[en] Traces of the Chernobyl fallout are still detectable in Finnish food. The quantities of radioactive cesium have, however, become more lower. All Finnish foodstuffs may be eaten without restrictions. Slightly less than half of the cesium received by Finns comes from fish, wild berries, mushrooms and game account for 30 per cent, agricultural and garden produce for slightly over 20 per cent of the total. The cesium contents of cultivated plants have been very low for some years now. The amounts of cesium in the bodies of Finns have also been decreasing. According to whole-body counting, an average Finn has 700 bequerels of cesium in his body, whereas in 1987 the figure was 2000 bequerels. (orig.)

[en] The deposition of ¹³⁷Cs from Chernobyl was very unevenly distributed. This resulted in big variations in foodstuffs especially those of wild origin. For estimation of internal doses groups of people were studied with whole-body counting techniques. A Helsinki group, deposition 3 kBq.m^-2, was studied from 1965 onwards and groups from Viitasaari, deposition 29 kBq.m^-2, and Aemmansaari, deposition 1.5 kBq.m^-2 were studied from 1987 to 1994. Special items in the diet of people from Viitasaari were local freshwater fish and from Aemmansaari reindeer meat. In spring 1987 the mean body burdens of the Viitasaari (10 kBq) and the Aemmansaari (7.4 kBq) were 4 to 5 times that of the Helsinki group (1.9 kBq). In 1994 only 15% of the maximum mean body burden in the Viitasaari group was found. In the Helsinki and Aemmansaari groups the corresponding percentage was about thirty. The great influence of the consumption of foodstuffs of wild origin was seen. (author)

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[en] Whole-body counter measurements of three different control groups were performed in order to monitor changes in radioactivity levels in Finnish people. The groups were from Helsinki and from the areas around the Loviisa and Olkiluoto nuclear power plants. The Helsinki group was measured with scanning-type, four-crystal, whole-body counter in an iron room, and the Loviisa and Olkiluoto groups with a mobile, shadow-shield, whole-body counter. The mean value of the ¹³⁷Cs/K ratio of the Helsinki control group in 1979 was 26 pCi/g (0.97 Bq/g), the same value as in 1978. The corresponding ratio for the Loviisa group was 25 pCi/g (0.93 Bq/g) as opposed to 30 pCi/g (1.10 Bq/g) in 1978, and for the Olkiluoto group 25 pCi/g (0.93 Bq/g) as opposed to 28 pCi/g (1.04 Bq/g) in 1978. (author)

[en] Some of the quality assurance tasks of whole-body counting are specific to that method of measurement, whereas others are similar to those of gamma spectrometric sample measurements. Quality assurance in whole-body measurement and the associated calculation of internal doses is a complex matter. The uncertainty in the measurement geometry between the radiation source and the detector is unavoidable when measuring humans. Quality assurance includes quality control with procedure and protocol descriptions, detector calibrations, instrument control, documentation of measurement results and evaluation internally or by outside persons. This evaluation also involves regularly repeated comparative measurements. An intercomparison study in the Nordic countries was carried out using a phantom that corresponded to a person weighing 62 kg. The radionuclides used were ⁶⁰Co, ¹³⁷Cs and ⁴⁰K. The phantom was circulated to seventeen laboratories. The results agreed well with the reference values. The results from this project showed that the preparedness for performing body and organ measurements in emergency situations has improved greatly since the Chernobyl reactor accident. (author)

[en] From 1962 to 1977 total body cesium 137 measurements were made of a group of Finnish Lapps, by the Department of Radiochemistry at the University of Helsinki using whole-body counting once or twice annually. At the beginning of 1986 it was decided that the Finnish Centre for Radiation and Nuclear Safety together with the Department of Radiochemistry would make measurements for the same Lapp group after an interval of almost ten years. The measurements were performed on April 5-8, three weeks before the Chernobyl accident, with a total of 88 Lapps participating. The aim was to re-estimate the internal dose from cesium-137 calculated in 1976 for one generation (1955-85) using the actual measured cesium 137 values from 1986. The mean cesium 137 body burden for male reindeer herders from Inari was found to be 5200 Bq and for female reindeer herders 2800 Bq. The body burdens for Lapps from other areas were lower, the mean for all men being 3800 Bq and for all women 2000 Bq. On average the cesium 137 burden in 1986 was 70% of the corresponding body burden in 1976. The inclusion of the results of these measurements in dose calculation did not alter the estimated internal effective dose equivalent of 13 mSv for one generation (1955-1985) of reindeer herding Lapps

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[en] Sludge samples from wastewater treatment plants were studied by the Finnish Centre for Radiation and Nuclear Safety from 1979 onwards. Sampling of sludge was extended to include more sewage treatment plants after the accident at the Chernobyl nuclear power station. The study was continued in some of the wastewater treatment plants in order to continuously follow the level of and changes in the fallout radioactivity. Sludge samples were also taken from treatment plants in communities close to the nuclear power stations at Loviisa and Olkiluoto. For a long time the most frequently detected nuclide in sewage sludge was ¹³⁷Cs originating from Chemobyl. The ¹³⁷Cs activity concentration in sludge varied in 1988 from 68 to 750, in 1989 from 16 to 480 and in 1990 from 11 to 300 Bq kg^-1 dry weight. The activation products in sludge originating from nuclear power stations in Finland were some becquerels per kilo, at the most about twenty becquerels per kilo dry weight. The most frequently detected medical radionuclide was ¹³¹I, frequently detected in almost all wastewater treatment plants

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