title: Soil-to-plant transfer factors of radioactive Ca, Sm and Pd isotopes: critical assessment of the use of analogies to derive best-estimates from existing non-specific data.
abstract: (45)Ca, (151)Sm and (107)Pd are three radionuclides present in low to intermediate in activity radioactive wastes for which no soil-to-plant Transfer Factors (TF) values are available to be used in biosphere models for Ecological Risk Assessment. In the absence of specific radioecological studies, this work reviews and analyzes the existing literature for stable isotopes of Pd, Sm and Ca in order to derive best estimates for TF values that could be used as Transfer Factors. Alternative methods of extrapolation are also critically assessed. The values have been classified according to climatic zone, plant class and soil type for each element. The overall geometric mean TF values (for all plants and conditions) was calculated as 8.4E-02 for Pd, for which the value of radioRu in TRS-472 is also available. The mean TF for Sm was 4.2E-04. This value was lower than the TF values for radioactive Ce that are proposed as alternative values for Sm in TRS-472. The former may be relevant for long term assessments and the latter could possibly used to describe the short term (151)Sm post-release behaviour. The mean value for Ca is 2.3E-01 but varies considerably among plants of a given class due to the variety of plant Ca uptake behaviors. Alternatively, to limit this variability, Ca data content for dry plant matter, as analyzed using the phylogenetic method, could be used to derive TF values if the conservation of isotopic ratio of (45)Ca to stable Ca in soils and in plants hypothesis is taken into account. The TF for Ca in sub-tropical zones is 10-fold lower than in temperate zones. There is a lot of data available about exchangeable Ca in soil, which mean that we could calculate an available TF. The analysis shows that Ca bioavailability is also a key factor within transfer.
authors: Institute for Radioprotection and Nuclear Safety (IRSN/PRP-ENV/SERIS), Laboratory of Bioavailability, Biogeochemistry and Transfer of Radionuclides (L2BT), Cadarache, Bat. 183, BP 3, 13115 Saint Paul-lez-Durance, France. Electronic address: pascale.henner@irsn.fr.
authors: Pascale
authors: P
authors: Henner
authors: Institute for Radioprotection and Nuclear Safety (IRSN/PRP-ENV/SERIS), Laboratory of Bioavailability, Biogeochemistry and Transfer of Radionuclides (L2BT), Cadarache, Bat. 183, BP 3, 13115 Saint Paul-lez-Durance, France.
authors: Pierre
authors: P
authors: Hurtevent
authors: French Agency for Radioactive Waste Management (Andra), Parc de la Croix Blanche, 1-7, Rue Jean Monnet, 92298 Châtenay-Malabry Cedex, France.
authors: Yves
authors: Y
authors: Thiry
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes / Q000378:metabolism; D008962:Models, Theoretical; D010165:Palladium / Q000378:metabolism*; D010802:Phylogeny; D010944:Plants / Q000378:metabolism*; D011834:Radiation Monitoring; D011850:Radioactive Waste; D011868:Radioisotopes / Q000378:metabolism*; D012493:Samarium / Q000378:metabolism*; D012990:Soil Pollutants, Radioactive / Q000378:metabolism*; D064091:Waste Disposal Facilities
chemical_list: D002132:Calcium Radioisotopes; D011850:Radioactive Waste; D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive; D012493:Samarium; D010165:Palladium; D002118:Calcium
keywords: Calcium; Palladium; Radionuclides; Samarium; Soil-to-plant transfer factor; Use of analogues