Volume 1

The nature of radioactive fallout and its effects on man : Hearings before the Special Subcommittee on Radiation of the Joint Committee on Atomic Energy, Congress of the United States, Eighty-fifth Congress, first session on the nature of radioactive fallout and its effects on man May 27, 28, 29, and June 3, 1957.

  • United States Congress Joint Committee on Atomic Energy
Date:
1957-1958
Catalogue details

Licence: Public Domain Mark

Credit: The nature of radioactive fallout and its effects on man : Hearings before the Special Subcommittee on Radiation of the Joint Committee on Atomic Energy, Congress of the United States, Eighty-fifth Congress, first session on the nature of radioactive fallout and its effects on man May 27, 28, 29, and June 3, 1957. Source: Wellcome Collection.

    1020/1050 (page 982)
    there is a definite threshold effect, and that until this threshold effect is exceeded, I am not going to stop a radioactive wristwatch. This power of the body to repair itself, other than the hereditary material, has important bearing on the amount of radiation that man can withstand without demonstrable evidence of harm. The present rate of testing of atomic weapons is such that the radia- tion from worldwide fallout is appreciably less than the background radiation. From the standpoint of heredity we should watch closely the levels of radiation. The National Academy of Sciences report on radiation indicates that the doubling dose for mutations probably is in the range of 30 to S0 r, but may be as low as 10 r; it has been suggested that it could pos- sibly go even as lowas 5. Many geneticists believe that 30 to 50 r may be the doubling dose. Representative Corr. Would you explain what you mean by a dou bling dose for mutations ? Dr. Warren. Yes. There are a certain number of mutations that occur in the race quite naturally at the present time. You have heard of infants that have been born with imperfectly formed digestive tracts, for example. You have seen people who have 1 blue eye and 1 brown eye. These are the extremes of the sorts of mutations, some insignificant and some significant. We have hundreds of thousands of genes, and a change, a mutation in any one of these will produce changes under appropriate circumstances in the cells that are derived wholly or in part from that. Senator Jackson. Mr. Chairman—at that point, how can you tell whether it is due to the inevitable process of genetics and how can you tell when it is due to outside influence? How can you trace it? Dr. Warren. Only by very careful experimentation. These esti- mates are based on the best experimental data that we have available at the present time. There is some evidence derived from the eighty- thousand-odd births that have been studied in Hiroshima and Naga- saki as well. So I would rather not answer that question in detail, because there are others who are geneticists who will be speaking. But in general I fee] that we have reasonably sound foundations to emphasize that probably 30 to 80 r is a pretty good estimate for a level of radiation that will bring about twice as many mutations as now occur in the population. Senator Jackson. But all mutations are not due to radiation. Dr. Warren. No, indeed; not all congenital effects are due to muta- tions. For example, mutations can be simulated very closely by injury done to a fetus in utero, if the mother has had an attack of German measles or certain of the other types of virus diseases. Senator Jackson. While you do not want to go into this, I take it, because this is more a problem for the geneticists, you feel that they can tag and differentiate between mutations that are a natural result— the inevitable mathematical conclusion out of so many births—and mutations due to the outside influence of radiation ? Dr. Warren. Yes. There is a very large-scale experiment that Dr. Russell, who is carrying on that experiment at Oak Ridge, will go into for you in the course of these hearings. | Senator Jackson. I think it would be very important because this goes to the heart of the problem and unless you can tag them and ot aA