GLOSSARY * tuila, Rarotonga, Wake Island, Kwajalein Atoll, Tongatabu and Viti Levu were operated by Task Force Project Groups or Hawaii to support the off-site rad-safe program. Facilities, equipment and personnel were available for radiochemical analysis of air, precipitation, water, milk, food and soil. The facility remains in operation as a part of a continuing pro- gram of monitoring several of the Hawaiian Islands. Bioenvironmental Monitoring The bioenvironmental program for Operation Dominic was under AEC contract with the University of Washington, Seattle, Wash. A final report of their data is found in “Radionuclide Content of Foodstuffs Collected at Christmas Island and at Other Islands of the Central Pacific During Operation Dominic, 1962,” UWFL-87, by Ralph Palumbo. . During the period April 7 to July 29, 1962, collections of foodstuffs, marine life included, were made from eight off-site islands and Christmas Island to ascertain the radionuclide content of the samples collected. In addition to samples collected by this group, USPHS off-site monitors furnished samples from areas not covered by the University of Washington scientists. Approximately 8,000 samples were collected during the time which covered pre-testing, testing and post-testing periods. Part of these samples were scanned promptly for radioactive content, however, a majority of the samples were returned to the University of Washington for complete analysis. BACKGROUND RADIATION: Nuclear (or ionizing) radiations arising from within the body and from the surroundings to which individuals are always exposed. The main sources of the natural background radiation are potasa ee a ee ge Weather Groups and on Nuku Hiva and Tahiti by French personnel. The purpose of the background stations was to document external radiation background and changes in background levels if they occurred. A USPHS rad-chem laboratory was established in Honolulu, sium 40 in the body, potassium 40 and thorium, uranium, and their decay products (including radium) present in rocks, and cosmic rays. BETA PARTICLE: A charged particle of very small mass emitted spontaneously from the nuclei of certain radioactive elements. Most (if not all) of the direct fission products emit (negative) beta particles. Physically, the beta particle is identical with an electron moving at high velocity. BIOLOGICAL HALF-TIME: The time required for the amount of a specified element which has entered the body (or a particular organ) to be decreased to half of its initial value as a result of natural, biological elimination processes. DOSE: A (total or accumulated) quantity of ionizing (or nuclear) radiation. The term dose is often used in the sense of the exposure dose, expressed in roentgens, which is a measure of the total amount of ionization that the quantity of radiation could produce in air. This should be distinguished from the absorbed dose, given in reps or rads, which represents the energy absorbed from the radiation per gram of specified body tissue. Further, the biological dose, in rems, is a measure of the biological effectiveness of the radiation exposure. DOSE RATE: As a general rule, the amount of ionizing (or nuclear) radiation to which an individual would be exposed or which he would receive per unit of time. ° EXPOSURE, EXTERNAL: Exposure to radiation that is delivered from a source outside of the body. EXPOSURE, INTERNAL: Exposure to radiation delivered from a source inside the body. Strontium 90 lodged in the bones is an example of internal exposure. EXPOSURE, WHOLE BODY: Exposure that involves the whole body rather than a specific organ. FALLOUT: The process or phenomenon of the fallback to the earth’s surface of particles contaminated with radioactive material from the radioactive cloud. The term is also applied in a collective sense to the contaminated particulate matteritself. The early (or local) fallout is defined, somewhat arbitrarily, as those particles which reach the earth within 24 hours after a nuclear explosion. The delayed (or world-wide) fallout consists of the smaller particles which ascend into the upper troposphere and into the stratosphere and are carried by windsto all parts of the earth. The delayed fallout is brought to earth, mainly by rain and snow, over extended periods ranging from months to years. FISSION PRODUCTS: A general term for the complex mixture of substances produced as a result of nuclearfission. A distinction should be made between these and the direct fission products or fission fragments which are formed * Based principally on The Effects of Nuclear Weapons. Glasstone, S. (editor). Documenta, U.S. Government Printing Office, Washington, D.C. April 1962. Superintendent of 49 48