Radioactive Iodine and Cesium in Travellers to Different Parts of Europe After the Chernobyl Accident

Abstract

Thyroid uptake of ¹³¹I was measured in 130 volunteers following the nuclear power plant accident at Chernobyl in April 1986. Ninety of these volunteers had been travelling in different parts of eastern Europe at the time of or immediately after the accident while 40 persons were permanently in Sweden. Also, 28 additional healthy volunteers, living in Sweden, were chosen for a long-term follow-up of the time-course of ¹³⁴Cs and ¹³⁷Cs whole body uptake. The highest levels of ¹³¹I were found in persons having visited Poland (mean value 3.27 kBq±3.68 SD, extrapolated to April 27) while persons that had stayed in other parts of eastern or northern Europe showed significantly lower levels (p<0.01). The whole body burdens of cesium radionuclides were barely detectable immediately after the accident but increased gradually throughout the observed period. After five months nine farmers from a high fallout area in central Sweden had reached mean values of 4.20 kBq (±3.34 SD) of ¹³⁴Cs and ¹³⁷Cs while six non-farmers from the Stockholm area showed significantly lower levels, 0.64 kBq (±0.24 SD, p<0.05). The radiation doses from the observed amounts of iodine and cesium isotopes reported in this study reflect only a marginal addition to the already existing dose from the natural environmental background radiation.