ATTACHMENT 9 RESEARCH REPORT AD A995149 WRAIR-IS-55 (AFSWP-893) NOVEMBER 1955 RECOVERY OF RADIOACTIVE IODINE AND STRONTIUM FROM HUMAN URINE -- OPERATION TEAPOT (U) James B. Hartgering Ariel G. Schrodt Edward C. Knoblock Alvin G. Burstein Richard D. McIver James E. Roberts LOGO WALTER REED ARMY INSTITUTE OF RESEARCH WALTER REED ARMY MEDICAL CENTER WASHINGTON, DC WALTER REED ARMY INSTITUTE OF RESEARCH Walter Reed Army Medical Center Washington 12, D.C. AFSWP-893 WRAIR-1S-55 November 1955 RECOVERY OF RADIOACTIVE IODINE AND STRONTIUM FROM HUMAN URINE --OPERATION TEAPOT (U) James B. Hartgering Ariel G. Schrodt Edward C. Knoblock Alvin G. Burstein Richard D. McIver James E. Roberts Department of Biophysics Project: 6-59-08-014, Biological and Medical Aspects of Ionizing Radiation Subtask No. 16: World-wide Contamination (Interim Report) NOT FOR PUBLICATION This report may not be reproduced without permission of the Walter Reed Army Institute of Research 1 Report Control Symbol: CSPRD-1 UNCLASSIFIED WRAIR-1S-55 November 1955 Project: 6-59-08-014 Subtask No. 16 RECOVERY OF RADIOACTIVE IODINE AND STRONTIUM FROM HUMAN URINE---OPERATION TEAPOT (U) ABSTRACT During Operation Teapot, 2,137 human urine specimens from a number of United States and foreign military stations were analyzed for iodine-131 and strontium-90 activity. Special processing and counting technics designed to measure low-level activities were utilized. A number of samples were found to contain radioactive iodine and strontium. An attempt was made to correlate urinary iodine activity with weather-yield and physical fallout data. Certain biological aspects of the problem are discussed and compared to theoretical models. 2 UNCLASSIFIED RECOVERY OF RADIOACTIVE IODINE AND STRONTIUM FROM HUMAN URINE -- OPERATION TEAPOT (S) I. Introduction This study was initiated to determine the variation of urinary excretion of certain fission materials by human subjects during the period required for atomic weapons testing at Operation Teapot. Because of the small yields of these particular test weapons, limited positive data were expected. The study was designed to provide base line information for the spring 1956 tests in the Pacific in which the yields are expected to be considerably greater. This report is concerned with the detection of radioactive iodine-131 and strontium-90. Previous experience at weapons tests with urinary excretion of fission materials by human subjects is reported by Cronkite et al. (1), Brennan et al. (2) and Thomas (3). The latter reports deal with individuals up to 8,000 miles from the test site. This report concerns itself primarily with an acute exposure problem as contrasted to the work by Larson (4) and others relating to the concentration of activity by plants and animals and their subsequent ingestion by man. II. Methods The collection process included selection of ten individuals from each of several United States stations, and a minimum of five subjects from each overseas areas. Stations were selected with a view toward reasonable coverage of the United States and a limited sampling throughout the world. To expedite collection and shipment of specimens, the larger military installations were utilized wherever possible. Figures 1 and 2 indicate the location of stations. Operation Teapot Weapons Data are listed in Table A. An attempt was made to utilize, insofar as possible, the same healthy adult male persons for the entire period of the study and to exclude any with a history of thyroid disease or previous known exposure to radioactive materials. Twenty-four-hour urine collections were scheduled to begin at 0800 each Tuesday and to continue at weekly _______________________ (1) Armed Forces Special Weapons Project ITR-923 - May 1954 (Secret). (2) Report of Project 1-M-54 on Thirty Service Men Exposed to Residual Radiation at Operation Castle and Supplement to Project 1-M-54 - July 1954. Brennan et al. (Secret). (3) Analytical Report of Radioactive Substances in Special Urine Samples - C.W. Thomas and D.C. Linton - General Electric Co., Richland, Washington (Confidential) (4) Armed Forces Special Weapons Project WT-612 (Confidential). 1 intervals beginning 25 January 1955. Final collection was made 24 May 1955. Specimens collected prior to 18 February 1955 were to serve as the pre-test controls. All samples were shipped by air to the Army Medical Service Graduate School (former name of Walter Reed Army Institute of Research), Walter Reed Army Medical Center, Washington 12, D.C., for analysis. Table A Shot Data* For Operation Teapot Date Yield F.B.R.** Type Height 18 Feb. 1.2 150 Air drop 755 ft. 22 Feb. 2.5 220 Tower 300 ft. 1 Mar. 7 320 Tower 300 ft. 7 Mar. 43 650 Tower 500 ft. 12 Mar. 3.6 250 Tower 300 ft. 22 Mar. 8.1 340 Tower 500 ft. 23 Mar. 1.2 150 Underground 67 ft. 29 Mar. 15 460 Tower 500 ft. 29 Mar. 3.1 250 Air drop 750 ft. 6 April 3.1 250 Air drop 36,000 ft. 9 April 1.5 200 Tower 300 ft. 15 April 24 560 Tower 200 ft. 5 May 30.0 600 Tower 500 ft. 15 May 30.0 600 Tower 500 ft. 172.5 series total *From ITR-1153, Summary Report of Technical Director, June 1955. **Fire Ball Radius in feet. 2 FOR REFERENCE SEE (6bb01) GRAPHIC 3 Fig. 1 - Map of US Collection Stations FOR REFERENCE SEE (6bb02) GRAPHIC Fig. 2 - Map of Stations For World Collection 4 To supplement the data obtained in examination of the urine samples for iodine, arrangements were made through the Armed Forces Institute of Pathology for collection of human thyroid glands. These glands were removed at the time of routine autopsy at Brooke Army Medical Center and Letterman Army Hospital. Cases of known thyroid disease or those having received isotope materials within the last year of life were to be excluded. Details of extraction and counting procedures for urinary iodine-131 are recorded in detail in Appendix B-1. Details of processing and counting procedures for the thyroid glands are recorded in Appendix B-2. Estimates of the amount of strontium-90 to be encountered were of such a law order of magnitude that it was necessary to combine several 24-hour specimens from a given station for a given week. Usually the specimens were pooled for several weeks. The details of extraction and counting procedures for strontium-90 are recorded in Appendix B-3. III. Results and Discussion Iodine. The complete data from United States stations for the period of the operation are listed in tabular form in Appendix A, Tables 1-17. A total of 2,137 individual specimens were processed. Individual values are recorded for each week and represent activity of a 24-hour urine collection. The disintegrations per minute (dpm) are corrected to time of collection of the sample. It should be noted that samples prior to 22 February are not recorded. These were not included because of possible inadvertent laboratory contamination (See Appendix B-1). However, communication with the New York Operations Office, Atomic Energy Commission, indicated the presence of gross fission material at some of their stations in the weeks prior to 22 February. Further, analysis of data from one reactor (Hanford)* indicated that relatively large amounts of iodine-131 were exhausted from the stacks during this period. The procedures used in this project are of such sensitivity that detectable amount of activity could have been due to reactor effluents. All specimens from foreign stations were essentially negative for iodine-131. However, considering the prolonged time (several half-lives) between collection and receipt of specimens, small amounts of activity originally present would have been undetectable. If one considers individual specimens from a single station on any one collection date, it is apparent that there is a marked variation between individuals. The most active sample may contain more than 10 times the activity of the least active sample. Larger variations occurred at stations close at Camp Mercury and the variation between samples generally diminished as the distance of the collection _______________________ *Health and Safety HW-36506 (Secret-Restricted Data) 5 station from the detonation site increased. Even so, it was not uncommon to find a few samples that differ by a factor of five or six in distant stations. The 24-hour urine showing the highest activity of any specimen assayed was from Camp Mercury, Nevada. The urine contained an iodine activity of 774 dpm corrected to date of collection. Therefore, 3.5 x 10-4 microcuries of iodine-131 were excreted by this individual over the 24-hour collection period. An interesting decay curve was obtained from a Camp Mercury sample which was first assayed 2 days after collection. The curve demonstrated the presence of iodine-133 as well as iodine-131 (Fig. 3). The presence of this very short half-life isotope (23 hours) strongly implicates inhalation as an important route of entry for man. In analyzing the data from stations showing appreciable amounts of activity, certain practical factors were considered. These included an attempt to correlate bomb yield and weather trajectories for a particular detonation with physical fallout measurements as obtained by Eisenbud* and by iodine excretion in the urine. Such correlation of physical and biological factors, combined with known or estimated weather and weapon data, would have obvious operational significance. Presentation of the above-mentioned parameters was facilitated by the construction of Figures 4 through 9. The material incorporated in these figures was obtained in the following manner: a. Iodine activity: Each value in the bar graphs represents the mean dpm for all individual 24-hour samples collected from the specified station on the indicated date. The mean value was selected as represented of the relatively acute environmental exposure and subsequent urinary excretion of iodine for an "average" individual. Variations in activity as noted in Appendix A, Tables 1-17, in general reflect biological factors such as the amount of respiratory exchange for 24 hours (dependent primarily on physical activity) and the several variables influencing uptake of iodine by the thyroid gland. It is assumed that the environmental exposure was the same for all individuals at a single station. b. Cloud trajectory information was obtained from maps drawn for each shot by the U.S. Weather Bureau**. Cloud altitudes are those used most frequently on available Weather Bureau maps. Any given ILLEGIBLE designates the presence of the cloud over the station at specified altitude and date. _________________________ *Physical fallout data obtained from New York Operations Office, Atomic Energy Commission, by Eisenbud and Harley. These data were collected using standardized fly paper technic and represent gross fission product activity exclusive of iodine and other volatile elements. **Cooperation of Dr. A. Machta is gratefully acknowledged. 6 FOR REFERENCE SEE (6bb03) GRAPHIC Fig. 3-Decay Curve Demonstrating The Presence of Both I131 and I133