Mobilization of radiocaesium in pore water of lake sediments

Comans, R.N.J.; Middelburg, Jack J.; Zonderhuis, J.; Woittiez, J. R. W.; Lange, G. J. de; Das, H. A.; Weijden, C. H. Van der

doi:10.1038/339367a0

Cited by 212 publications

(76 citation statements)

References 17 publications

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“…Numerous studies in which uncontaminated sediments were spiked with 137Cs or 134Cs and allowed to equilibrate for several weeks to several months also demonstrate that radiocesium is readily desorbed from sediment particles (e.g., Santschi et al, 1983;Torgersen and Longmore, 1984;Comans et al, 1991). ~37Cs mobility in lacustrine and marine sediments is also supported by pore water measurements which reveal small but significant quantities of dissolved 137Cs (Sholkovitz et al, 1983;Sholkovitz and Mann, 1984;Comans et al, 1989). In addition, sediment depth distributions of 137Cs, 239'24°pu, and 21°pb provide evidence of 137Cs mobility.…”

Section: Episodic Sediment Depositionmentioning

confidence: 68%

“…Comans et al (1989) report an inverse correlation between sediment Ka and ammonium concentration, suggesting that 13VCs is more strongly sorbed in ammonium-free sediments. However, Skan Bay pore waters are rich in ammonium with concentrations in excess of 2 mM at depths that coincide with the 137Cs peak (cf.…”

Section: Episodic Sediment Depositionmentioning

confidence: 99%

“…Given the variety of experimental methods and sediment types involved in these studies, there is remarkably little variability in reported Kd values. Distribution coefficients determined by tracer experiments and pore-water Comans et al (1989) 1For studies that encompass multiple regions, the values in parentheses represent the number of different sites from which sediment was obtained. 2Solid-liquid distribution coefficients (originally reported as mlp ..... ter ml -lsolid) were converted to mlpor~ water g-1solid assuming a solid matter density of 2.3 g ml 1.…”

Section: Episodic Sediment Depositionmentioning

confidence: 99%

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Episodic deposition and 137Cs immobility in Skan Bay sediments: A ten-year 210Pb and 137Cs time series

1994

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Sugai, S.F., Alperin, M.J. and Reeburgh, W.S., 1994. Episodic deposition and 137Cs immobility in Skan Bay sediments: A ten-year 2X°pb and 13~Cs time series. In: M.I. Scranton (Editor), Variability in Anoxic Systems. Mar. Geol., A geochronology time series provides a powerful tool for elucidating sedimentary processes such as episodic deposition and diffusive mobility of particle-reactive constituents. Depth distributions of 21°Pb and 137Cs from Skan Bay, Alaska were determined for sediment cores collected in 1980, 1984, 1987, and 1990. Sediment X-radiographs reveal distinct layers indicating that sediments were not continuously mixed by bioturbation. However, the geochronology time series is inconsistent with an undisturbed, steady-state sediment column. Profiles from 1980Profiles from , 1984Profiles from , and 1990 reveal subsurface regions in which 21°pb activity is relatively constant. In addition, the depth of the primary 137Cs maximum (reflecting the 1963 peak in atmospheric bomb testing) does not increase in a regular fashion between 1980 and 1990. The 21°pb and 137Cs geochronologies can be reconciled by removing the effects of an instantaneous depositional event. The average 2X°pb sedimentation rate (corrected for episodic deposition) in cores that were collected over a ten year period (0.241 +0.006 g cm -2 yr-1) is in excellent agreement with the average 137Cs sedimentation rate (0.258 _+ 0.008 gcm-2 yr-1) calculated from three stratigraphic markers [peak fallout (1963), first appearance in the sediment record (1952), and the Chernobyl accident (1986)]. The mobility of bomb-derived 13VCs under in situ conditions was evaluated by a time-dependent numerical model applied to the 137Cs time series. The model indicates that bomb-derived cesium is immobile in Skan Bay sediments with a solid-liquid distribution coefficient (Kd) of/> 105 (ml g-1).

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Section: Episodic Sediment Depositionmentioning

confidence: 68%

Section: Episodic Sediment Depositionmentioning

confidence: 99%

Section: Episodic Sediment Depositionmentioning

confidence: 99%

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Episodic deposition and 137Cs immobility in Skan Bay sediments: A ten-year 210Pb and 137Cs time series

1994

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“…However, observations on radiocaesium partitioning in anoxic freshwater sediments (Evans et al, 1983;Comans et al, 1989;Comans, 1999;De Koning et al, 2000) and the persistence of radiocaesium in water, fish, and plants after the Chernobyl accident (Jonsson et al, 1999;Smith et al, 1999;Smith et al, 2000), indicate that radiocaesium sorption must remain at least partly reversible.…”

Section: Introductionmentioning

confidence: 99%

Reversibility of radiocaesium sorption on illite

Koning

Comans

2004

Geochimica et Cosmochimica Acta

103

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“…Uptake by illitic clay minerals does not occur by ion exchange but rather by sorption onto frayed edge sites (Cremers et al, 1988;Comans et al, 1989;Smith et al, 1999), which are highly selective for cesium. Although illite has a higher selectivity for cesium, it has a much lower capacity than smectites because cesium cannot enter the interlayer sites.…”

Section: Csmentioning

confidence: 99%

Environmental Geochemistry of Radioactive Contamination

Siegel

Bryan

2003

Treatise on Geochemistry

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This report attempts to describe the geochemical foundations of the behavior of radionuclides in the environment. The information is obtained and applied in three interacting spheres of inquiry and analysis: 1) experimental studies and theoretical calculations, 2) field studies of contaminated and natural analog sites and 3) model predictions of radionuclide behavior in remediation and waste disposal. Analyses of the risks from radioactive contamination require estimation of the rates of release and dispersion of the radionuclides through potential exposure pathways. These processes are controlled by solubility, speciation, sorption, and colloidal transport, which are strong functions of the compositions of the groundwater and geomedia as well as the atomic structure of the radionuclides.The chemistry of the fission products is relatively simple compared to the actinides. Because of their relatively short half-lives, fission products account for a large fraction of the radioactivity in nuclear waste for the first several hundred years but do not represent a long-term hazard in the environment. The chemistry of the longer-lived actinides is complex; however, some trends in their behavior can be described. Actinide elements of a given oxidation state have either similar or systematically varying chemical properties due to similarities in ionic size, coordination number, valence, and electron structure. In dilute aqueous systems at neutral to basic pH, the dominant actinide species are hydroxy-and carbonato-complexes, and the solubility-limiting solid phases are commonly oxides, hydroxides or carbonates. In general, actinide sorption will decrease in the presence of ligands that complex with the radionuclide; sorption of the (IV) species of actinides (Np, Pu, U) is generally greater than of the (V) species.The geochemistry of key radionuclides in three different environments is described in this report. These include: 1) low ionic strength reducing waters from crystalline rocks at nuclear waste research 4 sites in Sweden; 2) oxic water from the J-13 well at Yucca Mountain, Nevada, the site of a proposed repository for high level nuclear waste (HLW) in tuffaceous rocks; and 3) reference brines associated with the Waste Isolation Pilot Plant (WIPP). The transport behaviors of radionuclides associated with the Chernobyl reactor accident and the Oklo Natural Reactor are described. These examples span wide temporal and spatial scales and include the rapid geochemical and physical processes important to nuclear reactor accidents or industrial discharges as well as the slower processes important to the geologic disposal of nuclear waste.Application of geochemical information to remediating or assessing the risk posed by radioactive contamination is the final subject of this report. After radioactive source terms have been removed, large volumes of soil and water with low but potentially hazardous levels of contamination may remain. For poorly-sorbing radionuclides, capture of contaminated water and removal of radi...

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Mobilization of radiocaesium in pore water of lake sediments

Cited by 212 publications

References 17 publications

Episodic deposition and 137Cs immobility in Skan Bay sediments: A ten-year 210Pb and 137Cs time series

Episodic deposition and 137Cs immobility in Skan Bay sediments: A ten-year 210Pb and 137Cs time series

Reversibility of radiocaesium sorption on illite

Environmental Geochemistry of Radioactive Contamination

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