"Source water" is defined as the independent water which exists of rather stable composition and in comparatively large amount. It has been formed under individually specific environment. Geothermal model is well illustrated by arrangement of the source waters which are defined as to reveal their formation situations, viz., their formation mechanisms and formed positions. Source water itself is made up of sources materials. The source materials considered are, rock, meteoric water, sea water, magmatic water, volcanic gas, fumarolic gas, etc. A great number sets of various combinations of the source materials may produce many kinds of source waters. Too many kinds of source waters mere cause confusion, however, in case constructing geothermal model. In order to avoid such undesired confusion simplified modeling is recommended by adopting less number of source waters as possible. Following 11 source waters are hence thought adequate; deep thermal water, ocean related thermal water, geothermal vaguely related water, volcanic themal fluid, high temperature steam heated water, low temperature steam heated water, alteration zone related water, deep seated warm water, sea water, low temperature metamorphic sea water and meteoric water. Their decisive criteria mainly on compositional characteristics are listed in the source water classification table. An algorism was thought out to select the appropriate souce water for the source water we have got to know through geochemical analysis. The principle of the algorism is score counting for the source water on the basis of the criteria in the source water classification table. This scoring algorism made it possible to select the adequate fundamental source water for individual interpreted source water as sufficient geochemically. The individual source waters occupy specified underground position and those spacial settlements are also limited concerning to mutual aquifer connenction and continuity. Thus geothermal model can be appropriately shown taking acount of source waters occuring in the area and of those mutual relation.

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The vertical distribution patterns of the major and trace elements in the paddy soils derived from weathered volcanic ashes (Kanto loam) were investigated to estimate the relative mobilities of the elements in the paddy environment. The mobilities were evaluated in terms of the ratios of elemental concetration in paddy soil to elemental concentration in Kanto loam, using Al as a reference element. The elements studied were classified into 3 groups: immobile, mobile and anthropogenic elements. Immobile elements, represented by Cu, Cr, V, Li, Sc, La and Sm, are either captured by the minerals resistant to weathering or strongly adsorbed on soil organic matter and/or clay minerals. Mobile elements are exemplified by Fe, Mn, Co and Ni. Their mobilization is due to the reduction and solubilization of insoluble oxides under reducing conditions, and can be described as a function of ionic radius of solubilized divalent ions. Anthropogenic elements include P, As and Zn, which are characteristically enriched in the topsoil. P is applied to the paddy as fertilizer, and As and Zn are possible impurities in the fertilizers. The importance of the mobility data of the elements in the environmental studies is also discussed.

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Chemical constituents (Cl^-, NO₃^- , SO₄^2-, NH₄⁺) of atmospheric aerosols were measured in Fuchu, Tokyo. The mean concentrations of these constituents were 7.42, 10.12, 6.16 and 4.61 μg/m³, respectively. Nitrate aerosol concentration was extremely high, and surpassed sulfate aerosol concentration. It was ascertained that the contribution of nitrate aerosols to the air pollution was remarkable in Fuchu area, compared with other regions. The concentrations of nitrate and sulfate aerosols showed high value in summer. The relationships between aerosol concentrations and meteorological factors were discussed. Aerosol concentrations were strongly affected by predominant surface wind direction. High concentrations of any constituents were associated with southerly wind. Whereas, temperature and solar radiation have no correlation with aerosol concentrations. The comparison between chemical composition of aerosols and of precipitations was also discussed.

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We have collected various kinds of gas samples, which are expected to be source of atmospheric methane. Chemical compositions and δ¹³C values of the gas samples were measured by using a gas chromatograph and a combined gas chromatograph/combustion/isotope ratio mass spectrometer (GC/C/IRMS ) system, respectively. Analytical precision of δ¹³C value measurement by using GC/C/IRMS system was examined. Overall error of measurement is between 1 ‰ and 2 ‰, estimated from repeated analysis of running standard gas and δ¹³C variation with the combustion efficiency. Observed δ¹³C values of the methane vary singificantly from -65.2‰ to -22.9‰, agrees well with data from literatures. Taking into account a positive correlation between ³He/⁴He ratios and δ¹³C values and a recent trend of atmospheric ³He/⁴He ratio, we discuss contribution of fossil fuel methane to the increase of atmospheric methane.

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