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 Rat! " Plutonium in soil is resuspended at rates similar to the soil material, e.g., the specific activity of soil equals the specific activity of air particulates, q 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 Oeetime tone the returning population, combining the farguments;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 pub- lished by the U. S, Dept. of Health, Education, and Welfare* for the ” yt ya a or *Air Quality Data, 1966 Edition, APTD 68-9 ” + we ’ ~, : t. Be . agWaa, : : Sahar: . . ft ow) . te ray vey . Sees . Lo a oe ’ * “y mmr, . . eg soy tu a age te Rew, Sey 1 eae y : ’ er we »- for ingestion of plants by man.r These assumptions are: 1, . oo ah’: = me a :