-22- “1 ni . DRA factors developed using soil sampled from the root zone of the vegetation under investigation showed a greatly reduced range of values in comparison with values developed earlier from unassociated vegetation and soi] “samples (28, 29, See also Table 17 this paper). The concentration factors developed from this survey are more precise ‘and provide a better basis for estimating the average radionuclide concentration which would be expected from crops planted in certain regtons within an island or on different islands. Despite the greater preciseness of concentration factors calculated from associated vegetation and soil data, these values still show some variability. This remaining variability can be accounted for by several factors acting either alone or in concert. 1}. These factors include: | differences in soil type, organic content and chemical characteristics | 2. differences in physiochemical properties of the radionuclides 3. differences in soil management practices 4. differences in irrigation practices 5. differences in the physiology, age and prior history of the | sampled plants ‘One would in fact expect to see some variation in sampling conducted within a specific tree just due to normal biological variability. In addition to the development of CF, the data from the large surface soil sampling program (5) were used to develop average soi] concentrations for four regions on Bikini Island and for the whole of Eneu Island. These average soil concentrations’ were then used in conjunction with the concentration factors we developed to predict the _ 5009891 7dq