Inhibition effect of transformation of ferrihydrite in granitic groundwater from the Mizunami Unederground Research Laboratory

Munemoto, Takashi*; Watanabe, Yusuke  ; Hayashida, Kazuki; Iwatsuki, Teruki  

Fe(III)-(oxyhydr)oxides are ubiquitous in soil and groundwater systems and due to the large surface area and high sorption capacity, they play important roles in the biogeochemical cycles of trace elements. Ferrihydrite is a metastable with respect to stable Fe-oxides such as hematite and goethite. The transformation experiments of ferrihydrite have been conducted in the laboratory, but little in the natural groundwater. In order to understand the transformation behavior of ferrihydrite in natural groundwater systems, we conducted transformation experiments of ferrihydrite in granitic groundwater. Consequently, our results suggest the transformation of ferrihydrite was probably inhibited by the aqueous components contained in the groundwater.