Deposition from the Chernobyl accident to Finland and especially Chernobyl-derived transuranium elements Np, Pu, Am and Cm have been studied ever since 1986 (Jantunen et al. 1993, Paatero et al. 1994 & 1998, etc.) and their geographical distribution in peat in Finland has been determined. All investigated transuranium elements have similar deposition pattern, having inhomogeneous distribution over Finland and the high-deposition area reaches from Uusikaupunki to Kuhmo, a belt from southwest to northeast across Finland.
Decomposition and separation methods have been developed for determining heavy metals (Zn, As, V, Cu, Co, Ni, U, Pb, and Cr) and radionuclides 90Sr, 238,239,240Pu and 241Am from archived human samples. Heavy metals have been determined with ICP-AES and radionuclides with liquid scintillation counting (90Sr) and alpha spectrometry (238,239,240Pu and 241Am) from lungs, bones, livers and lymph nodes. The ultimate goal of this study is to compare different heavy metals and radionuclides in relation to their concentrations in different organs and furthermore estimate possible enrichment from food chains and inhalation to man.
The amount and source of man-made radionuclides 137Cs, 90Sr, 238,239,240,241Pu and 241Am in Finnish arctic environment has been studied in archived long-term sample series. Isotope ratios of these anthropogenic radionuclides can act as “fingerprints” pointing out the contamination source: nuclear weapons testing, the Chernobyl accident, nuclear weapons-grade material, nuclear fuel enrichment, etc. Two main man-made radionuclide sources occur in Finnish environment: global fallout from atmospheric nuclear weapons testing in 1950-1960-decades and the Chernobyl accident in 1986.
Concentrations of 137Cs, 90Sr, 238,239,240,241Pu and 241Am have been determined in surface air of Sodankylä in 1963, and Rovaniemi in 1965-2011, to view changing levels and origin of these environmental contaminants in Finnish arctic.
Also lichen samples from different decades have been used for indicating radioactive contamination or non-contamination from the Chernobyl accident in Lapland. It has been found out in analysis of lichens and air filters that emissions during first days of Chernobyl reactor fire containing for example 137Cs reached Finnish Lapland, but emissions from later days containing heavier elements, like Pu and Am, did not range to Finnish Lapland. We have also studied accumulation and migration of the plutonium isotope 238Pu that was released from SNAP-9A (System for Nuclear Auxiliary Power) satellite failure over Mozambique in April 1964, in lichens of Lapland as a function of time.
Rapid-Tech project started in 2014 and during the first year, effective and rapid methods for determining Sr and actinides were summarized among Nordic countries (see NKS-336 report). The project continued as an inter-comparison exercise in 2015, and then the Radioecology group joined to Rapid-Tech. 90Sr and Pu isotopes were analyzed from reference materials and benefit of utilizing some novel techniques during radioanalytical separation procedure was evaluated.
An inter-comparison exercise of ICP techniques was organized among Nordic laboratories working in the fields of nuclear and radiochemistry in 2016. The purpose of the exercise was to explore and compare performances of different ICP instrumentations in determination of uranium and plutonium isotopes. Different instrumentations (Q-ICP-MS, SF-ICP-MS, MC-ICP-MS, and ICP-QQQ combined with different sample introduction systems), different using habits and different calculation and calibration methods produced a general overview of instrumental capacities in determination of uranium and plutonium isotopes among Nordic countries.
After inter-comparison, "ICP User"-seminar was held in Risö-DTU, Denmark, 25-27 September 2017 gathering experts, students and researchers together for networking and exchanging experiences in ICP MS techniques.