Effects of sorption on the evolution of porewater composition during sediment diagenesis

GEOC 122

Janet G. Hering, jhering@caltech.edu and Kate M. Campbell, katec@caltech.edu. Environmental Science and Engineering, California Institute of Technology, 1200 E. California Blvd., MC 138-78, Pasadena, CA 91125
The occurrence of elevated concentrations of arsenic in sediment porewater is often attributed to reductive dissolution of iron(III) oxyhydroxide carrier phases. If this dissolution is incomplete, however, arsenic released into the porewater can be resorbed onto the residual solid. The extent to which sorption can control dissolved arsenic concentrations will be examined in the context of a laboratory study of microbial reduction of iron(III) oxyhydroxides and a field study of iron- and arsenic-enriched reservoir sediments.