Due to the political regulation of rice production, the area of fallow paddy fieldsamounts to 6590 km², which corresponds to 30% of the total paddy fields registered in Japan. Understanding the material flow is essential for making an appropriatemangement and use of this broad area. In this study, a fallow paddy field in Kanazawawas flooded, and the carbon and nitrogen budgets were quantitatively investigatedthrough two years. In the field studied, 400-580 gC/m²/yr was fixed by the aquaticplants as a net primary production, 170-210 gC/m²/yr accumulated in soil, 10-60 gC/m²/yr of dissolved organic carbon was released into the surrounding water, and 220gC/m²/yr of organic carbon was estimated to decompose. In the nitrogen budget, 9-20gN/m2/yr was removed from the surface water during passing through the field, 15-18 gN/m²/yr was absorbed by the aquatic plants, and 4-22 gN/m²/yr accumulated in soil. From the nitrogen budget calculation, 8 gN/m2/yr was estimated to be denitrifiedinto the air. The present study demonstrates that the flooded fallow paddy field acts as acarbon sink within an initial several years of flooding, but that it also acts as adissolved organic carbon source to the surrounding water. The area accumulatesnitrogen in soil and removes nitrate from surface runoff by denitrification as well asby plant uptake.

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The effects of acid rain on inland waters can easily be seen in the mountainoussouthern area of Nagano Prefecture, where there is little buffering action from the zone of granite rock, and annual precipitation, at 2600 mm/y, is above the averagelevel of all over the prefecture. In this study, which was conducted in the village of Hiraya (situated in the southern region of Nagano Prefecture), the chemical composition of precipitation and stream water were measured in the summer season, when the amounts of acid deposition increase, and the short-term effects of acid rain on mountain streams were investigated. The electric conductivity of stream water, averaging 9.7, μ/cm, and alkalinity, averaging 0.042 meq/L, were both very low values. The stream water contained lowamounts of dissolved substances, and the water quality was similar to that of the riversof Yakushima Island, which is famed for its high levels of precipitation. From the results of continuous pH measurement of the mountain stream water, temporary drops in the pH level (pH6.5?→pH6.1) were observed during times of raised water levelsfollowing rain fall, while simultanenous increase in the concentrations of metal were also observed.

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The saturated magnetization (?D) of the ferrite sludge formed by ferrite processtreatment of wastewater containing heavy metal (nickel sulfate) and carboxylic acidswas measured over a wide concentration range of carboxylic acids. From the presentexperimental results, the effects of various carboxylic acids and their concentration on the wastewater treatment by ferrite process were discussed quantitatively. The saturatedmagnetization of the ferrite sludge was smaller than that of sludge containing nickel ion at the same concentration of carboxylic acid, and became smaller in the order of malic acid, citric acid and tartaric acid. The decrease of the saturatedmagnetization with increasing the concentration of carboxylic acid may be ascribed to the magnitude of the interaction between hydroxyl group and iron ion . Further, the concentration of nickel ion in treated water increased with the stability constant of carboxylic acid for nickel ion.

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CO₂ emission factor and specific energy consumption for polycarbonate production were estimated and compared among three manufacturing processes, i. e., batch interfacial, conventional melt and nonphosgenation melt processes. These values of conventional melt process were the smallest and those of nonphosgenation meltprocess were the largest among them. Adding reprecipitation process to batch interfacialprocess for removing impurities, such as, chlorine compounds resulted in largervalues than those of nonphosgenation melt process. An Improvement of nonphosgenationelt process was discussed from the view points of CO₂ emission and energyconsumption.

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