The human alimentary tract transfer and body retention of environmental polonium-210

Abstract

This paper presents the results of a 4 year study to investigate the human alimentary tract transfer factor(fA value) andbody retention of 210Po in shellfish. In the first 3 years, mussels (Mytilus edulis L.), cockles (Cerastoderma edule L.)and brown meat from crab (Cancer pagurus L.) were successively studied. In each year fivevolunteers (from a pool of seven) ate a suitable portion of the shellfish and provided 24 hsamples of excreta usually for 3 days before and for at least 7 days during andafter eating. Subsamples of shellfish were analysed to determine the intakes of210Po. Faeces were analysed and the data used to assess apparentfA values. Urine samples were analysed in the mussel and crab studies to provide urinary excretionparameters. Pb-210 was also analysed during the mussel study; the levels were low, leading tolarge uncertainties, but confirming the negligible effect of radioactive decay to its granddaughter210Po in the main study. In the fourth year, larger samples of brown crabmeat were eaten by five volunteers and faecal samples were taken atsuitable times over periods of up to 43 days to study body retention of210Po. The first∼7 days provided additionaldata on fA values. Pooledresults for the apparent fA for the whole study lay in the range 0.15–0.65 with a meanof 0.46; corrections for endogenous excretion suggest a truefA valueof ∼0.51, supporting the value of 0.5 currently used by the International Commission onRadiological Protection (ICRP). The retention data suggest a biological half-time of about40 days, in broad consistency with the 50 days currently used by the ICRP. Thus there isno strong evidence from this study suggesting a change in dose coefficient for210Po. Full experimental data are provided to allow independent further interpretation.