formerly USPHS/SWERL) took the responsibility for external radiation measurements, and for the collection and analysis of those land plants that are food items; the U of W Laboratory of Radiation Ecology was asked to sample and analyze other biological and environmental samples in 1969. Additional samples were collected in 1970, with the emphasis on air filters and soil samples. The former were analyzed and reported by the EPA (SWRHL-lllr). This report presents the results of the Laboratory's anlayses. 2. SELECTION OF SAMPLES AND SAMPLING SITES The sampling program was based on the objective of obtaining data for evaluation of potential radiological hazards to man. The samples were limited, for the most part, to things that might be eaten by returning Bikinians, except for land plants. Additional samples, for example, soils, crater sediments and groundwater, were taken to provide data for estimating the future distribution and amounts of radionuclides in the biota. The fish collected are in two main categories: the reef fish and the pelagic or "troll-caught" fish. The reef fishes are usually collected by throw nets by the Marshallese and are important items in their diet. Of the more than 700 species of reef fishes at Bikini Atoll, we selected three species commonly eaten by the Marshallese and representative of three feeding habits: the mullet*, a plankton feeder; the convict surgeonfish, a grazing herbivore; and the goatfish, a bottom-feeding carnivore. The specific radionuclides found in fish and their concentrations are often associated with feeding habit; hence this was a necessary consideration in selecting samples representative of the kinds of fish that would be eaten when the Bikinians return. A fourth kind of reef fish, groupers, was also collected as representative of the higher order carnivores. The troll-caught fishes are all high-order carnivores and fall into two broad subcategories: resident lagoon fish, ulua and dogtooth tuna, and migratory fish, yellowfin tuna. All were caught in or near Eneu Pass. Bikinians who were part of the clean-up crew cut filets from the yellowfin tuna and preserved them by salting. They said tuna is one of their favorite fish and, presumably, would fish for tuna if they return to Bikini. The invertebrates samples were the spiny lobsters (langouste), coconut crab and "giant" clams (Tridacna sp., and Hippopus hippopus). Some of the species of Tridacna never exceed a few centimeters in length, and only the smaller species were found in the vicinity of Nam (Charlie) Islet. The larger species were found near Bikini Island. * For a list of common names and scientific names, see Table 20. hyp CPE gs PERRB ES REZ REUTER ER EEE ES! Protection Agency's Western Environmental Research Laboratory (EPA/WERL,