NTS during the cascade impactor run was measured to be 70 ug/m>, Such derived values must, of course, be used with a great deal of discretion. They are based on simple model systems air, and do not consider the additional problems of resuspension of material from contaminated clothing or the resuspension of materia! which has been transferred to homes, Healy”° has which are believed to be generally con- considered these and servative, but individual situations can be other problems, and has provided tables tions. tion levels and home transfer levels. of "decision levels" for surface contamina- imagined which could exceed the predic- A decision level is based upon National Other Considerations Council on Radiation Protection and The above calculations relate only to Measurements (NCRP) recommended the resuspended air activity in ambient dose limitations, Because the derivations ~ Table 152. Decision levels 26 for soluble 239 Pu, and their equivalent in soil mass based upon the "acceptable soil concentration" from Table 151. Pathway Decision level A. Direct personal contamination 2x 107° nCi/em? Direct inhalation® 0.2 nCi/em” Direct ingestion? 8X 1074 uci Skin absorption*® B. 1aSS equivalent 1x 1075 atom? 0.2 g/cm2 0.8¢ Transfer (to homes) levels Resuspension® 0.01 .Ci/day 10 g/day Direct inhalation 0.01 wCi/day Direct ingestion 100 pCi/day 10 g/day Skin absorption 0.03 pCi/day 30 g/day 10° g/day aun, gs . . "The contamination level on clothing and skin that could result in inhalation of air at the MPC, for the public. burhe contamination level on skin or clothing that could result in ingestion of a quantity of radioactive material equivalent to the ingestion of water at the MPC, for an individual in the public. “"The total quantity of radioactive material maintained on the skin for 24 h/day that could result in absorption of a quantity equal to that which would be absorbed from the Gi tract if water at the MPC. for "soluble" isotopes for an individual in the public were ingest Guthe amount transferred per day that could result in air concentrations due to resuspension in a medium-sized home averaging at the MPC. for an individual in the public. uZ&