348 RADIATION STANDARDS, INCLUDING FALLOUT Representative Priczr. On page 1 you mention the newer findings have in fact reinforced your convictions concerning the complexity of radiation effects along with additional evidence of genetic effects of low doses of radiation, and demand a spirit of caution and reserve. Are you referring to the latest findings indicated in the recent FRC report ! Dr. Guass. At the time I wrote this testimony, I had not received a copy of the FRC report. I have since then had a chance to examine it. As far as the presentation of the problem of genetic damage is concerned, it appears to be based on the same data which I have discussed, and I see no reason to differ with the conclusions drawn. Representative Pricr. Does usual caution and reserve imply that a reversal of the present genetic findings may possibly show up from some presently knowneffect ? Dr. Grass. The experience of the past 3 years, since the last hearings, shows that new findings do turn up which change the appraisal of genetic damage, and these findings of Russell about the effects of a low dose rate are a casein point. If that had been the only newfinding that turned up, we would now cometo the conclusion that radiation was less damaging in producing mutations than we had formerly supposed, because most of the radiation from fallout would be at a low dose rate. But there have been other findings that offset that: The attention devoted to carbon 14 which was not included in the earlier estimates of damage; and the indication of the other effects to which I referred-— sterility effects, the chromosome losses producing such conditions as mongoloid idiocy and sexual aberrations. So, on the one hand, we lower the estimate we previously made. On the other hand, we increase it. These two pretty well offset one another as far as I can judge, and our original appraisal is still good. But we do think that we don’t knowall we should about the subject and therefore ought to be cautious about drawing conclusions. Representative Pricer. On page 8 you mention that in the case of female germ cells, the 0.8-roentgen rate sometimes yields an intermediate frequency of mutation. We understand that the 1954 fallout on the Marshallese people and the Japanese fisherman had this type of exposure from fallout. Has this level of exposure occurred toany others due to fallout? Dr. Guass. Not to my knowledge. I think the Marshallese would be about the only group that had received a fairly high dose rate, or what we call here an intermediate rate as far as the female is concerned, from fallout from weaponstests. Representative Pricr. Have the Marshallese shown any genetic effects to date? Dr. Grass. The number of children born to the irradiated individuals is so small thatit is not really to be anticipated that mutations would be discovered. To my knowledge, none have been discovered. T would say that the evidence we can get from the Marshallese is not likely to throw much lightonthe situation. Representative Price. On page 11 of your complete statement you said that 200 roentgens would produce sterilizing effect upon the female. Did any of the Hiroshima or Nagasaki survivors who were exposedin this range havefertility effects ? BAG BCG Tt DAMS Ledasscoapie aaECe + PRE RSERI ie