Concentrations of 129I and values of the 129I/127I ratio have been measured in over forty individual thyroids of human, cow and deer from Missouri. Deer thyroids show an average value of 129I/127I = 1.8 x 10-8 and 129I concentrations of 3 x 10-3 pCi per g of thyroid (wet weight). Thyroids of cow and human show successively lower values of the 129I/127I ratio and for the 129I content due to dilution of 129I from the natural geochemical cycle with mineral iodine in their diets. Analyses on a few thyroids from other areas are also reported.
(C)1978Health Physics Society