The two mcthods presented are the "resuspension-factor" approach and the mass~loading' ‘ approach, Soil concentrations of 239py that would be associated with the standard for 239Pu in air (0.05 pCi/m?) by the two methods are: Resuspension=factor approach . ... » « 1,000 pCi/g Mass-loading approach ...-+..+.e-s- 600 pCi/g A recent report, A Proposed Interim Standard for Plutoniun in Soils LA-5483-1IS, presents recomnendations derived from estinates of exposure through inhalation ‘considering the concentration of 239Pu in the very top surface soil. The following values were recornmended: 409 pCi/e - For ail particle sizes provided no more than 290 pCi/s in< 100/nn size fraction. A revised Maximum Permissible Concentration, IMC, of 9.3 nots for individuals was used in these determinations. large area contamination. The estimates apply to Levels several times larger could de permitted for lecalized deposition. The Task Group recognizes that the islands of Enewetak Atoll are small and that the areas of highest 239py in soil on these islands are smaller still. On the other hand the people live close to the soil. It is also recognized that experts are not in asreement as to the critical organ fer inhaled plutoniun, whether to use an average dose for this organ, or the model to be used to predict dose. in the interest of seeking a conservative yet flexible approach to considerations cf criteria to treat the probler :