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Savannah River Ecology Laboratory Annual Technical Progress Report of Ecological Research, June 30, 2001

Description: The Savannah River Ecology Laboratory (SREL) is a research unit of the University of Georgia (UGA) and has been conducting ecological research on the Savannah River Site (SRS) in South Carolina for 50 years. The overall mission of the Laboratory is to acquire and communicate knowledge of ecological processes and principles. SREL conducts fundamental and applied ecological research, as well as education and outreach programs, under a Cooperative Agreement with the U.S. Department of Energy (DOE) SRS near Aiken, South Carolina. The Laboratory's research mission during the 2001 fiscal year was fulfilled with the publication of one book and 83 journal articles and book chapters by faculty, technical staff, students, and visiting scientists. An additional 77 journal articles have been submitted or are in press. Other noteworthy events took place as faculty members and graduate students received awards. These are described in the section Special Accomplishments of Faculty, Staff, Students, and Administration on page 54. Notable scientific accomplishments include work conducted on contaminant transport, global reptile decline, phytoremediation, and radioecology. Dr. Domy Adriano authored the second edition of his book ''Trace Elements in Terrestrial Environments: Biogeochemistry, Bioavailability, and Risks of Metals'', which was recently published by Springer-Verlag. The book provides a comprehensive treatment of many important aspects of trace elements in the environment. The first edition of the book, published in 1986, has become a widely acclaimed and cited reference. International attention was focused on the problem of reptile species decline with the publication of an article on this topic in the journal ''Bioscience'' in August, 2000. The article's authors included Dr. Whit Gibbons and a number of other SREL herpetologists who researched the growing worldwide problem of decline of reptile species. Factors related to these declines include habitat loss and degradation, introduction of invasive species, environmental pollution, disease, global ...
Date: June 30, 2001
Creator: Bertsch, Paul M.; Janecek, Laura & Rosier, Brenda
Partner: UNT Libraries Government Documents Department

Mineral Surface Processes Responsible for the Decreased Retardation (or Enhanced Mobilization) of 137 Cs from HWL Tank Discharges

Description: Experimental research will determine how the sorption chemistry of Cs on Hanford vadose zone sediments changes after contact with solutions characteristic of high-level tank wastes (HLW). Our central hypothesis is that the high ionic-strength of tank wastes (i.e., > 5 mol/L NaNO3) will suppress all surface-exchange reactions of Cs, except those to the highly selective frayed edge sites (FES) of the micaceous fraction. We further speculate that the concentrations, ion selectivity, and structural aspects of the FES will change after contact with the harsh chemical conditions of HLW and these changes will be manifest in the macroscopic sorption behavior of Cs. We believe that migration predictions of Cs can be improved substantially if such changes are understood and quantified. The research will integrate studies of ion-exchange thermodynamics on the FES, with high resolution surface microscopies and spectroscopy to probe the structure of FES in Hanford sediments and to describe how the chemical environment of sorbed Cs changes when HLW supernatants promote silica dissolution and aluminum precipitation. Newly available atomic-force microscopies and high-resolution electron-beam microscopies afford previously unavailable opportunities to visualize and characterize FES. Our overall goal is to provide knowledge that will improve transport calculations of Cs in the tank-farm environment. Specifically, the research will: Identify how the macroscopic sorption behavior of Cs on the micaceous fraction of the Hanford sediments changes after contact with simulants of HLW tank supernatants over a range of relevant chemical ([OH], [Na], [Al], [K, NH4]) and temperature conditions (23-80 C). Reconcile observed changes in sorption chemistry with microscopic and molecular changes in adsorption-site distribution, chemistry, mineralogy, and morphology/structure of the micaceous sorbent fraction. Integrate mass-action-solution-exchange measurements with changes in the structure/site distribution of the micaceous-sorbent fraction to yield a multi-component/site-exchange model relevant to high ionic strength and hydroxide concentrations for prediction of environmental Cs ...
Date: June 1, 1999
Creator: Zachara, John M.; Bertsch, Paul M. & Serne, Jeffrey R.
Partner: UNT Libraries Government Documents Department

Linking Chemical Speciation, Desorption Kinetics, and Bioavailability of U and Ni in Aged-Contaminated Sediments: A Scientific Basis for Natural Attenuation and Risk Assessment

Description: The extent to which heavy metals and radionuclides pose an environmental hazard depends on their potential for release to and transport in the environment, i.e., environmental availability, and their potential for introduction into biological systems, i.e., bioavailability. Although there exists a substantial body of literature pertaining to the fate, distribution, and bioavailability of contaminant metals in model laboratory systems, few studies have examined the biogeochemical cycling of heavy metals in complex aged-contaminated soils and sediments at a fundamental level. Even fewer have coupled detailed information on chemical speciation from state-of-the-art microscopic analytical and spectroscopic techniques with macroscopic observations obtained using indirect chemical extractions, metal desorption and leaching experiments, and biological uptake and toxicity assays.
Date: June 1, 2003
Creator: Bertsch, Paul M.; Sowder, Andrew & Jackson, Brian
Partner: UNT Libraries Government Documents Department

Mineral Surface Processes Responsible for the Decreased Retardation or Enhanced Mobilization of {sub 137}Cs from HLW Tank Discharges

Description: Experimental research will determine how the sorption chemistry of Cs on Hanford vadose zone sediments changes after contact with solutions characteristic of high-level tank wastes (HLW). Our central hypothesis is that the high ionic-strength of tank wastes (i.e., > 5 mol/L NaNO3) will suppress all surface-exchange reactions of Cs, except those to the highly selective frayed edge sites (FES) of the micaceous fraction. We further speculate that the concentrations, ion selectivity, and structural aspects of the FES will change after contact with the harsh chemical conditions of HLW and these changes will be manifest in the macroscopic sorption behavior of Cs. We believe that migration predictions of Cs can be improved substantially if such changes are understood and quantified.
Date: June 1, 2000
Creator: Zachara, John M.; Serne, R. Jeffrey; Ellis, Paul D. & Bertsch, Paul M.
Partner: UNT Libraries Government Documents Department