Transfer of Natural Radionuclides in Terrestrial Food Chains—A Review of Investigations in Finland

Transfer of natural radionuclides 210Pb, 210Po, 238U, and 228,230,232Th in subarctic food chains has been studied in Finland since the 1960s. The unique food chain lichen-reindeer-man related to Sami people in Finnish Lapland and other food chain options, from berries or mushrooms to man, have been explored and the activity concentrations of natural radionuclides in biological samples determined. The results from Finnish radioecological studies are summarized and differences in bioaccumulation between different radionuclides are discussed. It was found out that, although a substantial amount of activity concentration data exist from the research projects executed in Finland during the last 6 decades, more data, especially from U and Th, in biological environment and humans would be useful, e.g., for modeling purposes and for improved assessment of bioaccumulation and adverse effects (both radiological and chemical) of radionuclides

Separation method for Pu, Am and Sr in large air filter sample sets

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Measurements and modeling of airborne plutonium in Subarctic Finland between 1965 and 2011

The activity concentrations of Pu-238,Pu-239,Pu-240 and Am-241 (for determining its mother nuclide, Pu-241) as well as activity ratios of Pu-238/Pu239+240, Pu-241/Pu239+240 and Pu239+240/Cs-137 and the mass ratio of Pu-240/Pu-239 were determined from air filter samples collected in Rovaniemi (Finnish Lapland) in 1965 to 2011. The origin of plutonium in surface air was assessed based on these data from long time series. The most important Pu sources in the surface air of Rovaniemi were atmospheric nuclear-weapon testing in the 1950s and 1960s, later nuclear tests in 1973-1980 and the SNAP-9A satellite accident in 1964, whereas the influence from the 1986 Chernobyl accident was only minor. Contrary to the alpha-emitting Pu isotopes, Pu-241 from the Fukushima accident in 2011 was detected in Rovaniemi. Dispersion modeling results with the SILAM (System for Integrated modeLling of Atmospheric composition) model indicate that Pu contamination in northern Finland due to hypothetical reactor accidents would be negligible in the case of a floating reactor in the Shtokman natural gas field and relatively low in the case of an intended nuclear power plant in western Finland.Peer reviewe

241Pu and 241Pu/239+240Pu activity ratio in environmental samples from Finland as evaluated by the ingrowth of 241Am

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Development of 3H, 14C, 41Ca, 55Fe, 63Ni radiochemical analysis methods in activated concrete samples

Development of H-3, C-14, Ca-41, Fe-55 and Ni-63 radiochemical analysis methods were carried out independently by two laboratories using both inactivate and activated concrete samples. Two preliminary radioanalytical procedures for the non-volatile radionuclides (Ca-41, Fe-55, Ni-63) and one Thermal oxidation method for the volatile radionuclides (H-3, C-14) were developed. The difficulties in the method development and analysis of results are discussed.Peer reviewe

Nuclear contamination sources in surface air of Finnish Lapland in 1965–2011 studied by means of 137Cs, 90Sr, and total beta activity

Radionuclides 137Cs and 90Sr and total beta activity were determined from air filters collected in Rovaniemi (Finnish Lapland) in1965–2011. Nuclear contamination sources present in the air filter samples as well as temporal changes in radionuclide concentrations were examined. Ozone observations and meteorological modeling were used in combination with radionuclide analyses to study the reasons behind the observed seasonal concentration variation. In general, the magnitude and variation in activity concentrations of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965–2011 corresponded well with values from other countries. However, the obtained results prove in practice that hardly any refractory or intermediate radionuclides from the destroyed Chernobyl reactor fuel were introduced to Finnish Lapland. The main source of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965–2011 has been intense atmospheric nuclear weapon testing in 1950s–1960s and later tests performed in 1965–1980, as well as leakages from underground nuclear tests in Semipalatinsk, 1966, and Novaya Zemlya, 1987. For 137Cs and total beta activity, the influence of Chernobyl and Fukushima accidents was detected.Peer reviewe