KK A5 om ae ee 3. ee ai : . and Bikint are very difficult but important processes to assess to estimate the cumulative exposure to plutonium from inhalation. Bennett’ has recently concluded that plutonium from resuspended fallout at New York presently contributes 0.3% and will ultimately contribute an additional 0.2% of the intake that occurs during the original deposition of the fallout debris during any time period. The soil plutonium levels on Bikini Island are certainly, on the average, higher thanfallout levels deposited in the United States®. Visual observations indicate that the formation of dust clouds or resuspension of surface materials by people or vehicles at Bikini is slight even during very long dry spells. However the available comparative aerosol data shows that some locations on Bikini Island have higher levels. of plutonium in the air than expected from world wide fallout and higher levels than those encountered in New York City during comparable periods. We shall show in a following section that resuspension may also contribute elevated plutonium levels to the ingestion pathway at Bikini. Comparable data on plutonium concentrations in the air exists only for the periods of late May to early June 1970° and May 197219. During the q 239,240 1970 sampling period, Pu levels in surface air were determined at five locations on Bikini Island. The aeolian concentrations during this period of 29 May to 2 June 1970 ranged from 60 to 540 aci/m= (aCi = attocurie).” The mean air concentration at 4 sites on the island of Eneu (Bikini Atoll) was only 40 aCi/m? during a comparable period.? Plotted in Fig. 1 as a function of latitude, are the average plutonium concentrations at ground level at air sampling stations of the HASL sampling network during June 1970.1! ? gs, ro ee fr:2a es — The