A Case study for evaluation of uncertainty of redox potential in deep groundwater

Mochizuki, Akihito; Sasamoto, Hiroshi; Mezawa, Tetsuya*; Miyakawa, Kazuya

no journal, , 

Redox potential of deep groundwater in the Horonobe area, Hokkaido, was measured, and uncertainty of the measurement and thermodynamic interpretation was evaluated. The redox potential of groundwater ranged between -250 and -100 mV, and the effect of the excavation of drifts on the redox potential is considered to be small in spite of its temporal variation. The redox potential is controlled by the reaction of chemical pairs of SO/FeS, SO/HS and CO(aq)/CH(aq). The comparison between the equilibrium potential for these reactions and the measured redox potentials suggests that 50 mV of uncertainty for the measurement of the redox potential is appropriate.