Deriving probabilistic soil distribution coefficients (K). Part 2: Reducing caesium K uncertainty by accounting for experimental approach and soil properties.

The solid-liquid distribution coefficient (K) is a key input parameter in radioecological models. However, its large variability hampers its usefulness in modelling transport processes as well as its accuracy in representing soil-radionuclide interactions. For the specific case of radiocaesium, the analyses of a Cs K soil dataset (769 entries) showed that values varied over a five order of magnitude range, and the resulting Cs K best estimate (calculated as a geometric mean = 2.

Deriving probabilistic soil distribution coefficients (K). Part 3: Reducing variability of americium K best estimates using soil properties and chemical and geological material analogues.

The solid-liquid distribution coefficient (K) is a key input parameter in radioecological risk models. However, its large variability hampers its usefulness in modelling transport processes as well as its accuracy in representing soil-radionuclide interactions. To assist in the selection of K values and their cumulative distribution functions for study areas without site specific information, a critically reviewed dataset was developed, containing more than 5000 soil K entries for 83 elements and an additional 2000 entries of K data for 75 elements gathered from a selection of other geological materials.

Deriving probabilistic soil distribution coefficients (K). Part 1: General approach to decreasing and describing variability and example using uranium K values.

A general approach is presented to derive probabilistic radionuclide distribution coefficients (K) in soils from a K dataset. The main aim was to derive informed estimates with a low inherent uncertainty by restricting the K value data to subsets based on key soil factors and the experimental approach used to calculate the K value (e.g.

Dependence of samarium-soil interaction on samarium concentration: Implications for environmental risk assessment.

The sorption and desorption behaviour of samarium (Sm), an emerging contaminant, was examined in soil samples at varying Sm concentrations. The obtained sorption and desorption parameters revealed that soil possessed a high Sm retention capacity (sorption was higher than 99% and desorption lower than 2%) at low Sm concentrations, whereas at high Sm concentrations, the sorption-desorption behaviour varied among the soil samples tested. The fractionation of the Sm sorbed in soils, obtained by sequential extractions, allowed to suggest the soil properties (pH and organic matter solubility) and phases (organic matter, carbonates and clay minerals) governing the Sm-soil interaction.