Quantification of Hydrological, Geochemical, and Mineralogic...

Quantification of Hydrological, Geochemical, and Mineralogical Processes Governing the Fate and Transport of Uranium over MultipleScales in Hanford SedimentsThis study is motivated by the scientific and technological needs of DOE sites in which contaminanttransport is influenced by coupling of anisotropic lateral flow and preferential finger flow, and is further complicated by themineralogical and geochemical variations present in natural subsurface sediments. The objectives of this research are to providevalidated scaling theories which can be applied to existing contaminant distributions and migration scenarios at Hanford. We willaccomplish this through an integrated multi-scale approach involving (1) Quantifying unsaturated hydraulic, mineralogical, andgeochemical transport parameters within small intact cores of sedimentary layers, (2) Upscaling these data using a combination ofnumerical, composite medium, and fractal approaches to compute effective, coupled hydraulic and uranium transport parameters, and(3) Validating this methodology by application of the effective parameters to progressively larger scales consisting of intactmultiple sedimentary beds that encompass both lateral and vertical transport of uranium. The unique aspects of our experimentsinclude the measurement of moisture retention, hysteresis, and unsaturated hydraulic conductivity using an innovative Ultra RockCore centrifuge, novel surface spectroscopic analyses, new scanning techniques for permeability and conductivity, and real-timeuranium transport in a natural, multi-layered, instrumented system. Our results will provide an integrated dataset to validatecoupled process models at mm-m scales in field-relevant, intact sediments. We will generate new insights on the influence ofscaling and coupled reactive transport to provide reasonable strategies to improve the prediction and remediation of contaminantmigration throughout the western U.S.