A REVIEW OF RADIONUCLIDES IN TIDE-WASHED PASTURES ON THE IRISH SEA COAST IN ENGLAND AND WALES AND THEIR TRANSFER TO FOOD-PRODUCTS

Close to the Sellafield Reprocessing Plant activity concentrations of many radionuclides including the long-lived Cs-137 and actinides on ti de-washed pastures bordering the Irish Sea are high compared with othe r terrestrial ecosystems in the United Kingdom, Despite the comparativ ely high deposition of radionuclides, contamination of agricultural pr oducts from tide-washed pastures is lower than would be predicted from studies in terrestrial ecosystems. This is because the main source of contamination in tide-washed pasture, radionuclides associated with s edimentary particles, has low availability for uptake by plant roots a nd in the gut of ruminants. Generalised Derived Limits (GDLs), publish ed by the National Radiological Protection Board (NRPB) are estimates of environmental radioactivity concentrations which would potentially be radiologically significant. These provide a benchmark against which environmental measurements can be assessed, In the past, several comp arisons of radioactivity concentrations in tide-washed pastures with G DLs have been made, but only some of these comparisons are valid since current approaches used to assess doses are not always strictly appro priate to these ecosystems. Directly applicable GDLs ave needed, and a re currently being developed by the NRPB. Copyright (C) 1996 Elsevier Science Ltd