4, RESULTS AND DISCUSSION The predominant radionuclides in the terrestrial organisms are i37cs and 30sr, whereas the marine organisms contain mainly ®69Co and >°Fe. The concentrations of these radionuclides in edible portions of organisms range from undetectable amounts to the following maximum values: 137¢s - 2260 pCi/g dry in the muscle tissues of a curlew from Nam I. 90sr — 204 pCi/g dry in the hepatopancreas of a coconut crab from Binini I. 60¢o - 219 pci/g dry in muscle and mantle tissue of a giant clam taken near Bikini I. >5Fe - 40,900 pCi/g dry in the liver of an ulua from Eneu Pass. The range in the concentration of a radionuclide in the same tissue from the same species at the same islet is wide. When detectable amounts of radionuclides are present, the minimum and maximum values often differ by factors of four or five and sometimes by a factor of ten. The values for concentration of radionuclides in individual samples are given in Tables 1 through 19. Dry weights were used for the basic calculations because the true water content of some samples is difficult to determine. The average concentrations of radionuclides were converted to a wet-weight basis for convenience in calculating daily intake from the diet; the conversions were made by using average wet to dry weight ratios for each kind of sample. 4.1 FOODS In general, there are no striking differences between the 1967 and 1969 average values of radionuclides for edible portions of foods of marine origin, including the sea birds. The differences tend to show a decline in radionuclide content, but there are not sufficient data to provide a basis for a reasonable estimate of rates of decline because of the large variability in the data and the many poorly defined factors involved in the uptake and retention of radionuclides by organisms in the natural environ- ment of Bikini. Some basic biological information, such as rates of growth and life spans of the fishes are not known and the chemical form in which the radionuclides are present in the lagoon waters can only be surmised. We do not even know, for example, whether the radionuclides and their stable isotopes are present in the same chemical form. Furthermore, there are no uncontestable data on the trace element content of lagoon waters and probably will not be until the techniques of sampling and processing seawater samples are greatly improved. However, some hypotheses can be made and conclusions can be drawn from certain data.