Storage and distribution of plutonium, 241Am, 137Cs and 210Pbxs in North Sea sediments

The net storage of the radionuclides Pu-238 (2.8 TBq), (239,) Pu-240 (75 TBq), Cs-137 (730 TBq), Am-241 (40 TBq) and Pb-210(xs) (2700 TBq) in North Sea sediments has been estimated from their concentrations in 40 boxcores. From comparison of Pu-238/Pu-239,Pu-240 ratios between those found in the sediments and those in atmospheric fallout and discharges from the nuclear fuel reprocessing plants at Sellafield (UK) and la Hague (France), it is concluded that the latter is the main supplier of plutonium to the Southern Eight, while the former is dominant in the remainder of the North Sea. About 7% of all Sellafield plutonium discharge is stored in North Sea sediments. The German Eight receives and stores plutonium and fine particulate matter mainly from the Elbe estuary. Of all Cs-137 transported through the North Sea, about 2% is stored in the sediment. Am-241 is scavenged faster than plutonium and is probably transported from Sellafield to the North Sea as Pu-241. (C) 2000 Elsevier Science Ltd. All rights reserved.