Coupled Hydrological and Geochemical Processes Governing the Fate and Transport of Radionuclides and Toxic Metals in the Hanford Vadose Zone PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Coupled Hydrological and Geochemical Processes Governing the Fate and Transport of Radionuclides and Toxic Metals in the Hanford Vadose Zone PDF full book. Access full book title Coupled Hydrological and Geochemical Processes Governing the Fate and Transport of Radionuclides and Toxic Metals in the Hanford Vadose Zone by M. A. Mayes. Download full books in PDF and EPUB format.
Author: M. A. Mayes Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
At the D.O.E. Hanford Reservation, accelerated migration of radionuclides has been observed in the vadose zone underlying the tank farms. Our goal is to provide an improved understanding and predictive capability of the coupled hydrogeochemical mechanisms responsible for observed migration. Our approach is to perform a suite of experiments ranging from novel surface interrogation techniques (e.g., XAS) to miscible displacement experiments on disturbed and undisturbed sediments from the Hanford, Plio-Pleistocene and Ringold formations. Results indicate during unsaturated conditions hydrologic processes governing transport are a strong function of sediment layering in the Hanford and Ringold formations. The transport of radionuclides and toxic metals (U, Cr(VI), Cs, Sr and Co) is influenced by reactive geochemical nonequilibrium, sedimentary mineralogy and solution chemistry. This research will provide new insights into how physical and mineralogical heterogeneities (e.g. stratification, pore regime connectivity, mineral composition along flowpaths) influence contaminant retardation and degree of geochemical nonequilibrium during transport.
Author: M. A. Mayes Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
At the D.O.E. Hanford Reservation, accelerated migration of radionuclides has been observed in the vadose zone underlying the tank farms. Our goal is to provide an improved understanding and predictive capability of the coupled hydrogeochemical mechanisms responsible for observed migration. Our approach is to perform a suite of experiments ranging from novel surface interrogation techniques (e.g., XAS) to miscible displacement experiments on disturbed and undisturbed sediments from the Hanford, Plio-Pleistocene and Ringold formations. Results indicate during unsaturated conditions hydrologic processes governing transport are a strong function of sediment layering in the Hanford and Ringold formations. The transport of radionuclides and toxic metals (U, Cr(VI), Cs, Sr and Co) is influenced by reactive geochemical nonequilibrium, sedimentary mineralogy and solution chemistry. This research will provide new insights into how physical and mineralogical heterogeneities (e.g. stratification, pore regime connectivity, mineral composition along flowpaths) influence contaminant retardation and degree of geochemical nonequilibrium during transport.
Author: Edgar Berkey Publisher: ISBN: Category : Nature Languages : en Pages : 416
Book Description
This book presents leading-edge research on subsurface contamination remediaton being conducted through the U.S. Department of Energy Environmental Management Science Program (EMSP), addressing (1) remedial science and technology, (2) characterization, fate, and transport, and (3) environmental sensing and monitoring.
Author: John S. Selker Publisher: CRC Press ISBN: 9780873719537 Category : Technology & Engineering Languages : en Pages : 356
Book Description
Vadose Zone Processes provides a unified, up-to-date treatment on the movement of water through unsaturated media. In addition to covering the basic equations governing the flow and fate of water in unsaturated media, the text covers the biogeochemistry of vadose environments and the statistical description of vadose processes. The authors emphasize maintaining an intuitive understanding of how the results are derived and how they are appropriately applied. This comprehensive and important book will be useful not only to those in traditional fields such as civil engineering, geology, crop science, chemical engineering, agricultural engineering, and hydrology but also in the newer environmental engineering fields including containment transport, pollution remediation, and waste disposal.
Author: Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
The overall goal of this research is to provide an improved understanding and predictive capability of coupled hydrological and geochemical mechanisms that are responsible for the accelerated migration of radionuclides in the vadose zone beneath the Hanford Tank Farms. The study is motivated by the technological and scientific needs associated with the long-term management of the enormous in-ground inventories of multiple contaminants at the Hanford site. Our objectives are to (1) provide an improved understanding of how lithological discontinuities within the sediments influence the propensity for preferential flow and matrix diffusion at different water contents, (2) quantify the significance of downward vertical advection, lateral spreading, and physical nonequilibrium processes on radionuclide transport under variable hydrologic conditions, and (3) quantify the rates and mechanisms of 137Cs, 235238U, and 99Tc interaction with the solid phase under various hydrodynamic conditions and to determine how physical heterogeneities (i.e. stratification, pore regime connectivity) influence the retardation and degree of geochemical nonequilibrium during contaminant transport.
Author: Scott Fendorf Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
Although the accelerated transport of {sup 99}Tc, {sup 137}Cs, and {sup 235}U within the vadose zone beneath the 200-West Area of the Hanford tank-farm area has been recognized, the mechanisms responsible for the vertical migration of the radionuclides is unclear. Does horizontal stratification enhance the lateral movement of contaminants, which in turn enhances vertical preferential flow due to perched water dynamics? Do physical heterogeneities, such as stratification and pore regime connectivity, influence the retardation and degree of geochemical nonequilibrium during contaminant transport? Recent modeling efforts of the problem have failed to yield answers to this question since they are inadequately parameterized due to the lack of sufficient quality data. Fundamental experimental research is needed that will improve the conceptual understanding and predictive capability of radionuclide migration in the Hanford tankfarm environment. Since geochemical reactions are directly linked to the system hydrodynamics, coupled geochemical and hydrological processes must be investigated in order to resolve the key mechanisms contributing to vadose zone and groundwater contamination at Hanford. Our research group has performed extensive investigations on time-dependent contaminant interactions with subsurface media using dynamic flow techniques which more closely simulate conditions in-situ. Of particular relevance to this proposal is the work of Barnett et al. (2000) who showed that U(VI) transport through Hanford sediments was highly retarded and extremely sensitive to changes in pH and total carbonate. What remains elusive are the geochemical mechanisms for uranium retention-necessary information for accurately simulating transport-and are thus the focus of this study. The experimental and numerical results from this research will provide knowledge and information in previously unexplored areas of vadose zone fate and transport to support EM's performance/risk assessment and decision-making process for Tank Farm restoration. By unraveling fundamental contaminant transport mechanisms in complex porous media, we provide an improved conceptual understanding and predictive capability of a variety of vadose issues within the DOE system.
Author: Commission on Geosciences, Environment, and Resources Publisher: National Academies Press ISBN: 0309069327 Category : Science Languages : en Pages : 289
Book Description
In the past decade, officials responsible for clean-up of contaminated groundwater have increasingly turned to natural attenuation-essentially allowing naturally occurring processes to reduce the toxic potential of contaminants-versus engineered solutions. This saves both money and headaches. To the people in surrounding communities, though, it can appear that clean-up officials are simply walking away from contaminated sites. When is natural attenuation the appropriate approach to a clean-up? This book presents the consensus of a diverse committee, informed by the views of researchers, regulators, and community activists. The committee reviews the likely effectiveness of natural attenuation with different classes of contaminants-and describes how to evaluate the "footprints" of natural attenuation at a site to determine whether natural processes will provide adequate clean-up. Included are recommendations for regulatory change. The committee emphasizes the importance of the public's belief and attitudes toward remediation and provides guidance on involving community stakeholders throughout the clean-up process. The book explores how contamination occurs, explaining concepts and terms, and includes case studies from the Hanford nuclear site, military bases, as well as other sites. It provides historical background and important data on clean-up processes and goes on to offer critical reviews of 14 published protocols for evaluating natural attenuation.
Author: M. A. Mayes
Author: M. A. Mayes
Author: Edgar Berkey
Author: 
Author: John S. Selker
Author: 
Author: Scott Fendorf
Author: Commission on Geosciences, Environment, and Resources
Author: 
Author: Lorne Graham Wilson
Author: Jin-Song Chen