-556- atarnu Island research (e.g., boat support), we will field a resuspension study on Engebi Island late this fiscal year or in FY 1979. Im Distributton of '37cs. In addition to the data presented itn the publication list, we completed the evaluation of 137Cs distribution in the canopy, small wood, trunk, roots, and litter of the major trees on Engebi !sland. The leaves contained about 20% of the activity fn the entire plant; wood less than 2.5 cm in diameter, 20%; wood between 2.5 under the canopy. >” and 7.5 cm in diameter, 102; and wood greater than 7.5 cm in diameter, 35%. Dead wood contained the remaining 15% of activity. The total activity in the tree was only 6% of that contained in the soil columr Our evaluation of the litter revealed that !5’Cs js leached rapidly from fresh litter and Is bound into the organified fraction of the soil. tn this form, the !37¢s is again available ‘o. recycling into the growing vegetation. The canopy and litter are therefore crucial steps in the cycling of radionuclides. ti de a: te Soil Moisture and Water Flow. As a result of the clearing of Engebi Island, we lost most of oar sensors and monitors of soil moisture and water flow in the soit! column. The water flow in the soil column and the seasonal changes In soil moisture are most [mportant in evaluating the availability, uptake, and cycling of radionuclides in me to obtain these data. pe the atoll ecosystem. 17. re We will reestablish the necessary field equipment tl ti EXPECTED RESULTS FOR FY 1979: Bikini Atoll lf We will maintain the test gardens and evaluate the uptake and concentration factors for the subsistence crops on Eneu Island. During this year, we wil! generate a data base sufficient to refine the initial dose estimates for Eneu fsland developed from the 1975 survey. In addition, the data from our initial resuspension experiment on the atoll! wil? be evaluated. We plan to field a follow-up experiment to provide the final data base for developing the general! resuspension model and. for refining the dose assessments via the inhalation pathway. We also will take advantage of our presence on the atoll to collect more data on the uptake, concentration, and time-dependence of radionuclides in the pandanus fruit which wilt be maturing on Bikini Island. Next to breadfruit, pandanus is the subsistence crop for which there is the least available data. The subsistence crops on Bikini island will continue to be used as permanent sampling stations to help evaluate the time-dependence of radionuctide removal from the Bikini environment. Ae Because Bikini and Eneu Islands are much less disturbed than the Enewetak Atoll, we will initiate studies of soil-water movement and the soil-water availability to plants on Bikini Atoll. Knowledge of the s* £ We