Table 4.1—SPECTROGRAPHIC ANALYSIS OF THE RADIOACTIVE PARTICLES REMOVED FROM THE LIFE-FLOAT DECKING Element Strength of lines* Al Ba M "7 Fe T Mn Na Si Sr T M Ww s Zn WwW Ca vs Mg vs *T = 0.001 to 0.01%. W = 0.01 to 0.1%. M = 0.1 to 1%. S=1 to 10%, VS = 210%. Those particles that were deposited on the life-float decking were influenced by a sea- ait water environment in which there is a comparatively high concentration of magnesium ion, sulfate ion, and a somewhat smaller one of bicarbonate ion. As the sea water slowly dissolved the slightly soluble calcium hydroxide in the particles, the liberated hydroxide ions reacted with the magnesium ions in the sea water to form a shell of insoluble magnesium hydroxide around the particles. On the exterior of the magnesium hydroxide shell, a layer of calcium carbonate was formed from the dissolved calcium ions and the bicarbonate ions of the sea water. On the interior of the shell, calcium ions from the soluble calcium hydroxide were precipitated by the sulfate ions of the sea water to form a zone of well-developed hydrated calcium sulfate crystals (gypsum). The prolonging of this leaching and precipitation process caused the formation of either completely or partially hollow particles. The radioactivity was found to be associated primarily with the inner core of undissolved calcium hydroxide. Little or no activity was found in the magnesium hydroxide-—calcium carbonate shell or in the calcium sulfate crystals. This leaching, by causing a partial solution and reprecipitation of the soluble calcium compounds, accounts for the adherence of the particles to the life-float decking. 4.2.38 Leaching of Activity The total collectors, consisting of a funnel and bottle, were exposed several days before the shot and were not collected until several days thereafter. Consequently there was a considerable amount of rain water in each collector, as well as a sample of the total fall-out. It was found that the liquid portion collected was active, and analysis of the samples showed that from 14 to 80 per cent of the total activity in the collectors was in the solid particulate. The average amount of leaching of activity into the rain water was approximately 50 per cent. No correlation could be found between location of the collector and the amount of leaching, Approximately 0.1 g of particulate that was collected in the dry state was allowed to leach in a surplus (500 cu cm) of distilled water for over one week to see whether there was a cor- 39