Stream Floc Processes Involving Ferrous Iron Oxidation in a Riparian Wetland
EMSL Project ID
50749
Abstract
One of the defining characteristics of wetlands is the permanent or intermittent presence of standing water. They provide many critical ecosystem services, including water storage, and fertilizer and contaminant removal. With respect to the latter, they have been described as the kidneys of the landscape and as such play an important role in water quality. Initial studies have shown that contaminant U in the Tims Branch riparian wetland located on the Savannah River Site, South Carolina, may be associated with poorly crystalline/amorphous Fe oxide formed as a result of ferrous iron coming into contact with O2(aq) in the rhizosphere and in streams or stream-bank porewater. It has also been noted that these Fe-oxyhydroxides, formed through in situ oxidation in the otherwise reducing wetland, are enriched in natural organic matter (NOM). These observations led us to hypothesize that the NOM-enriched Fe oxyhydroxides are especially important in binding dissolved radionuclides. In the stream, the flocs provide a vector that can promote transport during elevated stream flow. For this Limited Scope project, LA-ESI-FTICR-MS analysis of NOM associated with six samples recovered from an uncontaminated portion of Tims Branch will be analyzed. The results from these samples will provide insight as to how the NOM composition of the flocs differ from those in the stream (DOC) and the wetland sediments. The results from this Limited Scope project will enable us to plan better for a full 2-year proposal to EMSL that would complement other data generated as part of the Argonne National Laboratory’s – Hydrobiogeochemistry Wetland Scientific Focus Area, including synchrotron-based geochemistry and omics-based microbial community measurements.
Project Details
Project type
Limited Scope
Start Date
2019-04-29
End Date
2019-06-29
Status
Closed
Released Data Link
Team
Principal Investigator