation costs to flood damage from projected climate change is the same as those from current climate variability, these relationships are also applied to estimate the benefit of investment in mitigating flood damage from climate change. The conclusion is that optimized investment, taking into climate change consideration will effectively reduce the damage from climate change and promote the capacity to mitigate flood damage from climate variability and that consumption and production increase no matter whether climate change occurs or not.

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Global Mapping proposed by the Ministry of Construction of Japan in 1992 is a project to develop digital geographic datasets depicting the environment of the land area of the globe with consistent specifications and with international cooperation. Global Map of five countries including Japan had been completed and were released to the public in November 2000 from the ISCGM on the Internet as Global Map version 1. In addition, data of more than ten countries have almost been completed and will be released shortly. It is expected that effective use of the Global Map will be made as basic geographic information for research and study on global environment; consideration to take measures against global environmental problems; planning for disaster prevention, regional and infrastructure development, etc. The Global Map data were applied to develop a methodology to make an integrated assessment of natural environment and local economy of the overall region resulted from an international infrastructure development such as large scale water resource project. Further, application to Asia regional disaster prevention information system, UN Geographic Database, FAO's early warning system is being discussed. From 2001, Global Mapping Project enters into the second phase. At the same time, development of Global Map data shall be advanced for areas not yet done. On the other hand, efforts shall be made to encourage countries and areas not yet participated in the Project to decide the participation. Further, development of simple methodology to update the Global Map data, promotion of use and dissemination shall be made.

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It is an urgent subject to know the geographical distribution of potential arable land in order to estimate the potential land productivity in China. In this study we have developed a 2km-grid digital map of potential arable land of China in consideration of only natural conditions, such as topographical factors, climatic factors, and soil and water factors. Furthermore, we have developed a map of convertible arable land by overlaying with the map of potential arable land and that of actual arable land in 1997. The results showed that:(1) A large amount ofconvertible arable land is distributed in the north of China, such as Inner Mongolia, Heilongjiang and Liaoning Provinces, while a small amount of convertible land in the south and Qingzang Plateau;(2) Some areas in Shanxi, Shaanxi provinces in the Loess Plateau and Sichuan Province, which are considered not to be suitable for cultivation, have been cultivated. In such areas, cultivation should be stopped and cultivated land should be returned to grassland or forestland.

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Gypsum is obtained as byproducts from desulfurization equipment in coal fired power plant. Desulfurization gypsum was able to reclaim the alkali soil in China with 0.5wt%. This result add incentive that establish the desulfurization process in China. This research can solve food problem and acid rain caused by air pollution all at once. This paper reports on results of the alkali soil reclamation in China for 6 years.

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Experimental investigation has been done on flow stability in a pool of Ice-harbor type fishway. Flow discharge through the partition wall between pools can be expressed by sums of flow dischargesover weirs and that through submerged orifices. Flow discharge coefficients for both are determined experimentally for theadopted shape of the partition wall. The root mean square values of water height fluctuation in the pool and velocity fluctuation at the weir crest of the wall are introduced for stability indices. Stable flow condition for the pass of fish can be maintained within the range of designed flow conditions, when the ratio of orifice width to total channel width is equal to 0.24±0.04, which corresponds to the case when discharge through orifices is comparable to that over the weirs. To expand the effectiveness of the fishway for wider flow range, the partition wall having different crest height in the left andthe right side weirs is studied experimentally.

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A waterfall of about 3 meters in height exists in the middle reach of Iwase river in Miyazaki Prefecture. It is formed from the cracking welded tuff, and has collapsed many times by taking off sandy soil from the lower layer. As a result, the position of the waterfall has retreated by about 30m in 30 years. To restore the landscape of the waterfall, a repair construction for the waterfall was planned. Other purpose of this project is the inhabiting environment of aquatic plant kawagoromo. Kawagoromo has been specified as an extermination misgivings kind by the Japanese Environment Agency.
The repair method was selected from five methods, and at last the method of using pseudorock panel of the glass fiber reinforced concrete together with lock anchor was accepted. It is the best method for securingthe steady riverbed, reproducing the landscape and inhabiting of kawagoromo. In addition, a fish way like a naturalwaterway was set up on the left side of the waterfall.
After construction, not only the waterfall is prevented from retreating but an excellent riverenvironment is also reproduced.

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This study investigates a environmental change of village-vicinity forest in the eastern hilly area in Aichi prefecture during the past about one hundred years. Three cities of Seto, Kasugai and Owariasahi that support the Cyukyo economic area are picked up in this study as typical towns. The village vicinity forest in the three towns was recovered formerly from a bare hill due to afforestation and erosion control works, althogh after 1945 the village vicinity forest decreases gradually with increasing population, city area, and networks of road. Aichi World Exposition is planned to hold by developing a village-vicinity forest in theeastern hilly area in Aichi prefecture in the suburbs of Seto city, in 2005. An appearance trend of the word relatedenvironment in news paper is discussed in order to examine the degree of public interest for environmental problems with a large scale development.

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[in Japanese]

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Many efforts to realize ‘Zero-emission society’are being made. But the concept of ‘Zero-emission society’ only is not enough to solve major global environmental problems. From the point of view of Market Economy, rotating goods by making short-lived has been agreeable. But from that of principle of the earth, the way of such economic interests are wrong. Synchronizing all activities of human society with the Principle of the earth is a fundamental matter to keep all kinds of life (including the human race) on the earth sustainable.
Concretely, all kinds of products (not only made of natural materials) should be used for a longer time than the period in which the nature can recover completly. To make all infrastructure long-life, including those made of non-biological resourses, reduce the amount of waste from humansociety. Also by making long-life goods, the chance of recycling energy become less, and volume of CO₂ exhaust will be reduced.
We have to change the economic system into a ‘resources-stock’ type by making all kinds of goods and infrastructure long-lifed. The way means that pople will continue to stock their properties, and guarantees comfort to the following generations. By this reformation, the industries can manufact more valuable products, and can reduce their production costs. It make the economy stable without stagnation.

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In this paper, the thermal environment of Kanazawa city, which plays a central role in the Hokoriku region is studied based on various kinds of available data. It is found that the heat island has been progressing in Kanazawa. And the relationship between population and heat island intensity for Kanazawa city is obtained via regression analysis. Besides, it is shown that the sunshine hours and relative humidity have been decreasing, and the causes are discussed.

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Among various urban environmental issues, air pollution is a major challenge for many cities in East Asia. Public concerns over air quality increases with the rising standard of living as it exhibits direct risks to human health. Major sources of air pollution in large cities are automobiles, although there are other diverse sources such as factories. Air pollution caused by traffic is most notable and serious in mega-cities in which the number of vehicles is increasing much faster than the pace of population growth. Therefore, this study conducts a comparative analysis of air pollution caused by automobiles, energy consumption and urban transportation system in four mega-cities in East Asia, i. e., Tokyo, Seoul, Beijing and Shanghai.

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Per capita waste generation rate in China is decided by climate condition, economic or consumption level and household fuel by multiple regression analysis. Models for per capita waste collection rate are developed for whole nation, major city, and Shanghai. The total generation rate of China has been increasing rapidly during thepast twenty years because of urban population and per capita waste discharge increase, now per capita waste collection increase is slowing down and increase in total collection rate will mainly caused by urban population increase in the near future. There is geographic difference in per capita waste collection rate by analysis at province level; it is usually higher in colder northern area because coal is still used as family fuel. Major cities generally show cut in per capita generation rate at the primary phase of economic development because of popularization of gas using in family, then show increase with continues economic development. Share of organic materials and calorific value of waste in China's major cities keep increasing. China's domestic waste disposal systems need to be improved to meet the changed generation characteristics and demands for waste reduce, recycle and reclamation.

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World trends of urban population growth are already high, but motorization growth trends are much worse. In developing countries motorization is not only high, but also its rate is uncontrollably high, reaching rate over 10% per year. During the traffic jams, general average speed of all the vehicles is kept slow that the emissions of pollutant gases are evidences to be much higher than in a kilometer per person basis. Motorization tends are truly astonishing but alsohere the income-level distribution plays a key role in developing countries. The present study investigates features of sustainable transportation environment and future prospects for the adaptation policies of developing countries based upon Model Reference Adaptive Theory. In the case of La Paz City, Bolivia, the income-level distribution has a great influence on daily life citizens. The number of vehicles that cross each of the network on each peak period for each income level and trip purpose is estimated using GIS. The buses would provide service for the most congested routes and the current vehicles would feed the big buses system. Through this adaptive policy, the congestion would be significant reduced.

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Renewable energy (Solar power, Wind Power, Biomass, etc) is a power generation system which does not discharge carbon dioxide in process of power generation, and in order to consider as what can build sustainable energy system, it attracts attention as an effective means. In European Union and the United States, various policies for making renewable energy spread in electricity market is implemented focusing mainly on obligation of acquisition of the electric power generated by renewable energy in. This paper, through overview of the renewable-energy spread policy of some countries, analyzes and evaluates the effect and economical influence by the promotion policy for the photovoltaics and the wind power to which spread of the future is expected. The economical influences of measures toward the spread of renewable energy are verified analyzed by using the applied general equilibrium model. As a result, the introduction on the renewable energy is influenced by the investment subsidy to the renewable energy, which source is revenue of a carbon tax, and the change of the demand characteristic (consuming structure) accompanied by the increase of green consumers.

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The partial liberalization started in March, 2000 is the realistic selection between pursuit of the increase in efficiency by introduction of a market mechanism, and achievement of a public-benefit-subject unsolvable by the market mechanism, and cannot be a final solution. Electricity deregulation must be based on thefollowing points:
(1) environmental restrictions based on global-warming prevention,
(2) consistency with long-term energy policy including atomic power and renewable energy,
(3) achievement of universal service.
Japan does not have an organic act which covers the whole energy problems, and the fundamentalguideline should be indicated as an “energy policy act.” The range of liberalization will be expanded in 2003, but it is the extent of the range that is the problem. It will be necessary to limit the range of liberalization in order to maintain nuclear power generation. A financial mechanism like “electricity feed”, a “green certificate” and/orcarbon tax should be needed to expand renewable energy. Thus, the measure against warming in Japan should be considered within the viewpoint of structural reform, such as electricity deregulation and tax reform.

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We must investigate how to reduce the one-way type drink container, because it is the main reason of the rapid increase of trash in life system recently. We examine one-way glass bottle and PET bottle as study object from researches.
As the biggest problem, these capacities are very big. We must examine a method to decrease these capacities. We investigated how we could subdivide one-way glass bottle and PET bottle safely in order to recycle. The best method is to subdivide glass bottle by heat shock. We can adjust a size of glass pieces broken by temperature of heat shock. We investigated whether we could use them as construction materials. Maximum of unconfined compression strength of the mixture was 18.2 MPa. Unconfined compression strength of heat mixture depends on the grain size of mixing glass pieces and the content of mixing PET pieces. Heat mixture of PET pieces and one-way type glass pieces can be utilized as construction materials effectively.

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The formation of a recycle-oriented industrial complex needs collaboration with neighbor companies and the selection of the most effective recycling methods from available options. This study picks up Kitakyushu Eco town project in Japan as a representative case and attempts to reveal the enhancement process of the Eco-efficiency of the project under the existing industrial structure. Initially, Material flow at Kitakyushu eco town was surveyed which revealed the trouble with the existing plastics recycling system. This paper combines various plastics recycling technologies into several scenarios reflecting industrial structure and calculates the effect to the emission of global warming gas. As a result, it is shown that the collaboration with the regional industrial infrastructure makes the implementation of effective technology possible, and when coupled with appropriate transportation and distribution of resources, the Eco-efficiency of the project can be magnified.

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Eco-efficiency was prompted by WBCSD (World Business Council for Sustainable Development) as a major concept for company to make in enabling corporate progress towards sustainability. The purpose of this research is to show applicability of eco-efficiency as an evaluation indicator of company's activity to achieve sustainable society. Through investigation of several case studies collected by WBCSD showed that application of Eco-efficiency is still primitive stage. The following issues were pointed out.(1) Most of case studies just calculated limited aspects of environmental loading and various environmental influences were not fully considered.(2) To establish the different quantification method for each users of Eco-efficiency is important. In order to use Eco-efficiency as concept or tool to achieve sustainable society, it showed be more universal. Eco-efficiency with transparent data and calculation method should be used by various stakeholders. Key data to calculate Eco-efficiency depend on the purpose of each stakeholder. The stakeholders are categorized and possible definitions of Eco-efficiency for each stakeholder is discussed in this study.

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JSCE published “Agenda21/JSCE” as actionplan for environmental protection in March 1994. To realize this plan, the role of construction sectors (Planner, Designer, Constructor), they directly concern the construction activities, is essential. As the first step, many organizations of each sector have started to establish and implement EMS. The purpose of this sub-committee is to promote the environmental protection activities through · mutual understanding of each sector's EMS ·cooperation among three sectors by effective use of EMS

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The purpose of this paper is to advance a new qualification as an engineer to solve the problem of environmental preservation for the development project. The new qualification is called the environmental management specialist who has responsibility and authority in order to establish and implement environmental preservation needed for the development project. According to general requirements, environmental management specialist is required a project manger of environmental field for the development project as well as the environmental specialist of individual field.

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More than 70% of the carbon dioxide emitted during the various stages of construction works can be attributed to construction machinery and trucks (including dump-trucks), and emissions of carbon dioxide, especially from trucks, account for 1/3 of all emissions. As countermeasures against such emissions, (a) improvements in truck bodies and engines, (b) novel developments in design and construction methods, and (c) improvements in driving method are considered viable. Regarding Item (c), a training course for fuel-saving driving has been established for truck drivers of subcontractors, with the object of introducing and generalizing a fuel-saving driving method. The training course for fuel-saving driving comprises two types of training:“training by lecture” and “in-service training” for gaining actual experience of fuel-saving driving method, with a view to ensuring that drivers will adopt the “fuel-saving driving method” in their daily tasks, thus improving the fuel consumption rate and reducing carbon oxide emissions. The “in-service training” is to be conducted for the purpose of ensuring that the points of the fuel-saving driving method are confirmed and recognized by the drivers themselves in their actual driving before and after the “training by lecture.”
In this paper, the fuel-saving driving method as a way of reducing the volume of carbon dioxide emitted during the various stages of construction works is described. Next, a comparison is made between cases when the fuel-saving driving method is conducted and cases where it is not conducted, based on the data obtained from the “in-service training.” As a result, improvement in the fuel consumption rate of at least 30% could be confirmed, although this depends on the drivers. By introducing details of the training, the usefulness of the fuel-saving driving method is shown.

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The accumulation of the urban structure accompanied by economic growth brings a great environmental impact to a city and a nation as a construction by-product after the time lag about a half-century. In Japan, the quantity of the waste discharged from construction industry reaches about 100 million ton, and it is expected that their by-product will increase sharply in the near future by demolition of structures built at the high economic growth age. This has been a serious environmental subject also in many cities of developing countries including Asia where the rapid urbanization accompanied by economical development progresses from the end of the 20th century. Therefore, it is pressing need to promote recycling of a higher rank more and to construct circulated society.
The authors present the material-product chain management system of construction stocks from national scale viewpoint. Hierarchical recycle system for built environments are proposed. Secondly, authors focus on the urban scale recycling system for construction materials. Finally, planning scenarios and options for ecologically efficient urban environments and estimation systems are also presented.

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The neutralization (carbonation) of concrete not only has a great influence on the durability of reinforced concrete structures under ordinary atmospheric environment, but also becomes the basis of service life of these structures. The concentration of atmospheric carbon dioxide has the tendency of the gradual increasesince the latter half of the twentieth century, and is expected to drastically increase in the twenty-first century if no effective means are made to reduce it From the viewpoint of durability, this tendency is expected to change the mechanisms and accelerate the progress of carbonation of concrete and the deteriorkionof social capitals, and further cause the damage of the dwelling environment dueto unlawful dumping of waste concrete. This paper deals with new prediction/evaluation methods of the progress of carbonation of concrete by theoretical analysis and computer simulation considering these situations. Further, by modeling this tendency by a Gaussian step function, prediction of the progress of accelerated carbonation under step response method is discussed. Experimental results showthat the progress of carbonation by accelerated test under step response method obeys the linear law concerning elapsed time, not the parabolic law generally accepted under constant concentration of carbon dioxide.

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Social system and production system in the modem society are closely related to the wide field, and it becomes a complicated thing. Various environmental problems exist in the social structure. It is necessary to analyze the effect from various sides for the solution of such problems. Especially, the load to the environment may be made to increase in the integrated network infrastructure, if the consideration from the stage of plan and design to environmental harmony-ness is not sufficiently carried out. In this study, it stood at the viewpoint of life cycle of facilities until the disposal from the design, and environmental effect of disposal, operation and construction in the social foundation facility was determined quantitatively. Considering this background, as one step in solving these environmental problems the Life Cycle Assessment (LCA) technique for environmental impact assessment will be examined in this research. As the result, the LCA technique can be called that the application to social foundation facilities represented for the waste water treatment system is also sufficiently possible and that to also make in addition, the wide-area environmental problem to be an object is possible, and that it is a point the quantitative evaluation, and that it is the very effective environmental impact assessment technique.

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Cloud droplets grow on cloud condensation nuclei (CCN) with condensing the ambient water vapor in the atmospheric air parcel. The size of the cloud droplet in the equilibrium state is estimated usually Köhler Equation. However, Köhler Equation is based on the assumption that the cloud droplet grows in an infinitely large reservoir of water vapor at constant pressure, i. e., at constant saturation ratio. This assumption causes some erroneous results in the estimation of real size in the air parcel, although the assumption makes the calculation easy. Thereare two apparent deficiencies in Köhler Equation. One is that the equilibrium size cannot be decided in case of the larger saturation ratio than the critical ratio. The other is that the variation of the size with the number density of CCN, in other words the competitive growth, cannot be considered in the estimation ofthe size. In order to improve these deficiencies, the conventional Köhler Equation has been modified using the mass conservation of the water contained in the air parcel.

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A tool for forecasting future acidic depositions in Japan was developed. This tool (the TRAJEC: TRAns-sea of Japan and East China sea system) projects the future regional energy supply, calculates the emission levels of sulfur dioxides (SO₂) and nitrogen compounds, and estimates the geographical pattern of acidic deposition resulting from these emissions. Future acidic depositions in Japan were forecast using the TRAJEC. Sulfur deposition through 2030 was calculated from the source-receptor matrix for 1995 and the growth rate of emissions for the source subregion. In the case of the current legislation (CLE) scenario, anthropogenic SO₂ emissions in East Asia would grow by 34% and sulfur deposition in Japan would increase 16% between 1995 and 2030. This increase of sulfur deposition over these 35 years is slightly less than the contribution of volcanic emissions to overall sulfur deposition in Japan. In the case of the hypothetical worst-case scenario for China, sulfur deposition in several site, facing the Sea of Japan would double by 2030. In the case of the CLE scenario, nitrogen oxides emissions in East Asia would grow approximately 50% and nitrogen deposition in Japan would increase approximately 30%.

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Aerosol optical thickness on the East China Sea was evaluated by using radiances observed by Terra-MODIS. We measured optical and chemical properties of aerosols such as scattering and absorption coefficient, chemical composition, and optical thickness in Fukue Island, Nagasaki Prefecture. The optical thickness was calculated from the single scattering albedo, phase function, and reflectance of sea surface based on the measurement synchronized with Terra-MODIS. The evaluated optical thickness at the wavelength of 1μ m agreed well with that observed in Fukuoka. The optical thickness on the coastal sea of Korea Peninsula was larger than that on off the shore. This suggested that it is also important to determine the surface reflectance on the coastal sea that eutrophication or flowage of sand from rivers may occur.

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It is necessary to assess the spatial distribution and variation of optical properties and chemical species of atmospheric aerosols to estimate the direct effect on climate. In the western Pacific Ocean, where the pollutants are transported from the East Asia, there are little aerosol measurements available to estimate the climate effect. In this study the aerosol optical and chemical properties were measured in June-July 2000 in the western Pacific Ocean on board the research vessel Mirai. In the southern area of 30° N, it was found that the area was under marine background condition due to less concentration of anthropogenic elements of aerosols such as V, Ni and Pb than those in the area north of 30° N. In south of 30° N, absorption coefficient (σ_ap) were extremely low as those less than 2× 10^-7m^-1, and scattering coefficients (σ_ap) ranged from 80× 10^-7m^-1 to 212× 10^-7m^-1. The single scattering albedo (ω), then, ranged from 0.97 to 0.99, which shows the aerosols were highly transparent in summer in the western Pacific Ocean.

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Atmospheric concentrations of volatile organic compounds (VOCs), trace metals (vanadium, lead, etc), sulfate and elemental carbon (EC) were measured at Barrow, Alaska, USA (71.32N, 156.60W) during July, 1999-December, 2000. The concentrations of nine VOCs (i. e. Xylene, Ethylbenzene, Stylene etc.), EC, sulfate and four trace metals (i.e. Ni, V, As and Pb) showed a similar seasonal variation with a broad maximum extending from winter to spring. Because EC, trace metals and sulfate are major component of “Arctic haze”, good agreement of seasonal variations between these species and VOCs suggests that VOCs, together with EC, trace metals and sulfate, are transported over distances of several thousands of km from industrialized areas in mid-latitude.

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A method was developed to calculate radionuclides concentration in the Japan Sea. The concentration of radioactive fallout (¹³⁷Cs, ^239'240Pu) due to atmospheric nuclear weapons tests was calculated to verify in the Japan Sea the method by comparison between calculated and observed values. The flow field was calculated by Japan Sea circulation model, which was improved in vertical resolution. We confirmed that influence of seasonal change of flow field was small on calculated results of fallout concentration. Therefore, annual mean flow field was adapted for this method. ¹³⁷Cs and ^239'240Pu concentrations were calculated by this method. Calculated ¹³⁷Cs concentration agrees well with observed value. However, calculated ^239'240Pu concentration was underestimated. This result suggests that ^239'240Pu concentration in the Japan Sea might be affected by not only global fallout but also another source.

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Global chemical transport model (GCTM) has been developed and applied to see effects of biomass burning sources on atmospheric chemical environment in southern hemisphere. The model includes processes of advection, diffusion, chemistry, sub-grid scale cumulus convection, and wet- and dry-depositions. The model's chemistry part includes 40 species and 97 chemical reactions. Simulations were performed for about one month in September and October, 1994, when strong biomass burning occurred under the climatic condition of ENSO. We focused especially on ozone formation over Equatorial Asia, and evaluated relative importance of its local production from the sources of anthropogenic and biomass burning, and soil NOx emissions, and also long range transport from mid-latitudinal southern hemisphere. The results could successfully explain the reason of the formation of complex ozone vertical structure observed over Java Island around 7.5S and 112.6E.

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The organic lead added to gasoline to maintain its octane value, organochlorine agrochemical DDT widely used throughout the world were banned in early '70s in Japan, and the human exposure to them has been gradually decreased these decades. The atmospheric nuclear detonation tests, which were heavily practiced through' 60s, were also regulated substantially in early'70s, and the radioactive fallouts like Sr-90 and Cs-137 were reduced these decades. These environmental micropollutants were examined for their environmental fates, human exposures and human health risks in the last half century, by using the environmental risk evaluation model. Main results obtained in this study can be summarized as follows;
(1) Lead concentration in ambient air, DDT and radionuclides in an environment were reduced right after thereduction of their release to an environment, and the related health risks have also been reduced.
(2) The unleaded gasoline policy was evaluated to be effective for reduction of the potential health risks especially in the population group with the larger lead exposure. The base line lead exposure was not reduced because of the rather constant lead exposure through dietary pathway.
(3) The lifespan cancer induction risk of the reference Japanese due to the DDT was evaluated to be larger than 10^-5 level for people born before 1970, but for people born after 1970 the risk has been reduced to less than 10^-5 level by the ban of DDT use in early 1970's.
(4) The lifespan cancer induction risk of the reference Japanese due to the radioactive fallout Sr-90 and Cs-137 was evaluated to be10
-6 level for people born before 1960, but for people born after 1960 the risk has been reduced to less than 10^-6 level by the ban of the atmospheric nuclear detonation tests.

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The global ocean circulation model developed by CRIEPI was applied to the regional ocean around Japan. On the bases of the global warming computation by NCAR/CSM-1 (Climate System Model), the change of SST (Sea Surface Temperature) and Kuroshio around Japan was calculated in detail by using the regional ocean model. The effect of the global warming was summarized as follows; 1) The surface ocean circulation will be enhanced, especially, Kuroshio in the Pacific and Tsushima current in Japan Sea will become stronger, 2) SST will rise around Japan, especially in the east off Hokkaido, 3) The dynamic sea surface height will rise around Japan. The sea surface rise in the Kuroshio is remarkable in the Pacific side of western Japan.

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We observed nitrous oxide on the equator area from sea surface to deep water Jan.1999 andDec.1999. Nitrous oxide gas were greenhouse effect gas for earth, appear of 320-340ppbV in the atmosphere (before the industrial revolution it was 290ppbV), very long live in the atmosphere. Nitrous oxide gas generally was produced by biological reaction in sediments and combustion of biomes. It was, however, unknown shirk or source area in the earth. The air-sea interactions were very important for some elements cycle (carbon and nitrogen) in the earth. But, boundary condition and phenomenon were not clarified. In this observation, nitrous oxide of sea surface were about less than lOnM, MAX value were 40-50nM in depth of 500-1000m. Gas solubility was affected by water temperature and salinity, going east area nitrous oxide was increasing, as water temperature was decrease. All line of equator nitrous oxide concentration was changed by some meteorological condition (wind speed, wave height, water temperature et al.).Gas solubility changing was not only due to water temperature but wind speed and wave height. Nitrous oxide gas saturation value and sea metrology (wind speed, wave height) were correlation.

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Storing carbon dioxide in the oceans is expected to provide a useful means of tackling climate change. Especially, the availability of iron to marine phytoplankton has received considerable attention. There is a hypothesis that fertilizing the oceans with iron may help to reduce carbon dioxide in the atmosphere, because they increase the amount of carbon dioxide absorbed by phytoplankton in the oceans. In this study, we present data on the effect of the chemical form of iron on the growth of phytoplankton in artificial seawater media, in which we have varied the composition of dissolved iron species using synthetic chelators. It was found that chemical forms of iron in the culture media influenced the cell growth of phytoplankton. Under low-iron conditions, the phytoplankton growth was affected by the concentrations of synthetic chelators in the culture media. Under high-iron conditions, there was little difference in growth rates of phytoplankton between chelators in the media. On the basis of the data obtained, we discuss equilibrium conditions controlling the phytoplankton growth in the cultures.

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The characteristic of salt-water intrusion will change by sea level rise. This phenomenon could result in salt damage. So, it is important to clarify characteristics of salt-water movement to predict the intrusion. In this paper, it is attempted to represent all the mixing conditions of salt-water intrusion in the estuary by one model, which is based on a multi-layer flow of the one dimension. Toverify the applicability of the model, numerical calculation is performed by using the data from Egawa and Murasaki Rivers. Results indicate that the model would be applicable to all the mixing conditions of salt-water intrusion in the estuary. And the salt water intrusion affected by sea level rise is simulated.

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Adaptation is one of the most important research activities of responses to global warming and climate change. A number of adaptation options have been proposed for response strategies against sea-levelrise and climate change in coastal areas. The present paper discusses possibility of several technological options presently used to combat beach erosion and flooding as a potential candidate for the adaptation technologies. The paper also presents results of a questionnaire survey using the Analytical Hierarchy Process to study people's awareness to the proposed adaptation options and the order of their priorities.

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In this paper, using Hamasaji (Limonium tetragonum){the extinction uneasiness species}, Hamamatuna (S. maritima), Fukudo (Artemisia fukudo), Hamagou (Vitex rotundifolia), which is the kinds of the beach plant as an example, it grasped these habitat distribution and an inhabiting situation in Kumamoto Prefecture. It finds that the seashore, which has sand near the beach line in case of the high tide, is decreased. It investigated the situation of the seashore environment in Kumamoto Prefecture. There are few natural sandy beaches in Kumamoto Prefecture. The seashore, which has sand in entire of littoral, is not 1%. It considered relation between the inhabiting situation of the beach plant and the seashore environment. It found that the habitat of the creature in the seaside is lost by the artificial factor.

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Mikura Island, a small island 200 Kilometers south of Tokyo city, is known for giant trees thousands of years old that grow there. The objective of this study is to examine the feature of water and soil environment in which the giant trees could grow up, and to look for the way we can do for the preservation of nature. The various chemical microanalyses are mainly carried out on the water, rain and soil. Based on the analytical results, the national environment in Mikura Island is discussed.

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The investigations of coastal environment were performed from February 1997 to December 2000 at 620 places of Japan island seashores. The number of garbage drifted in seashores was counted and it was also divided according to its type and nationality. It is confirmed that large number of garbage have drifted from Japan and neighborhood countries such as China, Taiwan, Korea and Russia. In this study, the actual condition of coastal pollution by the drifted garbage is mainly described by the investigation in 2000. The ocean currents seem to be controlled the drifting direction of garbage. In Japan Sea, the high possibility that the most of garbage is drifted along Kuroshio and Tsushima Ocean current is pointed out. The investigation result of the remote islands in Japan Sea, Okinawa islands and Thailand seashores are arranged and compared.

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Nitrogen discharges in progressively increasing quantities promote eutrophication inthe closing area of the sea. In the last few years the great efforts have been made to increase in efficiency biological treatment process. Nitrogen reduction can be accomplished by biological nitrification and denitrification. But the biological nitrification is a problematic process, because the growth rate of nitrifying bacteria is very low. Consequently, economical treatment techniques are needed to meet demands for ammonia nitrogen control.
In this paper, we used the polysulphone hollow fiber (pore size of 0.1μm) as the support materials. The nitrification bacteria were immobilized on the surface of the hollow fiber through the medium of polyvinyl alcohol. Thesefibers of 300 pieces were modulated and used for nitrifying bioreactor. The synthetic wastewater was introduced through the outer surface and the oxygen needed for nitrification was delivered to the hollow fiber's inner side. Thenitrification rate and efficiency of this reactor were evaluated for one year. The denitrification bacteria were also immobilized on the surface of the hollow fiber. The reduction of the nitrate in the synthetic wastewater to nitrogen was investigatedby the denitrification reactor. We showed that the hollow fiber biofilm reactor was effective in denitrification of nitrate.

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This research aims at the practical use of adsorption storage method which uses activated carbon as adsorbent for an effective method to utilize of unused digestion gas in waste water treatment plants. Use of activated carbon, it's shape of porous surface, makes possible storage capability up to about 20 to 30 times than conventional low-pressure storage systems. Through the pilot plant experiment using activated carbon in the gas holding tanks, the basic characteristic of adsorption storage was clarified by evaluating of the adsorption capability, the influence of temperature and moisture and the influence of micro ingredients contained in digestion gas.

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The concentration of CH₄, CO₂ and N₂O discharged from treatment processes of a municipal sewerage plant where activated sludge processes have been operated were measured between October 2000 and March 2001, and following results were obtained.
1) Emission of CH4 was significant at both receiving and pre-aeration tanks in the clarifier.
2) Great amount of CO₂and N₂O gas was emitted from the aeration tanks. In particular, emission of N₂O was largely correlated with NO₂-N concentration.
3) Generation of global-warning-gas from the sewerage plant was calculated as 650, 94200, and 82kg/day for CH₄, CO₂and N₂O, respectively.

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Terrigenous nutrients and turbidity transported by rivers are important sources to affect the water quality in the neighboring coastal area. However the behavior near river mouths are not well known because of the physical and chemical influences by seawater intrusion. To get better understandings of the behavior, this study executed field observations at the Abukuma River mouth. The measurements show a thin mixing layer on the saltwater wedge, the change of the thickness by the intrusion distance and the tidal phase, and the distributions of turbidity having peaks near the mixing layer. Major part of nitrogen and phosphorus during flood is found in fine particles in the flow.

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Tsurunuma lake is in a eutrophic condition. T-P, chlorophyll-a and SS concentrations of lake water are relatively high. High-speed clarification process (1.0m³/h capacity) was tested for the purification of lake water. It was found that under 80-200 m/h mirror velocity condition, morethan 80% SS, 90% turbidity, 80% T-P and 80% chlorophyll-a removal rates were achieved. Thus, the high speed clarification process is usefull to apply for lake water purification.

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Today, we are facing to the increasing problems of treatment of soil highly contaminated by petroleum hydrocarbons. This may cause obstacles to land use or occasionally incur serious social problems. M icro-bubble entraining soil washing and bioremediation can be combined to form a technically and cost effective scenario to remediate the cotaminated soil.
The efficiency of the combined remediation system was investigated through a laboratory treatability test and a pilot-scale test. A treatability test was conducted to determine the effectiveness of each treatment and collect information to support the design. The optimum H₂0₂ and NaOH concentration and removal ratio for soil washing were determined to design the pilot-scale test. Microbial degradation rates and oxygen demand rates for bioremediation were also determined. A pilot-scale test was conducted to evaluate the efficiency of the combined system performance in the field. Micro-bubble entraining soil washing system showed 90-95% removal raio with 30, 000-50, 000mg/kg oil contaminated soil. 170m³ of soil washing treated soil (maximum concentration 3000mg/kg) was treated by bioremediation with various types. The landfarming method was the most suitable for the site; the concentration decreased under 300mg/kg in 2 months.

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