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Abe, Takeyasu; Iida, Yoshihisa; Sasamoto, Hiroshi; Ishii, Eiichi
Proceedings of Water-Rock Interaction (WRI-17)/ Applied Isotope Geochemistry (AIG-14) (Internet), 6 Pages, 2023/08
Cation exchange is one of important elementary reactions among water-rock interactions in sedimentary rocks. In order to model non-constant Na-K-Ca-Mg-H exchange selectivity of sedimentary rocks, exchange isotherms and pH dependence on cation exchange capacity of smectite were analyzed following active fraction model. As the result of comparison of exchangeable cationic composition between measured and calculated, selectivity coefficients determined in this study were preferred to those presented by previous studies. Using the coefficients and groundwater hydrochemistry reported previously, expected compositions of exchangeable cations were calculated. The results suggested that pH and total Na-K-Ca-Mg-H concentration of groundwater are important factors to interpret observed compositional variation in exchangeable base cations.
Yamaguchi, Akiko; Okumura, Masahiko; Takahashi, Yoshio*
no journal, ,
no abstracts in English
U/
U activity ratios from deep groundwater in siliceous aquiferKuribayashi, Chika*; Miyakawa, Kazuya; Ito, Akane*; Tanimizu, Masaharu*
no journal, ,
no abstracts in English
Takahashi, Yoshio*; Yamaguchi, Akiko; Yomogida, Takumi
no journal, ,
Developments in spectroscopy over the past 25 years have provided detailed information on trace elements in environmental samples. X-ray absorption fine structure (XAFS) techniques have been particularly useful in understanding redox states and local structure, and newer techniques have been developed. These techniques have enabled elemental comparisons and systematic understanding based on the periodic table, and have allowed a better understanding of the geochemical behavior of almost all elements in the periodic table. These developments and findings will be presented.
Francisco, P. C. M.; Shiwaku, Hideaki; Ishidera, Takamitsu; Tachi, Yukio
no journal, ,
Kikuchi, Ryosuke*; Fujimura, Tatsuya*; Sato, Tsutomu*; Otake, Tsubasa*; Otomo, Yoko*; Goto, Takahiro*; Suzuki, Satoru*; Taniguchi, Naoki; Suzuki, Hiroyuki*
no journal, ,