239, 05, 36 days, from July 7 to August 12, 1972, table results reported for 236, The collected 239, 240 Pu activity was concentrations ranged from 3.5 X 10 distributed lognormally with particle to 6.3 x 19°13 uCi/em?, with arithmetic size with an activity median aerodynamic and geometric means of 6,6 X 19° 15 and 7.9x 107 18 diameter (AMAD) of 3.0 um and a geometric standard deviation of 8.2, The uCi/ cm, respectively, Re- sults for four soil samples taken from 239, 2405, concentration varied from approximately the same location range 1.010714 to 3.9x 10 !4 uci/em3, from 128 to 202 dpm/g, with a mean of with an average of 2,3 X 19° !4 uCi/com? for the five samplers, -17 160 dpm/g!, At the present Because the arithmetic mean is a better representation of average time only limited data are available re- lung exposure, it is used to derive a re- garding the soil activity in the area, ~ suspension factor at this site: Four soil samples of depth 0-3 cm from 66x10 uci, em? approximately the same location have ¢ 160 dpm ,_cm® “1,8 g x O29 4 107 om ,, 2.22 x 10° dpm | .been analyzed with results !? of 2060 to 3 cm 3550 dpm/g, with a mean of 2700 dpm/g. m pCi Profile data from other locations at the -2xX10°/m. same general site indicate that about 90% This value is nearly an order of magni- of the total deposition is contained within tude higher than the one previously calcu- the top 2,5 cm of the soil”, lated, and reflects some of the inherent Measure- ments of soil density in the area average difficulties in the resuspension-factor 1.8 g/cm? , approach, i.e., that no allowance is made is therefore 2.3X 10° cm? 0.9 x 3 cm x The resuspension factor 14 : uCi x 10% cm. m x . fz 2700 dpm cm for the geometrical configuration of the 3 source and that higher ground activities “1,8 g may be present upwind, 2,22 X - 10° dom It is obvious that this approach is sub- uci =-3x1019m, ject to major uncertainties, but does Additional air samples were taken by of the resuspended air activities that may serve as an order-of-magnitude indication g the Reynolds Electrical and Engineering arise froma 239, 2405), contaminated Co. (REECo) on the edge of the contamin- area which has weathered for 15 to 20 yr. ated area during the pericd of February The data discussed above also demonstrate 1S71 to July 1972, with a sampling time unequivocally that resuspension of of approximately 48 hr 239, 2205. does in fact occur from such Measurements were made at four locations, but the 4 aged deposits and at ievels many orders most pertinent is the one which was most of magnitude higher than would be ex- frequently in the direction of strong winds pected if the often ncted decrease with from the strongly contaminated area and time were represented by a single exponen- where the highest air activities were tial function with a half-time of 35 to 70 recorded, days, Here, 254 individual air- filter samples were collected and detec- H-18