SESSION IV 179 DUNHAM: When yousay it concentrates, you mean compared to the concentration of radioiodine in the water? DONALDSON: Yes. The total activity of the water was 24,000 d/m/g, and the activity from the 113! in the algae was 30,000,000 d/m/g. UPTON: Rapid iodine turnover in this organism? DONALDSON: I rather doubt it. [ think it probably is maintained ata relatively high level and the limiting factor may be the amount of iodine available to it. UPTON: Is it a rapidly growing plant? DONALDSON: UPTON: Yes. It grows rapidly. So that it's building new cells and building in newiodine, DONALDSON: Yes. I think the specific concentrations are really germane to this sort of discussion because we base our intecpretatiornz on the familiar and forget that in nature there is a wide variety of uptake, We were also interested in the rate of transfer and elimination. In the discussion yesterday, Dr. Warren mentioned the radioactivity on the sides of the ships, but if you recall, these ships were aiwav4 upwind from the Jetonation, Thus the question would be, "How did the radionuclides, which would normally drift downwind, work their way upwind and become concentrated in the water around the ships, to be accumulated by the organisms on the sides of the ships?" Of interest, too, was the dispersal in the open ocean, intriguing thinga was the "breathing" of the atoll. with the tide. One of the It appears to pulse Of course, it is the nature of an atoll to be constantly leaching material out to the open sea, There are other interesting tranafers that we will be talking about, Ihope, as we go along. The usual transfer in our terrestrial areas is from the land to the sea, but in these atolls there is a very appreciable transfer, which takes place ina variety of ways, from the sea back to the land or the limited land area. Radionuclides are transformed by spray into the vegetation, and we find that this is a positive transfer. This occurred