UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
REGIONS
230
SOUTH DEARBORN
ST.
CMCAQO,
ILUNOI8
60604
(
,
<•»
-
-,,-v.->.i
I EPA
Region
5
Records Ctr.
MAR
2
D
1991
!
200SS1
REPLY
TO
ATTENTION
OF:
5RA-14
Honorable
John Glenn
United
States Senate
Washington,
D.C. 20510
Dear
Senator Glenn:
As
indicated
in our
December
18,
1990 letter
to you
regarding
the
design investigations proposed
for the
Industrial
Excess
Landfill
(IEL) Site
in
Uniontown, Ohio
the
United States Environmental
Protection Agency (U.S. EPA)
is
committed
to
properly designing
and
implementing
the IEL
remedy.
In
response
to
concern raised
by
the
public
and
members
of
both your
and
Senator
Metzenbaum's
staff,
the
U.S.
EPA has
incorporated
sampling
for
radioactive
compounds
in the
remedial design studies being conducted
at
IEL.
As
you are
aware,
U.S.
EPA has
proposed
to
sample
groundwater
and
landfill
leachate with comprehensive radionuclide analysis.
In
addition,
U.S.
EPA
will filter
the
Methane Venting System
(MVS)
stack influent
and two
pilot
gas
extraction wells
in the
center-
line
of the
landfill
for
radiological
particulates.
This letter
and
its
enclosures convey
the
results
of
U.S.
EPA's
statistical
analysis
of the
probability
of
detecting radionuclides
via
ground
water monitoring. This
statistical
analysis
and
ground water
model
involved much detail, requiring more time than originally
anticipated
to
complete. These
results
supplement
the
informa-
tion
provided
in our
earlier
correspondence,
which discussed
U.S.
EPA's
rationale
in
support
of our
decision
not to
characterize
the
waste material
by
soil core sampling with analysis
for
radionuclides.
The
results
of
that study revealed
the
proba-
bility
of
locating
a
hypothetical radioactive waste source
for
the
first time with
50,000
boreholes
to be
only 0.22.
In
the
enclosed ground water modeling report,
a
three-dimension-
al,
unidirectional analytical transport
model,
PLUME,
was
used
to
estimate
the
concentration
of
three potential radioactive sources
(cesium-137,
tritium,
and
uranium-234/238)
downgradient
from
the
landfill
at
selected time periods.
The
input parameters chosen
for
the
model were based
on
available site
data
and
accepted
modeling
practices.
It
should
be
noted that since
no
activity
data
for
downgradient radiochemical compounds exist
to
calibrate
the
model,
certain assumptions were made concerning
the
source
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