Plutonium and americium inventories in atmospheric fallout and sediment cores from Blelham Tarn, Cumbria (UK)

The objective of this paper is to report on the results of a study of 238Pu, 239+240Pu and 241Am inventories onto Blelham Tarn in Cumbria (UK). The atmospheric fallout inventory was obtained by analysing soil cores and the results are in good agreement with the literature: 101 Bq m−2 for 239+240Pu; 4.5 Bq m−2 for 238Pu and 37 Bq m−2 for 241Am. The sediment core inventory for the whole lake is compared to the atmospheric fallout inventory. The sediment activity is 60–80% higher than the estimated fallout activity, showing a catchment area contribution and in particular the stream input.