The Chernobyl accident. Transport of radionuclides to man living in northern Sweden.

Abstract

The pathways of 131I, 134Cs and 137Cs from the Chernobyl fallout to man were followed in the county of Västerbotten, Sweden. Reported airplane measurements had shown that the ground deposition of 137Cs was 3-40 kBq/m2 with hot spots with more than 80 kBq/m2. Multiplying with a factor of 0.6 gave the 134Cs deposition and an approximate factor of 20 the 131I ground deposition. The effective dose equivalent from 131I became low, less than 0.1 mSv, as the cows were stabled. The 137Cs activity concentration in different types of food was measured in approximately 8,000 samples. The most important sources of Cs intake in man were lake fish, elk (European moose) and reindeer. Variations with time was studied in detail for four types of lake fish. Whole-body measurements on more than 250 persons showed that no group of people on average received more than 1 mSv from food during the first year after the Chernobyl accident. However, single persons eating large amounts of reindeer meat received up to 2.5 mSv. People buying all their food in ordinary provision-shops got less than 0.1 mSv from the food during the first year. The present level of 90Sr activity concentration in man will only give an effective dose equivalent of 0.004 mSv/year, most of it being a result of the atmospheric nuclear bomb tests.