ANALYSIS OF THE CHEMICAL COMPOSITIONS OF GROUNDWATERS UTILIZING A LEACHING TECHNIQUE - AN APPLICATION TO THE ROKKO MOUNTAINS AND THEIR SURROUNDINGS.

The chemical composition of groundwaters from granitic alluvial plains is different from that from the clayey ″Kobe-group″ strata surrounding the Rokko mountains of Japan. The former groundwaters are dominantly rich in Ca and HCO//3, while the latter are rich in Na and HCO//3. In order to investigate the difference in the groundwater compositions, a chemical leaching technique was applied to samples of soils, well-sediments, and rocks collected from the Rokko mountains and their surroundings. From the results of leaching and adsorption experiments for cations, and from a comparison of the analytical values of the cations in groundwaters with the data of the leaching experiments on the key diagram, the association of the chemical species dissolved in groundwaters with the geological characters was analyzed.