Radionuclide sorption–desorption pattern in soils from Spain

Diffusion experiments for estimating radiocesium and radiostrontium sorption in unsaturated soils from Spain: Comparison with batch sorption data

“…For most soils, tubes were sampled at increasing diffusion times. As was expected from the fact that 137 Cs showed higher sorption than 85 Sr in the target soils [22], the diffusion times required to obtain changes in the activity concentration profile suitable for deducing D a values were much longer for radiocesium than for radiostrontium.…”

“…As radiocesium presented higher sorption than radiostrontium in the target soils [22], a higher retardation factor was expected for radiocesium and longer diffusion times were required for this radionuclide. Once the diffusion times elapsed, the soils into the tubes were sliced into small sections of 3-5 mm, each slice corresponding to one position in the diffusion tube along the one-dimension diffusion direction.…”

“…Previous data on radiocesium and radiostrontium sorption in the selected soils [22] allowed us to estimate the diffusion times required to obtain changes in the concentration profiles and to correctly derive the diffusion coefficients from the soil packing parameters. As radiocesium presented higher sorption than radiostrontium in the target soils [22], a higher retardation factor was expected for radiocesium and longer diffusion times were required for this radionuclide.…”

“…Here, radionuclide diffusion is also studied at increasing diffusion times to evaluate the existence of interaction dynamics of the target radionuclides in the soils examined. Finally, we compare the K d values calculated from the halfcell method with K d values obtained from batch experiments in a previous study [22], in order to further examine the effect of the methodology on the quantification of the K d and its implications for the risk assessment.…”

New best estimates for radionuclide solid–liquid distribution coefficients in soils, Part 1: radiostrontium and radiocaesium

“…Experimental conditions, such as the composition of the contact solution, contact (shaking) time, volume/mass ratios, and filtration of the resulting solution, often differ among laboratory studies (Benes et al, 1994). As the competitive effect of major ions has been widely described, especially when dealing with specific sorption sites, sorption experiments should be performed that simulate as closely as possible field conditions of interest, for example by reproducing the pH and ionic composition of the soil solution in the sorption medium (Staunton, 2004;Gil-García et al, 2008).…”