Thyroid uptake of iodine-131 and iodine-133 from Chernobyl in the population of southern Sweden.

The accident at the nuclear power plant of Chernobyl on April 26, 1986 led to radioactive contamination of many countries including Sweden. The population was exposed to released radionuclides, both by inhalation and from contaminated food. We have studied the content of gamma-emitting radioisotopes in the thyroid glands of a normal population from southern Sweden using measurements of samples taken at autopsy. The first samples are from a person who died on April 27, 1986. This report contains results for 131I and 133I. The time-activity curve for 131I shows an immediate uptake with a maximum 18-26 days after the accident. No measurable levels were observed after 93 days. We have found that the increase in dose equivalent to the thyroid for the population of southern Sweden due to the released 131I and 133I will be less than 0.1 mSv. This may lead to an increase in the incidence of thyroid cancer of 0.1% during a period of 25 yr.