Revealing the origin and ion-binding properties of dissolved organic matters in deep sedimentary groundwater

Saito, Takumi*; Nishi, Shusaku*; Sato, Hayato*; Miyakawa, Kazuya

no journal, , 

Dissolved organic matters (DOMs) play an important role for the fate of pollutants in surface and subsurface environments. For migration of radionuclides, the binding to DOMs modulates their aqueous speciation, reduce the adsorption on rock surface, and even enhance their transport, compared with non-sorbing tracers. The origin of DOMs in surface environments have been studied for decades and mechanistic models are proposed, which can describe ion-binding to major fractions DOMs (i.e. humic and fulvic fractions) over a wide range of environmental conditions. Nevertheless, our understanding on deep groundwater DOMs remains limited, and it is still disputable if model parameters calibrated for surface DOMs can be applied for their counterparts in deep subsurface environments. This study aims to reveal the origin of different DOM components in deep sedimentary groundwater and their ion-binding properties by fluorescence spectroscopy and high-resolution mass spectrometry. The results of both techniques are processed and correlated by multivariate analysis to find different DOM components and pursue their molecular characteristics. In the conference, we will present various molecular metrices describing the EEM components with the help of an advanced multivariate technique, which allows us to simultaneously process both the entire data sets of EEM and FT-ICR-MS data, consisting of the different data dimensions.