-21- 12.8 Summary and Conclusions The findings on the Marshallese population accidentally exposed to radioactive fallout 13 years ago allow accurate documentation of the effects of localized fallout radiation on human beings. Since this population did not protect themselves during the exposure to fallout, this represents an extreme case particularly in regard to the skin and from internally deposited radionuclides. The radiation exposure resulted in 3 general classes of injury: a. the syndrome of whole body radiation injury produced by penetrating gamma radiation, b. superficial radiation burns produced by soft radiation (beta and low energy X or gamma radiations), c. radiation injury produced by the deposition of radionuclides within the body resulting in late thyroid effects only so far. The most serious of the acute effects was related to the hematological depression from exposure to the gamma radiation. The time course of hematological changes differed in important aspects from that seen in most laboratory animals. lymphocytes showed an early depression. until approximately 6 weeks. The The neutrophils did not reach a minimum The platelet count fell in a regular fashion reaching a low at approximately 30 days. The rate of recovery of the blood elements in the Marshallese was slower than would be anticipated from. animal data and was not considered complete until about ll years after exposure. These findings are consistent with the incomplete data available on the Japanese exposed at Hiroshima and Nagasaki, with the findings in the Japanese fishermen exposed in the same accident, and with the findings on human beings exposed in reactor accidents. They are also consistent with findings in patients exposed therapeutically either to total body radiation or internally administered radionuclides. | As a result of this accident, the potentialities of serious injury to the 9001318