40 Appendix 6. The meanvalues are given in Table 17. The meanurinary levels of !37Cs and 9Srfor 19671969 are definitely lower than for 1965. The 1965/ 1969 ratio for 137Cs (nCi/liter) was 6.3/3.2 and for 9°Sr (pCi/liter), 10.1/4.5. Data over the 3year period 1967-1969 show some variation in both 9°Sr and 137Cs levels for both groups but no definite increase or decrease; therefore, it seems justifiable to assumethat the body burdens have not increased but have been roughly constant for the past 3 years. This indicates a state of equilibrium with minimal ailowancefor biological or physical decay. The drop in the urinary excretion levels of these isotopes suggests an interesting speculation concerning the influence of change in environmentalfactors. The lowered levels during the past 3 years might be due to increased consumption of foods brought in from the outside with less dependence on home-grownitems. The people received fallout compensation payments in 1966 and have had more moneyto buy imported foods. The 14 Bikini people living at Kili Island had urinary levels of 197Cs about the same as those of the Rongelap people living on the non-contaminated island of Ebeye and within the range of those of the Marshallese members of the medical team. The Sr level of the Bikini group was well below that of the Ebeye people. Since Kili Island is far to the south of the Pacific atom bombproving ground at Eniwetok and Bikini, there would be little contamination on that island; hence, as expected, the people have very low body burdens of these isotopes. When the people return to Bikini further tests of body burdens, including whole-body gammaspectroscopy,will be done on them and also on the Rongelap people. In preparation for the return of the people Bikini is undergoing a numberof procedures intendedto reduce the radiation contamination greatly. Amongthese are clearing away of scrub growth, planting of new coconut and pandanustreesafter replacementof the top soil in the area, removal of top soil around thevillage area and covering with clean coral, disposal of radioactive materials and debris from all the islands of the Atolls, and reduc- ing the coconut crab population. Mostof the food for a long ume will be brought from outside. Therefore, when the people return, the increase in body burdens is not expected to be anywhere near that measured in the Rongelap people on return to their island. The body burdensof radionuclides Table 18 Radionuclides in Coconut Crabs Year 17Cs, pCi/kg 1961 1140 1962 1964 1965 1969 Sr. pCi/g Ca 1227 (1317; 1086; 30,280 (39,292; 45,318; 66,234) 12,700 7,770 (8,540: 7,010) 1113; £378) 751 (865: 628; 724 780) 700 (910; 500) in the latter remained far below maximum permissible levels (see below, under SummaryofPast Findings). Table 18 shows the levels of 137Cs and 9Sr in the, coconut crabs over the years. The 137Cslevels have been dropping since 1960. The 9°Sr levels showed some reduction between 1961 and 1964 but very little after that. The disparity in reduction of the two isotopes may be caused by the molting crabs eating their shed shells, which con- ~ tain high concentrations of 9°Sr. It is unfortunate that the high °°Sr levels necessitate a continued ban of this favorite food, but the crabs are a deli- cacy rather than a dieary staple since they are not present in great numbers. HEMATOLOGICAL FINDINGS Peripheral blood studies were carried out on both the exposed and unexposed Rongelap people in 1967 and 1969 and on the exposed only in 1968. Blood studies were done on the Utirik population in 1969. Leukocyte and red cell counts were done electronically by Coulter counter.*# Platelet counts were done by phase microscopy*® in 1967 and by Coulter counter in 1969.44 Differenual counts were performed on Wright stained smears. Hematocrits were determined by the microcapillary method.46 Sera or plasma samples were collected each year for studies in U.S. laboratories. The hematological findings for the past 3 years are summarized in Tables 19 and 20 and in Figures 38 to 42. Individual counts are tabulated in Appendix 7 and mean counts over the years tn Appendix 8. Total leukocyte counts in the exposed Rongelap people still averaged slightly below those of the unexposed population duringthe last 3 years, but lymphocyte counts since 1965 have averaged slightly higher than the unexposed mean