Using a hydrous manganese oxide (HMO) doped gel probe to measure rates of reductive dissolution

GEOC 54

Claire Farnsworth, Kate M. Campbell, katec@caltech.edu, Cory White, and Janet G. Hering, jhering@caltech.edu. Environmental Science and Engineering, California Institute of Technology, 1200 E. California Blvd., MC 138-78, Pasadena, CA 91125
Reductive dissolution of redox-sensitive minerals such as manganese (Mn) oxides in natural sediments is an important mechanism for trace element mobilization into groundwater. A gel probe sampler has been constructed to study reductive dissolution of Mn-oxides. The gel consists of a polyacrylamide polymer matrix doped with hydrous Mn oxide (HMO). It is cut into slabs and placed into slots etched into a Plexiglas probe, and coved with a membrane filter. The probe is designed to be inserted into sediments and allowed to equilibrate with sediment porewater. The amount of Mn reductively dissolved from the gel is measured by comparing the amount of Mn initially embedded into the gel with the amount remaining in the gel after exposure to a reducing agent. In this study, gel probes were used to compare the rates of reduction by ascorbic acid, manganese reducing bacteria Shewanella oniedensis strain MR1, and natural sediments in a laboratory microcosm.
 

General Poster Session
7:00 PM-9:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Division of Geochemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006