36 days, from July 7 to August 12, 1972, The collected 23% 240 Pu activity was distributed lognormally with particle size with an activity median aerodynamic table results reported for 236, 239, 205. concentrations ranged from 3.5 X 10°}? to 6.3 x10 33 uCi/em, with arithmetic and geometric meansof 6.6 X 19° 9 and diameter (AMAD) of 3.0 um and a geo- 7,9X 10° 16 uCi/em’, respectively. metric standard deviation of 8.2, sults for four soil samples taken from The Re- 239, 2405, concentration varied from approximately the same location range with an average of 2.3 X 10° 14 uCi/em 3 from 128 to 202 dpm/g, with a mean of 160 dpm/g". Because the arithmetic 1.0 x 107!4 to 3.9x 10° !4 pci/em9, for the five samplers. At the present time only limited data are available regarding the soil activity in the area. Four soil sampies of depth 0-3 cm from approximately the same location have -been analyzed with results?! of 2060 to - 3550 dpm/g, with a mean of 2700 dpm/g. mean is a better representation of average lung exposure, it is used to derive a resuspension factor at this site: 6.6X10 uli, cm? 2 160 dpm’ em? 1,38 ¢ x 0,9 x 10° em y 2.22 x 10° dpm . 3 cm. m BCI Profile data from other locations at the =2xX10°9/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 caicu- the top 2.5 cm of the soi ?, lated, and reflects some of the inherent Measure- ments of soil density in the area average difficulties in the resuspension-factor 1.8 g/cem’ . approach, i,e., that no allowance is made The resuspension factor is therefore 2.3.x 10 ** uci, _¢ -1 cm” 2700 dpm x £m 3 1.8 g 0.9 10 cm y 2.22 x 10° dpm x 3 cm m uCi =3X10 -10 “‘/m. Additional air samples were taken by the Reynolds Electrical and Engineering for the geometrical configuration of the source and that higher ground activities may be present upwind, It is obvious that this approach is sub- ject to major uncertainties, but does serve as an order-of-magnitude indication of the resuspended air activities that may Q arise from a 239, 2405, contaminated Co, (REECo) on the edge of the contamin- area which has weathered for 15 to 20 vr. ated area during the period of February The data discussed above also ce monstrate 1971 to July 1972, with a sampling time of approximately 48 hr? Measurements unequivocally that resuspension of 239, 2405, does in fact occur from such were made at four locations, but the aged deposits and at levels mary orders most pertinent is the one which was most of magnitude higher than would be ex- frequently in the direction of strong winds from the strongly contaminated area and where the highest air activities were recorded, Here, 254 individual air- filter samples were collected and detec- pected ir the often noted decrease with time were represented ty a single exponential function with a half-time of 35 to 79 days.