2014:32 Technical Note, Assessment of the derivation and use of distribution coefficients and concentration ratios – Main Review Phase

This report presents a review of the approaches and databases which SKB have used to derive concentration ratios (CRs) and distribution coefficients (Kds) to consider if they are robustly derived and fit for purpose. Credible alternative approaches are also considered. The focus of this review are SKB reports R-10-28 and TR-10-07 which describe the available site specific data and the subsequent derivation of CR and Kd values respectively for application in human assessment.

The method applied by SKB to derive the CR and Kd values are based on a Bayesian approach that combines literature values with in-situ, on site data. Whilst the numbers of site data were often limited the authors have tried to make best use of these data in combination with literature data by using Bayesian updating. This is a relatively novel application of an established statistical approach to radioecology. Similarly, the authors have attempted to make best use of all their site samples by taking into account results below the limits of detection.