Clarify of origin and migration of substances in subsurface environment using stable isotope

研究了木川附近小森林盆地地下水和地表水的化学组成和氢、氧同位素，分析了地下水和地表水的来源和迁移行为。同时在大阪和歌山市采集了雨水样本并进行了分析。河流水化学依赖于雨季土壤水径流，而非雨季则依赖于地下水径流。雨水的离子浓度较河水、溪水和地下水低。小溪的水化学与河流的水化学几乎相同。由于沉积岩和土壤的风化和化学反应，地下水化学与河流化学不同。阐明了稳定同位素比率或河水取决于地下水径流，而地下水的同位素比率由流域内山脉的高度决定，雨水与河水的同位素比率差异表明地表径流是否存在。和歌山、大阪和桐林市的Cl^- in降水主要来自海洋。大阪和桐林市与城市活动相关的产品中硝酸盐和硫酸盐的浓度高于和歌山市。大阪和桐林市的平均pH值为5.2，而和歌山市的平均pH值为5.8。降水中的氧和氢同位素比随时间变化很大。从和歌山到大阪府的广大地区，氧、氢同位素比值的时间序列几乎一致，但差异很大。因此，降水中的氧和氢同位素比值被认为取决于空气中氧和氢同位素比值的变化。

Chemical composition, hydrogen and oxygen isotopes were studied for analyzing the origin and migration behavior or groundwater and surface water in the small forested basin near the Kinokawa. Also rain water was sampled at both Osaka and Wakayama cities and was analyzed. River water chemistry depended on the runoff of soil water in rainy period, however it did on the runoff of groundwater excluding the rainy period. Ionic concentrations of rain water were low as compared with those of river water, stream water and groundwater. Stream water chemistry was almost the same as river water chemistry. Groundwater chemistry, however, was different from river water chemistry due to the weathering and chemical reaction of the sedimentary rocks and soils. It was clarified that stable isotopic ratios or river waters depended on the runoff of groundwater of which isotopic ratios were determined by the height of mountains in the basins, and the differences of the isotopic ratios between rainwater and river water showed whether the surface runoff exists or not. Cl^- in precipitation sampled at Wakayama, Osaka and Tondabayashi cities were mainly derived from sea. Concentrations of nitrate and sulfate derived from productions accompanied with city activities in Osaka and Tondabayashi cities were higher than those in Wakayama city. The average pH values, 5.2 in Osaka and Tondabayashi cities were lower than 5.8 in Wakayama city. Oxygen and hydrogen isotopic ratios in precipitation were very variable with times. In spite of the variation widely, time series of Oxygen and hydrogen isotopic ratios showed almost the same values in the wide areas from Wakayama to Osaka prefecture. Therefore, Oxygen and hydrogen isotopic ratios in precipitation were thought to depend on the change or Oxygen and hydrogen isotopic ratios in air.