MSTRACT: the alpha-radioactive nuclide 210Po is known to be enriched in many components of the marlne biosphere. Particularly high concentrations of 210Po are found in the hepatopancreas of many marine invertebrates, maklng this organ one of the highest known natural radiation dose domains. Concentrations of many other elements in the hepatopancreas have been reported in the literature, and these are summarised and compared with those for 210Po. The enrichment factor concept is used, and a

more »

... e marine biogeochemical classification of the elements results. The enrichment factors for Ag. Cd and Se in the marine hepatopancreas are found to be even higher than that for 210Po; those for Cu. Hg. Sb and Zn are an order of magnitude lower, and those for all other elements for which data are available are at least one order of magnitude lower still. The idea that 2 ' 0~o is closely involved with biological processes in the ocean is given additional support.