18
6
Zn 5 peak.
The presence of zn°> is corroborated by the 0.5-mev
peak.
8 also shows the gamma-ray spectrum of noddy tern
Fic.
guano collected in this area.
,
over the 1.17 peak of Co
60
The 1.12-mev peak predominates
and the 0.51 peak of Zn
65
,
.
is evident.
Tne foliar contribution to the litter contains only cs*37 from
among the gamma-emitters.
.
137
90
.
toa
In undisturbed areas Cs
and Sr
are being deposited
with the litter and are thus replacing at the surface some of
the Cs
137
and Sr
90
.
lost by leaching.
:
tos
There is not sufficient
data from the field work to determine whether there eventually
will be a loss of these radionuclides from the soil-plant system,
or a steady state
(excluding physical decay of the radionuclides).
Long-term experiments, under simulated field conditions, with
monolith lysimeters
and controlled and uniform addition of the
radionuclides would define this point.
Young Soil
Fig. 9 gives the spectra of the 0 to l-inch, 1 to 2-inch,
.
and 9 to 10-inch increments of a young soil.
60
65
144
Co, 2n
~, Ce
-
prit4 and But? were detected only in the surface layers, and
with increasing depth the 0.60 to 0.66-mev photopeak region of
the spectra shifts toward the 0.60-mev peak of sb? ,
The spec-
trum of the 9 to 10-inch increment is compared with that of an
spt? spike in Fig.
10,
showing that the photopeaks of the soil
and spike gamma spectra are identical.
AS