Radioactive iodine and cesium in Bavarian citizens after the nuclear reactor accident in Chernobyl

In order to evaluate the radiation risk and to improve the procedure of prognostic estimations of a follow-up study of whole body radioactivity in human beings living in Munich or in an area within 100 km distance from it was initiated after the accident. A total of about 200 persons were examined. After the accident some of them changed their normal diet to avoid excessive intake of radioactivity, some continued their normal way of nutrition. Within 4 weeks following the accident special attention was paid to the measurement of 131I. One week after the accident the mean total body content of 131I was about 300 Bq. Subsequently it decreased with a halftime of 9.2 days. The total body content of 137Cs and 134Cs began to increase significantly 4 weeks after the accident. 14 weeks after the accident a plateau was reached at a level of 14 Bq 137Cs and 7 Bq 134Cs per kg body weight. This plateau was kept until 30 weeks after the accident. A second increase of the Cs radioactivity was observed in January 1987 due to the increasing radioactivity in milk and meat. This is a result of the use of contaminated hay harvested within the period right after the accident as winter feed for cattle. The dose equivalent commitment based on the authors measurements of 137Cs and 134Cs in 1986 ranged from 0.04 to 0.1 mSv