Effects of High-pH and High-Ionic-Strength Groundwater on Iodide, Pertechnetate, and Selenate Sorption to Hanford Sediments:  Final Report for Subtask 3a

Kaplan, D.I.; Ke, Parker; Orr, R. D.

doi:10.2172/1233

Cited by 18 publications

(32 citation statements)

References 8 publications

(14 reference statements)

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“…Because 99 Tc shows no sorption affinity onto Hanford sediment from both Hanford groundwater and simulated glass leachates, 99 Tc released from the vitrified waste in the proposed low-level radioactive waste disposal facility at the Hanford Site is expected to be highly mobile in both near and far-field regions. This result agrees with previous studies of 99 Tc sorption onto different Hanford sediments that showed essentially no adsorption [21,22].…”

Section: Radionuclide Sorptionsupporting

confidence: 93%

Sorption and transport behavior of radionuclides in the proposed low-level radioactive waste disposal facility at the Hanford site, Washington

Um¹,

Serne²

2005

Radiochimica Acta

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Distribution coefficient / Technetium / Iodine / Selenium / StrontiumSummary. A series of batch sorption and column experiments was conducted to investigate sorption and transport behavior of 99 Tc, 129 I, 79 Se, and 90 Sr on and through borehole sediments collected from the proposed low-level radioactive waste disposal facility at the Hanford Site (200 East Area). Batch sorption experiments were conducted on Hanford sediment using uncontaminated Hanford groundwater and simulated glass leachates spiked with individual radionuclides. Strongest sorption occurred for 90 Sr, while 79 Se sorption was intermediate, and 129 I and 99 Tc showed the least sorption affinities on Hanford sediment among these radionuclides studied. The results of column experiments that measured transport behavior of these radionuclides through Hanford sediment were similar to the mobility that can be calculated from the batch sorption results, that is high mobility for 99 Tc and 129 I compared to the intermediate and strong retardation for 79 Se and 90 Sr, respectively. These contaminant sorption data on sediments from below the proposed disposal facility, especially the tests using simulated glass leachate, corroborate values obtained for sediments collected in the past from near by locations and for generic solutions such as regional groundwater. These new data should provide more technical defensibility for past performance assessment predictions that did not use site-specific sediments and leachates. Further, the new data will be incorporated into future performance assessment activities that will update and improve past predictions.

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Section: Radionuclide Sorptionsupporting

confidence: 93%

Sorption and transport behavior of radionuclides in the proposed low-level radioactive waste disposal facility at the Hanford site, Washington

Um¹,

Serne²

2005

Radiochimica Acta

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“…The tests he reported were almost exclusively designed to measure the extent that radioiodine sorbs under Hanford subsurface conditions and were not designed to understand iodine speciation or sorption mechanisms (Gee and Campbell, 1980;Kaplan et al, 1998b;Kaplan, 1996;Serne et al, 1993;Um et al, 2004). Among the underlying assumptions in each of these laboratory K d measurements was that iodide, I -, is the primarily species in Hanford groundwater and that it sorbs to sediments through the reversible anion exchange process (meaning iodine adsorbs and desorbs at equal rates).…”

Section: Radioiodine Sorption Studies At Hanfordmentioning

confidence: 99%

Biogeochemical Considerations Related To The Remediation Of I-129 Plumes

Kaplan

Yeager

Denham

et al. 2012

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“…While the use of "fingerprinting" at the Hanford Site is still relatively new, it has the potential to provide significant support in defining the current and future risks associated with contamination currently residing in the vadose zone. Nitrate is generally at the front of vadose zone plumes at all sites studied Pb ( No data for A-AX; used T WMA; and IDF Pu ( No data for A-AX; used Kaplan et al (1998aKaplan et al ( , 1998b and expert opinion A.8 Sr in vadose zone; at B-110, there was some mobility for a few tens of meters below tank; at T-106, there was not much movement of 90 Sr below tank bottom; used No data for A-AX so used T WMA; and IDF A.12 No data for A-AX; used Kaplan et al (1998aKaplan et al ( , 1998b No data for A-AX; used , , and expert opinion Nitrate is generally at the front of vadose zone plumes at all sites studied Pb ( No data for B-BX-BY so used T WMA; and IDF ).…”

Section: 2mentioning

confidence: 99%

“…A.17 No data for B-BX-BY Farms; used Kaplan et al (1998aKaplan et al ( , 1998b , , and expert opinion Pb ( No data for B-BX-BY so used T WMA; and IDF Pu ( A.22 No data for B-BX-BY Farms; used Kaplan et al (1998aKaplan et al ( , 1998b values for both impact zones; used 3X increase for silt because Sr adsorption is quite sensitive to surface area , , and expert opinion , and expert opinion and Brown et al (2006) Pb ( No data for C WMA so used T WMA; and IDF A.27 No data for C Farm; used Kaplan et al (1998aKaplan et al ( , 1998b and expert opinion Pb ( Serne et al ( , 2002f, 2004b and IDF Pu ( Evans et al 2002) shows Se fairly mobile but less so than nitrate/ 99 Tc; used Kaplan et al (1998aKaplan et al ( , 1998b and Pb ( Serne et al ( , 2002f and 2004b and IDF A.36 Se not studied at SST WMAs; estimated no sorption in high impact zones, but allowed some sorption in intermediate zones based on Kaplan sorption versus pH work on IDF sediments; used 3X increase for silt SX-108 (Serne et al 2002f, Evans et al 2002 shows Se fairly mobile but less so than Nitrate/ 99 Tc used Kaplan et al (1998aKaplan et al ( , 1998b and Pb ( Pb ( A.45 Used SX-108 and T WMA; Serne et al ( , 2002f, 2004b and IDF A.47 Kaplan et al (1998aKaplan et al ( , 1998b Tc used Kaplan et al (1998aKaplan et al ( , 1998b Kaplan et al (1998aKaplan et al ( , 1998b Sn becomes a risk driver, a more realistic appraisal is warranted because Sn should not be mobile No data for T-TX-TY Farms; used Serne et al (1993) and expert opinion; used silt values for carbonate dominated sediments (assumed some sorption to carbonates) Pb(II) 3 0 10 10 3 100 No data available for these conditions, but Pb is not mobile under alkaline conditions Expert...…”

Section: 2mentioning

confidence: 99%

Geochemical Characterization Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

Cantrell¹,

Brown²,

Serne³

et al. 2008

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• Identify the type, quantity, lateral location, and vertical extent of specific contaminants (e.g., uranium, 99 Tc, 137 Cs, and 60 Co) in the vadose zone sediments• Understand the physical processes that affect the transport of contaminants in the sediments• When practical, identify the source(s) of contamination found in the sediment samples• When practical, determine if a link can be made between the observed vadose zone contamination and any known nearby groundwater contamination.Vadose zone characterization studies have been completed for sediment samples from SST waste management areas (WMAs) A-AX, B-BX-BY, C, S-SX, T, TX-TY, and U. Results of these studies are contained in numerous reports summarized in this data package, and have generated much of the geochemistry data reported in the field investigation reports for Hanford Site SST WMAs. The focus of this data package is to summarize the most current geochemical characterization data (as of December 31, 2007) conducted on vadose zone sediments beneath the SST farms and the Integrated Disposal Facility at the Hanford Site. A review of the empirical K d model, its applicability and limitations for use at the Hanford Site, is also presented as it provides a framework for discussing K d values listed in the summaries of the characterization data for the various SST WMAs.Much has been learned during these initial investigations. Results show that mobile contaminants, such as 99 Tc and nitrate, migrate much differently in the subsurface than previously believed by researchers. Conventional thinking was that after mobile contaminants entered the subsurface, they migrated in a nearly vertical path through the soil column. However, the vadose zone sediment characterization studies indicate that the geologic layering of the vadose zone sediments has an important impact on the direction and rate of migration of the waste liquids and dissolved contaminants. Fine-grained sediment lenses have been shown to cause significant horizontal spreading of leaked fluids within the vadose zone.In the sediment column, the zone of caustic attack, due to the interactions of the sediments with the high pH tank waste, can be determined by measuring the pH of the sediment. Soil pH has therefore become one of the key parameters measured when looking for waste discharge locations in the vadose 1 Resource Conservation and Recovery Act of 1976. 1976. Public Law 94-580, as amended, 90 Stat. 2795, 42 USC 6901 et seq. iv zone. Because tank waste is generally considered caustic (in excess of 1M free hydroxide), it is quite common to find elevated soil pHs (between 8.5 and 10) in the vadose zone adjacent to the point of waste release. However, because natural minerals present in the sediment act to neutralize the elevated pH tank waste, the area exhibiting elevated soil pH is considerably smaller than the footprint that has been impacted by more mobile constituents, such as nitrate or 99 Tc.When waste solutions containing high concentrations of dissolved sodium contact the sediment, sodium...

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Effects of High-pH and High-Ionic-Strength Groundwater on Iodide, Pertechnetate, and Selenate Sorption to Hanford Sediments: Final Report for Subtask 3a

Cited by 18 publications

References 8 publications

Sorption and transport behavior of radionuclides in the proposed low-level radioactive waste disposal facility at the Hanford site, Washington

Sorption and transport behavior of radionuclides in the proposed low-level radioactive waste disposal facility at the Hanford site, Washington

Biogeochemical Considerations Related To The Remediation Of I-129 Plumes

Geochemical Characterization Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

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