SLIDE 55 Status of plutonium measurements. The validity of the 239py data used to estimate the body burden at Rongelap Atoll in 1973 had been considered by an Energy Research and Development Agency ad hoc committee. The committee concluded that because of the possibility of urine-sample contamination these data were uncertain. This indeed may have been a factor since a radiochemical analysis of BRAVO debris indicated Rongelap Atoll was contaminated with Pu (Ts55). No special precautions had been taken when the urine samples were collected in the field, results. therefore not much credence could be given to these In 1976, three male adults at Rongelap Atoll provided urine samples for *?%pu analysis. Two yielded results below the minimum,detection limit of 3.7 x 10° Bq l (10 fCi 1 ) and one yielded 3.3 x 10 Bq l (90 fCi 1 1), The average of these values along with the 1973 adult average result that was reported by Conard (Co75) were used to derive potential body burdens. The estimates for 239p, adult body burden were not used to derive values of intake and committed effective dose equivalent since they may have been the result of an erroneous urine collection technique and not the resudf of internal deposition. The potential for contamination existed for Sr, however the impact of contamination on dose assessment was much greater for Pu. Questions concerning the 239py estimates have led to study of .ghe sampling and analysis procedures which indicated to us that some Pu in urine may not have been chemically recovered along with the tracer (Ry82). In August 1981, fecal and urine samples were obtained from Rongelap and Utirik residents and are to be analyzed after complete dissolution followed by a liquid solvent extraction technique. This method is being developed to be used in conjunction with a photon-electron rejecting liquid scintillation spectrometer developed by McDowell and duplicated by us for low-level alpha spectroscopy (Mc72). The question following additional analysis of urine collected in 1979 and 1980 from former Bikini Atoll residents. The urines were collected in a, ggntamination free environment and indicate higher than expected levels of Pu. Further analysis using fission track-etch techniques will be done to confirm these results. Additionally, a comparison population has been chosen and samples collected from them. The await analysis. 239py MEASUREMENTS Date Male Adult Population mBq d™' 239Du Excretion Rate 1974 1975 Bikini Males Bikini Males 0.9 0.7 1976 1979 Bikini Males Bikini Males 0.4 2 1976 Rongelap Males 1976 1973 Bikini Males 0.5 Rongelap Males, Females 53 9 2