concentrations in plant samples and Whenever the number of samples is from the average measured concentration large enough, in the associated O- to 25-cm soil are plotted against concentrations profile. in plants from the same sampling factor, We define the concentration CF, site; as soil concentrations the results are analyzed with linear regression methods. CF = pCi/g dry plant These linear regression results pCi/g dry soil are 'statistically significant" at To reduce the variability in average the O.l-level of a standard F test. soil concentrations For each combination of nuclide, (used to calculate the concentration factor), we used 2 plant organ, QO- to 25-cm soil profile that encom- statistically significant regression passes a large fraction of the effec- equations are compared tive absorptive root zone rather of the calculated concentration than to the median the deeper O- to 55-em profile that factors and a single representative encompasses the entire root zone. concentration factor is assigned. Concentration factors calculated on Predictions of radionuclide the basis of the average soil concen- levels in’ foodstuffs can be made tration in the upper 25 ecm of the from concentration factors if profile are somewhat greater but do measured soil concentrations are not differ substantially from those available; based on the deeper profiles ratios are also needed if lL and 2). (Tables All concentration factors reported here are therefore those however, concentration the only available data are from mature leaf samples. The concentration ratio derived from average O- to 25-cm soil is defined as the ratio of concentrations. centration in fruit to the concen- The average O- to 25-cm soil tration in leaves of or, weighted geometric mean for the one species separate concentrations, leaves of another species. profile. than measured at throughout the Concentration values less the minimum detection limit are set equal to the detection limit, following the U.S. Environmental wet Fagg, oa = ?soe art Gri c= Protection Agency technique. as the con- the same species; concentration is calculated as the various increments AANA and species considered, the concentration in leaves of to the concentration in We cal- culted preliminary raties for all available species from the 1975 Bikini survey. However, because of the small number of samples involved, a statistical analysis of results was not possible. these