Investigation of radioactivity concentration of 137Cs, 90Sr and 129I radioisotopes in thyroid samples

In this study, the gross alpha and beta activities and ¹³⁷Cs, ⁹⁰Sr and ¹²⁹I radionuclide concentrations in the feeds and thyroid samples obtained from a certain number of sheep, which were fed by Fırat University (Elazığ) Faculty of Veterinary Medicine with varying amounts of fresh lucerne, fodder, silage, straw and concentrate feed were determined. The ¹³⁷Cs, ⁹⁰Sr and ¹²⁹I radionuclide transfer coefficients were also determined. ⁹⁰Sr and ¹²⁹I are beta-emitting radionuclides. Sheep with high ⁹⁰Sr and ¹²⁹I radionuclide concentrations also have high gross beta radioactivity levels. When an intragroup comparison is performed, the radionuclide concentration in a sheep fed with maximum feed is at the highest level and vice versa. Moreover, the ¹³⁷Cs, ⁹⁰Sr and ¹²⁹I radionuclide transfer coefficients (F_f) for the thyroid samples obtained from the sheep vary between 0.4 × 10^-1 - 8.1 × 10^-1 d kg^-1, 0.4 × 10^-2 - 6.1 × 10^-1 d kg^-1 and 0.4 × 10^-1 - 7.3 × 10^-1 d kg^-1, respectively, and are higher than the expected F_f values and the results obtained in similar studies. The F_f values calculated for the thyroid samples of the straw and fodder group are lower than the F_f values calculated for the thyroid samples of the silage and fresh lucerne group. The radionuclide concentrations for ¹²⁹I were found to be higher than ⁹⁰Sr's in the thyroid samples.