Since the concentrations for many of the elements were cavsonesy low and the volumes of the ultrafiltrate were small, some of the analyses had to be made near or below their lower limit of reliability, Thus, the results for iron, aluminum, and copper, which are the important detona- tion products, are very much in doubt. However, some conclusions can be drawn. Sodium and potassium, as expected, are predominently in the liquid fraction, Magnesium and calcium, derived from both sea water and coral, are predominantly in the liquid fraction in the barge shot samples and predominantly in the solid fraction in the island shot samples. Calcium hydroxide being more insoluble than magnesium as well as constituting a larger percentage of coral had a greater tendency to be in the solid fraction than does magnesium. More than 85 per cent of the iron was always found in the solid fraction, Aluminum also was found predominantly in the solid fraction; however, lower total concentraticns of aluminum and lower pi tend to reverse this behavior, 303 CHEMICAL STATE OF NEPTUNIUM AND IODINE Experiments were carried out to determine the oxidation states of Np and I in the fallout material, These two elements contribute significantly to the gamma radiation of the fallout from nuclear detonations, and accordingly, their contamination-decontamination behavior is impor- tant. Furthermore, the decontamination of these two elements depends on their oxidation states since the sorption and solubility and chemical reactivity of each are dependent on it. Knowledge of the chemical behavior of a few of the important radionuclides in the fallout together with that of some of the stable elements could lead to 4 realistic and practical approach to the preparation of synthetic contaminants, 3.301 Onidation State of Neptunium The oxidation state of Np in fallout samples was determined for Shots 1 through 4. In order to carry out the determination, a fairly large amount of activity was required (sample reading of 20 to 30 mr/hr at surface of container’. 3e3elel Chemical Treatment of Samples The procedure for separating Np(IV) from Np(V) and Np(VI) was based on the extraction of Np(IV) into a 0.4 M TTA solution in benzene from a 2N-HCl aqueous phase. The Np(IV) back-extracts into an aqueous phase of SN-HCl. The chemical procedure is given in Appendix A, 3e30162 Neptunium The experimental reaults for Shots 1,2,3, and 4 are tabulated in Table 3.11. Two Shot 1 samples not listed in Table 3.11 were processed but the results were not considered satisfactory for the reasons given below. 6