RADIONUCLIDE CONCENTRATIONS IN FISH AND INVERTEBRATES FROM BIKINI ATOLL ABSTRACT This report is prepared to have in a single document a summary of all of the available data on the concentrations of radionuclides in samples of fish and invertebrates that were collected from Bikini Atoll between 1977 and 1984 for our analysis. Some results were presented in other published reports, and more detailed discussions of previously unpublished results are planned for future publications. provided here. Therefore, only a brief discussion of some results is As in other global studies, !3/Cs was found in the highest concentrations in edible flesh of all species of fish and in the lowest concentrations in the bone or liver. The mean concentration of !37Cs in muscle of reef fish from the southern part of the atoll is comparable to the global-fallout concentration measured in market samples of fish collected from Chicago, IL, U.S.A., in 1982. Strontium-90 is associated generally with non-edible parts of fish, such as bone or viscera. Twenty-five to fifty percent of the total body burden of ®0Co is accumulated in the muscle tissue; the remainder is distributed among the liver, skin, and viscera. The mean — concentration of ®0Co in fish has been decreasing at a rate faster than radiological decay alone. Most striking is the range of 29781 concentrations among different species of fish collected at the same time and place. Highest concentrations of 2978} were consistently detected in the muscle (and other tissues) of goatfish and some of the pelagic lagoon fish. In other reef fish, such as mullet, surgeonfish, and parrotfish, 2°7Bi was usually below detection limits by gamma spectrometry. Over 70% of the whole-body activity of 20781 in goatfish is associated with the muscle tissue, whereas less than 5% is found. in the muscle of mullet and surgeonfish. accumulated significantly in the muscle Neither 239+240py nor 24]Am is tissue of any species of fish. Apparently, 238Pu is in a more readily available form for accumulation by fishes than 239+240py. Based on a daily ingestion rate of 200 g of fish Flesh, dose rates to individuals through the fish-food ingestion pathway are well below current Federal guidelines. 5000555