Hanford Site Groundwater Monitoring for Fiscal Year 2005

Hartman, Mary J.; Morasch, Launa F.; Webber, William D.

doi:10.2172/889070

Cited by 78 publications

(97 citation statements)

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“…A similar linear adsorption isotherm was found for U(VI) adsorption onto coarse-grained Hanford formation sediments using two simulated 300 Area groundwaters (pH ranged from 7.5 to 8) and a solid-to-solution ratio of 100 g/L up to a U(VI) solution concentration of 3,000 μg/L (Serne et al 2002). In addition, because a linear isotherm was found to be valid up to 5 x 10 -6 M (~1 mg/L) of U(VI) initial concentration, and the existing groundwater plume contains dissolved U(VI) concentrations below 1 mg/L (Hartman et al 2005), a linear K d model can be applied to predict U(VI) transport in the 200-UP-1 groundwater condition. This statement should not be interpreted as meaning that the U(VI) K d value is constant if the groundwater chemical composition changes with space and time.…”

Section: U(vi) Adsorption K D S With Varying Dissolved Uranium Concenmentioning

confidence: 92%

Characterization of 200-UP-1 Aquifer Sediments and Results of Sorption-Desorption Tests Using Spiked Uncontaminated Groundwater

Um¹,

Serne²,

Bjornstad³

et al. 2005

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Se-79, and Np-237 during FY 2005. The study completed and summarized in this report will help determine the current risk of the groundwater plume and aid in choosing remediation alternatives for the COC in 200-UP-1 subsurface environments should remediation be necessary.Sediment characterization showed only 4 out of 13 core liner samples were intact, and the others were slough material that dropped to the bottom of the borehole before the split-spoon sampling. The intact samples showed typical Ringold Unit E characteristics such as being dominated by gravel and sand. Moderately reducing conditions are inferred in some core from borehole C4299. This reducing condition was likely caused by the hard tool process used to drill the wells. One core liner from C4299 (B19140) showed significant presence of ferric iron oxide/clay coatings on the gravel surfaces. The 200-UP-1 sediments do contain some clay minerals that exhibit significant cation exchange capacity and thus should be good adsorbents of cationic contaminants. This is especially true of the Ringold Lower mud sample, B19377, from borehole C4300. No highly contaminated sediments-including uranium-were found in the cores from the three new boreholes in the 200-UP-1 operable unit. The presence of slough and "flour" caused by hard tooling is a serious challenge to obtaining field-representative sediments for use in geochemical experiments to determine the adsorption-desorption tendencies of redox sensitive elements such as uranium.The adsorption of COC on intact Ringold Formation sediments and Fe/clay coatings showed that most of the anionic contaminants [Tc(VII), Se(VI), U(VI), Cr(VI), and I(-I)] did not adsorb well compared to cationic [Np(V), Sr(II), and Cs(I)] radionuclides. The high hydrous iron oxide content in Fe oxide/clay coatings caused the highest K d values for U and Np, suggesting that these hydrous iron oxides are the key solid adsorbent in the sediments that control the fate of U and Np. Enhanced adsorption behavior for Tc and Cr, and perhaps Se, on the composite B19136 and B19137 sediment was considered an "artifact" caused by the induced reducing conditions from the hard tool drilling.Additional U(VI) adsorption K d studies were performed on Ringold Formation sediments subjected to varying solution geochemical conditions such as varying the dissolved U and total bicarbonate/carbonate concentration in the groundwater to develop a more robust data base of U(VI) K d s. The <2 mm size fraction of three 200-UP-1 sediments showed a linear U (VI) adsorption isotherm up to 1 ppm of total U (VI) concentration in solution. This fact validates the use of a linear adsorption isotherm (K d ) to predict U (VI) adsorption for sediments in the 200-UP-1 groundwater plume. However, this is not the same as stating that the U (VI) K d value will be constant if the groundwater chemical composition at 200-UP-1 changes with space or time.iv The additional U (VI) K d s obtained from varying carbonate concentrations in solution indicated that U (VI) adsorption was stro...

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Section: U(vi) Adsorption K D S With Varying Dissolved Uranium Concenmentioning

confidence: 92%

Characterization of 200-UP-1 Aquifer Sediments and Results of Sorption-Desorption Tests Using Spiked Uncontaminated Groundwater

Um¹,

Serne²,

Bjornstad³

et al. 2005

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“…The 100-NR-2 OU contains the contaminated groundwater and aquifer. Hartman et al (2007) described remediation activities in the 100-N Area related to the groundwater contamination which are summarized below. As part of the source waste site remediation, contaminated soil was removed from 116-N-1 LWDF (see …”

Section: Introductionmentioning

confidence: 99%

Interim Report: 100-NR-2 Apatite Treatability Test: Low Concentration Calcium Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization

Williams¹,

Fritz²,

Mendoza³

et al. 2008

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SummaryEfforts to reduce the flux of strontium-90 ( 90 Sr) to the Columbia River from past-practice liquid waste disposal sites have been underway since the early 1990s in the 100-N Area at the Hanford Site. Termination of all liquid discharges to the ground in 1993 was a major step toward meeting this goal. However, 90 Sr adsorbed on aquifer solids beneath the liquid waste disposal sites and extending beneath the near-shore riverbed remains a continuing source to groundwater and the Columbia River. Researchers realized from the onset that the initial pump-and-treat system was unlikely to be an effective long-term solution because of the geochemical characteristics of 90 Sr; subsequent performance monitoring has substantiated this theory. Accordingly, the first Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) 5-year review re-emphasized the need to pursue alternative methods to reduce impacts on the Columbia River. 1Following an evaluation of potential 90 Sr treatment technologies and their applicability under 100-NR-2 hydrogeologic conditions, U.S. Department of Energy, Fluor Hanford, Inc. (FH), Pacific Northwest National Laboratory, and the Washington State Department of Ecology agreed the long-term strategy for groundwater remediation at the 100-N Area will include apatite sequestration as the primary treatment, followed by a secondary treatment⎯or polishing step⎯if necessary (most likely phytoremediation). Since then, the agencies have worked together to agree on which apatite-sequestration technology has the greatest chance of reducing 90 Sr flux to the Columbia River at a reasonable cost. In July 2005, aqueous injection, (i.e., the introduction of apatite-forming chemicals into the subsurface) was endorsed as the interim remedy and selected for field testing. Studies are in progress to assess the efficacy of in situ apatite formation by aqueous solution injection to address both the vadose zone and the shallow aquifer along the 91 m (300 ft) of shoreline where 90 Sr concentrations are highest. This report describes the field testing of the shallow aquifer treatment that was funded by FH.A low-concentration, apatite-forming solution was injected into the shallow aquifer in 10 injection wells during fiscal years 2006 and 2007, and performance monitoring is underway. The lowconcentration, apatite-forming solution consists primarily of calcium chloride, trisodium citrate, and sodium phosphate. The objective of the low-concentration Ca-citrate-PO 4 injections is to stabilize the 90 Sr in the aquifer at the test site, to be followed by high-concentration injections to provide for long-term 90 Sr treatment. Two pilot test sites at the east and west ends of the barrier, which are equipped with extensive monitoring well networks, were used for the initial injections to develop the injection design for the remaining portions of the barrier. Based on a comparison of hydraulic and transport response data at the two pilot test sites, it was determined the apparent permeability ...

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“…In addition to the 3D depth-discrete concentration data, the database was supplemented by including the 2D data sets used to map the COIs in the FY 2007 Hanford Site groundwater monitoring report (Hartman and Webber 2008). The use of the supplemental 2D data sets follows the approach used by Murray et al (2007), where the 2D data are used to provide additional constraints on the concentrations present near the water table and as supplemental data used for variogram analysis when sufficient data were not available to define the horizontal variogram.…”

Section: Data Sources and Documentationmentioning

confidence: 99%

“…A numerical grid of the elevation of the water table was created by P. Thorne (PNNL) in EarthVision (P. D. Thorne, PNNL, personal communication, 2008) with data supplied by J. McDonald (CHPRC) that had been used to contour the groundwater surface for the FY 2007 groundwater monitoring report (Hartman and Webber 2008). The elevation data were back-interpolated by M. Tonkin (SSPA) to provide estimates of the water table elevation for most wells in the database, and that table of water level elevations was imported into the Access database.…”

Section: Calculation Of the Depth Below The Water Tablementioning

confidence: 99%

“…The depthdiscrete data for each COI were converted to normal scores (Goovaerts 1997), and experimental variograms were calculated in three dimensions. Horizontal (2D) variograms also were calculated for the normal scores of the CTET, chloroform, and Tc-99 data sets compiled for the FY 2007 annual groundwater report (Hartman and Webber 2008). Those data sets employ the standard algorithm of selecting the most recent annual average for the period from FY 2005 through FY 2007 for which data are available.…”

Section: Geostatistical Mapping Of Coi Datamentioning

confidence: 99%

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Spatial Analysis of Contaminants in 200 West Area Groundwater in Support of the 200-ZP-1 Operable Unit Pre-Conceptual Remedy Design

Murray¹,

Bott²

2008

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SummaryThis report documents a preliminary spatial and geostatistical analysis of the distribution of several contaminants of interest (COIs) in groundwater within the unconfined aquifer beneath the 200 West Area of the Hanford Site. The contaminant plumes of interest extend within the 200-ZP-1 and 200-UP-1 groundwater operable units. CH2M HILL Plateau Remediation Company (CHPRC) currently is preparing a plan that identifies locations for groundwater extraction wells, injection wells, transfer stations, and one or more treatment facilities to address the contaminants of concern identified in the 200-ZP-1 CERCLA Record of Decision. To accomplish this, Fluor Hanford, Inc. (the previous site contractor) requested that Pacific Northwest National Laboratory (PNNL) provide numerical models of the three-dimensional distribution of selected COIs throughout the 200 West Area groundwater. The COIs included in the PNNL study were carbon tetrachloride (CTET), technetium-99 (Tc-99), iodine-129 (I-129), chloroform, plutonium, uranium, trichloroethylene (TCE), and nitrate.The project included three tasks. Task 1 involved the development of a database that includes all relevant depth-discrete data on the distribution of COIs in the study area. The database includes well construction information, well sample data for the COIs named above, fields describing the sources of the data, and data quality flags. The database includes all forms of the COIs identified above-for example, all plutonium and uranium isotopes included in the Hanford Environmental Information System, as well as total uranium and all forms of nitrate and chromium. The concentration and activity values summarized in the resulting tables of the Microsoft Access database are considered final for carbon tetrachloride, chloroform, and Tc-99 and were used in the subsequent analysis and mapping (Tasks 2 and 3). However, further work will be needed to transform and select concentrations for some of the other COIs when multiple forms of a COI are present in the database (e.g., chromium, nitrate, and uranium are present in multiple forms). In addition, some uranium and uranium-238 data in the database are measured in picocuries per liter and will need to be converted to micrograms per liter. The appendix to this report contains several electronic files that document in detail the data sources, transformations, and selections that were performed in assembling the database, as well as a copy of the database itself.The second task involved a spatial analysis of the three-dimensional (3D) distribution of data for the COIs in the study area. The main focus of the task was to determine if sufficient data are available for geostatistical mapping of the COIs in 3D. The results of that study indicate that sufficient data are available for 3D mapping of CTET, chloroform, and Tc-99 using geostatistical methods. Although the conclusions are preliminary, the number of data that appear to be available for the other COIs is much lower; geostatistical mapping of those COIs in 3D may not ...

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Hanford Site Groundwater Monitoring for Fiscal Year 2005

Cited by 78 publications

References 0 publications

Characterization of 200-UP-1 Aquifer Sediments and Results of Sorption-Desorption Tests Using Spiked Uncontaminated Groundwater

Characterization of 200-UP-1 Aquifer Sediments and Results of Sorption-Desorption Tests Using Spiked Uncontaminated Groundwater

Interim Report: 100-NR-2 Apatite Treatability Test: Low Concentration Calcium Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization

Spatial Analysis of Contaminants in 200 West Area Groundwater in Support of the 200-ZP-1 Operable Unit Pre-Conceptual Remedy Design

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