° OFFICIAL USE ONLY filtrate, but there was an undetermined amount that settled to the bottom. Other data suggest the material to have been about 10 percent soluble in water. In the event contaminated food is ingested it is possible that the total activity--soluble and insoluble--may find its way into the gastrointestinal tract since at times immediately following se fallout most of this activity probably would came from the surface contamination rather than the soileplant~-animal cycle. There may then follow some solubilizing in the acid stomach with subsequent removal from the tract before reach- ing the lower large intestine. Thus, it would appear that the assumption that ingested activity is associated with insoluble material, presents a limiting and unlikely case, yet probably being well within a factor of two of the actual case. Of course, if the assumption is accepted that all of the activity is insoluble then there would be no absorption into the body of the isotopes of iodine and of the bone seekers. However, as a limiting case again, it has been assumed that these isotopes are soluble and according to reference five. deposited The great solubility of these iodine isotopes has been observed so that this assumption too is probably well within a factor of two of the actual case. B. Biological Significance. After the estimation of radiation doses by any procedure the finsl step is an evaluation in terms of biological effects both for short and long terms. OFFICIAL USE ONLY -9.

Select target paragraph3