Kinetic box models for the uptake of radionuclides and heavy metals by suspended particulate matter: equivalence between models and its implications

Barros, H.; Abril, J.M.

doi:10.1016/j.jenvrad.2007.07.007

Cited by 7 publications

(4 citation statements)

References 18 publications

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“…The kinetics of the uptake will be described by a first-order reversible reaction plus an irreversible and non-saturated one, with constant coefficients k 1,2 , k 2,1 and k 2,3 with values 29, 46 and 0.24 h -1 , respectively, derived from laboratory experiments using 133 Ba as a tracer (Barros et al 2005). The mathematical equivalence between parallel and consecutive reactions has been demonstrated (Barros and Abril 2008); thus, a consecutive scheme was adopted here. Because we limit ourselves to studying the time evolution of concentrations during a 1-month period, year -1 , and an effective diffusion coefficient given by Eq.…”

Section: Evidence Of Non-ideal Deposition (Chernobyl Fallout Radionucmentioning

confidence: 99%

Radiometric dating of recent sediments: beyond the boundary conditions

Abril

Gharbi

2012

J Paleolimnol

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Most mathematical models for radiometric dating of recent sediments are particular solutions of a unique physical problem: the advective-diffusive transport of a particle-bound radiotracer within a sediment profile that undergoes accretion. Regardless of the particular assumptions about fluxes, sedimentation rates and the diffusion term, all models assume ideal deposition as a boundary condition at the sediment water interface, i.e. new radioactive input will be deposited above the previously existing material. In sediments with very high porosities, this assumption may be unrealistic, because a fraction of the incoming flux may penetrate rapidly through the connected pore spaces. This process will be referred to as non-ideal deposition. This paper reviews evidence from literature data, discusses the basic processes involved, and establishes the mathematical basis to incorporate non-ideal deposition into one-phase radiometric dating models, as depth-distributed local sources. Through analytical and numerical solutions, this work demonstrates that such penetration patterns can explain excess 210 Pb subsurface maxima, often observed in sediment cores, as well as penetration of 137 Cs to depths greater than expected from sedimentation rates and diffusion. These ideas are illustrated using examples from the literature in which sediment porosities were [90 %. Implications for radiometric dating include: (1) spurious accelerations in sedimentation rate inferred when applying the constant rate of supply model, and (2) erroneous chronologies, developed when using the maximum depth at which 137 Cs can be measured as a chronostratigraphic marker.

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Section: Evidence Of Non-ideal Deposition (Chernobyl Fallout Radionucmentioning

confidence: 99%

Radiometric dating of recent sediments: beyond the boundary conditions

Abril

Gharbi

2012

J Paleolimnol

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“…Monte et al, 2009;Barros and Abril, 2008), as well as their pathways in the world ocean (e.g. Harms and Karcher, 2003;Karcher et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Long-term simulations of the 137Cs dispersion from the Fukushima accident in the world ocean

Nakano

Povinec

2012

Journal of Environmental Radioactivity

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“…Solid particles have rugose and porous surfaces where uncompensated electric charges and more specific reaction sites are distributed (Eisma, 1993). The uptake of trace elements from the dissolved phase is a kinetic process that can be described by a set of parallel and consecutive reversible reactions, along with some irreversible components (Barros and Abril, 2008).…”

Section: The Physical Environment At the Swi Regionmentioning

confidence: 99%

“…Ba corresponds to the uptake of 133 Ba by suspended estuarine sediments of 20 g l − 1 with an external SSA of 0.010 m 2 g -1 (experimental data from . Co corresponds to the uptake of 60 Co by marine sediments (2 g underlying 20 mL of seawater) with a SSA by the BET method of 13 m 2 g -1 (experimental data from Børretzen and Salbu, 2000, and box model from Barros and Abril, 2008). Pu corresponds to the uptake of 239 Pu by natural aqueous suspension from the Guadalquivir River of 12.6 ppm with external SSA of 1.63 m 2 g -1 (experimental data and box model from El-Mrabet et al, 2001).…”

Section: Uptake Kinetics In a Porous Mediamentioning

confidence: 99%