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Abstract: The concentrations and vertical distribution of 239,240Pu, 241Am and 137Cs in the bottom sediments and water samples of Lake Päijänne were investigated. This lake is important, since the Päijänne area received a significant deposition from the Chernobyl fallout. Furthermore Lake Päijänne is the raw water source for the Helsinki metropolitan area. In addition no previous data on the distribution of plutonium and americium in the sediment profiles of Lake Päijänne exist. Only data covering the surface layer (0–1cm) of the sediments are previously available. In the sediments the average total activities were 45±15Bq/m2 and 20±7Bq/m2 for 239,240Pu and 241Am, respectively. The average 241Am/239,240Pu ratio was 0.45±0.14. The 241Am/239,240Pu ratio is lowest in the surface layer of the sediments and increases as a function of depth. The 238Pu/239,240Pu ratio of the sediment samples varied between 0.012±0.025 and 0.162±0.079, decreasing as a function of depth. The average activity in water was 4.9±0.9mBq/m3 and 4.1±0.2mBq/m3 for 239,240Pu and 241Am, respectively. The 241Am/239,240Pu ratio of water samples was 0.82±0.17. 239,240Pu originating from the Chernobyl fallout calculated from the average total activities covers approximately 1.95±0.01% of the total 239,240Pu activity in the bottom sediments. The average total 137Cs activity of sediment profiles was 100±15kBq/m2 and 19.3±1.4Bq/m3 in water samples. [Copyright &y& Elsevier]

The effect of industrial pollution on the behavior of plutonium and americium was evaluated in a pine forest in the vicinity of a Cu-Ni smelter in SW Finland. Soil and vegetation were sampled at distances of 0.5, 2, 4 and 8 km from the smelter. The vertical distribution of plutonium and americium was studied in litter, organic layer and mineral layers. The amount of Pu and Am in the litter layer increased and that in the organic layer decreased towards the smelter. Concentrations of plutonium and americium in different vegetation species decreased in the order mushrooms > lichens (Cladina spp., Cetraria islandica) > Empetrum nigrum > Vaccinium vitis-idaea. [ABSTRACT FROM AUTHOR]

Following the atmospheric nuclear tests in the '50s and early '60s radioecological research on the (sub)arctic food chain lichen-reindeer/caribou-man was initiated in Finland among other northern countries. The enrichment of radionuclides in this food chain can lead to exceptionally high body burdens among the indigenous Sami and Inuit populations consuming large quantities of the meat and edible organs of reindeer and caribou. In Finland, first fission and activation products and natural radionuclides were studied but in the early 1970s′ the investigations concerning transuranium elements were started. These studies have continued to the present as also the effects of the Chernobyl accident on the existence of neptunium, plutonium, americium and curium isotopes in the environment of northern Finland have been investigated. In addition to radioactivity measurements detailed dietary surveys were performed among the reindeer herders and other Sami persons to assess the human intake of radionuclides by ingestion. The main aim of this literature review is to summarize the obtained data concerning transuranium elements in the food chain lichen-reindeer-man in northern Finland but also some supporting data is included. • Subarctic food chain lichen-reindeer-man concentrates radionuclides efficiently. • Transuranium elements in this food chain has been studied since the early 1970s. • Also detailed dietary surveys were performed to assess the human intake ingestion. • This literature review summarizes the obtained data. [ABSTRACT FROM AUTHOR]