19 Psychic effects. The Japanese people exposed to the atomic bombings suffered acute psychic trauma from the horrifying experience they underwent and multiple injuries, burns, loss of homes, lack of food, disease, etc. In contrast, the Ron- gelap people were hardly aware of anything of great significance happening at the timeofexposure, and it was with relative calm and rapid adjustmentthat they went to their new homesto living conditions generally superior to those they were accustomed to. It is true that they have suffered some nostalgia for their homeisland but always with the knowledgethat they wouldreturn. (At the timeof this writing they havereturned to their homeisland andare living in completely rebuilt homes.) If there had been no hope of returningto their homeisland, the psychiceffects might have been serious. There waslittle real concern expressed abouttheir radiation exposure. It would seem, therefore, in the case of the ex- posed Marshallese that there has been little or no apparent psychic effect of this momentousevent. Superficial Beta Radiation Exposure The acute phase of the beta burnsof the skin was over by several monthsafter exposure with satisfactory healing taking place. No further breakdownor developmentof chronic radiation dermatitis has been noted in anyoftheselesions. It is of interest that about twice the incidence of pingueculae and pterygia had been noted in the exposed Rongelap people as in the unexposed groups during the past two years. Since manyof the people received a certain degree of beta radiation to the mucous membranes of the eyes (as evidenced by lachrymation and burning during the first day or two), it is possible that this may have influenced the increased incidence of these abnormalities. Internal Radiation Exposure In an acute fallout situation, iodine-131 is probably the most important absorbed isotope to be considered during the early period. In the Marshallese, the 300 rep estimated to have been delivered to the thyroid glands (100 to 150 from I’*? and 175 r from the gammadose) wasfar too low to produceany acute effect. (Possible long-term effects of this dose will be discussed below.) The conglomerateof ingested isotopes delivered about 3 mC of radiation to the gastro-intestinal tract duringthefirst day after radiation, but again this dose was too low for any acuteeffect. Internal concentration of other isotopes was far below any levels necessary to produce acute or subacute effects. LATE EFFECTS Investigations in animals andto lesser extent in man haverevealed certain late or long-term radiation effects. Some of the more fundamental of these are discussed below in relation to the Marshallese experience. Penetrating Radiation Premature aging and shortening of life span have been shownconclusively to occur in animals followingirradiation.’®'"?® Establishmentofcriteria for quantification of aging is notoriously difficult. Therefore, little or no data suitable for precise measurementof aging effects have been collected in the Marshallese. Accommodationtests ofthe eyes and audiometric analyses were carried out, but no detectable differences in these parameters were found in regard to age betweentheirradiated and unirradiated groups. As to premature aging, the senior author has observed these people at repeated intervals since their radiation exposure, and they do not appear to have aged faster or look older than similarly aged unexposed Marshallese persons. No doubtthe subtle changes which occur with aging would be difficult to detect overthis period of time. Estimates of the shorteningoflife span in the humanbeing have varied considerablyin different reports.”°-** In the Marshallese at three years post-exposure, only one of the 64 heavily exposed group had died. This compares favorably with five deaths among the 157 Utirik people who received the smaller exposure. Even though there are quite a few old people in the irradiated group, it is probably too soon to expect meaningfullongevity data. However, it would appear that some of the upperestimatesoflife span shortening in human beings are too high (someinvestigators estimate 30 or more days per r), since it would seem that even in this small population more evidenceof aging orlife span shortening ofthis magnitude would have been noted. Data on lon-