Studies of environmental radioactivity in Cumbria

Five stations collecting samples of atmospheric deposition were set up in north Cumbria along a line running inland from the coast for about 17 km. Sampling was continuous from September 1980 to September 1981. Monthly samples were analysed for 106Ru, 137Cs, 144Ce, 238Pu, sup(239,240)Pu, 241Am, 7Be and stable Na, Cl and Al. The objective of the work was to measure the deposition of radionuclides as a function of distance from the sea. By estimating the contributions to the deposition of nuclear weapon test material and of the atmospheric discharges from the British Nuclear Fuels plc works at Sellafield, the effects of the transfer to air and land of radionuclides in the sea could be established. The marine radionuclides were due to the discharges to sea from the Sellafield works. The measurements showed that the deposition was largely due to the sea-to-land transfer process. The highest depositions observed were at 20 m from high water mark, the annual values (rounded, in Bq m-2) being 106Ru, 500; 137Cs, 650; plutonium, 70; 241Am, 30. The highest concentrations in rainwater for the radionuclides studied were less than 3 per cent of the fresh water limits (drinking only) GDL values. The highest estimated accumulations in soil due to atmospheric deposition were less than 1 per cent of the limits. (author)