- 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,