EVALUATION OF THE RADIONUCLIDE CONCENTRATIONS IN SOIL AND PLANTS FROMTHE 1975 TERRESTRIAL SURVEY OF BIKINI AND ENEU ISLANDS Abstract . In June 1975, personnel from LLL Lea . : 60 Co, /6. for 90 Sr, Island (0.86 for a ¢ 137 239,240 and from other laboratories and 43 for agencies conducted a radiological 2.4 For oada). survey of the terrestrial environment activity is unevenly distributed over of Bikini and Eneu Islands the surface of these islands and that Atoll) (Bikini to evaluate the potential radiation dose to population. Cs, 3.0 for , Pu, We found that radio- the distribution of activity with the returning Bikini In this report, we pre- soil depth varies greatly in different parts of the islands. Concentrations sent measurements of the radionuclide in the soil of 905, and RSTn gs are concentration in soil profiles and in greater dominant species of edible and noned- and ible, indicator piants. cribe the use of and We aiso des- these data to derive relationships to predict the plant uptake of radionuclides from soil. Approximately 620 soil and vegeta- . than concentrations of 239, 240 Pu which, in turn, 241 Am are ; 6 greater than concentrations of Co. To quantitatively evaluate the plant uptake of 239,240 90 SY , 137 C s, and Pu, we develop soil-plant concentration factors as well as tion samples from Bikini and Eneu leaf-leaf and fruit-leaf concentra- Islands were analyzed by Ge(Li) tion ratios gamma for indicator and edible spectrometry and by wet chemistry. plant species from the same location. The predominant. radionuclides in In general, 137 these samples are 6006, 20 2 2 239,240), 24d and fh, ral, Cs, , In gene- the radionuclide concentrations the concentration factors 137. . . for Cs in terrestrial vegetation 90 are preater than those for sr. concentration factors Lor both of four areas of Bikini Island appear these nuclides exceed those for 239,240 , Pu by one to two orders of to approximate log-normal distribu- magnitude (10 to 100 times). tions. 90.6, and 239,240), , in soil from Eneu Tsland and from the The median surface-soil concentrations (pCi/g) of Eneu Island by fruit (0.067 for 6006, 4.1 for 706) leaves; 2.9 for t3/es. and 0.22 for lower than é 3 0.25 for 739>74 py 241 Am) are > . ten times those measured on Bikini The is less however, true for IST og, tribution of species to For nuclide uptake than that by mature the opposite is The relative con- the individual plant the internal dose,to man