Radioactivity of People in Finland after the Chernobyl Accident in 1986. Supplement 9 to Annual Report STUK-A55

摘要

After the reactor accident at Chernobyl on April 26, 1986 radioactive fallout was carried by air currents to most parts of Europe. The radioactive air currents reached Finland on April 27. Immediately after the arrival of such air in Finland, contamination of people by radioactive nuclides began via inhalation of this air. The ingestion route become important later, when radionuclides were transported via different foodchains to man. To determine the level of radionuclides in the body and to estimate the internal radiation doses caused by the Chernobyl accident, whole-body counting measurements were performed. The results of whole-body counting of six different groups of Finnish people measured during 1986 after the accident at Chernobyl are reported. Three were reference groups measured routinely once or twice annually, two groups were comprised of workers at nuclear power stations and one group consisted of 262 persons not belonging to any other group. The total number of whole-body counting measurements of persons in these groups in 1986 from the end of April to the end of December was 624. In April and May small amounts of /sup 131/I were detected in the thyroid. In June the first signs of /sup 134/Cs in the body were noticed. At the end of 1986 the mean /sup 134/Cs body burden for women and men in the Helsinki reference group was 730 Bq. The mean /sup 137/Cs body burden in women and men increased from 150 Bq in June to 1500 Bq in December. The differences in the deposition levels in the five fallout regions into which Finland was divided were reflected in the activity levels of the measured people. The weighted annual mean body burden for people in Finland at the end of 1986 was 370 Bq /sup 134/Cs and 820 Bq /sup 137/Cs. The maximum body burdens of /sup 134/Cs and /sup 137/Cs found in Finns in 1986 were 6300 Bq and 13000 Bq, respectively. (ERA citation 13:011557)