Evaluation of the interaction between deep groundwater natural organic matter and metal ions using fluorescence spectroscopy and multivariate analysis and arrangement of their origins

Nishi, Shusaku*; Miyakawa, Kazuya   ; Toda, Kanako*; Saito, Takumi*

In HLW disposal, NOM changes radionuclides behavior. For surface NOM, models that express bonding with metal ions under various conditions have been proposed. To use such models in the safety evaluation of geological disposal, binding reactions between NOM in deep underground and nuclides are evaluated, and features are compared with the NOM in surface. In March 2021, we focused on the fact that NOM fluorescence is extinguished by combining with metal ions, and conducted quenching experiments where europium was added to the deep groundwater containing NOM. Using PARAFAC, a multivariate analysis method, fluorescent NOM components that contribute to binding are identified, and properties and reactivity with europium are discussed. In this presentation, new samples are added for more comprehensive discussions.