Derivation of allometric relationships for radionuclides in marine phyla

¹ Westlakes Scientific Consulting Ltd., The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, CA24 3LN Cumbria, UK
² Nuclear Decommissioning Authority, Herdus House, Westlakes Science and Technology Park, Moor Row, CA24 3HU Cumbria, UK

Corresponding author: jordi.vives@westlakes.ac.uk

Abstract

An allometric scaling approach has been used to calculate biological half-lives of elimination (T_B1/2) and concentration factors (CF) for radionuclides in marine biota. Power functions of organism mass are fitted to a biokinetic database for plankton, seaweed, fish, crustaceans and molluscs, using data generated by us, in combination with reviewed data. Scaling of the CF to M^{-0.26 ± 0.09} is observed, compatible at ±1σ with metabolic theory predictions that metabolism scales to M^0.75. We also observe scaling of T_B1/2 to M^{+0.16 ± 0.03}, within the previously reported range +0.15 to +0.30 for biota from various environments and, at < ± 3σ, slightly outside turnover rate scaling predictions to M^-0.25. The elements for which the CF scales better allometrically are particle seeking, mainly lanthanides and actinides. Association of the independent term of the allometric power function a with the sediment-water partition coefficient K_d is strongest for these elements, possibly through binding to biological/organic matter. The findings from this study are relevant to extend the range of applicability of our biota dose assessment methodologies where data gaps in transfer exist.