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Past, Present, Future Erosion at Locke Island

Description: This report describes and documents the erosion that has occurred along the northeast side of Locke Island over the last 10 to 20 years. The principal cause of this erosion is the massive Locke Island landslide complex opposite the Columbia River along the White Bluffs, which constricts the flow of the river and deflects the river's thalweg southward against the island.
Date: August 8, 2006
Creator: Bjornstad, Bruce N.
Partner: UNT Libraries Government Documents Department

Sampling and Hydrogeology of the Vadose Zone Beneath the 300 Area Process Ponds

Description: Four open pits were dug with a backhoe into the vadose zone beneath the former 300 Area Process Ponds in April 2003. Samples were collected about every 2 feet for physical, chemical, and/or microbiological characterization. This reports presents a stratigraphic and geohydrologic summary of the four excavations.
Date: August 31, 2004
Creator: Bjornstad, Bruce N.
Partner: UNT Libraries Government Documents Department

Geologic Descriptions for the Solid-Waste Low Level Burial Grounds

Description: This document provides the stratigraphic framework and six hydrogeologic cross sections and interpretations for the solid-waste Low Level Burial Grounds on the Hanford Site. Four of the new cross sections are located in the 200 West Area while the other two are located within the 200 East Area. The cross sections display sediments of the vadose zone and uppermost unconfined aquifer.
Date: September 23, 2007
Creator: Bjornstad, Bruce N. & Lanigan, David C.
Partner: UNT Libraries Government Documents Department

Drilling Specifications: Well Installations in the 300 Area to Support PNNL’s Integrated Field-Scale Subsurface Research Challenge (IFC) Project

Description: Part of the 300 Area Integrated Field-Scale Subsurface Research Challenge (IFC) will be installation of a network of high density borings and wells to monitor migration of fluids and contaminants (uranium), both in groundwater and vadose zone, away from an surface infiltration plot (Figure A-1). The infiltration plot will be located over an area of suspected contamination at the former 300 Area South Process Pond (SPP). The SPP is located in the southeastern portion of the Hanford Site, within the 300-FF-5 Operable Unit. Pacific Northwest National Laboratory (PNNL) with the support of FH shall stake the well locations prior to the start of drilling. Final locations will be based on accessibility and will avoid any surface or underground structures or hazards as well as surface contamination.
Date: January 21, 2008
Creator: Bjornstad, Bruce N. & Vermeul, Vince R.
Partner: UNT Libraries Government Documents Department

Drilling, Sampling, and Well-Installation Plan for the IFC Well Field, 300 Area

Description: The 300 Area was selected as a location for an IFC because it offers excellent opportunities for field research on the influence of mass-transfer processes on uranium in the vadose zone and groundwater. The 300 Area was the location of nuclear fuel fabrication facilities and has more than 100 waste sites. Two of these waste sites, the North and South Process Ponds received large volumes of process waste from 1943 to 1975 and are thought to represent a significant source of the groundwater uranium plume in the 300 Area. Geophysical surveys and other characterization efforts have led to selection of the South Process Pond for the IFC.
Date: May 5, 2008
Creator: Bjornstad, Bruce N. & Horner, Jacob A.
Partner: UNT Libraries Government Documents Department

A Catalog of Geologic Data for the Hanford Site

Description: This report catalogs the existing geologic data that can be found in various databases, published and unpublished reports, and in individuals' technical files. The scope of this catalog is primarily on the 100, 200, and 300 Areas, with a particular emphasis on the 200 Areas. Over 2,922 wells are included in the catalog. Nearly all of these wells (2,459) have some form of driller's or geologist's log. Archived samples are available for 1,742 wells. Particle size data are available from 1,078 wells and moisture data are available from 356 wells. Some form of chemical property data is available from 588 wells. However, this catalog is by no means complete. Numerous individuals have been involved in various geologic-related studies of the Hanford Site. The true extent of unpublished data retained in their technical files is unknown. However, this data catalog is believed to represent the majority (>90%) of the geologic data that is currently retrievable.
Date: September 19, 2001
Creator: Horton, Duane G.; Last, George V.; Gilmore, Tyler J. & Bjornstad, Bruce N.
Partner: UNT Libraries Government Documents Department

A Summary of Fault Recurrence and Strain Rates in the Vicinity of the Hanford Site--Topical Report

Description: This document is one in a series of topical reports compiled by the Pacific Northwest National Laboratory to summarize technical information on selected topics important to the performance of a probabilistic seismic hazard analysis of the Hanford Site. The purpose of this report is to summarize available data and analyses relevant to fault recurrence and strain rates within the Yakima Fold Belt. Strain rates have met with contention in the expert community and may have a significant potential for impact on the seismic hazard estimate at the Hanford Site. This report identifies the alternative conceptual models relevant to this technical issue and the arguments and data that support those models. It provides a brief description of the technical issue and principal uncertainties; a general overview on the nature of the technical issue, along with alternative conceptual models, supporting arguments and information, and uncertainties; and finally, suggests some prospective approaches to reducing uncertainties about earthquake recurrence rates for the Yakima Fold Belt.
Date: August 1, 2012
Creator: Bjornstad, Bruce N.; Winsor, Kelsey & Unwin, Stephen D.
Partner: UNT Libraries Government Documents Department

Data Package of Samples Collected for Hydrogeologic and Geochemical Characterization: 300 Area RI/FS Sediment Cores

Description: This is a data package for sediment samples received from the 300 FF 5 OU. This report was prepared for CHPRC. Between August 16, 2010 and April 25, 2011 sediment samples were received from 300-FF-5 for geochemical studies. The analyses for this project were performed at the 331 building located in the 300 Area of the Hanford Site. The analyses were performed according to Pacific Northwest National Laboratory (PNNL) approved procedures and/or nationally recognized test procedures. The data sets include the sample identification numbers, analytical results, estimated quantification limits (EQL), and quality control data. The preparatory and analytical quality control requirements, calibration requirements, acceptance criteria, and failure actions are defined in the on-line QA plan 'Conducting Analytical Work in Support of Regulatory Programs' (CAW). This QA plan implements the Hanford Analytical Services Quality Assurance Requirements Documents (HASQARD) for PNNL.
Date: May 1, 2011
Creator: Lindberg, Michael J.; Bjornstad, Bruce N.; Lanigan, David C. & Williams, Benjamin D.
Partner: UNT Libraries Government Documents Department

Revised Hydrogeology for the Suprabasalt Aquifer System, 200-East Area and Vicinity, Hanford Site, Washington

Description: This study supports the Hanford Groundwater/Vadose integration project objectives to better understand the risk of groundwater contamination and potential risk to the public via groundwater flow paths. The primary objective of this study was to refine the conceptual groundwater flow model for the 200-East Area and vicinity.
Date: April 20, 2000
Creator: Williams, Bruce A.; Bjornstad, Bruce N.; Schalla, Ronald & Webber, William D.
Partner: UNT Libraries Government Documents Department

A Catalog of Geologic Data for the Hanford Site

Description: This report catalogs the existing geologic data that can be found in various databases, published and unpublished reports, and in individuals' technical files. The scope of this catalog is primarily on the 100, 200, and 300 Areas, with a particular emphasis on the 200 Areas. Over 2,922 wells are included in the catalog. Nearly all of these wells (2,459) have some form of driller's or geologist's log. Archived samples are available for 1,742 wells. Particle size data are available from 1,078 wells and moisture data are available from 356 wells. Some form of chemical property data is available from 588 wells. However, this catalog is by no means complete. Numerous individuals have been involved in various geologic-related studies of the Hanford Site. The true extent of unpublished data retained in their technical files is unknown. However, this data catalog is believed to represent the majority (>90%) of the geologic data that is currently retrievable.
Date: September 19, 2001
Creator: Horton, Duane G; Last, George V; Gilmore, Tyler J & Bjornstad, Bruce N
Partner: UNT Libraries Government Documents Department

Hanford Site Guidelines for Preparation and Presentation of Geologic Information

Description: A complex geology lies beneath the Hanford Site of southeastern Washington State. Within this geology is a challenging large-scale environmental cleanup project. Geologic and contaminant transport information generated by several U.S. Department of Energy contractors must be documented in geologic graphics clearly, consistently, and accurately. These graphics must then be disseminated in formats readily acceptable by general graphics and document producing software applications. The guidelines presented in this document are intended to facilitate consistent, defensible, geologic graphics and digital data/graphics sharing among the various Hanford Site agencies and contractors.
Date: April 30, 2010
Creator: Lanigan, David C.; Last, George V.; Bjornstad, Bruce N.; Thorne, Paul D. & Webber, William D.
Partner: UNT Libraries Government Documents Department

Borehole Data Package for One CY 2005 CERCLA Well 699-S20-E10, 300-FF-5 Operable Unit, Hanford Site, Washington

Description: This report supplies the information obtained during drilling, characterization, and installation of the new groundwater monitoring well. This document also provides a compilation of hydrogeologic and well construction information obtained during drilling, well development, and sample collection/analysis activities.
Date: March 29, 2006
Creator: Williams, Bruce A.; Bjornstad, Bruce N.; Lanigan, David C.; Keller, Jason M. & Rockhold, Mark L.
Partner: UNT Libraries Government Documents Department

Updated Conceptual Model for the 300 Area Uranium Groundwater Plume

Description: The 300 Area uranium groundwater plume in the 300-FF-5 Operable Unit is residual from past discharge of nuclear fuel fabrication wastes to a number of liquid (and solid) disposal sites. The source zones in the disposal sites were remediated by excavation and backfilled to grade, but sorbed uranium remains in deeper, unexcavated vadose zone sediments. In spite of source term removal, the groundwater plume has shown remarkable persistence, with concentrations exceeding the drinking water standard over an area of approximately 1 km2. The plume resides within a coupled vadose zone, groundwater, river zone system of immense complexity and scale. Interactions between geologic structure, the hydrologic system driven by the Columbia River, groundwater-river exchange points, and the geochemistry of uranium contribute to persistence of the plume. The U.S. Department of Energy (DOE) recently completed a Remedial Investigation/Feasibility Study (RI/FS) to document characterization of the 300 Area uranium plume and plan for beginning to implement proposed remedial actions. As part of the RI/FS document, a conceptual model was developed that integrates knowledge of the hydrogeologic and geochemical properties of the 300 Area and controlling processes to yield an understanding of how the system behaves and the variables that control it. Recent results from the Hanford Integrated Field Research Challenge site and the Subsurface Biogeochemistry Scientific Focus Area Project funded by the DOE Office of Science were used to update the conceptual model and provide an assessment of key factors controlling plume persistence.
Date: November 1, 2012
Creator: Zachara, John M.; Freshley, Mark D.; Last, George V.; Peterson, Robert E. & Bjornstad, Bruce N.
Partner: UNT Libraries Government Documents Department

Tier II Analysis of Vadose Zone Sediments from UPRS 200-E-81 and 200-E-86

Description: The overall goals of the Tank Farm Vadose Zone Project, led by Washington River Protection Solutions, are to define risks from past and future single-shell tank farm activities; identify and evaluate the efficacy of interim measures; and aid, via collection of geochemical information and data, the future decisions that must be made by the U.S. Department of Energy (DOE) regarding the near-term operations, future waste retrieval, and final closure activities for the single-shell tank waste management areas (WMAs). To meet the investigative goals of the Tank Farm Vadose Zone Project, the Environmental Sciences Laboratory performed geochemical analyses on vadose zone sediments collected within Waste Management Area C. Tier one analyses of UPR-200-E-86, which includes direct push probe holes C5952, C5958 and C5960, were performed between 3/25/08 and 4/14/08. Preliminary results were presented to CH2M Hill Hanford Group on 6/5/08. As a result of the tier one investigations, further tier two analyses were requested. Tier two investigations include particle size and mineralogy analyses on samples collected between 80 to 120 feet below ground surface that were found to contain high concentrations of chloride and sulfate. Tier one analyses on sediments retrieved near UPR-200-E-81, direct push probe hole C6394, were performed between 6/20/08 and 7/22/08. Preliminary results of the tier one analyses were presented on 8/15/08. As a result of the tier one investigations, further tier two analyses were requested. Tier two analyses include determining whether U-236 exists in samples at approximately 42 feet below the ground surface. Confirmation of U-236 will determine whether the U-238 seen in the leaches performed on samples at that depth is a result of contamination and not from leaching natural uranium. Using the water and acid extract U-238 concentrations from the tier one analysis, equilibrium Kd values were requested to be calculated. Additional tier two analysis ...
Date: April 1, 2009
Creator: Valenta, Michelle M.; Geiszler, Keith N.; Bjornstad, Bruce N.; Schaef, Herbert T. & Brown, Christopher F.
Partner: UNT Libraries Government Documents Department

A Catalog of Geologic Data for the Hanford Site

Description: This revision of the geologic data catalog incorporates new boreholes drilled after September 2002 as well as other older wells, particularly from the 600 Area, omitted from the earlier catalogs. Additionally, borehole geophysical log data have been added to the catalog. This version of the geologic data catalog now contains 3,519 boreholes and is current with boreholes drilled as of November 2004.
Date: August 1, 2005
Creator: Horton, Duane G.; Last, George V.; Gilmore, Tyler J.; Bjornstad, Bruce N. & Mackley, Rob D.
Partner: UNT Libraries Government Documents Department

Vadose Zone Hydrogeology Data Package for Hanford Assessments

Description: This data package documents the technical basis for selecting physical and geochemical parameters and input values that will be used in vadose zone modeling for Hanford assessments. This work was originally conducted as part of the Characterization of Systems Task of the Groundwater Remediation Project managed by Fluor Hanford, Inc., Richland, Washington, and revised as part of the Characterization of Systems Project managed by the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy, Richland Operations Office (DOE-RL). This data package describes the geologic framework, the physical, hydrologic, and contaminant transport properties of the geologic materials, and deep drainage (i.e., recharge) estimates, and builds on the general framework developed for the initial assessment conducted using the System Assessment Capability (SAC) (Bryce et al. 2002). The general approach for this work was to update and provide incremental improvements over the previous SAC data package completed in 2001. As with the previous SAC data package, much of the data and interpreted information were extracted from existing documents and databases. Every attempt was made to provide traceability to the original source(s) of the data or interpretations.
Date: June 1, 2006
Creator: Last, George V.; Freeman, Eugene J.; Cantrell, Kirk J.; Fayer, Michael J.; Gee, Glendon W.; Nichols, William E. et al.
Partner: UNT Libraries Government Documents Department

Geology of the Waste Treatment Plant Seismic Boreholes

Description: In 2006, the U.S. Department of Energy initiated the Seismic Boreholes Project (SBP) to emplace boreholes at the Waste Treatment Plant (WTP) site in order to obtain direct shear wave velocity (Vs) measurements and other physical property measurements in Columbia River basalt and interbedded sediments of the Ellensburg Formation. The goal was to reduce the uncertainty in the response spectra and seismic design basis, and potentially recover design margin for the WTP. The characterization effort within the deep boreholes included 1) downhole measurements of the velocity properties of the suprabasalt, basalt, and sedimentary interbed sequences, 2) downhole measurements of the density of the subsurface basalt and sediments, and 3) geologic studies to confirm the geometry of the contact between the various basalt and interbedded sediments through examination of retrieved core from the core hole and data collected through geophysical logging of each borehole. This report describes the results of the geologic studies from three mud-rotary boreholes and one cored borehole at the WTP. All four boreholes penetrated the entire Saddle Mountains Basalt and the upper part of the Wanapum Basalt where thick sedimentary interbeds occur between the lava flows. The basalt flows penetrated in Saddle Mountains Basalt included the Umatilla Member, Esquatzel Member, Pomona Member, and the Elephant Mountain Member. The underlying Priest Rapids Member of the Wanapum Basalt also was penetrated. The Ellensburg Formation sediments consist of the Mabton Interbed, the Cold Creek Interbed, the Selah Interbed, and the Rattlesnake Ridge Interbed; the Byron Interbed occurs between two flows of the Priest Rapids Member. The Mabton Interbed marks the contact between the Wanapum and Saddle Mountains Basalts. The thicknesses of the basalts and interbedded sediments were within expected limits. However, a small reverse fault was found in the Pomona Member flow top. This fault has three periods of movement ...
Date: May 11, 2007
Creator: Barnett, D. Brent; Fecht, Karl R.; Reidel, Stephen P.; Bjornstad, Bruce N.; Lanigan, David C. & Rust, Colleen F.
Partner: UNT Libraries Government Documents Department

Geology of the Waste Treatment Plant Seismic Boreholes

Description: In 2006, DOE-ORP initiated the Seismic Boreholes Project (SBP) to emplace boreholes at the Waste Treatment Plant (WTP) site in order to obtain direct Vs measurements and other physical property measurements in Columbia River basalt and interbedded sediments of the Ellensburg Formation. The goal was to reduce the uncertainty in the response spectra and seismic design basis, and potentially recover design margin for the WTP. The characterization effort within the deep boreholes included 1) downhole measurements of the velocity properties of the suprabasalt, basalt, and sedimentary interbed sequences, 2) downhole measurements of the density of the subsurface basalt and sediments, and 3) confirmation of the geometry of the contact between the various basalt and interbedded sediments through examination of retrieved core from the corehole and data collected through geophysical logging of each borehole. This report describes the results of the geologic studies from three mud-rotary boreholes and one cored borehole at the WTP. All four boreholes penetrated the entire Saddle Mountains Basalt and the upper part of the Wanapum Basalt where thick sedimentary interbeds occur between the lava flows. The basalt flows penetrated in Saddle Mountains Basalt included the Umatilla Member, Esquatzel Member, Pomona Member and the Elephant Mountain Member. The underlying Priest Rapids Member of the Wanapum Basalt was also penetrated. The Ellensburg Formation sediments consist of the Mabton Interbed, the Cold Creek Interbed, the Selah Interbed and the Rattlesnake Ridge Interbed; the Byron Interbed occurs between two flows of the Priest Rapids Member. The Mabton Interbed marks the contact between the Wanapum and Saddle Mountains Basalts. The thicknesses of the basalts and interbedded sediments were within expected limits. However, a small reverse fault was found in the Pomona Member flow top. This fault has three periods of movement and less than 15 feet of repeated section. Most of ...
Date: February 28, 2007
Creator: Barnett, D. BRENT; Bjornstad, Bruce N.; Fecht, Karl R.; Lanigan, David C.; Reidel, Steve & Rust, Colleen F.
Partner: UNT Libraries Government Documents Department

Electrical Resistivity Correlation to Vadose Zone Sediment and Pore-Water Composition for the BC Cribs and Trenches Area

Description: This technical report documents the results of geochemical and soil resistivity characterization of sediment obtained from four boreholes drilled in the BC Cribs and Trench area. Vadose zone sediment samples were obtained at a frequency of about every 2.5 ft from approximately 5 ft bgs to borehole total depth. In total, 505 grab samples and 39 six-inch long cores were obtained for characterization. The pore-water chemical composition data, laboratory-scale soil resistivity and other ancillary physical and hydrologic measurements and analyses described in this report are designed to provide a crucial link between direct measurements on sediments and the surface-based electrical-resistivity information obtained via field surveys. A second goal of the sediment characterization was to measure the total and water-leachable concentrations of key contaminants of concern as a function of depth and distance from the footprints of inactive disposal facilities. The total and water-leachable concentrations of key contaminants will be used to update contaminant distribution conceptual models and to provide more data for improving base-line risk predictions and remedial alternative selections. The ERC “ground truthing” exercise for the individual boreholes showed mixed results. In general, the high concentrations of dissolved salts in the pore waters of sediments from C5923, C5924 and C4191 produced a low resistivity “target” in the processed resistivity field surveys, and variability could be seen in the resistivity data that could relate to the variability in pore- water concentrations but the correlations (regression R2 were mediocre ranging from 0.2 to 0.7 at best; where perfect correlation is 1.0). The field-based geophysical data also seemed to suffer from a sort of vertigo, where looking down from the ground surface, the target (e.g., maximum pore-water salt concentration) depth was difficult to resolve. The best correlations between the field electrical resistivity surveys and borehole pore water data sets were obtained when ...
Date: June 1, 2009
Creator: Serne, R. Jeffrey; Ward, Anderson L.; Um, Wooyong; Bjornstad, Bruce N.; Rucker, Dale F.; Lanigan, David C. et al.
Partner: UNT Libraries Government Documents Department

Hydrogeology of the Hanford Site Central Plateau – A Status Report for the 200 West Area

Description: The Remediation Decisions Support (RDS) function of the Soil and Groundwater Remediation Project (managed by CH2M HILL Plateau Remediation Company [CHPRC]) is responsible for facilitating the development of consistent data, parameters, and conceptual models to resolve technical issues and support efforts to estimate contaminant migration and impacts (i.e., the assessment process). In particular, the RDS function is working to update electronic data sources and conceptual models of the geologic framework and associated hydraulic and geochemical parameters to facilitate traceability, transparency, defensibility, and consistency in support of environmental assessments. This report summarizes the efforts conducted by Pacific Northwest National Laboratory (PNNL) scientists in fiscal year 2008 (FY08) that focused primarily on the 200 West Area, as well as a secondary effort initiated on the 200 East Area.
Date: August 27, 2009
Creator: Last, George V.; Thorne, Paul D.; Horner, Jacob A.; Parker, Kyle R.; Bjornstad, Bruce N.; Mackley, Rob D. et al.
Partner: UNT Libraries Government Documents Department

In Situ Redox Manipulation Proof-of-Principle Test at the Fort Lewis Logistics Center: Final Report

Description: Pacific Northwest National Laboratory conducted a proof-of-principle test at the Fort Lewis Logistics Center to determine the feasibility of using the innovative remedial technology In Situ Redox Manipulation (ISRM) to treat groundwater contaminated with dissolved TCE. ISRM creates a permeable treatment zone in the subsurface to remediate redox-sensitive contaminants in groundwater. The permeable treatment zone is created by injecting a chemical reducing agent (sodium dithionite with pH buffers) into the aquifer through a well to chemically reduce the naturally occurring ferric iron in the sediments to ferrous iron. Once the reducing agent has been given sufficient time to react with aquifer sediments, residual chemicals and reaction products are withdrawn through the same well. Redox-sensitive contaminants such as TCE, moving in a dissolved-phase plume through the treatment zone, are destroyed. TCE is degraded via reductive dechlorination within the treatment zone to benign degradation products (acetylene, ehtylene). Analyses of sediment samples collected from post-test boreholes showed a high degree of iron reduction, which confirmed the effectiveness of the treatment zone.
Date: October 25, 2000
Creator: Vermeul, Vincent R.; Williams, Mark D.; Evans, John C.; Szecsody, James E.; Bjornstad, Bruce N. & Liikala, Terry L.
Partner: UNT Libraries Government Documents Department

Cultural Resources Review for Closure of the nonradioactive Dangerous Waste Landfill and Solid Waste Landfill in the 600 Area, Hanford Site, Benton County, Washington, HCRC# 2010-600-018R

Description: The U.S. Department of Energy Richland Operations Office is proposing to close the Nonradioactive Dangerous Waste Landfill (NRDWL) and Solid Waste Landfill (SWL) located in the 600 Area of the Hanford Site. The closure of the NRDWL/SWL entails the construction of an evapotranspiration cover over the landfill. This cover would consist of a 3-foot (1-meter) engineered layer of fine-grained soil, modified with 15 percent by weight pea gravel to form an erosion-resistant topsoil that will sustain native vegetation. The area targeted for silt-loam borrow soil sits in Area C, located in the northern central portion of the Fitzner/Eberhardt Arid Lands Ecology (ALE) Reserve Unit. The pea gravel used for the mixture will be obtained from both off-site commercial sources and an active gravel pit (Pit #6) located just west of the 300 Area of the Hanford Site. Materials for the cover will be transported along Army Loop Road, which runs from Beloit Avenue (near the Rattlesnake Barricade) east-northeast to the NRDWL/SWL, ending at State Route 4. Upgrades to Army Loop Road are necessary to facilitate safe bidirectional hauling traffic. This report documents a cultural resources review of the proposed activity, conducted according to Section 106 of the National Historic Preservation Act of 1966.
Date: February 2, 2011
Creator: Gutzeit, Jennifer L.; Kennedy, Ellen P.; Bjornstad, Bruce N.; Sackschewsky, Michael R.; Sharpe, James J.; DeMaris, Ranae et al.
Partner: UNT Libraries Government Documents Department

Uranium in Hanford Site 300 Area: Extraction Data on Borehole Sediments

Description: In this study, sediments collected from boreholes drilled in 2010 and 2011 as part of a remedial investigation/feasibility study were characterized. The wells, located within or around two process ponds and one process trench waste site, were characterized in terms of total uranium concentration, mobile fraction of uranium, particle size, and moisture content along the borehole depth. In general, the gravel-dominated sediments of the vadose zone Hanford formation in all investigated boreholes had low moisture contents. Based on total uranium content, a total of 48 vadose zone and periodically rewetted zone sediment samples were selected for more detailed characterization, including measuring the concentration of uranium extracted with 8 M nitric acid, and leached using bicarbonate mixed solutions to determine the liable uranium (U(VI)) contents. In addition, water extraction was conducted on 17 selected sediments. Results from the sediment acid and bicarbonate extractions indicated the total concentrations of anthropogenic labile uranium in the sediments varied among the investigated boreholes. The peak uranium concentration (114.84 µg/g, acid extract) in <2-mm size fractions was found in borehole 399 1-55, which was drilled directly in the southwest corner of the North Process Pond. Lower uranium concentrations (~0.3–2.5 µg/g, acid extract) in <2-mm size fractions were found in boreholes 399-1-57, 399-1-58, and 399-1-59, which were drilled either near the Columbia River or inland and upgradient of any waste process ponds or trenches. A general trend of “total” uranium concentrations was observed that increased as the particle size decreased when relating the sediment particle size and acid extractable uranium concentrations in two selected sediment samples. The labile uranium bicarbonate leaching kinetic experiments on three selected sediments indicated a two-step leaching rate: an initial rapid release, followed by a slow continual release of uranium from the sediment. Based on the uranium leaching kinetic results, quasi equilibrium can ...
Date: November 26, 2012
Creator: Wang, Guohui; Serne, R. Jeffrey; Lindberg, Michael J.; Um, Wooyong; Bjornstad, Bruce N.; Williams, Benjamin D. et al.
Partner: UNT Libraries Government Documents Department

Conceptual Models for Migration of Key Groundwater Contaminants Through the Vadose Zone and Into the Upper Unconfined Aquifer Below the B-Complex

Description: The B-Complex contains 3 major crib and trench disposal sites and 3 SST farms that have released nearly 346 mega-liters of waste liquids containing the following high groundwater risk drivers: ~14,000 kg of CN, 29,000 kg of Cr, 12,000 kg of U and 145 Ci of Tc-99. After a thorough review of available vadose zone sediment and pore water, groundwater plume, field gamma logging, field electrical resistivity studies, we developed conceptual models for which facilities have been the significant sources of the contaminants in the groundwater and estimated the masses of these contaminants remaining in the vadose zone and currently present in the groundwater in comparison to the totals released. This allowed us to make mass balance calculations on how consistent our knowledge is on the current deep vadose zone and groundwater distribution of contaminants. Strengths and weaknesses of the conceptual models are discussed as well as implications on future groundwater and deep vadose zone remediation alternatives. Our hypothesized conceptual models attribute the source of all of the cyanide and most of the Tc-99 currently in the groundwater to the BY cribs. The source of the uranium is the BX-102 tank overfill event and the source of most of the chromium is the B-7-A&B and B-8 cribs. Our mass balance estimates suggest that there are much larger masses of U, CN, and Tc remaining in the deep vadose zone within ~20 ft of the water table than is currently in the groundwater plumes below the B-Complex. This hypothesis needs to be carefully considered before future remediation efforts are chosen. The masses of these groundwater risk drivers in the the groundwater plumes have been increasing over the last decade and the groundwater plumes are migrating to the northwest towards the Gable Gap. The groundwater flow rate appears to flucuate in response ...
Date: July 1, 2010
Creator: Serne, R. Jeffrey; Bjornstad, Bruce N.; Keller, Jason M.; Thorne, Paul D.; Lanigan, David C.; Christensen, J. N. et al.
Partner: UNT Libraries Government Documents Department