I-129, I-131 and I-127 in animal thyroids after the Chernobyl nuclear accident

A small number of animal thyroids from Bad Hall, Austria; Ulm, Germany; and Steinkjer, Norway had I-131 (half-life 8.06 d) measured between 21 and 72 d following the nuclear accident at Chernobyl on 26 April 1986, Nine years later I-129 (half-life 1.57 x 10(7) y) fission product and natural I-127 were measured in the same thyroids, The mass ratios, I-129/I-131 were calculated to the date of the Chernobyl accident and they ranged between 13 and 71, These ratios are compared to the expected ratios within an operating nuclear reactor during 2 y of operation, where the I-129/I-131(-1) ratio never exceeded 30. The observed ratio of I-129 to natural I-127 in thyroids ranged from 5 to 200 times the ratio before the accident, except that the Norwegian thyroids had I-129/I-127(-1) ratios which mere less than the ratios of pre-Chernobyl thyroids from Ulm. These studies show the I-129 and I-131 from the Chernobyl accident were accumulated With natural I-127 in animal thyroids but the isotope ratios, calculated to the release date, had wide ranges. The I-131 radioactive exposure might be estimated from a fission product mixture by measuring I-129 in thyroids long after the exposure to I-131, but the results mould probably show a wide range of possibilities, The determining variables should be evaluated, We know of no previous data regarding both I-131 and I-129 in thyroid glands during the first 3 mo after the Chernobyl accident.