studies designed to predict migration rates of plutonium and americium
in specific soils.
Of the several sources listed in the previous section,
global fallout offers the most uniform source of plutonium and probably
will offer the best source for long term migration studies.
FRACTION OF TOTAL PLUTONIUM
lo-*
10"!
Global Fallout
FURIE
¥
rr
re
ee ee
v
q
deBortoli and Gaglione (1969) sampled sandy or loamy sand soils from the
environs of the Euratom Ispra Establishment, Ispra, Italy, in 1966 to
determine the depth of fallout 73%pu (729*?" Pu) penetration.
The 7?9Pu
distribution in two profiles collected some distance apart are shown
in Fig. 1, trace A.
The 7?%pu was found to a depth of 15-20 cm in
samples collected with a coring tool.
(Fowler et al,
1974).
The use of coring tools for the purpose of coliecting soil profile samples introduces a potentially serious cross-contamination variable.
It is possible that both the similarity cf profiles A and B, Fig. 1 and
the amount of plutonium reported at depth, resulted from crosscontamination introduced by the coring tool.
Profile C may reflect
a smaller degree of cross-contamination; however, it has not been shown
that the trench method prevents cross-contamination.
Hardy et al.
oO
N
de Bortoli and Gaglione
Ispra, Italy, 1966
ol
oO
NTS
DATA ADAPTED FROM:
Hardy
(1974)
North Eastham, Mass, |972
(1972) reported 7??py (779°?"°py) in soil profiles from
widely separated locations within the United States.
Less
than 5% of
the total 7?%pu was found in soil profile fractions below 30 cm.
of these same profiles were reported by Bennett
Some
(1976).
McLendon (1975) reported the results of studies to determine the verti-
cal distribution of
7?8pu and 73%pu (739+?""puy in the on-plant and
50
email ff,
Fig. 1.
a
5
A
Results
indicated that in most cases the
7?"pu and
?3%Pu
were localized in the top two increments and remained relatively immobile.
46
n_f_
tf _8.
a.
hah.
Global Fallout Distribution in Sandy Soils.
off-plant environs of the Savannah River Plant, Aiken, SC.
In 1973,
soil profile samples were collected by coring and slicing the cored
soils into 0- to 5-, 5+ to 15-, 15- to 22.5-, and 22.5- to 30-cm increments.
(1969)
Hardy and Krey
(1971)
Brookhaven, NY, [970
>
oO
file was also collected with a coring tool and compares closely with
the profiles taken in 1966 from Ispra.
In 1972, Hardy (1974) measured
739,2495) in a soil profile from North Eastham, MA., the first of a proposed
time series of profiles (Fig. 1, trace C).
This soil was not sampled
by a coring method; rather, samples were cbtained using a modification
of the trench method used by the Nevada Applied Ecology Group (NAEG) at
SOIL DEPTH (cm)
In 1970, Hardy and Krey (1971) measured 7239p (799,2"%DQ) to a depth of
25-30 cm in a sandy soil in Brookhaven, NY {Fig. 1, trace B},
This pro-
47