Determination of humic substances in deep groundwater from sedimentary formations by the carbon concentration-based DAX-8 resin isolation technique

炭素濃度に基づくDAX-8樹脂単離法を用いた深部堆積岩地下水中腐植物質の定量

寺島 元基  ; 遠藤 貴志*; 宮川 和也   

Terashima, Motoki; Endo, Takashi*; Miyakawa, Kazuya

Concentrations of humic substance (HS) in deep sedimentary groundwater were determined by the carbon concentration-based DAX-8 resin isolation technique. The groundwater samples were collected from test galleries at different depths in the Horonobe Underground Research Laboratory (URL) of Hokkaido, and two subsidence observation wells of Niigata in Japan. The analytical condition was optimized for the groundwater samples with a high salinity and a high concentration of DOM. The analytical results showed that the HS concentrations vary with the depth and the area. The HS proportions to DOM slightly varied with the depth. The regression analysis showed that the HS concentrations are positively correlated with the DOM concentrations. The low deviation of the HS proportions from the slope in the regression equation indicated that the slight variation of HS proportion can be trivial in the prediction of the concentration of HS. These results can provide a useful information on the HS concentration and its prediction from the DOM concentration in sedimentary groundwater.