C ( A guide for assessing the importance of a certain soil level of Pu on Enewetak can be arrived at by a set of conservative assumptions regarding the resuspension pathway, This is the "'critical'' pathway since the inhalation route to man is more hazardous than the soil-root pathway for ingestion of plants by man. These assumptions are: ae 1, Leon, Vat © tet Plutonium in soil is resuspended at rates similar to the soil ed ; s ewAd ¢ Laat material, e,¢,, the specific activity of soil equals the specific activity of air particulates, 2, All particles in air originate from local soil, 3. Plutonium in air is all in the respirable range of particle size and is soluble in lung fluids, Appendix II develops average lifetime exposure to particulates in air by Prtnnnt the returning population, combining thé‘ireumenic outlined above with an analysis of air concentrations and time-of-exposure weightings to be expected for the mix of environmental conditions associated with routine activities (ambient) and under special conditions which stir up the soil, In Table II are reproduced airborne particulate concentration data published by the U. S, Dept, of Health, Education, and Welfare* for the oe *Air Quality Data; 1966 Edition, APTD 68-9 , ri .o ae Se Ae + ee . ae tee ‘ aay 2 aE ’ — yescee ay ewes Ieper y “mone. Caeaeosee els ” >> ae, - PORTS~ er TT ge . oS mit ww , ite Be ie by" . i a ',a . i “ Vor or ‘ad Seng teee as ate es ot, =7 a ye R. oe 3 . wo. a Be gh ata TOgg NE sy Bg ER ee oh se ate! PO TT RT MEN a BS Se Be ees .