- 14 Soil Concentrations soil concentration of 239,240, for the northern The average half of Enewetak Atoll is 12 pCi/g (Ref. 1). The 24.vas ratio in the soil at Enewetak is 0.36 (Ref. 1). 239,240, Therefore, the present 241 am concentration is 239 2405, 12 pCi/g (0.36 241py (23924054) = 4.3 pCi/g 241am, Assuming the same ratio for 2415 1239 240p,, of 1.85, the 241py activity is 1.85 (12) = 22 pCi/g 41oy, The maximum grow in of 24lLan from this level of 7“pu is 22 (0.026) = 0.57 pCi/g When the calculated increase from 2 241a thoy of 0.57 pCi/g 2A is compared to 4.3 pCi/g of 241 am now present it represents a 13% increase. The total *4lam will be 4.3 + 0.57 = 4.87 pCi/g. When compared with the 12 pCi/g of 239 ,240 239 , 240 Pu present, the 241 Am level will be 41% of the Pu Ground Water The average 239 , 240 is 5.4 fCi/1 (Ref. 3). is 10 fCi/1. 241 Pu concentration in the ground water on Enjebi Using the 1.85 factor the 241 Pu concentration Am concentrations have not yet been measured but assuming a similar ratio for 241 Am t o 239 ,240 Pu in both the lagoon . 241 . water and ground water an estimate of the Am in ground water can be made. 5.4 £Ci/1 799>740py in ground water (4.3 £Ci/1 241"Am in lagoon water) /39 £Ci/1 in the ground water. 239 240 Pu 241, Decay of 24.ou leads to a 43% increase in 24.an concentration and the total 2 activity. in lagoon water = 0.6 fCi/1l 41 Am activity is 16% of the 239,240,