Delta (Utah), 2nd Idaho Palle (Idsho). The higheet Values of activity ‘in the alr were found at Elko, where 0.13 sicrocurie per cubic meter of air was observed about 3 hours after the sarface shot. The twenty-four hour average wae about 0.003 microcurie per cubie aster. The safe level agreed upon by the Feasibility Committee (July report) was 1.0 microcurie per cubic meter, Hence observed levels failed te approach permissible levels. In addition to the above close-in monitoring of fall-out primarily for safety reasons, a country-wide monitering program was alao in effect through the coordinating activities of the Health and jafety Division, HYoo, and the cooperation of AEC laboratories end contractors and the Weather Bureau. Results of this stuly will be reported later, but none of the observations indicated hazardous levels of radioactivity anywhere in the country. of ee. Analysie of sellsamples écllected frou the fali-cout from the and underground ahp at the Negada Test Site has provided useful data for the evaluation ‘the over-all health hasards of atomic explosions. Deposition ef radioactive particles on the land and absorption by plants is the begimning of a wajor pathoay for uptake by man of fiseion products and induced redinactive elenents. Additional samples of the dirt and fused glass of sodium, potaseiun and calcium silicates around the surfase sitearater have also been collected. This material has been sent to the ARC project at the U. 3. Department of Agricalture at Beltsville, Maryland for ehesical and particle size analysis and for studying its rate of uptake by plants growing in various soils. Mimate particles of the fused soil constitute an appreciable portion of the radicective dust eloud and it is desirable to know ite solubility and rate of olubilisation on various soils, especially eastern acid ones. Previous test of the fall-out en the scfl from around the ald Alemegordo test crater in New Mexico had indicated that the radioactivity was taken up by the plants very slowly over a period of several years, However, the western desert soil has an alkaline character while eastern seils are predominantly acid, It ia known that glasa silicates are many times more soluble in slightly acid solu- tions. Therefore, it is desirable to obtain more information on the rate at which radioactive fall-eut will be absorbed by plants from dust fros an underground? explosion. Senet gt loneneonge sttecta.| the soy or tenement acre ects which large mamber ofatomic basbs was begun several years &go. During the past few months, the question was again jected to careful seruting in the light of newinform ormation gleaned from recent bosb tests, and a revised report was prepared. In November, this report and the various questions of climatalogy, feli-cut and bislogical may result from the detonation o effects of bomb debris were carefully considered by an ef hoo committee of ad “a ry id 16—63110-1 DATE > ¥ tees | aro