The value of water quality both in municipal water use and recreational use is measured. The benefits of water quality improvement in municipal water use are measured empirically both from the supply side and from the demand side. On the supply side the benefits of water quality improvement are measured by means of a socalled cost-saving approach. On the demand side the costs of the averting behavior of consumers are considered to be one indicator of the benefits of water quality improvement. Whereas from the results of empirical application water quality improvement in Lake Biwa will bring cost saving of 4.1 billion yen year^-1, the benefits on the demand side are estimated to be at least 20.3 billion yen year^-1. As for recreational use it is suggested that the value of water quality would be estimated from the referendum voting style approach involves asking whether or not the consumer would be willing to pay some specified amount of money for a particular pair of water quality and some attributes in recreational sites. From a preliminary questionnaire, the difference between use value and nonuse value would exist among Japanese consumers.

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Strategies required to control pollution of the membrane in pervaporation (PV) process was investigated. Simple spiral-wound modules was used for the tests. During the long term operation the membrane got polluted, and were found to be most foulants on the membrane consisted of iron and aluminium . Oxalic acid was very effective to remove them. Pressure loss of the module could be controled by membrane cleaning using oxalic acid, reverse flow of feed or gas injection into feed. Foulants deposited on the membrane did not affect the removal rate of trihalomethanes from drinking water.

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Xenopus laevis embryos at blastula stage were exposed to 0.1ppt-100ppb 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) for 72 h, and then they were mainteined in TCDD-free dechlorinated water till 50 days after fertilization. Effects of TCDD could not be found at the concentration of 10 ppb and below. However, 6 of 13. larvae exposed to 100 ppb TCDD developed edemas in the head, breast and abdomen at 10-18 days after fertilization. Four of them died within a few days, and the remainder recovered from the edemas. The incidence of edemas and death in the 100 ppb group was significantly higher than controls.

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The application of Chemical Element Balance (CEB) air pollution model to ambient measurements of 15 non-methane volatile hydrocarbons (NMHC) is presented. Ninety six of a half hour samples were collected at three recepter locations (general air monitoring stations) in Osaka City in the early morning (6 : 30-8 : 30) during 1987-1988 and analyzed for the concentration of NMHC. The average ambient samples at each recepter location (n=16, in summer and winter, respectively) were evaluated for six sources of NMHC [three types of vehicles ; light duty gasoline car (LDG), super light duty gasoline car (SLD), LPG fueled car (LPG), gasoline vapor, solvent and petroleum refinery]. The average source contributions (n=48) at three receptor locations in summer and winter were as follows. Vehicles (LDG+SLD+LPG) ; 39.12% in summer and 45.64% in winter. Solvents ; 19.86% (summer) and 20.40% (winter), gasoline vapor ; 5.02% (summer) and 4.55% (winter), petroleum refinery; 13.53% (summer) and 13.61% (winter) and other (unexplained sources); 22.7% (summer) and 15.80% (winter). Vehicles were the largest source of the measured NMHC. In Japan, it has been too difficult to determine a vehicle source profile in CEB model, then a road-side data has been used. The results of this study may suggest that three vehicle source profiles are necessary in the adaptation of CEB model to urban atmospheric NMHC of Japan.

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Effects of sulfate load on bacterial propionate oxidation were examined in anaerobic sludge that had been acclimated with glucose as a carbon source for more than 1 month under each sulfate loads (0-0.475 mmol SO₄^2- ·1_-1·day_-1). Bacterial propionate oxidation rate in no-sulfate load sludge was 0.595 mmol·1_-1·hr_-1, but in the sludge of sulfate load of 0.475 mmol SO₄^2- ·1_-1·day_-1, propionate oxidation rate was 0.814 mmol · l_-1·hr_-1. Chloroform, a specific inhibitor of methanogenesis, completely inhibited propionate oxidation in no-sulfate load sludge. This suggests that H_2- producing propionate oxidizing bacteria was also inhibited by accumulation of H₂. owever, in the sulfate load sludge (0.118 mmol SO₄^2- ·1_-1·day_-1), propionate oxidation rate was decreased by chloroform to only 67% of that without chloroform. Molybdate, a specific inhibitor of sulfate reduction, decreased propionate oxidation rate to 58% in sulfate load sludge (0.475 mmol SO₄^2- ·1_-1·day_-1). These results show that propionate oxidation was stimulated by incompletely propionate-oxidizing sulfate reducers when the sulfate load was increased. Also, sulfate reducers competed for propionate with H₂-producing propionate oxidizing bacteria in the high sulfate load sludge.

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The effect of heavy-metal-pollution on soil, in terms of cellulose decomposition, was investigated, through the field survey of 3 areas (Toyama, Ohta, Tsushima) in Japan. The decomposition of cellulose was examined by measuring exo-cellulase activity, a component of the cellulase complexes. The results obtained are as follows. 1) The ratios (heavy-metal-content of each area/natural content) were on average : Toyama soils Cd 3.0, Zn 4.2 and Cu 1.2 ; Ohta soils Cd 6.5, Zn 6.6, Cu 28.0 ; Tsushima soils Cd 23.0, Zn 20.0, Cu 3.0. The degree of heavy-metal-pollution was in the following order : Tsushima> Ohta> Toyama soils. 2) A good co-relation between the heavy-metal-content and the exo-cellulase activity was observed only with Ohta soils, since the soils were sampled from a paddy field with small spacial variability. 3) The extraction way of heavy metals (exchangeable, total) made no difference on the relation to the exo-cellulase activity. 4) The exo-cellulase activity of air-dried soils were considerably lower than those of remoisted soils with Toyama and Tsushima soils, but no such consequences observed in Ohta soils. Therefore, the exo-cellulase activity data of remoisted soils is preferable to those of air-dried soils when observing the relation between the heavymetal-content and the exo-cellulase activity. Moreover, the relation was made clearer when dividing the exo-cellulase activity in terms of carbon content. 5) No relation was observed between heavy-metal-content and the exo-cellulase activity with Toyama soils, the least polluted of the 3 areas. On the other hand, negative relations were observed with Ohta soils and Tsushima soils, the most polluted of the 3 areas.

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Power inverse Gaussian (PIG) distribution is fitted to atmospheric daily-mean nitrogen dioxide (NO₂) concentrations in order to examine pollution characteristics of monitoring stations. PIG distribution with three parameters includes inverse Gaussian and lognormal distributions as the cases where the one parameter is the particular value. First, some properties of PIG distribution are derived and the roles of these parameters are considered. Secondly, the results of goodness-of fit of PIG distribution for NO₂ data are examined using the inverse Gaussian probability paper. PIG distribution may be appropriate for the majority of NO₂ data. It is, then, shown that the estimates of the parameter representing mean can hardly depend on those of the parameter which is considered as representing the degree of dispersion. Furthermore, on the basis of the estimates of three parameters, the differences of pollution structures can be realized between general air pollution monitoring stations and automobile exaust monitoring ones.

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The paper described usage of 196 private wells in Nara Prefecture during the period of February 1990 to December 1991. A quarter of the wells were used for all purposes in daily life because of their locations being away from the public water supply area. Although other domestics can use the public water supply systems, the well waters are still important in their daily life not only as drinking water, but also as the water for washing clothes, watering on the garden, and so on. The ground water level was higher in the middle of Nara Basin than in the other places in Nara Prefecture, and the average groundwater level in Nara was at -2.4 m depth from the groundsurf ace.

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