238pu (approximately 5% of the 239-240py) is present in fallout and can be
analytically distinguished from 239,240py, Elevated concentrations of the
238py isotope are found near Mound Laboratory, a plutonium fabrication
STILLWATER RIVER ——*
facility located in Miamisburg, Ohio.
Mound Laboratory releases 238py to the Great Miami River in three ways,
A 114,000-liter industrial wastewater tank normally containing 50—200 pCi
of 238py is periodically discharged directly into the river (Carfagno, pers,
RIP RAP
NIML
About 100 pCi per year is released from two stacks and settles
=
comm.).
out within 5 to 8 kilometers of the laboratory (Muller et al., 1974; 1975).
much of this
Pu then enters the river during rainfall and subsequent
erosion and runoff (Bartelt et al., 1974). Finally, there is a continual
movement of 238py enriched sediment from a series of ditches, canals,
ponds, and storm sewers which empty into the river, Most of the plutonium
in this enriched sedimentis a result of a spill in 1969 on the laboratory
grounds (Rogers, 1975), Although some of the enriched sediment has presumably been carried into the river by now, the remainder constitutes a
source of
Pu particularly important during rainstorms when sediment loss
is accelerated, Because the plutonium from Mound Laboratory ts the 238py
isotope and fallout plutonium is primarily 239.240py, ratios of 238pu to
239,240py are useful in indicating the source of plutonium in a sample,
CHAUTAUQUA —\—*i
SEVENMILE—>
CR.
MIAMISBURG
{
Hy ERANKLIN
BRIDGE opPAR
TRENTON
_
Y
MATERIALS AND METHODS
Samples were collected from sites upstream and downstream of Mound
Laboratory (Fig. 1).
Two sites, Rip Rap Bridge on the Great Miami River
Ay HAMILTON
and Stanley Avenue Bridge on the Mad River in Dayton, are 20—30 km upstream of Mound Laboratory and considered background sampling sites.
Fish were collected using gill nets, seines, and a portable electrofishing
unit. Several large carp were obtained as the result of a boom shocking
survey for Dayton Power and Light Company conducted by De Pauw University, Green Castle, Indiana, Crayfish were collected by hand or by seining.
All samples were frozen in the field and stored in freezers until analysis.
The samples were thawed, and wet weights were determined. They were
A
ce
ELIZABETHTOWN
Dp “VD
then dried to a constant weight at 105°C and ashed at 500°C, The ash was
homogenized and subsamples were spiked with 242pu as a yield monitor.
The samples were digested and analyzed for plutonium according to the
procedure of Nelson et al. (1973).
CLEVES
i;
Sp Q
RESULTS AND DISCUSSION
Mh
aq. v CINCINNATI
4
Qorp
Results of the analyses for the fish samples are summarized in Tables 1 and
2. These samples were whole fish unless otherwise stated. No goldfish
were collected at any background sampling site. The carp sample collected
in Dayton is upstream of Mound Laboratory's effluent discharge point and
518
Figure 1,
Great Miami River sampling sites,
que
519