Research Activities at U.S. Government Agencies in Subsurface Reactive Transport Modeling

Cygan, Randall T.; Stevens, Caroline; Puls, Robert W.; Yabusaki, Steven B.; Wauchope, R. D.; McGrath, Christian J.; Curtis, Gary P.; Siegel, Morris; Veblen, L. A.; Turner, David R.

doi:10.2136/vzj2006.0091

Cited by 9 publications

(3 citation statements)

References 104 publications

(102 reference statements)

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“…The field‐scale behavior of uranium under these conditions can be sensitive to hydrogeochemical variability [ Davis et al , 2004] and rate‐limited mass transfer processes [ Liu et al , 2004; Luo et al , 2007]. In these situations, the numerical simulation of coupled mechanistic models of surface and subsurface flow and multicomponent biogeochemical reactive transport [ Cygan et al , 2007; Zhang et al , 2008] can provide a useful framework for building understanding of these complex systems and developing remediation insights [ Greskowiak et al , 2006].…”

Section: Introductionmentioning

confidence: 99%

Building conceptual models of field‐scale uranium reactive transport in a dynamic vadose zone‐aquifer‐river system

Yabusaki

Fang

Waichler

2008

Water Resources Research

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[1] Subsurface simulation is used to build, test, and couple conceptual process models to better understand the persistence of uranium concentrations above federal drinking water standards in a 0.4 km by 1.0 km groundwater plume beneath the 300 Area of the U.S. Department of Energy's Hanford Site in eastern Washington State. At this location, the unconfined aquifer and the variably saturated lower vadose zone sediments are subject to significant variations in water levels driven by diurnal, weekly, and seasonal fluctuations in the Columbia River stage. In the near-river aquifer, uranium-contaminated sediments in the highly transmissive Hanford formation are subject to high groundwater velocities, daily flow reversals, and exposure to river water. One-and two-dimensional simulations of variably saturated flow and reactive transport based on laboratory-derived models of uranium sorption are used to assess the representation of uranium transport processes in the vadose zone-aquifer-river system. The simulations show that the various frequencies of river stage fluctuation are capable of driving significant inland transport above the average water table, which is in contrast to the net groundwater flow to the river. Inclusion of a rate-limited uranium mass transfer process model is notably more important to the timescales of the river stage-driven groundwater flow than for vadose zone flow driven by natural recharge. Spatially and temporally variable solution chemistry from the dynamic exchange of river water and groundwater in the unconfined aquifer is shown to significantly alter uranium mobility as represented by a multicomponent uranium surface complexation model.

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Section: Introductionmentioning

confidence: 99%

Building conceptual models of field‐scale uranium reactive transport in a dynamic vadose zone‐aquifer‐river system

Yabusaki

Fang

Waichler

2008

Water Resources Research

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“…Soil can be contaminated with radioactive elements naturally or through anthropogenic activity. There is a wide range of radioactive elements that occur naturally and cause concern (Cygan et al ., 2007); radon represents the largest natural radiation dose to humans (Appleton, 2007). Radon is a naturally occurring radioactive gas found in many parts of the world that accumulates in basements and other underground structures (Appleton, 2007).…”

Section: Element Toxicitymentioning

confidence: 99%

The effect of soil on human health: an overview

Steffan

Brevik

Burgess

et al. 2017

European J Soil Science

263

111

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Summary Soil has a considerable effect on human health, whether those effects are positive or negative, direct or indirect. Soil is an important source of nutrients in our food supply and medicines such as antibiotics. However, nutrient imbalances and the presence of human pathogens in the soil biological community can cause negative effects on health. There are also many locations where various elements or chemical compounds are found in soil at toxic levels because of either natural conditions or anthropogenic activities. The soils of urban environments have received increased attention in the last few years, and they too pose a number of human health questions and challenges. Concepts such as soil security may provide a framework within which issues on soil and human health can be investigated using interdisciplinary and transdisciplinary approaches. It will take the contributions of experts in several different scientific, medical and social science fields to address fully soil and human health issues. Although much progress was made in understanding links between soil and human health over the last century, there is still much that we do not know about the complex interactions between them. Therefore, there is still a considerable need for research in this important area. Highlights Soil is important to human health. Effects can be positive or negative, direct or indirect. Advances have been made in recent years. Inter‐ and trans‐disciplinary research is needed.

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“…Cygan et al . [] present a good review of the capabilities of the various numerical models available. In this manuscript, we focus on analytical solutions using the hyperbolic theory for 1‐D flow assuming local equilibrium and negligible dispersion.…”

Section: Introductionmentioning

confidence: 99%

Analytical solutions for flow in porous media with multicomponent cation exchange reactions

Venkatraman

Hesse

Lake

et al. 2014

Water Resources Research

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Multicomponent cation exchange reactions have important applications in groundwater remediation, disposal of nuclear wastes as well as enhanced oil recovery. The hyperbolic theory of conservation laws can be used to explain the nature of displacements observed during flow with cation exchange reactions between flowing aqueous phase and stationary solid phase. Analytical solutions have been developed to predict the effluent profiles for a particular case of heterovalent cations (Na 1 , Ca 21 and Mg 21) and an anion (Cl 2 ) for any combination of constant injection and constant initial composition using this theory. We assume local equilibrium, neglect dispersion and model the displacement as a Riemann problem using mass action laws, the charge conservation equation and the cation exchange capacity equation. The theoretical predictions have been compared with experimental data available at two scales-the laboratory scale and the field scale. The theory agrees well with the experimental data at both scales. Analytical theory predictions show good agreement with numerical model, developed using finite differences.

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Research Activities at U.S. Government Agencies in Subsurface Reactive Transport Modeling

Cited by 9 publications

References 104 publications

Building conceptual models of field‐scale uranium reactive transport in a dynamic vadose zone‐aquifer‐river system

Building conceptual models of field‐scale uranium reactive transport in a dynamic vadose zone‐aquifer‐river system

The effect of soil on human health: an overview

Analytical solutions for flow in porous media with multicomponent cation exchange reactions

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