: Concentration Ratios. avail- able at Enewetak Atoll. Very few locally grown crops are i i The test plots established on Enjebi (Janet) Island have provided data for that island; other than these test plots, the available trees are limited to one or two isolated trees on four or five islands in the northerm section of the atoll. Coconut trees are available in the southern half of the atoll but the radionuclide concentrations are very low and it is difficult to develop reliable data. As a result of the scarcity of locally grow foods at Enewetak which can be directly analyzed, we have developed concentration ratios between food products and soil (pCi/g wet weight in food/pCi/g dry weight in soil) for each radionuclide, using data obtained from our test plots on Enewetak and Bikini Atoils, from the coconut trees on Bikini Atoll which are now producing fruit, and from the few isolated trees on 4 islands at Enewetak Atoll. The mean, standard deviation, median and the high and low values for the concentration ratios developed from “samples collected through November 1978 are listed in Tables 10-13 fer 1376.) 90s,, 23942405, and for 241 poy respectively. The concentration ratios are developed from soil profiles taken to a depth of 40 cm through the root zone of the plants being sampled. This depth is used because from our observations thig depth encompasses most of the root zone of the subsistence plants we have looked at on Enewetak anc Bikini Atoll. A report on the root activity (10) of large mature coconut and banana trees showed most of the activity in the 0-60 cm depth which is consistent with our observations of the physical location a