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 238 Pu, 239+240 Pu and 241 Am 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+240 Pu; 4.5 Bq m −2 for 238 Pu and 37 Bq m −2 for 241 Am. 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.