and using an 8-in. Nal crystal, to improve the absolute measurement of trace amounts of other radionuclides that may be present. Sincé a total of 227 Marshallese persons were surveyed with the whole-bodycounter, in addition to numerous controls, the spectral analyses were performed with the aid of a 704 IBM cor: suter. Radiochemical Procedures Twenty-four-hour urine specimens were collected in plastic bottles and sent to BNL for radiochemical analysis. A modification of the method of Farabee*® was used for the analysis of Sr°°. Sr was precipitated as the alkaline phosphate, ashed with HNO, and H,O., and dissolved in dilute HNO,,. After the solution was brought up toa volume of 800 cc, the alkaline earths were complexed with EDTA, and the pH wasadjusted to 3.5. The solution was then passed through an ion exchange column (Dowex-50 in the Na form), and the column wasrinsed with 300 cc of a solu- tion of 1% citric acid and 0.75% EDTAat a pH of 5.0. The combined effluents contained >95% of the total Ca. The column wasthen rinsed with 6 NV HNO, to remove the Sr®*. Carrier Sr was added to the Sr®*° fraction and precipitated with 70% fuming HNO,,. Yttrium-90 was milked and counted by the method of the AEC Health and Safety Laboratory. ** The supernatant from the alkaline phosphate precipitation was measured and divided into two portions. One portion was scavanged for cesium with added carrier by means of a double precipi- tation of the aluminum sulfate and-the chloro- platinate.‘t The second portion was analyzed for K by flame spectrophotometry. , Food samples were weighed and dry-ashed in a muffle furnace at 800°C. The ash was weighed, and asmall portion was counted for gross beta activity. The ash was dissolved in dilute HNO, and processed by the method described above for * urine analysis. All counting was done in a low-level beta anti- coincidence type of counter, designed and built at BNL. Samples were mounted on glass fiber filter discs with nylon rings and discs and Mylar film. Samples were counted against NBS standards processed and countecl under identical geometry.*! Individual values for all the people examinedin 1959 may be found in Appendix 7 for gamma spectrographic analyses and in Appendix 8 for radiochemical analyses. Environmental Estimate One method used (the least quantitative) was the environmental estimate of body burden. The environmental estimate of internally-deposited Sr?? was made in two ways. In the first method, animals subsisting on diets similar to human diets were sacrificed and their tissues were analyzed radiochemically. A numberof rats were collected on Rongelap Island at 2, 4, and 5 years after the 1954 accident. If the diet of these rats, primarily land plants, was sufficiently similar to the diet of human beings inhabiting this area, the rat analy- ses might serve as indicators of the humaninterngl radiation contamination. The Sr°*°/Ca ratios of various tissues of these rats were measured direct- _ly and comparedto theratios of the food andsoil on Rongelap collected at the sametime; thatis, the environmental contamination was compared with the directly measured contamination in animal tissue. Extrapolation of the environmental data gives the equilibrium value which can be expected, whereas the direct measurement gives the value at the time of measurement (and thus the percent of the equilibrium value for the individual radionuclides). The Sr°°/Ca ratios for different plant foods on Rongelap varied greatly, and the diet of the rats was too uncertain for an “‘average” diet to be assumed. Therefore, for a body burden estimateit was necessaryto use the Sr*°/Ca values of the soil itself. The “‘strontium-calcium observed ratio” (OR) of Comar** was used to denote the preferential utilization of calcium in the following manner: Sr/Ca of sample The Sr®° discrimination ratio in the chain from soil (s) to bone (8) via plants ( p) can be expressed as follows: OR,.,=(OR,.,)(OR,-,) =(0.7)(0.25)=0.18 . ‘Se s it will be possible, by counting for longer periods All three of the above methods were used for estimating the body burdens of gamma- and betaemitting radionuclides in the Marshallese people. mae Mee In future whole-body counting of these people, RESULTS AND DISCUSSION a to that of the phaneom,avhich was counted for 30 min (Figure 52). saa.