This study introduced a hypertext version of contingent valuation questionnaires, and investigated the effects of placing links in the questionnaire. A protocol method was employed to record the detailed mental responses of 21 subjects. Our questionnaires asked the value of reducing CO₂ emissions under the scenario of utilizing more nuclear energy. Major results are as follows. First, we compared two types of hypertext links. Itwas found that our respondents preferred to follow the links dedicated to the explanation of specific topics rather than the links suited for looking up words from a selection of web sites. Second, we found the side effects of making links in questionnaires. The respondents who answered the questionnaire with links appeared to want to know more about other people's views on global warming than the respondents who could not use links. Besides, the respondents with usable links were more satisfied with the opportunity to join the survey than those without effective links. However, no difference between the two groups in the responses to the question of willingness-to-pay was detected in terms of the frequency of considering other people's views and the occurrence of fare share answers. Third, we tested two types of counter-symbolic-bias measures using links. One is to raise options other than the use of nuclear energy and the other is to provide negative information as well as good one on nuclear power plants. The use of each single measure appeared not to be effective, but the use of both measures at the same time reduced the happening of biased answers.

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Desires of contaminated soil and groundwater remediation have been apparently increased in recent years in Japan. However, more cost-effective and environmentally friendly remediation measures are being expected because of very high financial load on subsurface contaminants remediation. Environmental risk is firstly assessed using RBCA (risk-based corrective action) and remediation measures are compared in this research to evaluate its applicability to Japanese situation. At a trichloroethylene (TCE) contaminated site, based on detected TCE content at source zone and site hydro-geological condition, Tire 2 risk assessment results showed that risk of down-gradient groundwater ingestion receptor exceeds the target risk on current condition. Remediation target was then discussed by considering present receptor and potential receptor, and also risk assessment results were compared with present Environmental Quality Standard (EQS), including soil leaching standard and groundwater standard. The results show that, method like RBCA can give a more rational and cost-effective remediation target. However, to introduce risk management concept into environmental management, it is still necessary to get social acceptance supposing contaminated soil will be very well managed and no any environmental problems will be caused even the contaminated soil is left in-situ.

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European union is going to standardize and harmonize its environmental lows by CEN-ISO norms. CEN-ISO are the NGOs who organized for standardizations. The base of european harmonization for environmental analysis is to use any scenario of pollution exposure, which origin is in the wastes characterizations. This study aims to explain some strategies of european wastes (include contaminated soil) characterizations, and to show the strategies of their environmental harmonization.

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For taking an effective countermeasure based on measurements of toxicities of wastes, it is necessary to employ bioassays alongside leaching test. We examined leachability of organic compounds in 6 waste deposit samples, such as fly and bottom ashes, by standard and modified leaching tests. Leachability of organic compounds was much varied by the condition of leaching test. To evaluate the toxicity of waste samples, three different bioassays, in vitro cytotoxicity test using human cell lines, Daphnia acute immobilization test and Algae growth inhibition test, were applied to leaching test samples. The results of these bioassays were affected by osmolarity of the samples varied from 10 to 622 mOsm/kg. To evaluate the effect of osmolarity, osmolarityresponse curves of the three bioassays were collected. By using the standard curves, it was elucidated that significant toxicity was observed in leaching solutions of waste samples. Further bioassay can reveal the toxicity, which can be explained by the presence of organic compounds.

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Various chemicals may exist in the rice field soil. This research is focused on polycyclic aromatic hydrocarbons (PAHs) and pesticides in the rice field soil. Content of such chemicals in the rice field soil were evaluated. As a result, it was confirmed that PAHs constantly remained in the soil throughout a year. Of 14 targeted materials for pesticides, only two materials were detected and remaining of agricultural chemicals in the soil was not confirmed. In order to evaluate elution behavior of PAHs after feeding of polluted soil under homo's in vivo condition, the in vitro bioavailability test was done. As a result, the elution of PAHs from the soil was confirmed under the small intestines condition. Moreover, the exposure examination that used the extraction of the rice field soil was done. Extracts of the soil were exposed to the homo origin culture cell, and the EROD activity which used the medicine enzyme metabolic reaction of the inclusion quality in the doing soil was evaluated. As a result, the existence of the EROD activity inducement factor was confirmed from the soil inside.

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Generation of molten slags will increase more accompanied with recently or newly built melting furnaces for industrial or municipal solid waste. Slags are utilizable for construction materials like a road subbase or a filling material. However, prior their utilization it is necessary to evaluate an environmental impact on a soil/groundwater system. This paper describes an estimation of groundwater contamination in utilization of molten slags (slags from automobile shreddered dust and municipal solid waste, and electric arc furnace slag) in the environment by column tests using a simple model proposed by Hjelmer et al. In addition according to the concept of the newly enacted soil pollution control law, taking into account of the risk of direct ingestion, the testing method of acid extraction is applied to the molten slags. In the column test a typical elution pattern of most elements was an early washout and the next diffusion leaching, while different patterns were observed in several elements; silicon was affected by the pH of the leachate and barium concentration increased gradually. Thus the released amount by a column test was generally a little more than that by the batch-type leaching test (the Japanese Leaching Test No. 46; JLT 46) under the same liquid/solid ratio of 10. This might indicate the JLT 46 method give an effective estimation result as well as a column test. Such toxic heavy metals as lead and arsenic were estimated not to be influential to make groundwater quality of interest increase up to the Environmental Quality (EQ). Easily soluble elements like sodium might affect 65% on the maximum of the EQ. An alkaline electric arc slag released calcium highly, and the estimation showed a possibility of an increase Ca concentration over the tap water quality (200 mg/L) in a severe condition. The ratios of "quasi-total" or "effective" contents using HCl extraction to the true total content of almost all elements were analogous in the same slag sample. This indicates the decomposition of silicate network by acid made the release of Si and also cationic modifier ions.

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