Resuspension-factor approach ........ee24 1,000 pCi/g Mass-loading approach ....ccccccccccccces 600 pCi/g A recent report, A Proposed Interim Standard for Plutonium in Soils LA5483-MS, presents recommendations derived from estimates of exposure through inhalation considering the concentration of ©39Pu in the very top surface soil. The following values were recommended: 400 pCi/g - For all particle sizes provided no more than 200 pCi/g in < 100/mm size.fraction. A revised Maximum Permissible Concentration, MPC, of 0.3 pCi/m? for individuals was used in these determinations. The estimates apply to large area contamination, Levels several times larger could be permitted for localized deposition. The Task Group recognizes that the islands of Enewetak Atoll are small and that the areas of highest 239Pu 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 agreement as to the critical organ for inhaled plutonium, whether to use an average dose for this organ, or the model to be used to predict dose. It is the view of the Task Group that available biological and environmental information is not adequate to establish general guidance for cleanup of plutonium contaminated soil. However, guidance for a particular set of circumstances or conditions can be developed ona case-by-case basis using conservative assumptions and safety factor. The following guidance is recommended only for use in making decisions concerning plutonium cleanup operations onislands of Enewetak Atoll: 1. Any areas or locations where soil concentrations of 239 Dy are greater than 400 pCi/g should receive corrective action with contaminated soil removed for disposal. IN—-8