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1.

図書

図書
研究代表者今泉洋
出版情報: [新潟] : 今泉洋, 1998
シリーズ名: 科学研究費補助金(基盤研究(C)(2))研究成果報告書 ; 平成8年度〜平成9年度
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2.

論文(リポジトリ)

論文(リポジトリ)
青塚, 潤 ; 王, 瑩 ; 佐藤, 貴之 ; 片岡, 憲昭 ; 今泉, 洋 ; 狩野, 直樹
出版情報: Radioisotopes — Radioisotopes.  63  pp.283-291,  2014-06.  日本アイソトープ協会
本文リンク: http://hdl.handle.net/10191/30807
概要: トリチウム(3H又はT)が環境中に及ぼす影響と水素を含む化合物との反応性を定量的に評価するために,6-Chloronicotinic Acid又は5,6-Dichloronicotinic AcidとHTO蒸気との間の水素同位体交換反応(T -for-H交換反応)を,50~70℃の温度範囲で固―気系で観測した。得られたデータにA"-McKayプロット法を適用することで,この反応における各官能基の速度定数(k)を求めた。これらのkを相互比較した結果,以下のことが明らかになった。(1) ピリジン誘導体においてCOOH基の反応性はCl基の数や位置の違いに依存しており,次のようになった;(m-位及びp-位のCl基):(p-位のCl基):(Cl基なし)=1.9:1.5:1.0。(2) 未知のニコチン酸誘導体の反応性は,本研究で得られたHammettプロットを使って推定することができる。(3) A"-McKayプロット法を使うことで,官能基を持つ物質においてTの挙動をマスク剤なしで非破壊的,定量的に解析することができる。(4) 本研究で用いられた手法は,物質における官能基の反応性を求めるための手法として役立つことが期待される。<br />In order to quantitatively evaluate the influence of tritium(3H or T) in ecosystem and the reactivity of materials having H atoms, the hydrogen isotope exchange reaction(T-for-H exchange reaction) between 6-Chloronicotinic Acid(or 5,6-Dichloronicotinic Acid) and HTO vapor was observed at 50-70℃ in the gas-solid system. Applying the A"-McKay plot method to the data obtained in the reaction, the rate constants of the functional groups in each material were obtained. Comparing these constants, following four matters have been found in the T-for-H exchange reaction. (1)With regard to pyridine derivative, the reactivity of carboxyl groups depends on the number and position of chloro groups;(meta-position and para-position of chloro groups):(para-position of chloro groups and meta-position of hydrogen):(meta-position and para-position of hydrogen)=1.9:1.5:1.0. (2)The reactivity of the unknown nicotinate derivatives can be obtained by applying the Hammett plot obtained in this work. (3)Using the A"-McKay plot method, the reactivity of each functional group can be obtained nondestructively, quantitatively, and be analyzed without using any masking reagent. (4)The method used in this work may be useful to determine the reactivity of the functional groups in similar materials. 続きを見る
3.

論文(リポジトリ)

論文(リポジトリ)
Tiemuer, Adiljiang ; 狩野, 直樹 ; 今泉, 洋 ; 李, 冲 ; 渡部, 直喜 ; 鄭, 永杰
出版情報: Radioisotopes — Radioisotopes.  62  pp.409-421,  2013-07.  日本アイソトープ協会
本文リンク: http://hdl.handle.net/10191/30806
概要: 新潟県における湖沼水の水質及び同位体的特徴を把握するため,新潟県内の湖沼(佐潟,鳥屋野潟)試料中の酸素安定同位体比(δ18O)や栄養塩濃度(窒素,リン)を測定し,中国黒竜江省のジャロン湿地と比較・検討した。その結果,(1)δ18O値が高くな った要因として,佐潟は生物学的要因,ジャロン湿地は蒸発による影響が大きいと推測される,(2)県内の湖沼はジャロン湿地に比べると富栄養化の進行は小さい,等がわかった。<br />In order to reveal the quality and isotopic characteristics of lagoon waters in Niigata Prefecture in recent years, the nutrients concentrations of nitrogen (N) and phosphorus (P) as well as oxygen stable isotope ratios(i.e., δ18O) in water samples of Sakata and Toyanogata were measured.Samples were regularly taken at the fixed sampling points from these lagoons, and depth distribution was surveyed at one point in Toyanogata. In addition, δ18O and nutrients concentrations of water samples in Zhalong Wetland at Heilongjiang Province in China were also determined.Consequently, the following matters have been mainly clarified. (1) δ18O values of sample waters in Zhalong Wetland are generally large probably because of the effect of evaporation, whereas those of Sakata lagoon are large which may be due to the biological process such as the activity of plankton. (2) Considering the results of nutrients concentrations, the water quality of lagoon (Sakata and Toyanogata) waters in Niigata Prefecture is better than that of Zhalong Wetland in China. 続きを見る
4.

論文(リポジトリ)

論文(リポジトリ)
澤田, 佳則 ; 今泉, 洋 ; 狩野, 直樹
出版情報: Radioisotopes — Radioisotopes.  57  pp.233-240,  2008.  日本アイソトープ協会
シリーズ名: http://hdl.handle.net/10191/7010
本文リンク: http://hdl.handle.net/10191/7166
概要: トリチウム(^3H又はT)が環境中の種々の物質の官能基に及ぼす影響を定量評価するために,T標識ポリ(ビニルアルコール)と各種脂環式アルコール(又はカルボン酸)との間の水素同位体交換反応(T-for-H交換反応)を,50~90℃の温度範囲で固 液反応の形で観測した。得られた観測データにA"-McKayプロット法を適用することで,この反応の速度定数(k)を得た。このkを用いることで,各試料物質の環中の炭素数とその物質の反応性との関係を定量比較することができた。更に,各試料物質のOH基(又はCOOH基)のH原子に直結するO原子上の相対電荷が反応性に及ぼす影響を明らかにするため,MOPAC法を用いた。以上の結果と以前得られた結果とから,T-for-H交換反応における脂環式アルコール(及びカルボン酸)に関して,次のことがわかった。(1)脂環式アルコール(及びカルボン酸)の反応性は,温度に依存する。(2)その物質中の官能基が直結している母体の炭素数が増加するにつれ,反応性は低下する。(3)脂環式カルボン酸の反応性は脂環式アルコールよりも低く,脂環式アミンより高い傾向にある。(4)MOPAC法により求められたO原子の相対電荷とkとの間には,アルコールについては相関性があるが,カルボン酸については顕著な関係は認められない。(5)側鎖を持つ脂環式カルボン酸は,これを持たないものよりも反応性が低い。(6)脂環式カルボン酸は脂肪族直鎖状カルボン酸よりも反応性が高いと推測される。(7)目的物質の溶媒として1,4-ジオキサンを用いるとp-キシレンを用いたときよりも反応性が低くなる傾向がある。(8)MOPAC法とA"-McKayプロット法とを用いると,各種脂環式化合物の実態的分析が一層可能となる。(9)本研究で行った種々の手法は,環境に及ぼすTの影響評価を行うための手法として有用である。<br />In order to quantitatively evaluate the influence of tritium (^3H or T) on various functional groups in environment, the hydrogen isotope exchange reaction (T-for-H exchange reaction) between tritium-labeled poly-(vinyl alcohol) and each aliphatic cyclic alcohol (or carboxylic acid) has been dynamically observed in the range of 50 to 90℃. Consequently, the activities of the aliphatic cyclic alcohol and carboxylic acid increased with increasing reaction time. Applying the A"-McKay plot method to the observed data, the rate constants (k) for these materials were obtained. Using the k, the relation between the number of carbon atoms in the ring in each alcohol and the reactivity of the alcohol was quantitatively compared. Then, to clarify the effect of relative atomic charge of O atom (connected with the H atom in the hydroxy (or carboxy) group in the material) on the reactivity of the material, the MOPAC method was used. From both the above-mentioned and the obtained previously, the following nine items were found as to aliphatic cyclic alcohols (and carboxylic acids) in the T-for-H exchange reaction. (1) The reactivity of aliphatic cyclic alcohols (and carboxylic acids) depends on the temperature. (2) The reactivity of the cyclic materials decreases with increasing number of carbon atoms in the ring. (3) The reactivity of the aliphatic cyclic carboxylic acid seems to be smaller than that of aliphatic cyclic alcohol, and be larger than that of aliphatic cyclic amine. (4) For aliphatic cyclic alcohols, correlation exists between k and relative atomic charges of O atom obtained by the MOPAC method, but the tendency for aliphatic cyclic carboxylic acid is not clear. (5) As to having the same number of carbon atoms in each ring. the reactivity of the aliphatic cyclic carboxylic acid including the side chain is smaller than of the aliphatic cyclic carboxylic acid including no side chain. (6) The reactivity of aliphatic cyclic carboxylic acid is larger than that of aliphatic normal carboxylic acid. (7) The reactivity of these materials dissolved in 1,4-dioxane is smaller than that in p-xylene. (8) Using both the MOPAC and the A"-McKay plot methods, the actual analysis of aliphatic cyclic alcohols can be more possible. (9) The method used in this work is useful for evaluating influence of T on environment. 続きを見る
5.

論文(リポジトリ)

論文(リポジトリ)
田村, 潔 ; 今泉, 洋 ; 狩野, 直樹
出版情報: Radioisotopes — Radioisotopes.  56  pp.593-603,  2007-10.  日本アイソトープ協会
シリーズ名: http://hdl.handle.net/10191/7010
本文リンク: http://hdl.handle.net/10191/7126
概要: トリチウム(^3H又はT)が生態系に及ぼす影響と水素を含む種々の化合物の反応性を明らかにするため,安息香酸誘導体とT標識ポリビニルアルコールとの間における水素同位体交換反応(T-for-H交換反応)を50~90℃の温度範囲で観測した。その結 果,反応時間の軽過と共に誘導体の放射能の増加が認められた。得られた観測値に対してA"-McKayプロット法を適用することで,各誘導体の官能基ごとの速度定数(k)を求め,この定数を相互比較することで,以下のことが明らかとなった。(1)各官能基の反応性には,温度依存性が見られる,(2)固液系の各官能基の反応性は固気系の反応性のおよそ7~12倍である,(3)官能基の共鳴効果によって反応性比に2倍近い差が生じる,(4)A"-McKayプロット法を使うことでマスク剤無しでの実態分析ができる可能性が高い,(5)今回得られた結果を基に,一般環境下での交換反応の推論が可能である,(6)本研究で用いた安息香酸誘導体のCOOH基の反応性はHammett則に従うと推測できる,(7)本研究で得られた結果は,T汚染の防止やTの挙動を明らかにする上で利用できる。<br />In order to clarify the effect of tritium (^3H or T) on both the ecosystem and the reactivity of compounds including Hatoms, the hydrogen-isotope exchange reaction (T-for-H exchange reaction) between each substituted hydroxybenzoic acid and tritium-labeled poly (vinyl alcohol) was observed in the range of 50 to 90℃. As a result, the radioactivity of the compounds was increased with the reaction time. Applying the A"-McKay plot method to the observed data obtained, the rate constants (k) of the functional groups in each compound were obtained. Comparing k with each other, the following seven matters have been clarified, (1) The reactivity of substituted hydroxybenzoic acid (and carboxylic acid) depends on temperature. (2) The reactivity of each functional group in the liquid-solid system is about 7 to 12 times the reactivity in the gas-solid system. (3) The reactivity of a certain substituted benzoic acid may be twice as large as that of another substituted one by resonance effect. (4) Applying the A"-McKay plot method, the reactivity of substituted hydroxybenzoic acids can be clarified under the condition of non-masking reagent. (5) The exchange reaction under a general environment can be inferred based on this work. (6) The reactivity of the carboxyl groups of the substituted hydroxybenzoic acid can be deduced by applying the Hammett rule. (7) The method used in this work is useful for evaluating the influence of T to environment. 続きを見る
6.

論文(リポジトリ)

論文(リポジトリ)
今泉, 洋 ; 斎藤, 博美 ; 狩野, 直樹
出版情報: Radioisotopes — Radioisotopes.  55  pp.183-190,  2006-04.  日本アイソトープ協会
シリーズ名: http://hdl.handle.net/10191/7010
本文リンク: http://hdl.handle.net/10191/7106
概要: トリチウム標識ボリ(ビニルアルコール)と各種脂肪族ジアミンとの間で,水素同位体交換反応(T-for-H交換反応)が,50~90℃の温度範囲で観測された。その結果,反応時間の増加とともに,ジアミンの放射能の増加が認められた。このようにして得ら れた観測データにA"-McKayプロット法を適用することで,この反応の速度定数(k)を得た。このようにして得たkを用いて,ジアミン中のメチレンの数とその反応性との関係を定量比較できた。更に,ジアミンのアミノ基のN原子上の相対電荷がそのジアミンの反応性に及ぼす影響を明らかにするため,MOPAC法を用いた。以上の結果と以前得られた結果とから, T-for-H交換反応における脂肪族ジアミンに関して,次の五つの事柄がわかった。(1)各ジアミンの反応性は,そのジアミン中のメチレンの数が増加するにつれ,減少する。(2)ジアミン中のメチレンの数が1,3,5と増えた場合の反応性の低下率は,2,4,6と増えた場合の低下率よりも大きい。(3)幾つかの化合物の反応性に及ぼす温度の影響は,(ジカルボン酸)<(ジアミン)<(ジオール)<(芳香族化合物)の順である。(4)ジアミン中のメチレンの数が奇数の場合,ジアミンのN原子の相対電荷は,メチレンの数の増加とともに減少する。偶数の場合は,ジアミンのN原子の相対電荷は,メチレンの数の増加とともに増加する。(5)本研究の手法とMOPAC法とを用いることで,ある溶媒中のジアミンの立体配置を見積もれる可能性が高い。<br />The hydrogen-isotope exchange reaction (T-for-H exchange reaction) between tritium-labeled poly (vinyl alcohol) and each normal chain diamine has been observed in the range of 50 to 90℃. Consequently, the activity of the diamine increased with increasing reaction time. Applying the A"-McKay plot method to the obsetved data thus obtained, the rate constants (k) for the diamines were also obtained. Using each k thus obtained, the relation between the number of methylene groups in the diamine and the reactivity of the diamine was quantitatively compared. Then, in order to clarify the effect of relative atomic charge of N atom in the ammo group on the reactivity of the diamine, the MOPAC method was used. From both the above-mentioned and the obtained previously, the following five items were found as to normal chain amines in the T-for-H exchange reaction, (l) Increasing the number of methylene groups in each diamine leads to decreasing k for the diamine. (2) The decreasing ratio of the reactivity of the diamine, where the number of methylene groups in each diamine increases from one to three (and to five), is larger than the decreasing ratio of the reactivity of the diamine, where the number of the methylene groups in the diamine increases from two to four (and to six). (3) The effect of temperature on the reactivity of several compounds is in the following order: (dicarboxylic acids) <(diamines)<(diols)<(aromatic compounds). (4) When the number of methylene groups is odd, the relative atomic charge of the N atom in the amino group decreases with increasing number of methylene groups in the diamine. When the number of methylene groups is even, the relative atomic charge of the N atom has a tendency to increase with increasing number. (5) We have a high possibility that the structure of normal chain diamine in a certain solvent may be stereo-chemically estimated by applying both the MOPAC method and the method used in this work. 続きを見る
7.

論文(リポジトリ)

論文(リポジトリ)
今泉, 洋 ; 長澤, 智史 ; 狩野, 直樹
出版情報: Radioisotopes — Radioisotopes.  55  pp.709-718,  2006-12.  日本アイソトープ協会
シリーズ名: http://hdl.handle.net/10191/7010
本文リンク: http://hdl.handle.net/10191/7107
概要: 生態系に及ぼすトリチウム(^3H又はT)の影響とHを含む物質の反応性を明らかにするため,同一分子内に異なる3種の官能基を持つL-システイン酸とL-システインの反応性を追究した。これらの物質とHTO蒸気との間の水素同位体交換反応(T-for- H交換反応)を50~70℃の温度範囲で観測し,得られたデータとA〝-McKayプロット法とを用いて各々の反応を解析した結果,次のことが明らかになった。(1)異なる3種の官能基を持つこれらの化合物中の各官能基の反応性は温度の上昇に伴い増加する。(2)L-システイン酸中のSO_3H基の反応性は,COOH基の反応性のおよそ2.6倍であり,NH_2基の反応性のおよそ5.8倍である。(3)L-システイン中のSH基の反応性は,COOH基の反応性のおよそ1.4倍であり,NH_2基の反応性のおよそ3.5倍である。(4)NH_2基は電子求引性の大きい置換基が置換すると反応が促進されるが,COOH基ではあまり影響がない。(5)異なる3種の官能基を持つ脂肪族化合物について,A〝-McKayプロット法を使うと,その物質の反応性を,マスク剤等を使わないで非破壊的・同時分析的に明らかにできる。(6)ある種の物質へのT取込みの程度を,非破壊的・定量的に明らかにできる。(7)本研究で得られた結果は,環境中のT汚染防止のために役立ち,また今後,複数の官能基を持つある種の物質の反応性を追究するための解析手法として役立つ。<br />In order to clarify both the effect of tritium (^3H or T) on the ecosystem and the reactivity of materials having H atoms, the reactivity of L-cysteic acid (or L-cysteine) having three different kinds of functional groups was studied. The hydrogen-isotope exchange reaction between each compound and HTO vapor (T-for-H exchange reaction) was observed at 50-70℃, and the reaction was analyzed with both the A"-McKay plot method and the data obtained from the exchange reaction. The following seven matters have been consequently found in the T-for-H exchange reaction. (1) The reactivity of the functional groups in each compound increases with increasing temperature. (2) As to L-cysteic acid, the reactivity of SO_3H group is 2.6 times greater than that of COOH one, and is 5.6 times greater than that of NH_2 one. (3) As to L-cysteine, the reactivity of SH group is 1.4 times greater than that of COOH one, and 3.5 times greater than that of NH_2 one, (4) The reactivity of NH_2 group progressed by the substituent having large electron-attractive effect, however, the reactivity of COOH group does not so progress by such a substituent. (5) Applying the A"-McKay plot method, the reactivity of the three functional groups in each aliphatic compound can be nondestructively and simultaneously clarified under the condition of non-masking reagent. (6) Degree of T-incorporation in a certain material can be nondestructively and quantitatively clarified. (7) The results obtained in this work is useful to prevent T contamination in the environment and to clarify the reactivity of the materials having plural functional groups, and the method used in this work can be also useful as a analytical method to obtain the reactivity of multi-functional groups in a certain compound. 続きを見る
8.

論文(リポジトリ)

論文(リポジトリ)
今泉, 洋 ; 長澤, 智史 ; 篠原, 雪彦 ; 狩野, 直樹
出版情報: Radioisotopes — Radioisotopes.  54  pp.139-143,  2005-05.  日本アイソトープ協会
本文リンク: http://hdl.handle.net/10191/29846
概要: The hydrogen-isotope exchange reaction (T-for-H exchange reaction) between tritium-labeled poly (vinyl alcohol) and each cycloamine dissolved in 1, 4-dioxane has been observed at 50-90°C. Consequently, the quantitative relation was obtained between the reaction time and the increase in the tritium activity of the cycloamine. The reaction was dynamically analyzed with both the A''-McKay plot method and data observed. Moreover, in order to clarify the effect of the relative atomic charge of the N atom (in the amino group) on the reactivity of the cycloamine, the MOPAC method was introduced. As to cycloamine, the following three matters have been consequently found in the T-for-H exchange reaction: (1) the reactivity of each cycloamine decreases with increasing the number of carbon atoms in the ring of cycloamine, (2) the rate constant (k) for each cycloamine depends on the reaction temperature, (3) the correlation is found between the relative atomic charge of the N atom in the NH2 group and k for the cycloamine. 続きを見る
9.

論文(リポジトリ)

論文(リポジトリ)
狩野, 直樹 ; 佐藤, 明史 ; 今泉, 洋
出版情報: Radioisotopes — Radioisotopes.  53  pp.415-425,  2004-07.  日本アイソトープ協会
本文リンク: http://hdl.handle.net/10191/6818
概要: 新潟県における近年の環境水の同位体的・化学的特徴についての知見を得ること,更には環境水動態の新たな評価方法を確立するため,新潟県のいくつかの河川水や地下水について,酸素安定同位体比(δ^<18>O)及び主要イオン濃度,pH,電気伝導度の測定 を行った。その結果,以下のことが明らかになった。(1)河川水中のδ^<18>O値は,概ね-11‰~-10‰の値を示す,(2)地下水のδ^<18>O値は,河川水より平均1.5‰程度高く,また年間の変動幅も±1.0‰程度と小さい,(3)河川水上流部近傍の地下水よりも河川水下流部近傍の地下水の方が,年間を通して高いδ^<18>O値及び電気伝導度を示す,(4)大部分の主要イオンにおいて,夏期と冬期に,その濃度が高くなり,春期に濃度が低くなる傾向を示す,(5)周辺地下水の主要イオン濃度の方が河川水の主要イオン濃度より全体的に高い値を示す,(6)河川水において,上流から下流に向かうにつれ,主要イオン濃度は高くなる傾向を示す,(7)河川水におけるδ^<18>Oと電気伝導度との相関関係は,上流部ほど(下流部に比べて)良い(上流部ほど両者の相関係数が高い)。<br />To reveal the characteristics of environmental water in Niigata Prefecture in recent years, and to establish a new evaluation method for the behavior of the environmental water, oxygen stable isotopic ratios (i.e., δ^<18>O), concentrations of major ions, pH and EC (electric conductivity) in water samples from several rivers and those from groundwater in Niigata Prefecture were measured. Isotopic measurements were performed with a stable isotope ratio mass spectrometer (Mieromass PRISM). Consequently, the following matters have been found. (1) The δ^<18>O values of river waters in Niigata Prefecture are generally -11‰ to -10‰. (2) The δ^<18>O values of groundwater in Niigata Prefecture are generally 1.5‰ higher than that of river waters and the variation is about ±1‰ throughout the year. (3) The δ^<18>O values and the conductivity of groundwater located in the downstream area are higher than those in the upstream throughout the year. (4) The concentrations of major ions of river waters were almost higher in summer and winter than those in spring. (5) The concentrations of major ions in groundwater were higher than those in river water. (6) The concentrations of major ions in river water tend to increase with the downstream from the upstream. (7) The relationship between the conductivity and δ^<18>O values in river water was relatively close (i.e. The correlation coefficient between them is large) in the upstream area (by comparing with that in the downstream). (Received February 16, 2004) 続きを見る
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論文(リポジトリ)

論文(リポジトリ)
狩野, 直樹 ; 藍原, 弘行 ; 小島, 令 ; 竹内, 香代子 ; 佐藤, 明史 ; 今泉, 洋
出版情報: Radioisotopes — Radioisotopes.  52  pp.65-80,  2003-02.  日本アイソトープ協会
本文リンク: http://hdl.handle.net/10191/6820
概要: 新潟県の降水および河川水中の酸素安定同位体比(δ^<18>O)を1999年~2002年まで測定した。δ^<18>O値の測定は,安定同位体比測定用質量分析装置を用いて行われた。その結果,以下のことが明らかになった。(1)降水におけるδ^<18 >O値の平均値は-9‰程度であり,季節によって±7‰程度の変動を示す,(2)新潟県内の各地点(9観測地点)において,同位体比の季節変動は,互いに似た挙動を示す,(3)降水におけるδ^<18>O値は,6月および1月において小さく,8月において大きい,(4)1月において,降水のδ^<18>O値と温度との間の相関関係が1年中で最も顕著に見られる,(5)冬期における降水のδ^<18>O値の変動幅は,他の季節より小さい,(6)新潟県の河川水におけるδ^<18>O値の平均値は,-11‰~-10‰程度であり,年間を通して大きな変動は見られなかった(±2‰程度),(7)河川水中のδ^<18>O値は,融雪水や降水が河川水中に流入するときに変動しうる,(8)地下水中のδ^<18>O値の変動幅は,河川水に比べて小さい。<br />Oxygen stable isotopic ratios (δ^<18>O) of the precipitation and some river water samples in Niigata prefecture were measured from 1999 to 2002. Isotopic measurements were performed by a stable isotope ratio mass spectrometer. Consequently, the following matters were found. (1) The mean δ^<18>O value of precipitations was -9‰, and the variation of ±7‰ was shown throughout the year. (2) All of 9 observation points, the seasonal behavior of isotopic ratio was similar to each other. (3) In June and January, δ^<18>O value of precipitations was small, and was large in August. (4) In January, the relationship between the temperature of observation points and δ^<18>O values in precipitation was most remarkably found throughout the year. (5) The variation of δ^<18>O values in precipitations in winter is smaller than that in the other seasons. (6) The mean δ^<18>O value of river waters in Niigata prefecture was about -11‰ to -10‰, and the variation was not so large (±2‰) throughout the year. (7) δ^<18>O values of river waters may vary when the melted snow or the precipitation flow into the rivers. (8) The variation of δ^<18>O values in groundwater was smaller than that in river waters. (Received August 22, 2002) 続きを見る