o» 2a In view of the above considerations we would limit the average con- centrations of various radioisotopes in the total food and water supply of members of non-occupational groups to one-tenth of the values given in Table 3, NBS Handbook 52. As far as the welfare of a person eating a radioactive fish is concerned, the amount of radioactivity permitted over a period of several weeks or months, if uniformly mixed at this concentration through the total food and water intake, could be taken in a single eating of fish with no significant difference in effect. However, since methods of handling and distributing food make it impractical to determine the average concentration of radioactivity in individual diets, for administrative reasons it is desirable to reject individual fish or other items of food which contain levels of radioactivity materially above the accepted maximum permissible average level. Since it is sometimes impractical to detect every item which would be rejected on this basis, it is worth observing that occasional failure to detect individual items at much hig.ier levels would not be expected to raise ' the average levels of radioactivity in the diets of individual consumers above maximum permissible levels. For short periods of time the radioactivity in the diet may be much higher than the values discussed above without effects on the consumer. Attached are copies of Bulletin TB-11-8, issued December 1952 by our Federal Civil Defense Agency, suggesting total activities in water and food supplies which, it is believed, could be accepted for short periods of time in complete safety. Since it is impractical under field conditions to determine the concentrations and the radioisotopic composition of radioactive materials on or in fish or other items of food, one needs some practical criterion for rapid screening of items requiring further examination from those which almost certainly meet established standards. Fast April, as a result of conversations with the Federal Food and Drug Administration and other federal agencies, the Division of Biology and Medicine of the United States Atomic Energy Commission suggested that, as a tewporary standard, individual fish be accepted if the gamma radiation, measured 5 cm from the surface of the fish, does not exceed 0.1 milliroentgen per hour. In terms of the response of GoM survey instruments commonly used in the United States, this corresponds to from 300 to 600 counts per minute with the tube shielded to exclude beta radiation. based on thefollowingassumptions: (1) (2) This value was The radioactivity had been deposited on the outside of the fish after the fish was taken from the water; When processed for food, all of the radioactivity deposited on the ontside of the fish would be retained in the outer two inches (S om) of flesh; (3) The radiation is measured at about two weeks after the explcsion from which the radioactivity came: DOS ARCHIVES