Agriculture, Food Supplies, and Atomic Radiation

A good alternative title for this presentation would be “The College Views the Calculated Risk,” for there are other risks of importance just now besides those covered by medical care insurance. Recently, for example, the Executive Committee of the College had a press conference in New York with leading science writers of newspapers and magazines in an effort to suggest accurate sources of information and to prevent further unfortunate interpretation of last June's National Academy of Science report, published in booklet form under the title “The Biological Effects of Radiation: Summary Reports,” and simultaneously released as a “Report to the Public.” Six subcommittees of the Academy reported on the effects and danger of atomic radiation in the field of genetics, pathology, meteorology, oceanography and fisheries, agriculture and food supplies, as well as medical and dental uses of x-rays. Only the medical and dental uses and the possibility of H-bomb fall-out seem to have made “scare headlines.” As is the usual custom with reports made by x-ray specialists to physicians who consult them, the Committee made a division between the objective findings and the conclusions which might be derived therefrom. With the objective findings of most of the distinguished scientists on the Committee, we have little quarrel, although many of us feel that the genetic experiments on fruit flies, guinea-pigs, rabbits, or other lower animals can be compared with but limited scientific accuracy to the effect x-ray exposure may have on the human race. Yet to be untangled in the public mind is the fact that much of the report deals with the dangers of radiation to the entire population from fall-out. Present levels of all radioactive fall-out substances are far below the danger point and, while we must be ever alert in this new atomic age, some persons may find it reassuring to know that the maximum effects of the present overall radiation of the fall-out type are not to be expected for another fifty generations, which is to say about a thousand years from now. Although the public has in many cases not grasped the distinction, we continue to try to make it clear that fall-out radiation is something very different from x-ray examinations by properly trained doctors using appropriately shielded equipment, involving small areas of the body. The National Committee on Radiation Protection, under the able direction of Lauriston Taylor, has issued handbooks in the last quarter century on radiation protection, the sum total of which is almost 2 inches thick. Further, we make every effort to teach medical students as well as our fellow practitioners to treat radiant energy with great respect. In the meanwhile, our some five thousand radiologists continue to be guided by the principle which they have always observed, namely, “the minimum necessary exposure,” in making medical x-ray examinations.

As a result of the nuclear accident at the Fukushima Daiichi nuclear power station (FDNPS) after the Great East Japan Earthquake on March 11, 2011, volatile radionuclides including iodine-131 were released into the environment and contaminated open-field vegetables, raw milk, tap water, etc. It is important for the health care of residents to correctly comprehend the level of their exposure to radioactive substances released following the accident. However, an evaluation of the internal exposure doses of residents of Fukushima Prefecture as a result of the ingestion of foods, which is indicated in the report issued by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)1 is based on a number of assumptions. For instance, the estimation assumes that foods were ingested as usual, without regard to the places to which residents were evacuated after the accident, the places where food shipment restrictions were imposed, and so forth. The present report aims to improve the accuracy of estimation of the amount of food actually ingested at evacuation areas, in order to reduce as much as possible the level of uncertainty in conventional values estimated directly after the accident, which were in fact values based on conservative assumptions. More concretely, as basic source material to more accurately estimate internal exposure doses from food ingestion, various patterns of evacuation and dietary habits at the time of the accident of the residents of 13 municipalities in Fukushima Prefecture who were evacuated during the period from directly after the accident of March 11, 2011 until the end of March are clarified in this report. From survey results, most of the food that evacuees took immediately after the accident was confirmed to have been sourced from either stockpiles prepared before the accident, or relief supplies from outside of the affected areas. The restriction orders of food supplies such as contaminated vegetables and milk, and tap water intake were implemented within several days after the major release of radionuclides on March 15, 2011. In addition, collapse in supply chains, i.e., damage to distribution facilities, lack of transportation vehicles or electricity, and the closure of retail stores, contributed to a situation where food or supplies contaminated with iodine -131 were not consumed in large quantities in general, even before the food restriction order. Since people consumed tap water and water from other sources before the implementation of restriction orders in affected areas, we surveyed the status of water as a potential route of internal exposure.