= ‘Osewrrauatiase x ws Bi s apn * ut ey ne 3,0 z SECTION I. RADIATIONS 1. Natural Background and Medical Exposures As far as is known, man always has and alwayswill livein an environment filled with nuclear radiation. There are radioactive materials present naturally in the ground, the sea, and in Us TESTS 1358 the air. Cosmic rays bombard us from outer space. Naturally occurring radioactive materials in our food supply irradiate us from within. To these levels of radiation exposures are now added those from fallout—but these radiations (gamma rays and beta par- és US Cb EMEWETOR tS US TESTS 1954 1956 1958 cD 23 JOWNSTON IS US TESTS 1958 1982 CHRISTMAS IS TESTS -1962 WK.TESTS 1957. 1958 FIGURE1. ticles) are no different in kind from those emanating from a LOCATIONS of NUCLEAR WEAPONS TEST SITES osSse WOVATA ZEMLY. TEST SITE A. GENERAL BACKGROUND INFORMATION natural sources. Nor is there any evidence that they produce any fundamentally different biological effects. The radiations from natural sources and from medical, industrial, and scientific uses of radioisotopes and X-ray machines, and their biological effects, have been studied intensively for many years. To repeat, radiation exposures from fallout are in addition to those from natural sources but they are just that — additions of more of the same type of radiation. Fallout has not introduced a new and strange agent into our environment with completely unpredictable results. Indeed, a Committee of the National Academy of Sciences-National Research Council has stated: “, .. Despite the existing gaps in our knowledge, it is abundantly clear that radiation is by far the best understood en- vironmental hazard .. .”? TABLE 1.— Radiation Exposures from Natural Background and Medical Sources Natural Background (annual exposures) Total) oo... ccceccesescneeeteeeeeseseseeaesseueesseessceurccsaeessuneeans Gammarays (from terrestrial sources) and cosmicrays... 0.1 (varies). Potassium 40 (internal)................ccc ccc ccccececcneceveeveneeenes 0.018 (varies). Carbon 14.00... ccc cece ececcceeeeseecesuececceenecesnesaueareauanes 0.001 Medical Exposures Chest X-ray (per exposure)........0......c cece cece cece teats ceeeeeeeeees Back X-ray (per exposure).......... 0.0... c cece cece eee ececeeeeeeteeeenes Photofluorogram (per exposure)....................:0::0000 about... vi Roentgens 0.085-0.20 0.2 0.4 0.5-2.0 Gastro-intestinal series...........0.....ccceccccecceceeseeceeeueenenes about... 30.