Soil vapor extraction (SVE) is one of the effective techniques of removing volatile chlorinated hydrocarbon contaminants from soil. However, the extracted soil gas needs further treatment. In this work, adsorptive treatment of soil gas using regenerable activated carbon fiber (ACF) was investigated. The equilibrium relation of tetrachroloethylen (PCE) adsorbed on ACF was accurately expressed by the Dubinin-Radushkevitch equation, which enabled prediction of the amount of PCE adsorbed at given temperature and concentration. Then, adsorption and desorption of PCE and other volatile organic compounds (VOCs) in contaminated soil at a commercial cleaning factory were investigated using a newly developed steam-regeneration ACF adsorption apparatus installed at the field site. Due to high temperatures of the soil gas extracted and the resulting decrease in relative humidity thereof, reduction in the amount of PCE adsorbed on ACF by coadsorption of water vapor was negligibly small. The amount of PCE adsorbed on ACF to a breakthrough did not reach the amount predicted for a single gas phase of PCE. When the exhausted ACF was regenerated with steam, PCE was desorbed almost completely. In this regeneration, more than 30 species of hydrocarbons derived from petroleum-based detergents, which were not detected during a soil contamination survey at the site, were also desorbed. It is assumed that the coadsorption of these hydrocarbons led to the reduced amount of PCE adsorbed on ACF.

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The present study was carried out to evaluate comprehensively the estrogenicity, immunotoxicity and mutagenicity of environmental water concentrates prepared by the XAD-2 resin column concentration method. This investigation focused on water from the river basin of Lake Biwa-Yodo River. Estrogenicity was detected by the yeast two-hybrid system and the measurement of alkaline phosphatase activity in human endometrial adenocarcinoma cell line (Ishikawa cells). Although the two methods differed in sensitivity and magnitude of estrogenic activity for lake water and river water containing endocrine-disrupting chemicals (EDCs), estrogenicity was detected in all sampling points except the Katsura River (Miyamae bridge). These results suggested the co-existence of materials with EDCs in environmental water, which inhibited the detection of estrogenic activity. Immunotoxicity was evaluated by the mouse splenic lymphocyte mitogenesis test using lipopolysaccharide and concanavalin A as specific mitogens for B cells and T cells, respectively. Some of the water samples showed specific depression effect on B cell and T cell mitogenesis. Furthermore, the Salmonella/microsome assay (Ames test) with TA98 and TA100 strain series was used to determine the mutagenicity. In all the sampling points, the direct/indirect-frameshift mutagenicity was detected. These results indicated that the yeast two-hybrid system and the measurement of alkaline phosphatase activity in Ishikawa cells, the lymphocyte mitogenesis test and the Ames test are important for evaluating comprehensively each endpoint because there is no relevance among these different toxicities.

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The influence of algae on hydrogen production by a purple non-sulfur bacterium, Rhodobacter sphaeroides RV, the control of algal growth using a blue cellophane film and the hydrogen production by photosynthetic consortia were investigated by the batch culture using artificial substrate at 30°C. The influence of algae on hydrogen production was studied using pure culture of R. sphaeroides RV and coculture of algae and R. sphaeroides RV. Hydrogen production with the without a blue cellophane film was evaluated. Hydrogen production without the blue cellophane film in the coculture decreased by 15% compared with that in the pure culture. On the other hand, there was no significant difference in the amount of hydrogen production in cultures with the blue cellophane film. By absorbing the lights with wavelengths ranging from 600nm to 700nm, the blue cellophane film effectively controlled algal growth. The chlorophyll-a concentration in the coculture without the blue cellophane film increased by 1.5 times that of the initial concentration. On the contrary, the chlorophyll-a concentration in the co-culture with the blue cellophane film did not increase from the initial stage of the experiment. Moreover, hydrogen production was not inhibited in the pure cultures with or without the blue cellophane film. It is possible for the photosynthetic consortia to produce hydrogen from nonsterilized wastewater, although there is a decrease in hydrogen production of about 12% compared with that in the pure culture.

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Recently, it has been expected the social infrastructure system must be changed to an environment ally friendly one. Therefore, we proposed a new evaluation method, “ecodesign”, to establish an environment ally friendly system of social infrastructure and performed an evaluation using the proposed method. Four renewal methods for urban water supply systems were evaluated in order to improve the quality and safety of drinking water: Four 1) high-level purified drinking water supply system, 2) domestic water recycling system, 3) movement of treated sewage discharging point to lower reaches, 4) water supply system with PET bottles. We evaluated each water supply system using to ecodesign approach based on citizens' evaluations, the amount of carbon dioxide emission and cost. Accordingly, the domestic water recycling system is the best system from the viewpoint of “ecodesign”. Therefore, we consider that an ecodesign evaluation, with adequate evaluation items provides us important information for planning and implementation of projects to improve social infrastructure.

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