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Title: Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer

Abstract

Biologically mediated reductive dissolution and precipitation of metals and radionuclides play key roles in their subsurface transport. Physical and chemical properties of natural aquifer systems, such as reactive iron-oxide surface area and hydraulic conductivity, are often highly heterogeneous in complex ways that can exert significant control on transport, natural attenuation, and active remediation processes. Typically, however, few data on the detailed distribution of these properties are available for incorporation into predictive models. In this study, we integrate field-scale geophysical, hydrologic, and geochemical data from a well-characterized site with the results of laboratory batch-reaction studies to formulate two-dimensional numerical models of reactive transport in a heterogeneous granular aquifer. The models incorporate several levels of coupling, including effects of ferrous iron sorption onto (and associated reduction of reactive surface area of) ferric iron surfaces, microbial growth and transport dynamics, and cross-correlation between hydraulic conductivity and initial ferric iron surface area. These models are then used to evaluate the impacts of physical and chemical heterogeneity on transport of trace levels of uranium under natural conditions, as well as the effectiveness of uranium reduction and immobilization upon introduction of a soluble electron donor (a potential biostimulation remedial strategy).

Authors:
 [1];  [1];  [1];  [2];  [3];  [1];  [4];  [3]
  1. Pacific Northwest National Laboratory (PNNL)
  2. University of Wisconsin, Madison
  3. Lawrence Berkeley National Laboratory (LBNL)
  4. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1003638
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geosphere; Journal Volume: 2; Journal Issue: 4
Country of Publication:
United States
Language:
English

Citation Formats

Scheibe, Timothy D., Fang, Yilin, Murray, Christopher J, Roden, Eric E, Chen, Jinsong, Chien, Yi-Ju, Brooks, Scott C, and Hubbard, Susan S. Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer. United States: N. p., 2006. Web. doi:10.1130/GES00029.1.
Scheibe, Timothy D., Fang, Yilin, Murray, Christopher J, Roden, Eric E, Chen, Jinsong, Chien, Yi-Ju, Brooks, Scott C, & Hubbard, Susan S. Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer. United States. doi:10.1130/GES00029.1.
Scheibe, Timothy D., Fang, Yilin, Murray, Christopher J, Roden, Eric E, Chen, Jinsong, Chien, Yi-Ju, Brooks, Scott C, and Hubbard, Susan S. Sun . "Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer". United States. doi:10.1130/GES00029.1.
@article{osti_1003638,
title = {Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer},
author = {Scheibe, Timothy D. and Fang, Yilin and Murray, Christopher J and Roden, Eric E and Chen, Jinsong and Chien, Yi-Ju and Brooks, Scott C and Hubbard, Susan S},
abstractNote = {Biologically mediated reductive dissolution and precipitation of metals and radionuclides play key roles in their subsurface transport. Physical and chemical properties of natural aquifer systems, such as reactive iron-oxide surface area and hydraulic conductivity, are often highly heterogeneous in complex ways that can exert significant control on transport, natural attenuation, and active remediation processes. Typically, however, few data on the detailed distribution of these properties are available for incorporation into predictive models. In this study, we integrate field-scale geophysical, hydrologic, and geochemical data from a well-characterized site with the results of laboratory batch-reaction studies to formulate two-dimensional numerical models of reactive transport in a heterogeneous granular aquifer. The models incorporate several levels of coupling, including effects of ferrous iron sorption onto (and associated reduction of reactive surface area of) ferric iron surfaces, microbial growth and transport dynamics, and cross-correlation between hydraulic conductivity and initial ferric iron surface area. These models are then used to evaluate the impacts of physical and chemical heterogeneity on transport of trace levels of uranium under natural conditions, as well as the effectiveness of uranium reduction and immobilization upon introduction of a soluble electron donor (a potential biostimulation remedial strategy).},
doi = {10.1130/GES00029.1},
journal = {Geosphere},
number = 4,
volume = 2,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • Biologically-mediated reductive dissolution and precipitation of metals and radionuclides plays a key role in their subsurface transport. Physical and chemical properties of natural aquifer systems, such as reactive iron oxide surface area and hydraulic conductivity, are often highly heterogeneous in complex ways that can exert significant control on transport, natural attenuation, and active remediation processes. Typically, however, few data on the detailed distribution of these properties are available for incorporation into predictive models. In this study, we integrate field-scale geophysical, hydrologic, and geochemical data from a well-characterized site with the results of laboratory batch reaction studies to formulate numerical modelsmore » of reactive transport in a heterogeneous granular aquifer. The models incorporate several levels of coupling, including effects of ferrous iron sorption onto (and associated reduction of reactive surface area of) ferric iron surfaces, microbial growth and transport dynamics, and cross-correlation between hydraulic conductivity and initial ferric iron surface area. These models are then used to evaluate the impacts of physical and chemical heterogeneity on transport of trace levels of uranium under natural conditions, as well as the effectiveness of uranium reduction and immobilization upon introduction of a soluble electron donor (a potential biostimulation remedial strategy).« less
  • No abstract prepared.
  • A series of chemical transport simulations in saturated porous media are conducted to examine the coupled impacts on chemical mobility induced by nonuniform sorption reactions and heterogeneous flow fields. The simulations involve the calculation of fluid flow and chemical migration within highly resolved, three-dimensional cubic regions with synthetically derived material properties. Nonuniformities in subsurface materials are represented as randomly correlated hydraulic conductivity and sorption partition coefficient fields. Transport computations are based upon a random walk particle model, appropriately modified to treat equilibrium sorption reactions. Current experiments focus on four hypothetical constituents, one being inert, and the other three independently obeyingmore » linear, Freundlich, and Langmuir partitioning relationships. Results show distinct effects of the nonuniform flow and sorption processes on the overall displacement, dispersion, and partitioning/retardation and the breakthrough behavior of the constituent plumes, as well as on the sharpening fronts and skewed concentration profiles associated with nonlinear partitioning models. 37 refs., 9 figs., 4 tabs.« less
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