Impact of natural organic matter on U speciation and mobility in groundwater
EMSL Project ID
48747
Abstract
Uranium (U) contamination of aquifers is a persistent problem at DOE legacy ore processing sites and, contrary to initial predictions, many plumes are not attenuating with natural groundwater flushing. In these sediments, U is typically enriched in organic-rich fine-grained lenses of sediment that are interspersed with the coarser aquifer material. Natural organic matter (NOM) plays an important role in retention and redox transformations of U in these sediments. The scientific focus of the proposed work is to identify key characteristics of NOM that are likely to be important to U biogeochemistry within the U-enriched zones to constrain the mechanisms controlling U mobility in aquifers. We propose (i) to examine how NOM chemistry influences U speciation through complexation in laboratory batch reactor systems and aquifer sediments, using nano-scale secondary ion mass spectrometry (NanoSIMS) coupled with sub-micron synchrotron-based x-ray microscopy measurements. We further propose (ii) to determine functional group abundances, molecular size and composition in NOM from reactor systems and U-rich zones within aquifer sediments using high-resolution Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) in combination with a suite of solid- and liquid-state nuclear magnetic resonance (NMR) techniques.
Project Details
Project type
Exploratory Research
Start Date
2015-03-11
End Date
2015-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members