~is fot Taped ake Bi tee = 1 ate ee age BARES — 2etoute. eneretnameeehhRSae C xe @ ani 100 picocuries per em” would contain about 4 x 10° particles per square meter. If all of these particles were on the soil surface and therefore available for resuspension, there would be initially only 4 particles per cubic meter of air for a resuspension factor (RF) value of 107°, This air concentration would decrease exponentially with a half-life of around 30-40 days as the particles remaining on the soil surface become less available for resuspension. The Concentration Guide for continuous inhalation of 239py is 1 pCi/m (averaged over one year for the individual in the population). Thus, initial ground concentrations of 100 picocuries per gram (assuming a gram per em® of surface) may be taken to correspond to a deposition of 10° pCi per square meter. For a RF value of 1076, the initial air concentration would be 1 pCi per cubic meter. This value would decrease as a function of time because the plutonium becomes less available for resuspension. Based on the highest reported plutonium level at Bikini Island, 190 pCci/g, and assuming this plutonium to be recently deposited and on the surface, a conservative estimate is that the total lifetime dose to the lung would not exceed 70 millirads. Other Data. A brief verbal report was obtained April 6 from Dr. Robert Conard of Brookhaven National Laboratory who has just returned from conducting another in the series of medical studies for the natives Mo 2 ( MTYS )22