-12- both dust and sea spray so that the total mass obtained by integrating the volume distribution and multiplying by a density factor would not be expected to agree with the dry, residual mass loading measured by HV andCIP. The relatively good agreement obtained between the different measurement systems indicated in Tables 1, 2, and 3 gives us the confidence to draw conclusions about the significance of resuspension for enhanced inhalation exposure in this worst case example. If the total plutonium activity (pCi g-l) is obtained by integration of the curves of Figure 1; we find that there is a significant change in the aerosol plutonium activity relative to the plutonium activity of the surface soil. Let us define an enhancement factor (EF) as follows: . ~F = total aerosol activity (pCi g-l) . soil activity (pCi g-]) Upon investigation of the enhancement factors, we find that the values apparently were less than one under normal conditions (Table 4) probably because of selective resuspension of non-radioactive particles whichserved to dilute the plutonium activity. There is no evidence how this occurred. Marten surmises ratio values should be greater than one, but gives no evidence (8). The ratio of organic particles to calcareous soil particles remained about constant (10%) as determined by X-ray fluorescence on the PD filters exposed at this site during the same period. Me know from previous studies that one component of organic matter, plant leaves, had a ratio of 10-3 plutonium concentration relative to soil and could serve to dilute the inorganic aerosol. ) -. TABLE 4. Enhancement factors for plutonium activity of aerosols on Bikini Island (HV data). Soil Activity (pCi q-l) Aerosol . . ~;;;v;:$ 5/6-8 15.3 47.5 3.10 Stabilized bare soil 5/10-11 15.3 14.7 0.96 Stabilized bare soil 5/12-16 15.3 10.5 0.69 Coconut grove 5/8-16 8.01 Road with traffic 5/8-16 4.10 Site Disturbed-bare Date soil 3.29 10.3 Enhancement Factor ::_: 0.41 2.5 Under dusty conditions, EF values exceed one such as in the cases of the disturbed bare soil (3.1) and the road with ”traffic (2.5). So_there.are. two. .djfferent factors producing increased plutonium aerosol concentrations (aCi m-3~ ciyr.i.ng-unusual resuspension. T~e...aer~~ol_dust“concentration increases, but also .__.. the plutonium activity.increases. For e~ample, averaged over 10 HV instruments’ ._..,.---., ..... - . ..--4- -...- . . . / , ..-.< . L ..