A radiochemical displacement method for the determination of micro amounts of Hg (II) has been developed. 65Zn was displaced from the Zn-1- (2 pyridylazo-2-naphthol) complex at pH 5 in borate buffers by Hg (II) . 10-80 μg of mercury could be determined. Interference of various metal ions and methods for suppression have also been carried out.
Iodine-131 concentrations in thyroid glands of cows, oxen and swine carried in the Yokohama slauterhouse were measured. The γ-ray spectral analysis was done with a Ge (Li) detecter. It is considered that131I in thyroid glands of domestic animals resulted from Chinese open-air nuclear tests and radioactive materials used at medical facilities. It is presumed that131I from medical facilities was taken in swine thyroid glands from the leavings of meals of patients.