Soeae 11 Pandanus and coconut samples contg ined, as is common for plants yon the Marshall Islands, naturally occurring ‘~K and fallout radionuclides !3/cs and 90sy. Of the three Pandanus and three 1ggconut tissues analyzed, the edible fruit of the Pandanus had the highest | Cs values, 15 to 31 pCi/g. 90 was highest in the leaves of the Pandanus. limits of detection. Strontium Plutonium levels were below the Three species of fish were collected at Rongerik Atoll. Potassium-40 was the only radionuclide present in quantities above 0.6 pCi/g. Cobalt-60 and Cs levels were less than 0.6 pCi and “Sr values were below the limits of detection. The 137¢5/40K ratio in the three coconut crabs from Rongerik was 2.5+0.6. Cesium-137 values in the muscle and hepatopancreas averaged 29 and 10 pCi/g, (dry) except in one hepatopancreas sample which had a concentrationnagf 4.3 pCi/g. In the exoskeleton Osr levels averaged 44+5 pCi/g, while 13/cs levels ranged from 2.5 to 3.5 pCi/g. Utirik Atoll In April and November, 1974, samples of soil, plants and marine organisms were collected at Utirik Island. These samples were analyzed for gamma- emitting radionuclides and some were also analyzed for 20Sr and/or Pu. Results are shown in Appendix Tables 9 (fish), 12 (soil), 13 (plants), and 14 (clams). Five surface soil samples collected in the interior of Utirik Isiand_ had radionuclide concentrations of Jess than one pCi/g except for 137¢s and 905r values which averaged 2.8+1.6 and 2.7+1.7 pCi/g, respectively. ' The edibj¢_ fruit from a Pandanus plant located near the center of Utirik Island had a !3/cs level of 67 pCi/g. No other fallout radionuclides were above the limits of detection. Bananas from Utirik had low levels of fallout (0.5 pCi/g or less) in the edible portion of the fruit. The marine organisms, fish ane Tridacna clams, collected in the lagoon (80 ¢0 Utarik sasay low levels (<IpCi/g) of the three fallout radionuclides 90Sr and ) measured. Naturally occurring 49K values averaged out °g pCi/g in the tissues of fish and clams. Rongelap Atoll Samples of soil, plants, fish, clams, and coconut crabs were collected on several islands of Rongelap Atoll? in April and November/December, 1974. All samples were analyzed for gamma-emitting radionuclides and selected samples for 90Sr and Pu. Results of these analyses are shown in Appendix Tables 6 (coconut crabs), 9 (fish), 13 (plants), 14 (Tridacna clams), and 15 through 21] (soil). Coconut crabs were collected from six islands in Rongelap Atoll. Four were from the southern islands of Arbar and Busch (lowest radiation levels at Rongelap), five were from the northeastern islands of Mellu and Kabelle (medium radiation levels) and four were from the northern islands of Lukuen and Lomuilal (highest radiation levels). The mean 137Cs and 30sr levels in the muscle tissue of the coconut crabs 7s shown in Figure 3. Levels of 90sy and '3/cs are highest in coconut crabs collected on the northern and northeastern islands of Rongelap Atoll. we