9}

with depth.

The last section of the core, which contained about 20-407

yylimeda, showed a large increase in radionuclide concentrations which, unforbalimeda

tunately, cannot be verified as a real characteristic of the sediment column
without a deeper core.
The distribution of 600, and 2075; concentrations in the core are unusual

in that decreasing concentrations (with increasing depth) were not present in
the upper 10 cm of the sediment core.

While the concentration of 60¢4 is

relatively constant in the upper 12 cm of the core, the concentration of 2075;
increases 40% with increasing depth between the 2-4 and 8-10 cm sections.
Below the 8-10 cm section in the core, the concentration of

207

Bi decreases

“much Tike that found for 24 An, 15. and '37e5, however, the concentration of

6809 is more constant with depth.

The distribution of

239+240

Pu ratios

measured in different sections of the core are divided by the ratio of 21.1
found in the 18-20 cm section.

Below the 18-20 cm section, the ratios in-

crease with depth from 92.9 to 144, while above the 18-20 cm section the
ratios ranoe from 72.7 to 88.4
The ordering sequence of the radionuclide concentrations measured in this
core varied with depth.

Below the 0-2 cm section, the order changed from that

shown in Figure 19 to the order: Pu > Eu > Am > Co > Cs > Bi in the 2-6 cm
region; to Pu > Eu > Am > Co > Bi > Cs in the 6-26 cm region (one section

differed); to Co > Pu > Eu > Am > Bi > Cs between 26 and 38 cm (one section
differed): to Pu > Eu > Am > Co > Bi > Cs in the 38-40 cm region.
Station 8-20 Sediment Core.
The distribution of 23942405, aare and WoEy concentrations in this

core (Figure 24) are again quite similar and decrease with depth by 50% at
about the 9 cm section.

At 11 cm in the core, a sharp break occurred between

the finely divided material in overlying sections to sand.

Considering the

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