Benzene concentration in some regions has not yet attained the atmospheric standard regulated in 1997. Although the exhaust gas from the vehicles is considered to be the main source of benzene, the emission factor of vehicles that are actually running has not been evaluated correctly. Assuming that the ratio of the emission amount of nitrogen oxide to the emission amount of benzene is equivalent to the ratio of nitrogen oxide concentration to benzene concentration, the emission factors of gasoline car and diesel car were estimated as 12.3mg/km and 13.0mg/km, respectively at Shijonawate roadside monitoring station. Benzene concentration around this station was calculated by a numerical model with a simple building configuration and it could be reproduced comparatively well. Benzene concentration around Uchide roadside monitoring station, where the Hanshin. Expressway exists, was also calculated using the same technique. This result also correctly reproduced the observation concentration. It was suggested that the benzene concentration near the road can be presumed by the numerical model with a simple building geometry .

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Considering the recent discussions on global warming, CO₂ emissions reduction by not only developed but also developing countries is becoming the important issue. Although the worldwide uniform-rate carbon tax (UCT) is the cost effective method to reduce CO₂ emissions, it heavily burdens on developing countries economically. Since such a policy might be opposed by developing countries and is against "common but differentiated responsibilities" of UNFCCC, it will be hardly achieved successfully. Thinking of those, the effect of the variant-rate carbon tax (VCT) is discussed from the policy viewpoint regarding the environmental (CO₂ emissions) and the economic (GDP) aspects. VCT is based on the imputed price and is compared with UCT by the simulation analysis using the appliedd general equilibrium model. The world economy is classified into 15 industries and 14 regions in the model. Each tax is imposed on all industries. Consequently, although VCT reduced CO₂ emissions slightly smaller than UCT, it generated positive GDP effects on developing countries unlike UCT. Regarding the importance of worldwide introduction of CO₂ abating policies and avoidance of excessive economic burdens on developing countries, VCT has higher fairness and policy effectiveness than UCT.

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Soil depth is an important parameter used in multimedia models for estimating the environmental fate of bio-accumulative chemicals in such uncultivated land as forest and grassland. In this study, by using six hypothetical chemicals with different Log K_OW values as the targets, the impacts of changes in the uncultivated soil depth upon the environmental persistence and the mass fraction partitions of these chemicals were evaluated under four different emission scenarios based on the well-used EQC model. The results showed that, for all emission scenarios, the environmental persistence and the mass fraction partitions varied in terms of the soil depths. The most remarkable variance was found for both scenarios that represented a complete emission to soil and an equal emission to air, water and soil, respectively. Besides, sensibility analysis results indicated that, for chemicals having Log K_OW values above four, the impacts of changes in the soil depth became no longer notable; and a tendency of residence within the surface 5 cm layer of the soil medium was revealed. These coincided with those obtained based on the OECD guideline and other existing data, thus suggesting that a depth of 5-20 cm for uncultivated soils, which has been conventionally used in existing multimedia models, may overestimate the contribution of the soil medium. It is concluded that soil depth of 5 cm is sufficient; especially for multimedia models aimed for assessment of the environmental fate of highly bio-accumulative chemicals having Log K_OW above four.

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In most small irrigation streams in Toyama prefecture, the pH values are above 7.5 which is the upper limit of for the quality standards of irrigation water. In order to clarify the cause of this phenomenon, an investigation of the water quality in an irrigation stream was carried out. In the stream, the pH rose downstream and varied diurnally to become higher in the daytime. When the water from the stream had been left in a tank for 5 hours, the pH of the water decreased from 7.7 to 7.4. The result shows that the high pH in the stream was due to the decrease in the content of carbon dioxide in the water. The highest value in the pH of the stream was observed near noon, and the lowest value, lower than RpH, was observed at night. In addition, the pH diurnal variation increased with the increasing quantity of attached algae in the stream. It was concluded from our findings that the pH diurnal variation in the irrigation stream in Toyama prefecture was due to a change in the photosynthetic activities of attached algae. Key Words: irrigation water, pH, attached algae, photosynthesis, carbon dioxide

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This paper is concerned with the governance structure for the emerging environmental and technological risks originated from such areas of "food safety", "electromagnetic field", and "biological invasive species" in which high uncertainties are involved in finding scientific evidences for assessing and managing risks. A new interdisciplinark framework is constructed to evaluate the governance structure for those emerging riss areas. Our framework revealed that: 1) Scientific knowledge and evidences of the emerging risks with high uncertainty are differently perceived and evaluated by a variety of stakeholders based on their values and perspectives, and they are amplified or attenuated in their socio-cultural environments. The lack of any proper risk communication among stakeholders will lead to the collapse of the reliability of regulatory and management systems in our technological society. 2) It is "risk literacy" that enables the stakeholders to make an appropriate informed choice of risks in a proactive way to "multiple characters of risks: 3) To attain better governance toward the emerging risks, it is critical to install a social information platform of "early warning and precautionary actions" by enhancing the scientific education and training of "risk literacy" in our technology society.

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Food safety is an increasingly important public health issue. Governments all over the world are intensifying their efforts to prevent food-borne adverse effect to human health and to improve food safety. These efforts are in response to an increasing number of food safety problems and rising consumer concerns all over the world. The basic concept regarding the governance for food-borne risk is proposed by Codex Alimentarius Commission (abbreviated as Codex). Each government in the global community has the responsibility to construct its own food safety regulatory system on the basis of risk governance procedure for the consumer health protection proposed by Codex. In this report, we studied the international comparison about the functional and institutional situation of food safety regulatory measures among some countries in Europe and other regions. Furthermore, in order to evaluate these existing systems and measures of the governance for risk from the viewpoints of adequacy, effectiveness and confidence, we tried to design the comprehensive framework of the evaluation which has the accurate standards and indexes.

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An early warning support system for food safety risks was developed. This system is designed for people to facilitate the detection of signs of the risks from a variety of documents that are scattered in the WWW. The system comprises two parts, the clearinghouse and the Risk Path Finder. The former is a database of documents related to food safety risks, which are retrieved from the WWW by using GoogleWebAPIs. The latter visualizes relationship between terms and documents and enables users to find paths from the sources to the risk events. For this function, the system utilizes GETA, the generic engine for transposable association, and Dua1NAVI, A user-interface for text retrieval by using GETA.

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In this paper, we discuss lay people s perception, recognition and attitudes towards some of the EMF issues from the societal governance point of view. EMF issue has typical feature of newly emerged risk: that is un-reached scientific assessment on its health damage beyond thermal impacts, but uncertainties remain depending on the exposure levels of different frequencies. Under this circumstance, we think "Precautionary framework" will be the main principle for societal governance of this issue, and we carried out the Internet survey on lay people of 5, 000 nationwide in Japan to investigate people' s attitude to precautionary principle. After logit regression analysis, significant factors affecting pro-precautionary measures are: anxiety and dependence of mobile phone use, but anxiety of power line is not significant. This is because individual controllability of factors: usage of mobile phone is controllable for individuals, while power line is not.

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Many countries encounter the risk of suffering by invasive species with the rapid globalization of the world economy. In Japan, the Invasive Alien Species Act, which controls invasive species risk, has been enforced in 2005. However, there are still many difficulties in enforcing the risk governance due to the poor public awareness about the invasive species risk. In order to highlight regulatory and systemic problems with the invasive species risk governance in Japan. First, we surveyed governance system regarding Biosecurity of New Zealand for comparative study on invasive species risk governance. Second, we studied the requirements of risk literacy and risk governance with respect to information media of the invasive species risk problem through a questionnaire survey. Next, we established the relation between generation and information media by cluster analysis, which clearly resolved generation gaps that cause of digital divide. Finally, we discuss the requirements of governance system for widespread risk literacy.

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