the consumption of one liter of milk per day) would rise to a maximum of 1.6 F, where F=atoms (1-129) /m?, on the first day of contamination. The material available to me indicates that the limiting sensitivity of neutron activation analysis is 10"? gram of iodine 129.73, This is equivalent to approximately 5x10° atoms. Using the relationship between iodine 131 and iodine 129 given by Dr. Mays, and the above factors, the following conversions can be derived (assuming one liter of milk consumed per day): Infant Thyroids 3x 108 atoms (1-129) gram of thyroid Adult Thyroids 5x 10® atoms (1-129) gram of thyroid = 0.8 rad to children’s thyroids from iodine 131; = 8.0 rad to children’s thyroids from iodine 131. Data presented by Eisenbud‘ suggest that, on the average, adults consume only one third as much milk per day as children. This would suggest that 5x 10° atoms (1-129)/gram of adult thyroid = 24 rad to childen’s thyroids from iodine 131. Following Shot Nancy of the Upshot-Knothole Series we estimated that children received 30 rad. This would suggest that neutron activation analysis is sufficiently sensitive, at least for this test, even with small tissue specimens. Actually, by pooling the tissue samples, it would be adequate for many othertests. For example, 5x10*® atoms (I-129) /100 gram of adult thyroid=0.24 rad to children’s thyroids from iodine 131 (assuming only one third liter of milk consumed per day for adults). REFERENCES 1. Tamplin, A. R. and H. L. Fisher. “Estimation of dosage to thyroids of children in the U. S. from nuclear tests conducted in Nevada during 1952 through 1955.” University of California Lawrence Radiation Laboratory (Livermore), UCRL-14707, 1966. 2. Nuclear Science and Engineering Corporation. “Survey of iodine-129 concentrations in thyroid tissues.” Progress report. Nuclear Science and Engineering Corporation, Pittsburgh, NSEC-88, 1963. 3. Studier, M. H., C. Postmus, Jr., J. Mech, R. R. Walters, and E. N. Sloth. “A generalized procedure for the isolation of iodine without carrier~Its determination by neutron activation using I'2% as an isotopic tracer.” Argonne National Laboratory, ANL-6577, 1962. 4. Eisenbud, M., B. Pasternack, G. Laurer, Y. Mochizuki, M. E. Wrenn, L. Block, and R. Mowafy. “Estimation of the distribution of thyroid doses in a population exposed to 13! from weapons tests. ” In Fallout, Radiation Stand- ards, and Countermeasures, Hearings before the subcom- mittee on research, development, and radiation of the Joint Committee on Atomic Energy, 88th Cong., Ist Sess., 1963. Washington, D. C., U. S. Govt. Print. Off, 1963, Pt. 2, pp. 1158-1172 or Health Phys. 9: 1281-1289, 1963. REVIEW NEW RADIOIODI ESTIMATION OF DOSAGE TO THYROIDS OF CHIL DREN IN THE U.S. FROM NUCLEAR TESTS CON DUCTED IN NEVADA DURING 1952 THROUGH 1955 By Arthur R. Tamplin and H. Leonard Fisher. Lawrence: Radiation Laboratory, University of California, Livermore Bio-Medical Research Divison, May 10, 1966. UCRL-14707 WO SCIENTISTS in the Bio-Medical Research Divi sion of the University of California’s Lawrence: Radiation Laboratory at Livermore have published a1 important piece of work estimating radiation dosag to the thyroids of children exposed to iodine 131 fall out in the early years of testing. The report by Arthur R. Tamplin and H. Leonar: Fisher represents a significant refinement of previou estimates, and substantiates the earlier conclusion b CNI, Charles Mays and Harold Knapp that man children received doses ranging from a few rads up t more than a hundred rads (S/C, August and Novembe 1963 and the Joint Committee on Atomic Energy Heai ings of the same year). While previous studies focuse ESTIMATED DOSES OF IODINE 131 to the thyroids « children from nuclear testing at the Nevada Test Site, 195 1955. The numbers give estimated doses at various locatior throughout the United States, and the shaded portions ind cate areas where the dosage is estimated at 10 rads® or mor SAMPLING STATIONS Boise, Idaho Pocatello, Idaho Cheyenne, Wyoming Rock Springs, Wyoming St. George, Utah Salt Lake City, Utah Flagstaff, Arizona Albuquerque, New Mexico Roswell, New Mexico Denver, Colorado Grand Junction, Colorado Scottsbluff, Nebraska Concordia, Kansas Goodland, Kansas Amarillo, Texas Dallas, Texas Fort Smith, Arkansas Des Moines, Iowa Memphis, Tennessee Milwaukee, Wisconsin Grand Rapids, Michigan Cleveland, Ohio Buffalo, New York New York, New York Boston, Massachusetts New Haven, Connecticut *A rad is the basic unit for measuring the absorbed dose of iomz radiation per gram of matter. It is the amount of energy imparted matter per unit mass of material. DOE ARCHIVES Scientist and Citiz