18
species and the concentrations and physical-chemical forms of plutonium in
natural waters.
However, as stated by Silver (op. cit.), the behavior of
nlutonium presents a far less troublesome problem than the definition of
“natural water."
The complex chemical and variable situation existing within
the biologically productive environment at Bikini illustrates this problem
well.
Schell (1974a) has reported on the physical-chemical states, in situ-
of 155,
239+240
Pu, and
24)
Am and other radionuclides in Bikini Lagoon.
Europium and americium both apparently exhfbi
soluble components, with JE xe
Mw
a yb
the >.3 pm particulate fraction containing 18-100 and 30-100 percent of Mee”
yo
radionuclides, respectively.
The remaining fraction was found as <.3 yma
was interpreted as being colloidal-particulate material.
Plutonium, on the
other hand, was found to exhibit a large “soluble” fraction with the <.3um
fraction showing a large variability in relative proportion and the ».3 um
particulate fraction comprising between 4 and 75 percent of the total activity.
In summary, there exists an interesting question as to the deoree to
wich certain radionuclides (Ce, Pm, Eu, Pu, Am, Np, etc.) have been released
fro- their sphere of influence in the original fallout particle.
[t is also
evident that the very refractory nature of plutonium dioxide, which is a
eessitle form of condensed plutonium, could have a significant effect on its
sutsequent environmental behavior and redistribution.
ascut the behavior of americium in the environment.
Very little is known
Although a great deal
rrre {s known about plutonium, the complexities of its distribution between
y Bossible physical states is troubling. Evidence exists that Pu02 (C03)2
‘s te dominant soluble plutonium species in seawater, in vitro, although
rae
“tivers model (op.cit.) would predict that the low complex forming tendencies
c* the #6 state favor it as the dominant state in seawat
er.
The presence of
*t* very stable and insoluble compounds Pu0o and colloidal Pu (IV) probably
.