EPA-520/3-75-02]
••^••^^•v
PRELIMINARY DATA ON THE OCCURRENCE OF
TRANSURANIUM NUCLIDES IN THE ENVIRONMENT
AT THE RADIOACTIVE WASTE BURIAL SITE
MAXEY FLATS, KENTUCKY
U. S. ENVIRONMENTAL PROTECTION AGENCY
Office of Radiation Programs
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PRELIMINARY DATA ON THE OCCURRENCE OF
TRANSURANIUM NUCLIDES IN THE ENVIRONMENT
AT THE RADIOACTIVE WASTE BURIAL SITE
MAXEY FLATS, KENTUCKY
\
G. Lewis Meyer
February 1976
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RADIATION PROGRAMS
WASHINGTON, D.C.. 20460
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FOREWORD
The Office of Radiation Programs carries out a National Program
designed to evaluate man's exposure to ionizing and nonionizing radiation
and to promote development of controls necessary to protect the public
health and safety and assure environmental quality.
Within the Office of Radiation Programs, problem areas have been
defined and assigned a priority in order to determine the level of effort
expended in each area. One of these, the waste management problem
area, has been assigned a high priority and requires the participation
and cooperation with several State and Federal agencies. This is one
of a series of reports directed at a specific Environmental Protection
Agency task of establishing action guidelines for radioactive waste
management and disposal based on radiation exposure levels. Other
reports, recommendations, and State assistance are being developed
and executed to fulfill EPA obligations in the management and disposal
of all types of radioactive waste including high-level wastes, low-level
wastes, transuranium-contaminated wastes, mill tailings, naturally-
occurring radioactive wastes and wastes from decommissioned nuclear
facilities.
This report discusses the disposal of low-level wastes at a specific
site, Maxey Flats, and the possibility of whether plutonium is migrating
from the trenches. The important points in this paper are; (1) plutonium
and other radionuclides are out of the trenches; (2) the data suggest that
plutonium may be migrating through the ground; and (3) this occurrence
can and must be prevented in the future.
The potential for a health hazard is not an issue in this paper.
Health authorities from the State of Kentucky, the Nuclear Regulatory
Commission, and EPA have all advised that the levels of plutonium
detected in the environment at Maxey Flats do not constitute a health
hazard at this time. Likewise, EPA earth scientists do not believe
that the mechanisms suggested in this paper regarding plutonium1 s
mobility in the environment apply to the disposal of plutonium in a
deep geologic disposal situation such as has been suggested for the
ultimate disposal of high-level and transuranium-contaminated wastes.
Rather, the problems discussed herein are believed to be associated
with the disposal of plutonium and other radionuclides in shallow landfills
in humid climates using present methods.
111
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The Nuclear Engineering Company, Inc., under the direction of
the Kentucky Department for Human Resources and with recommendations
from the Nuclear Regulatory Commission, has taken significant actions
which have entailed considerable expenditures in time, money, and man-
power to correct the problems described herein. These efforts are
recognized but were not within the scope of this report which basically
is a scientific report using this site as a field laboratory to evaluate
the existence of pathways for the movement of buried radioactive
waste to the environment.
Review comments were received from the Nuclear Regulatory
Commission (NRC), the Energy Research and Development Agency
(ERDA), and the Nuclear Engineering Company, Inc. (NECO) and were
quite valuable to the final editing of this report. Where it seemed
appropriate, the suggested changes were incorporated into the report;
in some cases EPA disagreed with the comment. Several valid
suggestions were too cumbersome to incorporate within our publication
schedule. The comments of ERDA and NRC and our responses to them
are included as Appendixes D and E. More than one hundred comments
and considerable exhibits were submitted by NECO. These comments
were considered in detail and some suggested changes and data were
incorporated; they are, however, too lengthy to present herein.
Five preliminary EPA-funded studies at the Maxey Flats facility
are in the final stages of completion. These studies cover the hydrogeo-
logy, the occurrence of radionuclides, the pathways for radioactivity
to man, and the inventories of wastes buried at the site. Publication
of these reports has been given a high priority and is expected within
the next few months.
I encourage users of this report to inform the Office of Radiation
Programs of any omissions or errors. Your additional comments
or requests for further information are also solicited.
W. D. Rowe, Ph.D.
Deputy Assistant Administrator
for Radiation Programs
IV
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ACKNOWLEDGEMENTS
The author is grateful to the Kentucky Department for Human
Resources for the use of the Pu data from their "6-month" report.
David T. Clark was requested to participate as a co-author of this
paper but could not because of pressing official duties; however,
details about the site, its operations, and the sample data furnished
by Mr. Clark were invaluable.
Other investigators at the site including H. Kolde (US EPA,
evaporator study) D. M. Montgomery (USEPA, environmental path-
ways study) and H. H. Zehner (USGS, hydrogeological study) and the
staff of the Nuclear Engineering Company, Inc. (Site operator) who
generously gave access to preliminary data from their studies
and contributed through stimulating discussions of the phenomena
they observed and by critically reviewing this paper. Thanks are
also due to I. J. Winograd and J. E. Dieckhoner for their critical
reviews and discussions.
Special acknowledgement is given to Philip S. Berger, for his
assistance in preparing this paper, and to Mrs. Hattie M. Leonard
and Ms. Ella M. Thomas of the clerical staff for typing it.
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CONT ENTS
Chapter Page
FOREWORD iii
ACKNOWLEDGEMENTS v
ABSTRACT x
1. INTRODUCTION 1
1.1 Background 1
1.2 Scope 2
2. BURIAL OPERATIONS . . 2
2.1 General Operations 2
2.2 Water Management Program 3
3. SITE DESCRIPTION 5
3.1 General Setting 5
3. 2 Geology , 5
3.3 Hydrology 8
3.4 Hydrogeology and Potential Pathways 9
4. SOURCE TERM 13
4.1 Waste Volume and Activity 13
4. 2 Waste Character 15
5. RADIOCHEMICAL DATA 16
5.1 Data from "6-month" Study 16
5.2 Sampling Methods 18
5. 3 Other Radiochemical Data 20
6. INTERPRETATION 21
6.1 General 21
6.2 Background and Contamination Levels 23
6.3 The Leachates, A Mobile Source 26
6.4 Other Sources of Contamination 27
6.5 Surface Runoff Pathway 28
6.6 Interflow Pathway 33
6.7 Subsurface Pathway 36
6.8 Atmospheric Pathway 42
VI
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Chapter Page
7. ENVIRONMENTAL IMPLICATIONS OF MAXEY
FLATS PLUTONIUM DATA .......... 44
7. 1 Low-Mobility Concept of Plutonium .... 44
7.2 The Mobile Concept of Plutonium 45
7. 3 Behavior of Plutonium When Buried in a Landfill
at Maxey Flats 47
SUMMARY AND CONCLUSIONS 50
REFERENCES , 52
APPENDIXES
A. Cross-contamination of soil samples by using dirty
coring device 57
B. Cross-contamination of well samples by using dirty
sampling device (bailer) 59
C. Concentration of Pu-238 and Pu-239 and ratio of Pu-238 to
Pu-239 in suspended solids and soluble portions of water
samples collected from test wells at Maxey Flats burial
facility . 62
D. EPA responses to the review comments of the Energy
Research Development Agency on, "Preliminary data
on the occurrence of transuranium nuclides in the
environment at the radioactive waste burial site, Maxey
Flats, Kentucky" 63
E. EPA responses .to the review comments of the Nuclear
Regulatory Commission on, "Preliminary data on the
occurrence of transuranium nuclides in the environment
at the radioactive waste burial site, Maxey Flats,
Kentucky" 69
FIGURES
1. Generalized geological cross-section of the Maxey Flats
Region, Kentucky
VII
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Page
2. Stratigraphic column and lithologic description of the
geology at Maxey Flats, Kentucky (after McDowell,
et al [13]; unit thickness from EM CON [18] ) 7
3. Schematic diagram of water pathway at Maxey Flats ... 10
4. Photo of jointed Nancy Member 12
5. Projections (as of 1972) of burial growth rates for volumes
of waste and quantities of Special Nuclear Material at Maxey
Flats burial facility 14
6A. Concentration of Pu-238 in samples collected from soils,
test wells, and streams in and around the Maxey Flats
burial facility during the KDHK's "6 -month" study 19
6B. Concentration of Pu-239 in samples collected from soils,
test wells, and streams in and around the Maxey Flats
burial facility during the KDHR's "6-month" study 19
6C. Ratio of Pu-238/239 in samples collected from soils,
test wells, and streams in and around the Maxey Flats
burial facility during the KDHR's "6-month" study ..... 19
7. Location and summary of concentration of Pu -238 and
Pu-239 and ratio of Pu-238 to Pu-239 in "on-site" soil
samples collected at Maxey Flats burial facility by KDHR
in their "6-month" study. Locations of soil core samples
are also shown. (Adapted from maps by EMCON, [18]
and Clark [1]) 29
8. Location and concentration of Pu-238 and Pu-239, and ratio
of Pu-238 to Pu-239 in "off-site" soil and sediment samples
collected around Maxey Flats burial facility by KDHR in
their "6-month" study. (Adapted from U.S. Geological
Survey, Farmers, KY., and Plummers Landing Quadrangle
topographic map.) 31
9. Schematic cross-section of trench area of Maxey Flats
burial facility showing the concentration of Pu-238 and
Pu-239 and ratio of Pu-238 to Pu-239 and the spatial
relationships of the soil cores collected in the KDHR
"6-month" study ' 34
Vlll
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Page
10. Schematic of construction of test wells at Maxey Flats for
which Pu data are presented in this Report. (Based on
Information presented by EMCON [18].) . 37
11. Three dimensional isometric stratigraphic panel diagram.
which shows the wells 3E, 6E, 8E, 10 E, and HE, the
geologic formations they penetrate, the potential source
term, some of the hydrology, and potential zones where
contamination could enter in the subsurface beneath the
Maxey Flats burial facility 41
TABLES
I. Concentration of Pu-238 and Pu-239 and ratio of Pu-238 to
Pu-239 in samples collected from soils, test wells, arid
streams in and around the Maxey Flats burial facility
during the KDHR's "6-month" study 17
II. Concentration of Pu-238 and Pu-239 and ratio of Pu-238 to
Pu-239 of leachates and leachate-contaminated liquids
in tank storage at the Maxey Flats burial facility 22
HI. Concentration of Pu-238 and Pu-239 and ratio of Pu-238 to
Pu-239 in control or background samples collected at
Frankfort, Kentucky, and at Maxey Flats by the KDHR
during their "6-month" study with a brief statistical
summary . . 24
IV. Summary of well construction, geologic, and hydrologic
data for five test wells 3E, 6E, 8E, 10E, and HE at the
Maxey Flats burial facility which where sampled for Pu by
KDHR during their "6-month" study and by RNEB-CINC . . 38
V. Concentration of Pu-238 and Pu-239 and ratio of Pu-239 to
Pu-239 in suspended solids/sediments and soluble portions
of water samples collected from test wells at Maxey Flats
burial facility 39
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ABSTRACT
Between 1963 and 1974, approximately 104,000 m3 of solid
"low-level" radioactive waste were buried at the Maxey Flats, Kentucky,
site. These wastes contained approximately 80 kg of plutonium-239 and
a large undetermined quantity of other plutonium isotopes. In 1972,
elevated levels of radioactivity were detected in monitoring samples
collected near the burial facility by the Kentucky Department for Human
Resources (KDHR).
Subsequently, the KDHR conducted a special radiological study of
the burial site and its environs. Based on the concentration of plutonium
present or the ratio of plutonium-238 to -239, 49 of 50 samples collected
on or near the burial site were contaminated with plutonium from a source
other than atmospheric fallout. Plutonium was detected in surface, soil,
in soil cores 90 cm deep, in monitoring wells, and in streams which
drain the site.
During the past 13 years, infiltrating precipitation collected in the
burial trenches, forming a mobile plutonium-contaminated leachate. The
chemical form, pathways, and mechanisms by which the plutonium moved
out of the trenches have not been explained satisfactorily. Hydrogeological,
radiological, and environmental pathways studies of the burial site are
in progress.
The primary conclusion drawn from the hydrogeology of the site
and the environmental radioactivity data is that plutonium has moved
from the facility; possibly via several pathways including surface water
runoff, atmospheric fallout from an evaporator, lateral migration
through the soil, and migration through jointed subsurface geologic
formations.
This paper presents the plutonium data with interpretations of
its occurrence and possible significance from a hydrogeological and
environmental perspective.
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1. INTRODUCTION
1. 1. Background
The State of Kentucky authorized the establishment of a commercial
radioactive waste disposal facility in the State in early 1962 in the
hopes of attracting nuclear industry [1 ]. A site in Fleming County
known as Maxey Flats was evaluated and was deemed suitable for the
disposal of solid radioactive waste. In January 1963 the Nuclear
Engineering Company, Inc. (NECO) was issued a license to operate
the disposal facility and in May 1963 the first radioactive material was
buried at Maxey Flats.
In 1971, the Kentucky Department for Human Resources (KDHR)
decided additional studies were needed at Maxey Flats because (1) of
the exponential increase in quantities of radioactive materials,
particularly transuranium-contaminated wastes, and (2) of growing
concern that precipitation infiltrating the completed trenches and
saturating some of the buried wastes might affect the containment of
the radioactive material.
In late 1972 environmental monitoring detected elevated levels of
radioactivity in the Maxey Flats environs. In November 1973 the
KDHR initiated a six-month special environmental monitoring study
[2] to identify the source and extent of these increased levels of
environmental radioactivity. More than 50 samples were collected
and analyzed for Pu-238 and Pu-239 as part of this study.
The KDHR in their six-month study and the independent Environ-
mental Protection Agency (EPA) through indepentent investigations
concluded that the disposal site at Maxey Flats was contributing
radioactivity and Pu to the environment. As a result, the State limited
further burial of Pu and other transuranium-contaminated wastes at
Maxey Flats by license modification in 1974.
It should be emphasized that both State and EPA scientists have
stated that the activity detected in the environment around Maxey Flats
does not create a public health hazard at this time [2, 3]. For example,
the levels of Pu detected in the samples collected during the KDHR's
six-months study are only a few thousandths of the Maximum Permiss-
able Concentration listed in the National Bureau of Standards "Handbook
69" and Kentucky Administrative Regulations 902 KAR 100: 025. The
potential for health hazard is not an issue in this paper. The important
points are that (1) Pu and other radionuclides are out of the trenches
and (2) it appears that Pu may be migrating via the water pathways.
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1.2. Scope
The hydrogeology of Maxey Flats, the Pu data, and an interpretation
of their interrelation are presented from a straightforward hydrological
point of view. The literature on Pu and its occurrence in soils and its
mobility in the ground is also reviewed. The following quote exemplifies
a widespread view of Pu in the ground:
" Chemical and physical characteristics of plutonium (the principal
transuranium element) are such that migration in soil or ground-
water is unlikely. Deep well samples taken at the perimeter of the
burial sites have not shown any detectable plutonium, thus, indicating
that the buried plutonium has remained immobile. " (From USAEC
announcement of proposed rule-making on disposal of transuranium-
contaminated wastes.) [4]
The occurrence of Pu at Maxey Flats, as seen from the data collected
by the KDHR, raises some questions about our concepts of Pu mobility
in the environment. For this reason, it seems important to present
the data and a possible interpretation of its occurrence and migration
to the experts on plutonium geochemistry. The four major objectives
of this paper are: (1) to present the Pu data from Maxey Flats; (2) to
determine if Pu is migrating from the burial site; (3) if Pu is migrating,
to determine how and by what pathways migration may be occurring;
and (4) to comment on the significance of the Pu data from a hydrogeo-
logical and environmental perspective.
2. BURIAL OPERATIONS
2.1. General Operations
Low-level radioactive wastes are shipped into the Maxey Flats
burial facility by truck, and until 1972, both solid and liquid wastes
were received for burial [1], The receipt of liquid wastes was pro-
hibited thereafter.
Most wastes are shipped to Maxey Flats in 55-gallon steel drums
or in wooden and cardboard boxes and are buried in their shipping con-
tainers. The primary consideration in the design of the "burial" con-
tainer is containing the wastes during shipment and protecting the
workers. The containment capabilities of the steel drums under water-
and leachate-saturated conditions are negligible, especially since
many are crushed when dumped randomly into the trench and during
compaction of the trench cap.
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With few exceptions, the solid wastes are buried in large rectangu-
lar common trenches and covered with earthen caps. These trenches
range in length from 76 to 110 m and are 15 m wide and 6 m deep.
Trenches are excavated to full size before burial begins. The floor of
the trench is sloped one degree to a sump and a stand pipe is placed
in the sump. After being logged in and surveyed, the truck with the
wastes is backed to the working face of the trench and the wastes are
dumped randomly into the trenches from the truck. Particularly large
items and those items emitting high levels of radiation in casks are
emplaced by crane. In the past, the wastes were covered with dirt
daily to reduce radiation exposure and spread of contamination. Now,
they are covered temporarily with a reinforced plastic cover.
When filled, the trench is capped with a minimum of 1 m of the soil
and shale excavated from it. The cap is mounded to encourage runoff and
is compacted with a sheepsfoot roller to reduce infiltrating precipitation
and facilitate runoff. Since 1971 shallow-rooted ground cover, such as
fescue grass and clover, has been planted to prevent erosion.
Liquid wastes received from off-site in the past were solidified on
site and placed in special "L" series trenches. Commonly, the liquids
were mixed with cement and paper in a cement mixer and the cement-
paper mixture was poured into a polyethylene-lined trench. When the
trench was filled, the polyethylene sheeting was lapped over the top of
the radioactive cement-paper mixture and the trench was capped with
earth. Although disposal of off-site liquids was stopped in 1972, large
volumes of radioactive liquid wastes were until recently being generated
onsite in the trenches by infiltrating precipitation. The treatment of
these liquid wastes is described later in Section 6. 8.
2.2. Water Management Program
By 1972, some of the completed trenches were filled or partially
filled with infiltrating precipitation. A water management program was
initiated to remove this water from the trenches and to prevent further
entry of water. The two-part program was designed on the assumption
that most of the water in the trenches originated from precipitation falling
onto the trenches rather than from groundwater. One part was directed
towards water removal and included: (1) dewatering the trenches by
pumping; (2) storing the leachates in surface storage tanks; (3) reducing
the volume of the leachate by evaporation; (4) solidifying the evaporator
residues; and (5) burying the solidified residues on-site. The other part
was directed at reducing the infiltration of precipitation and included:
(1) adding fill to the caps; (2) compacting the caps further; (3) reshaping
the cap profiles to encourage runoff; (4) designing and engineering an
integrated surface drainage system for the site; and (5) planting and
maintaining shallow-rooted ground cover to reduce erosion of the cap.
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There is no question that the water management program has had
many beneficial effects in reducing the potential for the migration of
radioactive contaminants from the trenches. It has not been without
minor problems, however. Dewatering and evaporation operations
have reduced leachate accumulation in the trenches; however, spillage
of the leachate during pumping operations and leakage from the storage
tanks have caused some surface contamination [6]*. The evaporator
plume may have added another potential pathway for the migration of
Pu; however, there is no reason to believe that the consequences of
this pathway are large. The cap renovation program has halted erosion
of the caps and should reduce the infiltration of precipitation into the
trenches. However, growth of a shallow-rooted ground cover on the
caps may, to some degree, maintain a degree of permeability in them.
As of yet unpublished data from KDHR and EPA studies [8, 9,10]
indicate that water management activities (trench dewatering and
leachate evaporation) have been a source of small but measurable
surface contamination which at present does not pose an immediate
health hazard. However, this low-level of contamination, together
with the hydrogeology of the site, greatly complicates scientific studies
at the site. For example, several natural paths for surface runoff and
overland flow cross over several potential points of subsurface dis-
charge, obscurring, or at least making it difficult to determine whether
the source of contamination detected is from subsurface discharge or
from operational activities.
Viewed in the long term, it is difficult to imagine that either the
State or the operator will continue to dewater the trenches for hundreds
or thousands of years the hazardous lifetime of the wastes. Yet,
unless the cap improvement program is truly effective in developing a
nearly impervious cap, long-term pumping could be required.
* NECO reported that all leakage from the tanks was safely contained
within a berm around the tank farm with no hazard to operating personnel
or the public [7],
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3. SITE DESCRIPTION
3.1. General Setting
The burial ground is situated on Maxey Flats, a flat-topped, highly-
dissected ridge in the Knobs region of Kentucky. The ridge rises approx-
imately 100 m above the wide, flat, alluvial-filled valleys (locally called
hollows). The upland surface is gently rolling and is generally less than
600 m wide.
The Maxey Flats region has a humid continental climate with sharp
contrasts between winter and summer temperatures. The mean annual
precipation ranges from 100-120 cm and averages about 110 cm [11].
Much of the region is cleared for agricultural use; tobacco, corn, and
forage are the major crops. A few scattered farm families live
along the ridge and in the hollows; however, the area around Maxey
Flats has a low population density, in general less than 4-10 people
per km2 [12]. Only the upland surfaces and slopes are heavily forested.
These are predominantly the oak-hickory ecotype and some may be un-
cut, first growth forest. The chief mineral resources are limestone,
sand, and gravel.
3.2. Geology
Maxey Flats is located on the eastern flank of the Cincinnati arch and
is directly underlain by shales, siltstones and sandstones that gently dip
to the southeast (4. 7 m/km). A generalized geologic cross-section of the
rocks that outcrop at the burial site and a brief lithologic description
are presented in Figures 1 and 2 [13],
At Maxey Flats only the lower 12 m of the Nancy Member of the
Borden Formation are present. The trenches are entirely within the
Nancy Member. It is a poorly fissile, green shale, which is plastic
when wet and which has siltstone and sandstone interbeds. The
Farmers Member, the lower unit of the Borden Formation, directly
underlies the Nancy Member. It is a ledge-forming, well sorted,
indurated, very fine grained, evenly bedded, quartzose sandstone with
shale interbeds less than 1 m thick. This highly competent formation
has well developed jointing and fracturing. The Henley Bed, a 1. 5 m
thick, greenish-gray clayey shale with 2-5 cm thick sandstone and
siltstone interbeds, lies at the base of the Farmers Member.
Papadopulos and Winograd [14] wrote that open joints and bedding
planes can be seen in outcrops of the sandstones and siltstones at the
base of the Nancy Member in the Farmers Member and Walker [15]
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FIGURE 1. GENERALIZED GEOLOGICAL CROSS-SECTION Of THE MAXEY FLATS REGION, KENTUCKY.
BURIAL FACILITY
.. BORDEN I NANCY MEMBER ^>
REGOLITH (WEATHERED ZONE). /FORMATION 1 FARMERS MEMBER
1000 FT.
(305M)
5UNBURY SHALE
BEDFORD FORMATION
OHIO SHALE
THE BEDROCK CONTACT OF THE REGOLITH
(WEATHERED ZONE) ON THE RIDGE TOPS.
COLLUVIUM ON THE SLOPES, AND ALLUVIUM
IN THE VALLEY BOTTOMS IS NOT TO SCALE
AND IS SHOWN FOR ILLUSTRATIVE PURPOSES
ONLY.
UPPER CRAB ORCHARD FORMATION
700 FT.
(Z13M)
1 KM
500
1000
2000
3000
4000
5000 FEET
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FIGURE 2. STRATIGRAPHIC COLUMN AND LITHOLOGIC DESCRIPTION OIF THE GEOLOGY
AT MAXEY FLATS, KENTUCKY (AFTER MCDOWELL, ET AL.)
UNIT THICKNESS FROM EN EMCON (17).
| SYSTEM
SERIES
FORMATION
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AND BED
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SHALE SEQUENCE 1 M OR MORE THICK BETWEEN SANDSTONE BEDS
SANDSTONE AND MINOR SHALE SANDSTONE. LIGHT BROWNISH-GRAY TO YELLOWISH-BROWN, VERY
FINE GRAINED. WF.l.l SORTED. WELL INDURATED. MEDIUM TO THICK UEOOED. TABULAR.
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AND WORM 1') TRAILS COMMON TO ABUNDANT ON UPPER SURFACES OF BEDS, SOLE MARKINGS
LOCALLY COMMON SHALE, GREENISH GRAY, CLAYEY, SILTY, SIMILAR TO SHALE OF OVER-
LYING UNIT. OCCURS AS PARTINGS ANO INTERBEDS AS MUCH AS 1 M THICK; THICKEST AND
MOST ABUNDANT IN UPPER PART FORMS STEEP SLOPES WITH ABUNDANT LEDGY OU'rCROPS,
NRIMS FLAT TOP RIDGES THROUGHOUT MOST OF QUADRANGLE. UNIT THICKENS UNIFORMILY TO
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I \ FORMS STEEP TO MODERATE SLOPES. WITH THIN SOIL COVER CONTAINING ABUNDANT SHALE
1 \ CHIPS LOCALLY WELL EXPOSED. BASAL CONTACT SHARP, GENERALLY COVERED. THICKNESS
\ \ NOTABLY UNIFORM THROUGHOUT QUADRANGLE.
1 \ SHALE DOMINANTLY GREENISH-GRAY TO LIGHT OLIVE GRAY SILTY CLAY SHALE; WEATHERS
1 \ REDDISH TO YELLOWISH BROWN. CONTAINS PYRITIC NODULES AND NUMEROUS VERY THIN SILT-
1 I STONE LENSES. LOCALLY A THIN BED OH LENS OF VERY FINE GRAINED SANDSTONE OCCURS
—
£
$
0
\ SEVERAL FEET ABOVE THE BASE; BASAL FEW FEET COMMONLY COMPOSED OF INTERBEDDED
\ DARK-GREY ANO OLIVE GRAY SHALE WITH THIN SILTSONE RIBS FISSILITY POOR, WEATHERS
V TO IRREGULARLY SHAPED CHIPS. UNIT GENERALLY COVERED. OCCUPIES PROMINENT BENCH
\ ON TOPOGRAPHIC NOSES AND MOST HILLSIDES. BASAL CONTACT IS ACCURATELY INDICATED
1 IN MOST PLACES BY ABRUPT BREAK IN SLOPE AND BY NATURE OF SHALE CHIPS IN SOIL.
SHALE DARK-GREY TO BLACK. HIGHLY CARBONACEOUS. WEATHERS MEDIUM GRAY TO LIGHT BROWN,
HIGHLY FISSLE, SPARSELY PYRITIC. PYRITIC CONCRETIONS AS MUCH AS ft CM IN DIAMETER,
FRESH EXPOSURES CHARACTERISTICALLY CONSPICUOUSLY JOINTED GREENISH-GRAY CLAY
SHALE IN BEOS AS MUCH AS ABOUT 3.3 M THICK OCCURS LOCALLY. ESPECIALLY 15 TO 20
M BELOW TOP OF UNIT' LOWER PART OF UNIT. TO AS MUCH AS G M ABOVE BASE. COMMONLY
CHARACTERIZED BY INTERBEDOEO GREENISH CLAY SHALE AND BLACK SHALE. UNIT FORMS
STEEP SLOPES. LOCALLY WELL EXPOSED. BASE UNCONFORMABLE; CONTACT PLACED AT BREAK
IN SLOPE. OR, LOCALLY WHERE INDICATED BY SPRINGS AND SEEPS OF SULFUROUS, IRON-RICH
WATER
•'""CLAY SHALE. MOSTLY GREENISH-GRAY TO GRAY, WITH THIN ZONES OF BROWNISH RED TO
BROWNISH YELLOW. BEDDING INDISTINCT; MOSTLY POORLY FISSILE; RELATIVELY IMPERMEABLE
VERY PLASTIC WHEN WET. FEW BEDS OF DOLOMITIC SILTSTONE AS MUCH AS 20 CM THICK NEAR TOP
-------
noted the occurrence of small quantities of water seeping from well-
developed joints in the lower part of the Borden Group (now the Borden
Formation).
3.3. Hydrology
Papadopulos and Winograd [14] have recently described the occur-
rence of groundwater at Maxey Flats. The uppermost water table is
perched in the soil zone above the poorly permeable Nancy Member
and slopes southeastward paralleling the regional dip. This water
table supplies the shallow dug wells on Maxey Flats. Hopkins [16] re-
ported that deeper wells elsewhere on Maxey Flats have water levels
as much as 9 m below the perched water in the soil zone. The lower
water levels may represent a lower perched water table or may be
evidence of decreasing head with depth, which would suggest vertical
ground water movement, probably through joints and fractures, within
the Nancy Member. Other perched water tables may exist within the
sandstones of the Farmers Member and conceivably in the Sunbury
Shale above the reportedly expansive clay-shales of the Bedford
Formation [17].
The main water table occurs in the Ohio Shale [17]. This unit
supplies several domestic wells in the Maxey Flats region. The Upper
Crab Orchard Formation, a shale which is plastic when wet, underlies
the Ohio Shale and may be thought of as the hydrologic basement for the
Maxey Flats site. Papadopulos and Winograd [14] point out that the
near-perennial nature of the creeks in the hollows surrounding Maxey
Flats indicates that the creek discharge is primary base flow from
the Ohio Shale and/or the Upper Crab Orchard Formation and possibly
from the colluvium blanketing parts of the slopes around the site.
The formations at Maxey Flats are, in general, aquitards through
which the intergranular movement of groundwater is very slow. How-
ever, hydraulic tests of wells indicate that water can move along the
joints and bedding planes. Walker [15] reported that the loss of water
during a pressure test of a well* indicated that there are individual
channels (joints) large and continous enough to constitute a potential
pathway for the migration of contaminants from the trenches. EMCON
[18] reported a 100 percent loss of drilling water a number of times
in the Nancy, Farmers, Sunbury, and Ohio Shale during drilling and
coring operations. More recently, Zehner [17] reported conducting
withdrawal hydraulic tests which indicate that water movement occurs
along joints and/or bedding planes.
* Assuming that no leakage occurred around the packers, the results of
Walker's tests indicate that injection rates range from 0. 00006-0.015
[d/s)/m] (kgf/cm3 ) [14].
-------
It should be emphasized that the formations at Maxey Flats are
aquitards with very low effective porosity. However, this low
effective porosity, which occurs along joints and bedding planes,
could cause the channeling and movement of groundwater at un-
expectedly high velocities.
3.4. Hydrogeology and Potential Pathways
Papadopulos and Winograd [14] summarized the present knowledge
about the hydrogeology of Maxey Flats as follows, ".. .the stratigraphy
of Maxey Flats is well known and its local hydrologic boundaries
approximately defined" but, "the hydrogeology of the site is poorly
understood. " They further warn that, The strata beneath Maxey
Flats... are aquitards whose fractured nature and low permeability
constitute major obstacles to successful quantitative definition of
the hydrogeology of the region, regardless of funding. " It is hoped
that the preliminary hydrogeologic investigation presently underway
[19] and the more detailed investigation soon to be commenced [20]
will show them to have been pessimistic.
The basic hydrogeologic (and water pathways) model for Maxey
Flats is complex. It is believed that water is the primary mobilizing
agent for Pu, that it is the primary driving force for the Pu, and
that it is the primary pathway from the burial site at this time.
Almost all water discharging from the site and from the subsur-
face formations beneath it originates from precipitation falling on the
site. This water discharges from the site by the following paths:
surface runoff; interflow or movement through the shallow soil zones;
and subsurface bedrock flow. These three flow paths form the three
potential water pathways for the migration of Pu from the site. The
evaporator plume may constitute a fourth pathway for Pu. Figure 3
represents a schematic of the major flowpaths for water (pathways
for contamination) passing through the system.
Water entering the ground as recharge moves downward and
laterally through the hydrogeologic system with its movement com-
plicated by differences in permeability between strata, the dip of the
strata, and ext nsive jointing. There is strong theoretical evidence
for this interpretation as well as numerous examples from like hy-
drogeolgic settings. Walker [15], Whitman [21], Papadopulos and
Winograd [14] and Zehner [19] also used this basic interpretation.
Field evidence, the presence of perched water beneath the site, and
repeatedly measured water levels in many of the E-Series wells [17]
further supports this interpretation.
-------
Figure 3. Schematic diagram of water pathways at Maxey Flats
THtS INSET IS INTENDED TO CONVEY THE
COMPLEXITY OF THE MIXING OF THE
DIFFERENT FLOW PATHS DOWN THE MAIN
EAST DRAINAGEWAV,
10
-------
It is believed that the gentle dip of the strata to the east-southeast
at 4. 7 m/km causes much of the perched and main water tables to
slope and discharge to the southeast. A groundwater divide certainly
must exist beneath the burial facility because water discharges all
along the flanks of Maxey Flats beneath the burial facility. Its location
may be, however, altered by the infiltration of leachates from the
trenches. The dip of the strata, plus grading and earthmoving activities
also cause the land surface at Maxey Flats to slope southeasterly,
channeling most surface runoff from the site into a main east drain-
age way.
The extensive jointing throughout the Nancy, the Farmers, the
Sunbury, and the Ohio Shale probably causes the greatest complications.
Whereas the layering and slope just described tend to channel and
direct the movement of water through the system with some predict-
ability, the fracturing makes it very difficult to predict the direction
and rate of subsurface flow. It also greatly increases the permeability
of a series of otherwise virtually impermeable shale, siltstone, and
sandstone aquitards.
A less obvious but equally serious effect of jointing and fracturing
is the reduction in the ion exchange reaction between the rock media
and contaminants. Most of the strata are shale and siltstone, which
usually have good-to-excellent ion exchange capacities when pulverized
and tested in the laboratory. The ion exchange interaction between
the earth media and contaminated liquid (leachate) is usually counted
on as an important safety factor in the land burial of radioactive wastes.
This presupposes that contaminants dissolved from the wastes will
come in contact with and be sorbed on the clay particles during their
migration by intergranular flow through the formations. If the con-
taminants migrate along fractures as probable at Maxey Flats rather
than between individual silt- and clay-size particles, the effective
surface area of the silt and clay exposed to the contaminant is greatly
reduced, thus by-passing the ion exchange process to a large extent.
Logs of test wells drilled on Maxey Flats commonly report the
presence of vertical joints or fractures. Many of the joints have
been described as weathered or iron-stained [18], indicating that
groundwater has passed through the joints. Iron-stained joints can
also be seen in the walls of the trenches excavated into the Nancy
Member and in outcrop. The jointed character of the burial media,
the Nancy Member, can be seen in Figure 4. The under lying
Farmers Member, Sunbury Shale and Ohio Shale Formations are
also highly jointed. [13,15,14,18]
11
-------
Figure 4. Photograph of jointed Nancy J> .ember (picture was taken
while standing in bottom of an open trench).
12
-------
4. SOURCE TERM
4.1. Waste Volume and Activity
From 1963 when disposal operations began through 1974, 104,000 cubic
meters of solid and 2,250, 000 1 of solidified liquid radioactive wastes
were buried at Maxey Flats. These wastes included 1, 638, 000 curies of
by-product materials *, 349, 000 grains of special nuclear material (SNM)*,
and 158,000 pounds of source material* [1]. The volume of of solid wastes
buried at Maxey Flats represents 35% of the volume and 65% of the activity
of all wastes buried at commercial burial facilities in the United States
during 1963-1974.
It became clear quite early that the assumed burial rate of 750 curies
per year was a gross underestimation [1]. The actual and projected (as
of 1972) annual rates of burial are shown in Figure 5. The annual
volume of waste buried at Maxey Flats increased almost exponentially
through 1971. The apparent decrease in burial rate in 1971-1972 is
believed to have resulted from labor/administrative difficulties
at Maxey Flats and to diversion of waste to the commercial disposal
facility at Barnwell, South Carolina, which opened in 1971.
Of direct interest to this paper is the increase in the amount of special
nuclear material being buried between 1963 and 1972 --a doubling approxi-
mately every 1. 3 years (Figure 5). The State limited further burial of Pu
and other transuranium-contaminated wastes at Maxey Flats by license
modification in 1974 partly it is believed as a result of this phenomenal
growth in the burial rate of special nuclear material. The distribution and
quantities of Pu-238, Pu-239, and other specific isotopes in the SNM cate-
gory which were buried at Maxey Flats are not known. Although the Pu-239
was recorded separately and more than 80 kg were reportedly received,
the accuracy of the records is uncertain [1]. Preliminary printouts of
data from a detailed inventory indicate that many shipments were re-
corded only as Pu, Pu-xxx, U, and U-xxx [22]. Better identification of
transuranium isotopes buried at Maxey Flats may require reviewing
individual invoices with the originators of the waste.
* By-product material (radioisotopes produced in reactors), special
nuclear material (plutonium and enriched uranium), and source
material (uranium and thorium) are defined in USAEC Rules and
Regulations, 10 CFR 20 [23].
13
-------
FIGURE 5. PROJECTIONS OF BURIAL GROWTH RATES FOR VOLUMES
OF WASTE AND QUANTITIES OF SPECIAL NUCLEAR
MATERIAL AT MAXEY FLATS BURIAL FACILITY ( AS OF 1972).
10
ADMINISTRATIVE PROBLEMS
BARNWELL OPENS
10
63 64 65 66 67 68 69 70 71 72
TIME IN YEARS
73 74
75
-------
In a preliminary inventory [1], detailed hand tabulations were
made from the shipping records of two trenches. In Trench 30,
2, 300 g of Pu-239 were identified out of a total of 48, 000 g SNM.
In Trench 32, 13, 000 g of Pu-239 were identified out of a total of
54, 000 g SNM.
4.2. Waste Character
"Low-Level" radioactive waste is now called "other than high
level waste" and now includes everything except "high-level"
radioactive waste*. In brief, any waste, including transuranium
contaminated wastes, which is not "high-level" waste can now be
buried at commercial disposal sites, regardless of its activity or
hazard potential, unless there are specific site regulations against
it.
Most of the wastes buried at Maxey Flats are believed to be
large volume, low-hazard-potential solid wastes such as paper
trash, cleanup materials and liquids, packing material, broken
glassware, plastics, protective clothing, radioactive carcasses of
experimental animals and contaminated equipment. The most recent
description which the author could find of the wastes actually being
buried at commercial burial sites [24] estimated that 70 percent
by volume of these wastes would be paper materials and that the
density of the total waste would be about 10 Ibs/ft (0.16 gm/cm3 ).
High-activity wastes such as sealed sources, reactor resins, filters,
and irradiated reactor parts have also been buried. A large number
of records list the isotopes shipped only as "mixed fission products,"
"low specific activity," "not specifically identified, " and other non-
specific identifications [1].
KDHR and EPA studies [1, 22, 25] have found that for practical
purposes no information is available on the chemical or physical
character of the wastes which have been buried at Maxey "Flats.
* The AEC divides radioactive waste products into two categories,
"high-level wastes" and "other than high-level wastes". "High-level
wastes are defined as, "aqueous waste resulting from the operation
of the first cycle solvent extraction system, or equivalent, and the
concentrated waste of subsequent extraction cycles, or equivalent, in a
facility for reprocessing irradiated reactor fuels". The AEC group
all other wastes in the category, "other than high-level wastes ' [23].
15
-------
5. RADIOCHEMICAL DATA
5.1 Data from "6-Month" Study
The scope of this paper has been limited to a detailed examination
and interpretation of the Pu data collected by the KDHR in a special
6-month study of the burial site and its environs, 1973-1974. Literally,
thousands of additonal analyses are available for other isotopes from
other studies and which contained H-3, Co-60, Sr-89, Cs-134, and
Cs-137, in concentrations greater than background or fallout, indic-
ating that other radioactive contaminants have moved or migrated also;
thus tending to support the conclusion that Pu has moved or migrated.
These additional data have been used or referenced occasionally to
confirm conclusions reached from (1) the Pu data and (2) knowledge
of the hydrogeology of the site. However, extensive discussion of these
additional data was not possible in this report. There are exceptions,
however, which include (1) approximately 40 Pu analyses of leachate
which was stored in the tank farm, (2) additional Pu analyses of
samples from wells, and (3) listings of other radionuclides detected
in effluents from Maxey Flats.
Four reports are presently in preparation which will present to
the interested reader the bulk of the additional data and a much broader
picture of the environmental impact of burial operations at Maxey
Flats. These include (1) the radiological impact of burial opera-
tions [10], (2) the impact of the evaporator as a potential pathway [8],
(3) the pathways to man for radiocontaminants from the site [9],
and (4) a detailed analysis of the radioactive waste inventory buried
at Maxey Flats [22,25].
The "6-month" study was conducted by the KDHR between November
1973 and May 1974 and covered a six-mile radius of the site [2].
During this study, more than 400 soil, surface water, and ground
water samples were collected in and around the burial facility, including
a number of control samples for determining background levels. All
samples were analyzed for tritium, gross alpha, and gross beta.
In addition, 36 samples were analyzed for specific gamma emitters
and Sr-89 and Sr-90; approximately 60 samples were analyzed for
Pu-238 and Pu-239; and 14 samples were analyzed for U-234 and U-238.
Results of the Pu analyses are presented in Table I. The analyses
were performed by the USAEC's Health Services Laboratory (HSL),
Idaho Falls, Idaho, and Environmental Analysis Division, LFE Laboratory
(LFE), Richmond, California, using the analytical techniques described
by Sill, Puphal, and Hindman [25] and the HASL Procedures Manual [26],
respectively.
16
-------
TABLE I . CONCENTRATION OF 238PU AND 239PU AND RATIO OF 238PU TO 239PU IN SAMPLES
COLLECTED FROM SOIL, TEST WELLS. AND STREAMS IN AND AROUND THE MAXEY
FLATS BURIAL FACILITY DURING THE KDHR'S "6-MONTH" STUDY.
w
UJ
a
1
—
5
UJ
u. -* a.
« jj Z
- 5 w
to
ul
-J
UJ
H
M
u.
u.
O
§
o
rfM'li
28
29
JO
ni
Hi'
!f
'. r.
i*;
1C'.
!«*
I4>
152
HI
IW
1560
Hit
1619
1782
I7B5
114
115
116
117
i:c
II?
1)4
11'.
120
171
12)
121
125
126
116
1)8
142
14)
144
145
117
150
15!
IS'.
157
I5e
238
Pu
0.07
0.1)
0.09
0.1) .
0.13
0.05
4.75
Il.K
;.!)
0. !0
0.24
0.67
0.81
0.10
7.5
s.6
)3.0
6.0
22.0
0.57
0.076
1.92
0.13
O.I)
0.034
0.15
0.1!
6. SI
6. OS
1.78
0.60
0.09
0.49
0.14
0 12
2.49
0.49
41. 9«
8.15
2.55
12.70
0.109
. 0.029
0.65
0.15
20.0
1.79
239
Pu
0.05
0.34
0.03
0.06
0.0)
0.02
0.19
0.1!
0. 14
p. if,
n.tii
o.n
0.057
0.111
0.018
0.22
0.12
0.59
0.19
0.47
0.073
O.Z96
0.99
0.044
0.14
0.088
0.01
0.0!
0.6)
2.31
0.475
0.09
0.09
0.37
0.01
1.48
0.0)
2.76
0.50
i.)7
1.24
.018
0.024
5.8
0.07
0.49
0.15
2)8/219
Pu
1.4
0.4
1.0 '
2.2
4. 1
? 5
1* .9
?8/'
7.1
l.>
! !
Il.R
7.6
7.9
34.1
71.6
5';. 9
31.6
16.8
;.e
0.26
1.9
1.1
0.9)
0.)9
15.0
II. 0
10.5
2.1.
3.7
8.9
1.0
1.3
14.0
1.7
16.3
15.2
16.)
1.9
10.2
6.1
1.2
O.I!
1.6
14.2
11.9
SAMPLE ( 1) LOCATION and (2) DESCRIPTION
(1) Approiimately 1.5 m from east end of Trench 10; (2) Soil core. 60-75 cm depth.
(!) Appro«imately 1.5 m from northeast end of Trench 10; (2) Soil core. 0-50 cm depth.
(D Approximately 1.5 m from northeast end of Trench 7; (2) Soil core, 25-50 cm depth.
(!) Appro. Imately 1.5 m from northeast end of Trench 7; (2) Soil core, 50-75 cm depth.
(1) App o Imate y 1.5 the . e, pt
(I) Ljst end of Trench 26 east nf trench monument 1.5 m; (2) Soil core, 50-75 cm depth.
(D Same core hole as sample 1)9; (2) Soil core, 25-50 cm depth.
(D Same core hole as sample 1)9; (?) Soil core, 50-75 cm depth.
(!) fast end of Trench 26 (different core hole than samples 1)9. 140, and 141)- (?) <011 core, 50-75 cm depth.
'U West end of Trench 33L. 3 rt from fence; (2) Soil core, 50-75 cm depth.
(!) rtrainaoe flitch north of Trench 3)L; (2) Soil core, 0-25 cm depth.
11) last end of Trench 10, 1.5 m frni- end of trench; (2) Soil core, 75-92 cm depth.
(!) Last end of Trench 1(1. 1.5 m from end of trench; (2) Soil core. 0-75 cm depth.
(!) Cast end of Trench 2. 1.5 m from end of trench: (2) Soil core. 0-75 cm depth.
ID Well «t. total depth 15 in: (2) Suspended solids and sediments.
(1) Well 31. total depth 27 n; (2) Suspended solids and sediments.
(1) Well lit. total depth 15 m; (2) Suspended solids and sediments
ID Uell 6C, total depth 15 m; (2) Suspended solids and sediments
(!) Uell lit, total depth IS m; (2) Suspended solids and sediments.
(!) Stream discharging from Orip Spring Hollow; (2) Silt, sand, and gravel from stream bottom.
(|) Spring-fed pond at McRoberts farm below Ohio Shale-Upper Crab Orchard contact; (2) Sllr. -.anrl. and
gravel from stream bottom.
(1) Spring apparently Issuing from outcrop of Ohio Shale in draw leading to eastern "lain drainage from •
(1) Stream fed by same spring as No. 116 at road; (2) rlay and silt.
(1) "Sulfur" spring near base of Maxey flats at east side of entrance to No Name Hollow; (2) Silt, clay.
and organic matter.
(1) Pond in alluvium at ;tc")oherts farm, nrin Sprinn Hollow: (2) Silt and clay.
(D West of well 12C, 73 m linear, 12 m elevation drop, not on main west drainage patfi; (2) Soil core, 0-15
en depth collected 60 cm back Into hill under shale out crop. ;
(D west of well 12E, 137 m linear, 30 m elevation drop at wet weather spring near shale outcrop; (2) Soil
core, 0-25 cm depth.
'
(I) At fence. 8 m north of main east drain; (2) Soil core, 0-75 cm depth.
(I) Main east drain at fence: (2) Soil core, 0-75 cm depth.
ID lain east drain, H m above tractor road; (?) Soil core, 0-15 cm depth. Immediately overlying sandstone
layer.
(1) Main east drain setting basin, just below fence; (2) Sediment core. 0-15 cm depth.
(I) Main east drain at precipice formed by farmers sandstone beds; (2) Soil core 0-25 cm depth.
(1) North of main drain In vicinity of -ell 31: (?) fcrnst loan corn, n-25 cm depth.
(D At Trench 27. In direction of well lot, IS m west of fence; (2) Soil core. 0-25 cm depth.
(!) At northwest corner of tank farm, 8 m west of fence: (?) Snll core, 0-25 cm depth.
(D Main drainage at south gate; (2) Forest loam core, 0-15 cm depth.
(1) Sou; main drainage, 8 m elevation drop from soul'' fence; (2) Soil core. 0-25 cm depth.
(1) Main south drainage at precipice, near outcrop of Fanners sandstone: (2) forest loam core, n-15 cm depth.
(1) Northeast site drain flowing west to east just inside berm: (2) Soil core. 0-75 cm c'epth.
(1) Northeast site drain flowing west to east j'tst Inside fence; (2) Soil core, 0-25 cm depth.
(1) Northeast end of tank farm, just Inside berm; (2) Soil core, 0-75 cm depth.
(1) Soil from new, unused tench No. 42; (2) Sol! core. 0-25 cm depth^
(1) 'lest to "ast drain, southi-wst of Trench 2: (2) Soil core. 0-25 cm denth.
(1) West of Trench 31. ) m Inside fence; (2) Soil core, 0-25 cm depth.
J)JSCHARCE_ST*ClCjfnr "iapornor^ _ __
(!) "Drainage dltch~Bl"onq west'slde'of Trench 40. by sump pipe: (2) Soil core, 0-25 cm depth.
17
-------
Inter-laboratory comparison,of Pu analyses for the ."6-month"
samples are not available. However, there is no question about the
presence of Pu from -a. source other than fallout in the environment
in and around the burial site. Both HSL and LFE detected Pu in
concentrations well above background levels in almost all samples
they analyzed. In addition, above background concentrations of Pu
were also found in samples collected and analyzed by EPA's RNEB [3],
Radiation Management Laboratories [7], and Teledyne Isotopes, Inc. [7],
which supports the presence of elevated levels of Pu reported by HSL
and LFE. When the data are placed in ascending order of concen-
tration or ratio of Pu-238 and Pu-239 as in Figure 6a, 6b, and 6c,
the analyses from the two labs appear from simple inspection to be
normally distributed throughout the 50 samples. Therefore, from
these simple tests, it has been assumed that (1) the Pu concentrations
reported were real and (2) the concentrations reported for each sample
were not significantly affected or skewed by the laboratory which did
the analysis.
The data have been grouped into four suites for interpretation:
(1) off-site samples; (2) on-site samples; (3) core samples in the
trench area; and (4) well samples.
5.2 Sampling Methods
The samples collected for Pu analysis during the "6-month"
study were composed of soils and fill material from the trench and
operational areas; soil and organic material from the area surrounding
the site; clay, silt, and sand from the stream beds, ponds, and spring
outfalls; and suspended solids and sediments from the monitoring
wells. No water samples were analyzed for the "6-months" study.
The soil samples were collected with either an Oakfield hand
coring device or a "Little Beaver" power auger. The Oakfield coring
device is pushed into the ground by hand and will take a core 25 cm
long by 2. 5 cm in diameter. With the use of extensions, cores can
be taken to a depth of 90-100 cm, if no cobbles or hard rock are
encountered. The "Little Beaver" is a gasoline-powered Archimedes
screw-type auger which can, under favorable conditions, take a 10
cm-diameter sample to a depth of approximately 150 cm. Pond, stream,
and spring outfall samples were collected by scooping up the upper
3-5 cm of the bottom material.
Samples of water and entrained solids from the wells were
collected with a bailer with a foot valve. However, only the suspended
solids from these samples were analyzed from the "6-months" study
18
-------
i
-CONTAMINATED-
{.on* iniT OF
COWTAMINATIOM 10 1 DP«W1>
5
(•ACKGROUNO 0.003 OPM/OI,
FMURE iA. CONCENTRATION OF 2*Vll IN SAMPLES COLLECTED FROM SOIL8.TE8T WELLS, AND
rTHEAMt IN AND AHOUND THE MAXEV FLATS BURIAL FACILITY DURING THE KDHR'8
"•-MONTH" STUDY.
FIQUIII *•. CONCENTRATION OF 2>*PU IN SAMPLES COLLECTED FROM SOILS, TEST WELLS, AND
STREAMS IN AND AROUND THE MAXEV FLATS BURIAL FACILITY DURING THE KDHR'8
••*-MONTH"»TUDY.
«CONTAMINATED-
LOWER IWIT OF USPECTIO
CONTAMINATION (RATIO • 0.91
-iGflS
M M
RAtiO-011
JtH u II
.
s s s
FKIURE «C. RATIO Of Z"/Z" PU IN SAMPLES COLLECTED FROM SOIL
THE , TEST WELLS. AND STREAMS IN AND AROUND
THE MAXEY FLATS BURIAL FACILITY DURING THE
KOHR-S "«-MONTH" STUDY.
a
a
ON
OFF
CORE
*€LL
116
LEGEND
AEC HSL
IFE LABS
- OHSITI: SAMPLE
-OFF SITE SAMPLE
• CORE SAMPLE
• WELL SAMPLE
- SAMPLE NUMBER
19
-------
samples. Analyses are, however, available from the other studies [7, 9]
for both suspended solids and the water from the wells. There is no way
of knowing at what depth interval a sample was collected with this device.
The suspended solids in the well samples were filtered in the labo-
ratory, ashed at 450 C, pulverized in a mortar, and passed through a
28-mesh sieve. From the portion that passed through, 5-10 g was re-
moved, sealed in a plastic "Whirlpak" bag, and shipped for analysis.
The other samples were dried in an oven, pulverized, and treated much
like the well samples thereafter.
The question that must be asked at the outset is whether the
"6-month" samples were inadvertently contaminated during the collection
process by using contaminated samples devices. And if this was a
possibility, would the samples therefrom be totally unreliable because
of cross-contamination? The possible effects of cross-contamination
on the Pu data are discussed in detail in Appendixes A and B and
it was concluded that cross-contamination would not significantly affect
most of the key samples. Additional samples were collected from
soils, stream sediments, and wells by EPA scientists and particular
care was taken to avoid cross-contamination. Pu concentrations
in these EPA samples [9] were in concentrations similar to those
found in the "6-month" study samples—thus tending to support the
conclusions based on other considerations that cross-contamination
of the samples did not significantly affect the Pu data from the KDHR's
"6-month" study. Samples collected from the wells by the site operator
also contained Pu both in the suspended solids and in the soluble
portion, further supporting the quality of the KDHR data.
In brief, the samples were collected by experienced health physicists
who were familiar with environmental sampling methods, the site, and
operations there. More importantly, the Pu data tell a coherent story
and independent Pu data collected by other scientists support this story.
Therefore, it is believed that the 50 Pu analyses from the "6-month"
study represent an excellent set of reconnaissance samples which cover
most of the pathways for the movement of transuranium nuclides in the
environment at Maxey Flats.
5. 3 Other Radiochemical Data
The KDHB collected samples of liquids from approximately 40 stor-
age tanks which contained leachates pumped from the trenches as part of
the site water management program. Therefore, it is believed that these
analyses represent the radiochemical character of the leachates in the
trenches. Specific radionuclides detected by the gamma scan
20
-------
included Mn-54, Co-60, Zn-65, Ru-106, Sb-125, Cs-134*, and Cs-137.
technique included Mn-54, Co-60, Zn-65, Ru-106, Sb-125, Cs-134*.
and Cs-137. They were also analyzed for Pu-238 and Pu-239, the
results of which are presented in Table II. The analyses were
performed on whole samples evaporated to dryness by USEPA's
Eastern Environmental Radiation Facility (EERF), Montgomery,
Alabama, using the analytical techniques described by Strong and
Lieberman [27].
More than 300 different radionuclides reportedly have been buried
at Maxey Flats [22]. Many of these have short half lives or are in
small quantity. However, the following radionuclides which could
significantly affect the hazard potential of any discharges from the site
have been identified in the leachate or in monitoring and special study
samples: H-3, Mn-54, Co-58, Co-60, Zn-65, Sr-89, Sr-90, Ru-106,
Sb-125, 1-131, Cs-134, Cs-137, Ac-228, U-234, U-238, Pu-238,
Pu-239. These latter radionuclides have played an important role
in (1) serving as a double tracer to confirm transuranium contami-
nation** at some sample stations and (2) interpreting hydrogeological
phenomena and potential pathways.
6. INTERPRETATION
6. 1. General
Sixty samples were collected for Pu analysis during the KDHR's
"6-month" study. They were not, however, random samples. The
sample plan was designed specifically to determine if any of the trans-
uranium nuclides were migrating--and if so, along what pathways,
how much, and how far. The actual sampling points which were
selected were at or near places where: (1) significant radioactive
contamination had been found earlier; (2) significant alpha contami-
nation had been found earlier; or (3) surface or subsurface water
flowed from the site.
The E-series wells were specifically sampled because it was
considered unlikely that contamination would have migrated t;, them.
Therefore, de Acting Pu in them would be considered highly significant.
* The presence of Cs-134 in samples indicates contamination from
reactor wastes.
-••-'• Unless specifically stated otherwise, "contamination" and "trans-
uranium contamination" refer to Pu (or other radionuclide) contamination
from a source other than fallout and specifically the wastes at. the site.
21
-------
TABLE II
239
CONCENTRATION OF PU AND PU AND RATIO OF
TO
'PU OF LEACHftTES AN) LEACHftTE-CONTAMINATED LlflJIDS IN TANK STORAGE
AT M MAXEY FLATS BURIAL FACILITY
HIGHEST VALUE
LOWEST VALUE
AVERAGE VALUE
(UNWEIGHTED BY VOLUH)
AVERAGE VALUE m
(WEIGHTED BY Vou*€)(1)
238
3293
.42
239
Pu
(Dm/to
163
HOT DETECTED
9.02
217 10.12
238/239.
(RATIO)
97.3
1
23
22.6
Pu
(1) THE DATA REPRESENT IKDIVIDUAL FVl ANALYSES FROM 39 TANKS CONTAINING
APPROXIWTELY 2.5 MILLION LITERS OF LEACHATE WITH WIDELY VARYING
CONCENTRATION. THEREFORE, AN AVERAGE VALUE WEIGHTED BY VOLUME OF
LIQUID WAS ALSO CALCULATED.
22
-------
In interpreting the occurrence of Pu at Maxey Flats, it is necessary
to discriminate between several types of.contamination. There are:
(1) contamination from atmospheric fallout and (2) contamination from
a source other than fallout (i. e., the wastes and within the latter case;
(2a) contamination resulting from surface spills and waste management
operations; or (2b) contamination resulting from natural migration from
the trenches. The data and methods used in making these discriminations
were the Pu-238 and Pu-239 concentrations, the Pu-238/239 ratio and the
type and location of the samples. These tools were used successfully to
discriminate between (1) fallout and (2) contamination from a source. For
those samples which were determined to be contaminated by ratio or con-
centration of Pu-238 and Pu-239, the location of the sample and its position
within or relation to the hydrogeologic system were used so far as possible
to discriminate between (2a) contamination from spills and operations
and (2b) that from migration or movement via the water pathways.
6. 2. Background and Contamination Levels
Background levels from atmospheric fallout of Pu (including Pu
originating from weapons testing and SNAP generator burn-up) in the
Kentucky-Ohio-Indiana area of the central United States are commonly
around .02 dpm/g for Pu-239 in surface soils*; Pu-238 concentrations
are commonly 4-8% of Pu-239 levels; with a resultant Pu-238/239
ratio of . 15 or less [28],
To establish background levels for the "6-month" study, the KDHR
collected and analyzed ten soil samples for Pu-238 and Pu-239. Six of
these samples were collected in Frankfort, Kentucky, (approximately
130 air km from Maxey Flats) and analyzed by the LFE Laboratory.
Four samples were collected from an unused trench at Maxey Flats
and were analyzed by HSL. The background Pu data are presented
in Table III. The six samples from Frankfort contained low concen-
trations of Pu-238 and Pu-239 with Pu-238/239 ratios which are
in general agreement with regional fallout data and would not indicate
contamination.
However, the four samples from the unused trenches contained
unusually high Pu-238/239 ratios (mean ratio was 1.4). A recheck
of the laboratory analysis worksheets and the U-234/238 ratios
(approximately 1) indicate that the analyses were normal in all
* The reference gives a range of . 02 - . 05 dpm/g for background
Pu-239 concentration. As can be noted in Table III, the mean Pu-239
concentration in the Frankfort background sampes was less than . 001
and in the Maxey Flats samples, which show signs of contamination,
less than . 03.
23
-------
TABLE HI.
CONCENTRATION OF 23i PU AND 2M PU AND RATIO OF
231 PU TO 239 PU IN CONTROL OR BACKGROUND SAMPLES
COLLECTED AT FRANKFORT, KENTUCKY, AND AT MAXEY FLATS
BY THE KDHR DURING THEIR "6-MONTH" STUDY
WITH A BRIEF STATISTICAL SUMMARY.
SAM1'I.!-:S M'.MHKH
K-l
F-2
F-3
F-H
F-5
F-6
KY BKG
KV HKCi
KY BKCI
KV BKCl
238 '
Pu
(dpm/f>)
.0017 ' 367°
.00098 ^ 88%
.00006 I 75%
.000
.00000
.0018 ' 50%
.040 1- 10'fir
.0:10 + 13%
.023 ' 17"i
. 028 i 7%
230
til
(dpin/g)
. 00644 +• 26%
.0122 « 20%
. 00594 ^ 25%
.0116 > 25%
.00716_|_32%
.00792 t32%
.0151 20%
.025 i 16%
. 0:10 * 13%
. 036 f 67o
238/239
(Ratio)
. 3
. 1
. 2
< . 1
'.001
. 2
2.7
1.2
.8
.8
STATISTICAL. FAR AM b'T UHS
FRANKFORT AHliA SAMPLliS (F-l tliri
r-6)
NTMI3r:li UK SAMPt.KS 6
RAXt'iK .00000 tn
Ml.; AX .0001! 9
MKDIAN .0001)7
\1.X\I-;1! M.A'IS SA.MI'I.KS (-1 KV
N'LMHrJR <)!• SAMI->I.I'iS
RANCK
\U-:AX
\U-:I;IA.\
. 023 lu 010
.030
. 02H
.005U4 to .0122
.OOR5
.00754
.015 to .036
.027
.028
'•. 001 to . 3
. IS
. 15
.8 to 2.7
1.4
. 9!)
(1) ANAI.YSKS I'KRKOR.MIvL) BY LFr: I..AHORATOiTY, IUCIIMONI). CALIF.
(2) ANAI.VSKS ri-:RFOHMi-;iJ (iV MSI., IDAHO I''AIJ..S.
24
-------
respects [29]. The possibility of sample contamination during
collection and preparation prior to shipment was considered and is
possible. An alternate possibility is that environmental concen-
trations of Pu are slightly but' perceptibly elevated in and around
the burial facility and that the general geologic framework is
contaminated as a result of burial operations. This latter case
would explain the contamination found in the background samples
collected at Maxey Flats, in the sample from an unused trench
(No. 151) and the sample across No Name Hollow from the site
(No. 118). If the Pu-238 data for the entire suite of 50 samples is
plotted oh probability paper in the same order as on Figure 6a,
a group or "family" of possibly "lightly contaminated " samples
which lies between No. 128 and No. 156 is quite noticable. The
fact that the background samples collected at Frankfort well away
from the burial site contained more or less regional fallout back-
ground levels of Pu may also support the theory of a generally
higher level of Pu at Maxey Flats.
It was concluded that the four "background" samples from Maxey
Flats were collected from contaminated soil and do not represent
fallout background levels of Pu.
To avoid, so far as possible, controversy as to whether a sample
was contaminated by wastes or fallout, concentrations and a ratio
for Pu-238 and Pu-239 were chosen which, it is believed, are high
enough so that few will question that they represent contamination
from the wastes. A sample was interpreted as being contaminated
by wastes if: (1) the Pu-238 concentration was 0. 1 d pm/g (50 times
greater than background); (2) the Pu-239 concentration was 0. 1
dpm/g (5 times greater than background; and (3) the Pu-238/239
ratio was 0. 9 (6 times greater than background). *
Inspection of the data in graphical form also helped to establish
the boundary for contamination. Histograms of the Pu-238 and
Pu-239 concentrations and Pu-238/239 ratios are presented in
Figures 6a, 6b, and 6c. For Pu-238 (Figure 6a), a break between
fallout and contamination can be made between Samples 130 and
148 which, it is felt, is quite conservative. For Pu-239 (Figure
6b), no distinctive break is apparent. However, to choose a
conservative level, the break is made at . 1 dpm/g between Samples
125 and 149. For the Pu-238/239 ratio (Figure 6c), a break occurs
between Samples 119 and 118 which appears to satisfy the need
for both a conservative and natural break in the data to pick the
fallout-contamination boundary.
* The Pu-238/239 ratio of 0. 9 is not the calculated ratio between
Pu-238 and Pu-239 in (1) and (2) just preceding but was chosen
by the author for use in this paper and for reasons described in
the following paragraph. Regardless, it is a very defendable ratio
for indicating contamination from a source other than fallout.
25
-------
After criteria were established as to what concentrations and
ratio of Pu-238 and Pu-239 reasonably indicated contamination from
wastes, an evaluation of the degree of Pu contamination in and
around Maxey Flats was possible. Inspection of the basic data in
Table I and Figures 6a, 6b, and 6c shows that of the 50 samples
(1) 43 are contaminated based on their Pu-238 content; (2) 28 are
contaminated based on their Pu-239 content; and (3) 46 are con-
taminated based on their Pu-238/239 ratio.
Intercomparison of Pu-238, Pu-239, and Pu-238/239 data within
each sample (Table I) strongly reinforces t*he fact that virtually all
(49 out of 50) of the samples collected are contaminated with Pu from
a source other than fallout. It is also apparent that there is much
more Pu-238 in the Maxey Flats soils than is usual and that the ratio
of Pu-238/239 in these soils is unusually high for environmental
samples in this area of the United States. Shipping records show
that several major shippers of Pu-contaminated waste generate wastes
which are rich in Pu-238 and which have high Pu-238/239 ratios [6].
6. 3. The Leachates. a Mobile Source
In the trench dewatering portion of the water management program,
leachates have been pumped from the trenches into steel storage tanks
and then evaporated. Ten million or more liters of leachates have been
pumped from the trenches to date. More than 2.4 million liters of leach-
ates were stored in the tanks at the time of the "6-month" study. Total
samples of the liquid,, including suspended and dissolved fractions, were
collected from 44 of these tanks and analyzed for Pu by EPA's Eastern
Environmental Research Facility; these data are summarized Table II.
Although the liquids in tank storage are not representative of the
leachates under in situ conditions, they can furnish useful information
about the availability of Pu for migration. From a summary of these
data (Table II.) it can be seen that the leachates in the trenches may
contain, on the average, 217 dpm/ml Pu-238 and 10. 12 dpm/ml Pu-239
with a Pu-238/239 ratio of 22. 6. There is, without question, Pu-238 ana
Pu-239 in the leachate available for transport, regardless of whether it
is suspended or dissolved and there are indications that sot ;o of the Pu
may be in solution based on samples collected from the test wells (see
discussions in Section 6. 6 and 6. 7). The very high ratio of Pu-238 to
Pu-239 is noteworthy.
Each trench and the waste buried therein has a unique inventory of
Pu in a unique waste matrix. It may, therefore, be a unique source
term which will produce/ a unique leachate in the trench/. However,
as these leachates migrate downward into the deeper subsurface
formations, they will be subject to mixing, dispersion and dilution
26
-------
occurring within the various perched and regional waterbearing for-
mations. The end result may well be the discharge from the subsurface
of a contaminated ground-water which reflects the average composition
of all the leachates but possibly with several subgroups.
6.4. Other Sources of Contamination
There are potential modes of contamination at Maxey Flats other
than the hydrogeologic pathways described in the following subsections.
The Pu-contamination seen in the surface and near surface samples
at Maxey Flats could have originated from: (1) surface spillage during
general operations; (2) surface spillage during trench dewatering
operations; (3) leachate which overflowed from the trenches and then
infiltrated downward; (4) the use of previously contaminated fill to cap
the trenches; or (5) cross-contamination by using contaminated sampling
equipment. It is acknowledged here that some of the contamination
in some of the samples possibly could have been caused by one or
more of the five modes. Therefore, the author evaluated the potential
for the various modes of contamination to affect the major points
of this paper and to alter its major conclusions. The evaluation of
cross-contamination by a dirty sampling device is included in
Appendixes A and B.
If one takes a piece of Pu data, waves the spectre of contami-
nation in the air, and considers no other points than, "what if, " one
can say contamination may possibly affect,the data. If, however, one
considers the radiochemical data, hydrogeological data, operations,
the configuration of the sampling devices, and a number of other factors
all together as they affect the quality of the Pu data, it is possible to
come to the reasoned conclusion that the sources of contamination do
not significantly affect the Pu data and do not rule out or lessen the
importance of interflow and subsurface migration as potential pathways
for Pu migration.
The lack of vertical stratification of Pu concentrations in the cores
appears to minimize causes 1, 2, and 3 (surficial origin). A search of
the literature has failed to identify any pertinent recorded instances
where significant amounts of Pu have migrated downward from land
surface greater than 30 cm by intergranular movement. * If the Pu in
the leachate were sufficiently mobile to migrate downward 90 cm with-
out significant vertical attenuation (causes 2 and 3; surficial origin), it
should also be capable of migrating laterally without attenuation--thus
* The migration of Pu in the Z-9 trench at ERDA's Hanford facility
[30] did not seem comparable to the situation at Maxey Flats. Down-
ward migration of a few meters along fractures was reported in the
welded tuffs at Los Alamos, N. M. [31].
27
-------
reinforcing the possibility of Pu migration via the interflow pathway.
Recent data from the E-series wells in which Pu was found to be in
solution [7] strongly supports the conclusion that the Pu is indeed
in a sufficiently mobile form to migrate via interflow through the
soil and through the subsurface.
It has been suggested that the surface contamination is a result
of using soil and fill which was contaminated by spillage during
general burial operations and possibly from surface spillage during
trench dewatering operations [6, 7], Acceptance of this theory (cause
4) would require identification of a large source of contaminated soil
and fill. From this, the questions follow where did this Pu-con-
taminated soil/fill come from and how was it contaminated during
routine burial operations ?
It has been suggested that the Pu contamination detected in the test
wells was the result of contamination running into the well from land
surface and or by cross-contamination during sampling. McCullough
reported that the wells were constructed to prevent downward leakage
[32]. Even so, the possibility that downward leakage may have occurred
along a void between the grout and the wall of the wellbore has been
suggested. However, the probabilities seem low that the grout would
be bad on all nine wells (especially well 3E which was grouted from
0 to 18 m). It seems less probable that sufficient Pu contamination
was spilled around the well for it to migrate 15 to 27 m undiluted and
unattenuated. Further, four of the test wells (IE, 2E, 6E, and 8E)
are located away from the operational areas where spillage should
not occur. Cross-contamination is discussed in detail in Appendixes
A and B and Section 6. 7.
To recapitulate, it is recognized that Pu contamination from opera-
tions and sampling may have occurred; but it would not significantly
affect the conclusions that (1) there is widespread Pu contamination
in and around the site and (2) it is also very possible that Pu may be
migrating via the water pathways.
6.5. Surface Runoff Pathway
To determine whether or not Pu contamination was moving via sur-
face pathways at Maxey Flats, 'surface soil samples were collected in
the burial/operational area, along major drainageways from the site,
and at other selected points. Figure 7 shows the location and Pu values
of surface and near-surface soil samples collected close-in to the burial
* The migration of Pu in the Z-9 trench at ERDA's Hanford facility
[30] did not seem comparable to the situation at Maxey Flats. Down-
ward migration of a few meters along fractures was reported in the
welded tuffs at Los Alamos, N. M. [31].
28
-------
FIGURE 7. LOCATION AND SUMMARY OF CONCENTRATION Of 238 py AND 239 PU AND RATIO OF
238 PU TO 239 PU IN "ON-SITE" SOIL SAMPLES COLLECTED AT MAXEV FLATS BURIAL 'FACILITY
BY KDHR IN THEIR "6-MONTH" STUDY. LOCATIONS OF SOIL CORE SAMPLES DISCttSSISD UNDER
"INTERFLOW" AND SUSPENDED SEDIMENT FROM TEST WELLS DISCUSSED UNDER "SUBSURFACE"
ARE ALSO SHOWN. (ADAPTED FROM MAPS BY EMCON, 1973, AND CLARK, 1973.)
29
-------
area. Figure 8 is a smaller scale map showing the location and Pu
values of soil and sediment samples collected ' off site", well outside
of the controlled area. Inspection of the Pu values in these two figures
shows that all of the "on-site" samples and 8 out of 9 "off-site" samples
were contaminated.
Twenty-one soil samples were collected within or close to the con-
trolled (fenced) operational area and were analyzed for Pu-238 and
Pu-239. Analyses of 15 soil cores and 19 well samples collected
within the same area are also available but are discussed separately.
A summary of the "on-site" Pu data is presented in Figure 7. Based
on their Pu-238 and Pu-239 contents and their Pu-238/239 ratios, all
samples but possibly one are contaminated. This latter sample, No.
151, was collected from an unused trench. It may be contaminated if
judged on Pu-238/239 ratio alone. However, the Pu-238 and Pu-239
values are low enough so that the error of analysis might affect the
ratio. There can be little doubt, however, that there is widespread
"on-site" surface contamination.
The spatial distribution of the "on-site" sample locations is shown
in Figure 7. Areas where surface runoff is likely to occur are also
shown schematically. The "on-site" surface samples are so distributed
that it must be concluded that Pu is moving via the surface pathway.
The original source of the surface contamination cannot, however, be
determined. Potential sources include leachate overflowing from the
trenches, evaporator fallout, spillage during routine operations,
spillage during dewatering operations, lateral migration through the
soil to the surface, or a blend of all of these sources.
The location of the soil cores and the monitoring wells which are
discussed later are also shown in Figure 7.
The locations of the off-site samples are shown in Figure 8. A
brief discussion of the Pu values of each "off-site" sample point and
their relationship to the hydrogeology and potential pathways at
Maxey Flats follows:
Sample 114; Contaminated stream sediment which could represent
contamination from any or all of four pathways (surface, interflow,
subsurface, and evaporator) discharging into Drip Springs Hollow.
Located more than 1500 m from the burial trenches via the shortest
surface flowpath.
30
-------
FIGURE 8. LOCATION, CONCENTRATION OF 238 PU AND 239 PU , AND
RATIO OF 238 PU TO 239 PU IN "OFF- SITE " SOIL AND SEDIMENT SAMPLES
COLLECTED AROUND MAXEY FLATS BURIAL FACILITY BY KDHR IN THEIR
"6-MONTH" STUDY. (ADAPTED FROM U.S. GEOLOGICAL SURVEY
FARMERS, KY., AND PLUMMERS LANDING QUADRANGLE TOPOGRAPHIC MAPS.)
OM-S)Tt IMtl LOCATIONS
Q CONIMMtATtOOM BAMO'"Su
Q COMTAMMATtD ON BAOT OF "Su
f) CONTAMIMATIDONtASISOF rWnahiftATIO
CONtAMMATEO ON kAStS Of lJ*fti AND "V.
SAMPLE
POINT
114
115
116
117
118
119
127
134
135
Z38pu
(DPM/G)
*0.57
0.076
*1.92
*0.18
*0.13
0.034
*0.50
#0.15
*0.11
239Pu
(DPM/G)
0.073
#0.296
*0.99
0.044
*0.14
0.088
0.05
0.01
0.01
238/239pu
(RATIO)
*7.81
0.256
*1.93
*4.09
*0.98
0.386
*10.00
* 15.00
*11.00
* INDICATES CONTAMINATION
-------
Samples 115 and 127; Contaminated pond sediment and soil,
respectively, which could represent contamination from any or all
of the previously discussed pathways down the west drainage way
from the site. Contamination from surface runoff is strongly sus-
pected for both. At No. 115, the pond may also be spring-fed, the
source of which could either be interflow, subsurface flow, from
the bedrock or alluvium, or a blend of both. No. 127 may also be
fed by interflow, subsurface flow, or a blend of both.
Samples 116 and 117; Contaminated stream sediment which could
represent contamination from all pathways down the main east drainage
way from the site. Contamination from surface runoff is almost certain
at both points. However, No. 116 is a sediment collected below a spring
which may be fed by interflow, subsurface flow, or a or a blend of both.
Sample 118; Decomposed vegetation from a "sulfur" spring (Ohio
Shale spring?) across No Name Hollow from burial site; it is separated
from the site hydrogeologic system. The atmospheric pathway should
be the only pathway which could contribute Pu. From its location, the
sample should represent background or close to it. It is contaminated
by the criteria used herein and fallout from the evaporator plume is a
possible source of the contamination.
Sample 119; Sediment from pond in Drip Spring Hollow beneath burial
site"It may be fed by surface runoff, interflow, subsurface flow from
the bedrock and alluvium, or a blend of all these.
Samples 134 and 135; Slightly contaminated soil. Samples 134 and
135 are particularly interesting because they are adjacent to Well 12E,
in which a zone of radioactive contamination was detected at a depth of
approximately 13-14 m by geophysical logging. Subsequent bore hole
geophysical logging of the hole by the U.S. Geological Survey using the
gamma spectral method identified the presence of specific waste-
associated radionuclides Co-60, Cs-134, and Cs-137 [33] . Three
factors suggest that the contamination is from subsurface flow: (1) the
description of the sample locations, "back into the hill under a shale
outcrop;" (2) the sample locations are down the hill at the same ap-
proximate elevation as the zones of contamination which were detected
in Test Well No. 12 [17], would be expected to outcrop; and (3) the
Pu-238/239 ratios are relatively high, as were the ratios in other
surface samples from the test wells. Contamination of these samples
by surface runoff and interflow is possible. No. 134 was not on a'sur-
face runoff path, however, but could be on an interflow path.
32
-------
6. 6. Interflow Pathway
A well-developed soil zone, 1-5 m thick, covers Maxey Flats
and its slopes and is present in the trench area of the site. In
addition, the trenches are capped with mixed soil and shale which
was excavated from them. This cap material is completely disturbed
and disaggregated and has many of the properties of soil. Because
some of the trenches filled to grdund-level or near-ground-level
with leachate, interflow, or the lateral migration of water through
the soil, is a potential pathway for the migration of Pu. Leachates
overflowing from the trenches or discharging to land surface or soils
on the slopes below the site could also contribute contamination to the
interflow pathway.
It is difficult to determine whether the movement of Pu by inter-
flow is occurring along the flanks of the site because of the intimate
intermix of the surface, interflow, and subsurface pathways in this
area (see inset, Figure 3). However, on top in the relatively flat
or gently sloping trench area, the pathways are less mixed and a
preliminary evaluation of migration by interflow seems possible.
Fifteen cores were taken from soil or cap material close to the
trenches and range in depth from land surface to 90 cm (see Table
I for a description of their location). The spatial relationships of
these cores and their Pu concentrations are shown in cross-section
in Figure 9. Observations which can be made about the cores, their
Pu content, and their hydrogeologic relationships follow:
- Most of the cores are believed to be trench cap material based on
their location and depth.
- All 14 of the cores are contaminated based on the general criteria
stated in Section 6.2.
- There was no apparent diminution or "plating out" of Pu with depth,
although experience elsewhere shows that little or no Pu migrates
downward below 15 cm (see discussion in Section 7. 1).
- The Pu-2.^3/239 ratios for cores near Trench 26 are very high and
resemble some of the ratios in the leachate--possibly suggesting
a common source.
We know from operational reports and a special study [21] that some
of the trenches were filled, or nearly so, with a potentially mobile
source of Pu contamination--the leachate. The cores were collected
33
-------
FIGURE t. SCHEMATIC CROSS- SECTION OF TRENCH AREA OF MAXEV FLATS BURIAL FACILITY SHOWING THE CONCENTRATION
OF 23< PU AND23* PU AND RATIO OF 2M PU AND TO 23> PU AND THE SPATIAL RELATIONSHIPS OF
THE SOIL CORES COLLECTED IN THE KDHR t-MONTH STUDY.
TRENCH ML AREA
TRENCH? AREA
TRENCH 2 AREA
TRENCH 10 AREA
TRENCH 26 AREA
u>
10-
20-
30-
40-
u
I 50-
uj
° 60-
70-
80-
90-
100
I
= 149
238Pu-0.24
239Pu-0.11
238/239^,22
e
= 1*8
2J8Pu-0.10
239Pu-0.03
238/239pu_3.3
€
238Pu-0.30
239Pu-0.04
s132
2»Pu-0.13
239Pu-0.03
238/239^,4.3
238/239^,2.5
»129 ^
238Pu-0.13
239Pu-0.34
-,28 e
238Pu-0.07
239Pu-O.OS
238/239pu_,4
•
I
DARKENED PORTION Of CORE HOLE
INDICATES CORE SAMPLE TAKEN
AND Pu DATA AVAILABLE
a 152 (BOTTOM IS CM )
238Pu-0.67
239Pu-0.057
238/239pu_11.8
»139 ^
238Pu-4.75
238/239pu_25
a 140
"153 238Pu-13.30
(COMPOSITE) ZSSp,,^^,
^Mpu-O.S* Z38/2;
239Pu-0.11
238/239pu_76 l14,
238Pu-4.04
239Pu-0.14
= 148
238^.,, 3
239Pu-0.16
238/239^.,,
-10
-20
-30
-50
>-60
- 70
-80
-90
100
O
m
HORIZONTAL SCALE CONSTRUCTIVE
CMTUMNATIDOMMSIlOf "St, ««J *
cOMTAnrnukiio em •ASH o* "V, *«« *
-------
at the east or southeast end of the trenches which one can logically
infer to be downgradient from the trenches assuming that the dip of
the beds and mounding of leachate in the trenches influenced the
direction of water movement in the trench area. This would be the
direction then in which these leachates would migrate, if they migrated.
The following hydrogeologic information suggests that Pu could migrate
from the trenches via the interflow pathway: the trenches were filled
to land surface; the soils had some degree of permeability; and a
hydraulic gradient existed--therefore interflow or lateral migration
of the leachate through the soil should have taken place.
Based on the core data, there is Pu contamination of the soil
and cap material in the trench area at Maxey Flats down to a depth
of 75-90 cm. This contamination appears to be relatively uniform
from land surface downward to at least 90 cm depth with little sign
of stratification or preferential distribution. Further, it can logically
be inferred that the contamination extends below 90 cm and possibly
to the base of the weathered zone. If there is no obvious stratification
of Pu down to 90 cm, there is no good reason to limit or fix a point
below 90 cm where stratification should begin except at some natural
hydrogeologic boundary. The base of the fill or weathered zone is
such a natural boundary. To use a specific example, in the Trench
26 area, the probability that the concentration of Pu drops to "zero"
at 92 or 95 cm is low when it is obviously contaminated to the 1-4
dpm/g level at 90 cm.
The core data together with the hydrogeological information
available suggest a situation where the trenches filled with leachate
and the leachate migrated laterally through the soil and cap material
away from the trenches or overflowing from the trenches had saturated
the areas sampled. One could reasonably expect to find stratification
of Pu concentrations downgradient away from the trenches.,
While lateral migration was occurring, downward infiltration could
be expected through the bottom of the trenches into the Nancy and
Farmers Members because the trenches extend below the weathered
zone into the jointed Nancy Member.
Based on information about wastes buried at other sites it is believed
that decontamination solutions are buried with low-level wastes. If
confirmed, these decontamination solutions possibly acting in conjunction
with organic acids which are commonly generated in land fills such as
Maxey Flats could act to put Pu and other radionuclides into a complex
or anionic form which could readily migrate with the movement of the
leachate and soil water. Although the same information is not available
for the surface soil and soil core samples, the presence of Pu in soluble
form in the wells [7] supports the hypothesis that it may be present in
soluble form in the near surface soil zones, also.
35
-------
It has been suggested that the Pu contamination seen in the surface
and near surface samples atMaxey Flats could have originated from
other sources (Section 6.4). This possibility is recognized; it does
not, however, lessen the possibility that the migration by interflow
may have occurred.
6.7. Subsurface Pathway
In 1973, EMCON Associates, Inc., a geological consulting firm,
constructed 14 monitoring wells around the perimenter of the con-
trolled area of the burial site. These wells were constructed and
completed at different depth intervals for the primary purpose of
monitoring for contamination in the different subsurface formations
beneath the site. They also had the secondary purpose of identifying
water-bearing horizons or aquifers beneath the site. Excellent
information is available on the character and depth of the different
subsurface formations because core samples of the formations
penetrated by the wells are available [18], Figure 10 and Table IV
give details on Wells 3E, 6E, 8E, 10E, and HE.
The following points argue against the introduction of significant
Pu-contamination having been introduced into the wells by means
other than subsurface migration:
- The Pu-238/239 ratios found in some of the wells are higher
than ratios generally found at land surface.
- The cross-rcontamination mechanism does not seem adequate
to produce the. concentrations and ratios of Pu actually observed
in the wells (see Appendixes A and B).
- At least some of the wells in which Pu contamination was detected
were not on paths where overland runoff from contamination areas
could easily flow around the wells and run down the annulus of the
well to cause contamination.
- Independent sampling by three organizations (KDHR, EPA's RNEB,
and the site operator) found Pu contamination in nine wells (IE, 2E,
3E, 6E, 8R, 10E, 11E, 12E, and 13E) in 20 out of 20 suspended
sediment samples reported on thus weakening the arguement for
cross-contamination (Table V).
- Other radioactive contaminants were found in the wells (H-3, Co-60,
Cs-134, Cs-137).
- Pu has been found in solution in four samples from two wells.
36
-------
FIGURE 10. SCHEMATIC OF CONSTRUCTION OF TEST WELLS AT MAXEV
FLATS FOR WHICH PU DATA ARE PRESENTED IN THIS REPORT.
(BASED ON INFORMATION PRESENTED BY EMCON)
WELLS
6E AND 11E
LAND SURFACE
WELL 3E
WELLS
8E AND 10E
,
•&
oof
'••*.'•"
0
PERFORATIONS
GRAVEL PACK
CEMENT GROUT
pTL,
N ,
-143 mm
DIAMETER
BORING
76 mm DIAMETER
CORE BORING
m
vpa
PERFORATIONS
37
-------
TABLE IE. SUMMARY OF WELL CONSTRUCTION, GEOLOGIC, AND HVDROLOGIC DATA
FOR TEST WELLS AT THE MAXEV FLATS BURIAL FACILITY WHICH WERE SAMPLED
FOR PU BY KDHR DURING THEIR "6-MONTH" STUDY AND BY RNEB-CINC.
MTKR t.FVFLS
u>
oo
rasr
KH.I.
roT-u ni i'
(METI.RS)
Tl1
SVIRFH RITORTPP MEASURED
3C
6E
8E
ion
2~.4 2(i.
15.2 15.
27.4 27,
27.4 28.
1
5
-
1
OF PERMEABILITY
LAN!)
SURFACF
ELEVATION
IM)
511.4
318.7
518.5
520.1
PEPTH .
TO hATF.R
(M)
25.6
15.1
24.2
2'. 8
ELEVATION
Of WATER
LEVEL
on
235 . S
•315.6
294. 1
292.5
nrrm
00
12.5-12.8
17.1-17.9
21.0-21.6
25.6-25.9
PERMEABLE
FORMATIONS
FARMERS
FARMERS
FARMERS
SUNBURY
RELATIVE
KATER
PRODUCTIVITY
OF KELLS
MODERATE
MOPERATF
r.oon
FAIR
HROUTI-D
INTERVAL
(M)
0-18
0-3
0-3
0-3
FORMAT 1 3NS
M1NITOREP
BY KEI.L
SUNBURY
NANCY, FARMERS
NANCY, FARMERS,
SUNBURY (UPPER)
NANCY-, FARMERS,
SUNBURY (UPPER)
(UPPER)
HENLEY ,
HENLEY,
15.6
15.4-13.1 505.7-30S.O
VANCY, FARMERS
(1) Based on loss of drilling fluids during coring and drilling operations.
(2) All of the formations penetrated are aquitards; the test wells do not produce water like a water well does. The relative
productivity of the test wells is defined as follows: fair. tlr:i\vclo\vn recovery less ih:tn 3u cm ;ifier 2 weeks: moHer:iio.
drawdown recovery approximately 30 cm in 2 weeks; and good, drawdown recovery 180 cm in 8 days.
-------
Table V. Summary of concentration of Pu-238 and Pu-239 and ratio
of Pu-238 to Pu-239 in suspended solids and soluble portions
of water samples collected from test wells at Maxey Flats
burial facilities. (2)
Suspended
Solids Soluble
Number of analyses
Number of Samples Contaminated with Pu
(On Any Basis)
Number of Samples Contaminated with Pu
(On Basis of Pu-238)
Number of Samples Contaminated with Pu
(On Basis of pu-239)
Number of Samples Contaminated with Pu
(On Basis of Pu-238/ 239 Ratio)
Number of Wells Sampled
Number of Wells contaminated with Pu
(On Any Basis)
Suspended
Solids "
Pu-238 Pu-239 Pu-238/239 Pu-238
(djDm/g) (dpm/g) (Ratio) (dpm/1)
High Value 33.3 1.2 71.7 28.9
Low Value 0.18 0.013 0.7 0.02
(l)
Median Value 7.9 0.21 32.9 NA
(l)
Mean Value 11.9 0.69 31.1 NA
20 15
20 4
20 2
11 2
C1)
20 NA
9 7
9 3
Soluble
Fti-239 Pu-239/239
(dpm/l) (Ratio)
3. 3 13
0. 01 NA
(l) (1)
NA NA
(l) d)
• NA NA
11 Not applicable because of insufficient data.
"27 Detailed data is presented in Appendix C.
T/ Based on 20 samples.
£/ Based on 15 samples.
39
-------
The Pu data from the "6-month" study and other sources when
taken with the hydrogeologic data are adequate to establish that the
potential for subsurface migration exists. Other radiochemical data
[2, 9] also suggest that Pu may be migrating via the subsurface path-
way. To help the reader understand the complex relationships
between these diverse data, a 3-dimensional isometric stratigraphic
panel diagram which shows the wells, the geologic formations they
penetrate, the potential source term, some of the hydrology, the
potential pathways, and potential zones where contamination can occur
is presented in Figure 11. Observations made about the potential
source term, the monitoring wells, and their interrelation with the
subsurface hydrogeology follow:
- There were leachate-filled trenches [21] which could serve as a
potential source of contamination (FACT).
- The hydrostatic head of 4-6 m of leachate [21] which existed in
some of the trenches in the past could have furnished considerable
driving force for this source term (FACT).
- Joints in the burial media and underlying subsurface formations
[15,14,17,18] are potential pathways for migration through other-
wise low-permeability rocks (FACT).
- Zones of subsurface permeability have been reported [15, 18];
therefore, potential pathways do exist for downward subsurface
migration of Pu (FACT).
- Water has been detected and repeatedly measured in the monitoring
wells [17, 19, 34], establisheing that presence of what are believed
to be perched aquifers and a regional water table. Because in-
filtrating precipitation is the most likely source of groundwater
beneath the site—these waterbearing zones tend to support that
downward movement does occur. (HYPOTHESIS held by six
geologists) [15,21,14,34, 17 and this report],
- Pu has b^en detected in suspended solids and sediments in wells
3E, 6E, 8E, 10E, and HE in the 6-month study [2]. Pu has been
detected in suspended solids and in solution in wells IE, 2E, 3E,
6E, 8E, 10E, HE, 12E, and 13E in other studies (FACT) [7,9].
40
-------
F.GURE 11. SCHEMAT.C Of CONSTRUCTS OF TEST WELLS AT MAXEY FLATS FOR WH.CH PU DATA ARE PRESENTED ,N TH.S REPORT.
10E (1060
TYPICAL TRENCH UEACHATE
LAND SURFACE
ESTIMATED DEPTH
OF FORMATIONAL
COM ACT BASED ON
CORRELATION FROM
OTHER WELLS
-------
- Based on the depth the casing was emplaced and grouted, and
assuming that the grout is effective, Pu could possibly have
entered the wells from the following depths and formations: Well
3E, 18-26 m from the top of the Bedford and the Sunbury; Well
6E, 3-15 m from the Nancy and Upper Farmers; well 8E, 3-28
m from the Nancy, Farmers, Henley, and Upper Sunbury
(permeable zones reported at 17-18 m in the Farmers and at
25-27m in the Sunbury); Well 10E, 3-28 m from the weathered
zone, Nancy, Farmers, Hanley, and Upper Sunbury; Well HE,
3-16 m from the Nancy and the Upper Farmers (FACT) [18].
- The Pu-238 concentrations in the well samples are very high
relative to all other samples collected in the "6-month1 study;
all fall within the 94 percentile (FACT) [2].
- The Pu-238/239 ratios in the well samples were very high relative
to all other samples collected in the "6-month" study (all fall
within the 94 percentile) [2], They were also similar to ratios in
the leachates, possibly suggesting a common source. Preliminary
analyses from RNEB-CINC also indicate that the well samples
have very high Pu-238/239 ratios (FACT) [3].
It is believed that the preceding observations strongly support
the following hypothesis: (1) there is a mobile potential source of
Pu-contamination (the leachates); (2) there was and possibly still
is a driving force (the hydrostatic head of the leachate); (3) there
are subsurface pathways for the migration of Pu (the joints); and
(4) Pu was detected in the wells. Therefore, the information
available suggests the possibility that Pu may be migrating from
the trenches via the subsurface pathway. Additional information
and studies are required to confirm this, however.
The occurrence of very high concentrations of Pu-238 and
Pu-238/239 ratios in the wells compared to other samples collected
at Maxey Flats (excluding the leachate samples) is significant.
6. 8. Atmospheric Pathway
Volume r eduction of the leachate by evaporation prior to its
solidification is an integral part of the water management program
for the site. The liquid to be evaporated is pumped into a settling
* The author personally made the crude but simple test for water
in the wells by dropping a small pebble into the well and listening
for a splash as indicating the presence of water. A splash was
heard in 8 or more of the wells. Later, Zehner in his studies has
routinely measured water levels with automatic water-level
recorders and/or chalked steel tape.
42
-------
tank, allowed to settle for several hours, pumped into the evaporator
vessel, heated by a submerged propane burner, and evaporated at
a rate of approximately 19 1/min. The vapor is passed through a
mist eliminator and then discharged to the atmosphere through a
10 m stack. The evaporator was designed specifically for Maxey
Flats operations. The evaporator "bottoms , or concentrates, are
periodically pumped into a holding tank to await solidification.
Pu-contaminated liquids go into the evaporator; therefore, the
vapor plume discharging from it is a potential pathway for Pu. Al-
though possible, volatilization of Pu is not necessarily suspected.
However, the discharge of extremely small particles is of concern.
RNEB-CINC has detected 11 mostly long-lived radionuclides in the
stack effluents including H-3, Na-22, Co-60, Sr-90, Ru-106, Sb-125,
1-131, Cs-134, Cs-137, Ra-226, Ac-228, and gross alpha [5]. Pu
analyses of the stack effluent are not yet available.
One sample collected during the 6-months study may be directly
related to the evaporator pathway. Sample 157, which was collected
from soil directly beneath a drip from the discharge stack, had
20 dpm/g Pu-228, .49 dpm/g Pu-239, and a Pu-238/239 ratio of
11.93.
The physical aspects of the evaporation process may be of con-
cern when dealing with radionuclides which are known to occur in
extremely fine particles, such as Pu-238 and Pu-239.* First,
suspended solids in the liquid to the evaporated are removed by
settling, a process which may not be very effective for extremely
fine particles. ** Any solids carried over into the evaporator vessel
are subjected to considerable turbulence during evaporation by the
submerged flame. The fall back of finely divided particles into the
"bottoms" may not be as complete as anticipated. Second, the
decontamination efficiency of the system drops off as the "bottoms"
become more concentrated. Therefore, controlling the concentra-
* Volatile radionuclides are also of concern but are not the subject
of this paper.
•''•'• This potential problem should be largely eliminated now because
the pre-treatment of the leachate with flocculating agents is reportedly
greatly reducing the suspended solids in the liquid going into the
evaporator.
43
-------
tion of the evaporator "bottoms" is essential to maintaining uniform
decontamination efficiency in an evaporator system. In a pre-
liminary report, RNEB-CINC noted a low correlation between the
feedstock going into the evaporator and the effluent discharging
from the stack [8]. Lack of precise control of the concentration
of the "bottoms" is one possible answer to the apparent lack of
correlation.
Contamination via the atmospheric pathway would certainly
provide a plausible answer to why a number of the samples in
the 6-month study appear to be "lightly contaminated" on the
basis of their Pu-238 content and Pu-238/239 ratio.
7. ENVIRONMENTAL IMPLICATIONS OF MAXEY FLATS
' PLUTONIUM DATA
7. 1. Low-Mobility Concept of Plutonium
To date, there have been few field reports that Pu has migrated
when buried in the ground. To the contrary, Pu has the reputation
of being sorbed on the soil within several centimeters of contact.
Reichert [35] reports that by 1962, all of the radionuclides released
to the seepage basins at the Savannah River Plant (SRP), except Pu
had been detected in the surrounding groundwater. Fennimore [36],
also at SRP, concludes that Pu does not move through soil even
under a constant hydraulic head.
The studies on the migration of Pu in the environment have been
influenced by its mode and place of occurrence and possibly by the
type of Pu. By far, the largest source of Pu in the environment has
resulted from deposition on soil and water surface due to fallout,
accidents, and releases from normal operations. Therefore, much
of the research in recent years has been concerned largely with the
fate of plutonium deposited on soil surfaces. In addition, much
emphasis has been placed upon field investigations of migratory
pathways at semiarid sites. Laboratory investigations have
concentrated largely on column studies of Pu leach rates and soil
adsorption capabilities of a media occurring during the intergranular
flow of a contaminated liquid through pulverized media.
Researchers seem to generally agree that Pu is effectively
retained in the uppermost part of the soil column and is not
available to infiltrating water even under humid climatic conditions.
44
-------
A commonly accepted axiom is that Pu does not migrate deeper than
15 cm below the surface in soils, unless they are disturbed [37, 38,
39,37], Some workers [41,42] suggest that the downward dispersal
occurs by mechanical movement of Pu-contaminated particles.
Hajek [43], working on the behavior of Pu in subsurface disposal
at Richland, Washington, concluded that movement by contact
diffusion would be less than 10 cm after 240, 000 years, and that a
maximum of 0.1% of the plutonium would be leached by infiltrating
ground water. Rhodes [44] reports that soil sorption of Pu was
greater than 97% between pH 2 and 8. Wilson and dine [45] were
able to remove less than 1% of the Pu in a soil column using stand-
ard (agricultural) leaching techniques.
7.2 The Mobile Concept of Plutonium
A number of agents and conditions can increase the mobility of
Pu when it is buried in the ground. A few of these are described
briefly below.
-- Pu can, in the presence of certain agents, form complexes
which are difficult to remove from solution and such
complexes would not be expected to be retained by soils
[46].
— The mobility of Pu in Soils with extraction solutions has
been demonstrated using an equilibrium method. It was
concluded that Pu was extracted due to the formation of
anionic acetate complexes* and not the effect of the
extracting cations [44], Similar results were recorded with
organic solvents which are used during nuclear fuel repro-
cessing operations [47],
-- Pu uptake by plants may be enhanced by successive cropping
and the passage of time. Although Pu uptake by perennial
ryegrass was low, it increased over a two-year period.
It was detectable in the third harvest of the first growing
season in an acid soil and increased four-fold in the second
year [48,49].
* It is interesting to note that acetic acid is a common product of the
anaerobic decomposition process in landfills.
45
-------
-- The uptake of fallout Pu by clover increased 7-fold over a
period of five years; the increase was believed due either to
more roots coming in contact with Pu as the plants aged or that
natural organic materials resulting from root tissue decay
complexed with Pu [40]. (The potential complexing of Pu by
plant activity may be more important than its uptake by plants).
-- Uptake of Pu was more than three times greater in a moder-
ately acid forest soil (such as found in the humid East) than in
calcareous soil (such as found in the arid West) [50].
-- Chelating agents such as DTPA (diethylenetriamine pentacetic •
acid) can cause a 20-fold increase in Pu uptake by alfalfa [51].
-- Studies of the effects of chelating agents on the availability
and mobility of Pu in eco-systems are important in view of
the commercial use of chelates in supplying micronutrients to
crops and plants [42].
-- Subsurface hydrogeologic and hydrochemical parameters affect
the sorptive capacity of a soil including pH, redoxpotential. Eh,
and moisture content [14],
— Soil sorption capacities are minimized if Pu transport occurs
along fractures or joints rather than interstitially because of the
reduction of rock or soil surface area exposed to the contaminant.
Christenson and Thomas [31] have reported that Pu released to
seepage basins has been able to migrate to depths of at least 8. 5
m through fractures in the Los Alamos Tuff. They mentioned
the possibility that organic complexes were responsible for the
transport of Pu; however, they felt that the Pu movement took
place along fissures.
Price [42] and Francis [41] present excellent reviews of the
published studies on the distribution and fate of transuranium
elements in the environment. Price concludes that the behavior
and fate of transuranium elements in the environment is poorly
understood. Francis concludes that the mobility of Pu after deposition
on the surface of rich prairie or forested soil developed in a temperate
to subhumid or humid climate is unknown.
Gera [52] more recently has introduced data from volcanic environ-
ments which suggests considerable geochemical mobility for Pu but the
data are too scanty and too restricted to provide a reliable indication of
46
-------
the general behavior of Pu in geologic systems. He noted that the
migration of Pu colloids through geologic formations would be
restricted by filtration and surface sorption, rather than by ion
exchange. Gera further noted that the mechanism of infiltration in
humid areas could be significantly different than in arid areas and
that biologic processes could also contribute to the downward .move*
ment of Pu.
7.3. Behavor of Plutonium When Buried in a Landfill at Msixey Flats
In the previous sections, the author presented "just the facts"
or what reasonably could be deduced from the facts. This section
is more hypothetical in nature. Herein* an attempt is made: (1) to
make the connection between a radioactive waste disposal site
as presently operated in a humid climate and a common landfill
garbage dump and (2) to suggest that somewhere in the processes
going on within the landfill trenches at Maxey Flats and elsewhere*
there is some special mechanism which is able to mobilize Pu
contrary to common accepted concepts of Pu's immobility. The
author would like to state specifically that he does not believe that
the mechanism(s) suggested here regarding Pu's mobility in the
environment apply to the disposal of Pu in a deep geologic disposal
situation such as been suggested for the ultimate disposal of high-
level and transuranium-contaminated wastes. Rather* the special
problems addressed here are associated with the shallow disposal
of Pu and other radionuclides in landfills in humid climates using
present methods.
The Maxey Flats burial facility has had a number of operational
problems such as trenches filling with water* erosion and subsidence
of caps* and the movement and possibly migration of leachates from
the trenchesi These and other problems are normal to most conven-
tional landfills In humid climates--and Maxey Flats is basically a "*
iandriu wnicn accepts only a special type of waste. Two important
causes or these problems are: (l) the landfill process which greatly
alters the natural hydrogeologic system of a site and (2) the large
amounts of contaminated solid waste which are placed in an environ-
ment favorable for its dissolution and dispersal.
To understand the problems at Maxey Flats and how it is possible
for Pu to migrate, an understanding of what happens to waste after it
is buried in a landfill is helpful. Therefore, a brief description of the
"life cycle" of a landfill follows: (1) the trench is excavated, and
quite often, as at Maxey Flats, from material with relatively low per*
47
-------
meability; (2) the trench is filled with high porosity, permeable, com-
pressible wastes which contain organics and a wide range of chemical
forms; (3) the wastes are covered with an earthen cap which is'often
more permeable than the original pre-trench soil and rock, in effect,
creating an infiltration gallery; (4) some of the precipitation whidh
falls on the cap, infiltrates into the trench and soaks the wastes; (5)
leaching of the waste begins, aided by the presence of organic matter,
bacterial action, the formation of organic and inorganic acids, and
chelating agents; (6) the trench leachate begins (i) to migrate down-
ward and laterally because of the hydraulic head imposed by the
leachate in the trench and/or (ii) to overflow at land surface in
springs and seeps at some low point between the cap and the undis-
turbed earth; and (8) as the wastes continue to soak and leach, they
compact, undermine the trench cap, increase the infiltration of water
into the trench, and thereby increasing leachate generation.
Landfill leachate commonly has 50, 000 - 80, 000 nag/1 chemical
oxygen demand, 11, 000 mg/1 of volatile acids, 6, 000 mg/1 of organic
acids, and pH ranges of 3. 7 to 8.5 [53, 54]. Constituents which
possibly might release or mobilize contaminants from the waste
include acetic, proprionic, isobutyric, butyric, and valeric acids.
In brief, landfill leachates may contain agents capable of putting
into solution generally insoluble elements such as plutonium.
Detailed analyses of the non-radioactive constituents of the
Maxey Flats leachates are not available. If, however, it is recalled
that the wastes entering a commercial radioactive waste burial facility
may typically contain (1) 70% by volume paper and plastic material,
(2) numerous laboratory animals, and (3) organic compounds, and
are often packed in wooden crates and cardboard boxes (which are
organic material), it can be seen that "other-than-high-level" wastes
make quite a rich feedstock for generating a very potent landfill
leachate. In the absence of additional information, it seems reason-
able to assign at least some of the characteristics of k "typical"
landfill leachate to the Maxey Flats leachates. . ,
Preliminary analyses of leachates collected from trenches at the
commercial radioactive waste disposal facility in West Valley, New
York, indicate that they may be similar in character to common landfill
leachates [55], Nineteen different organic peaks were identified including
acetic and butyric acids. In addition, Pu was detected in both the dis-
solved and suspended fractions of the West Valley leachates. In one
sample, approximately 5% of the Pu in the leachate was in the 'dissolved
fraction; the other 95% was in the suspended fraction.
48
-------
As noted earlier, Pu was detected in the leachates at Maxey Flats,
but the analyses were on the total leachate samples, so it is not known
whether the Pu was suspended, dissolved, or both. Finding Pu in soluble
form in the wells [7] makes it reasonable to suspect, however, that Pu
is in dissolved form in the leachates. From what is known about the
wastes buried at Maxey Flats, it seems reasonable to suspect that Maxey
Flats leachates share many of the characteristics of common landfill
leachates, also.
After reviewing what little is known about the behavior of Pu in the
environment, it appears that the climate, the geology, and the burial
conditions at Maxey Flats include many of the factors which would tend
to mobilize Pu or to reduce its retention in the ground--and few factors
which would tend to immobilize it. For example, it is known or it can
be reasonably inferred that:
- Maxey Flats has a humid climate and acid forest soil.
- Grasses and clovers have been grown on the caps and cropped
for the past several years.
- The burial media and underlying strata are jointed and fractured
which reduces their effective sorptive action on contaminants
passing through them.
- Pu forms complexes with volatile and organic acids, chelating
agents, and decontamination solutions from nuclear facilities.
The Pu complexes once formed are difficult to remove from
solution and are not readily retained by soils.
- Volatile and organic acids are generated naturally in landfill
leachates in large volumes. Landfill leachates commonly
contain 10,000 - 15,000 mg/1 volatile acids - and it is belie ed
there are similar leachates in the trenches at Maxey Flats.
-r One can reasonably infer that wastes containing decontamination
and cleanup solutions from nuclear facilities have been buried
in the trenches.
The migration of leachates from landfills even in arid and semi-
arid climates is a reported fact; in a humid climate leachate migration
or movement is almost de rigueur. Referring more specifically to
radioactive, waste disposal sites, the migration or movement of radio-
activity has been reported at the commercial burial site at West Valley,
New York [56]; at the burial site at the Oak Ridge National Laboratory,
Tennessee [57], and at a former A EC facility at the Palos Hills Forest
Preserve (near Argonne National Laboratory), Illinois [58],
49 •
-------
Therefore, the author believes that the widespread occurrence
of Pu and its distribution in the leachates, soils, soil cores, and
wells at Maxey Flats are indications that (1) Pu possibly has been
mobilized by one or a combination of the above agents and (2) has
migrated through the soils and subsurface formation at Maxey Flats.
This report does not try to specifically define how or in what form
Pu is migrating; its primary purpose is to call attention to the very
likely possibly that it is migrating.
8. SUMMARY AND CONCLUSIONS
Wastes containing more then 80 kg Pu-239 have been emplaced
in trenches where water infiltration has occurred. Pu and other
radionuclides have been leached or released from the wastes
to form a Pu-contaminated leachate. Therefore, a large source
term of Pu is available at Maxey Flats in a mobile form.
There are at least four potential pathways available for the
migration of Pu at Maxey Flats. These include: (1) the surface
water transport of contaminants which reach land surface; (2)
interflow, or lateral migration of contaminants via water move-
ment through the soil; (3) subsurface migration of contaminants
along joints and bedding planes in the underlying strata; and (4)
atmospheric dispersion via the evaporator plume.
Available hydrogeologic information indicates that there are,
or recently have been sufficient driving forces to cause the Pu-
contaminated leachate to migrate. The hydrostatic head of 4-6 m
of the leachates in some of the trenches is or was sufficient to
cause lateral and downward migration of the Pu-contaminated
leachates. The normal erosional processes are sufficient to cause
surficial migration of Pu once it reaches land surface, either
through operational activities, leakage from the trenches or lateral
migration through the soil. The evaporator plume is a potential
pathway for any Pu entrained therein.
Pu in above background concentrations has been detected outside
the trenches and the controlled area: (1) in on-site and off-site
surface soils and stream sediments; (2) in soil cores evenly
distributed to a depth of 90 cm; (3) in well samples 15-27 m deep;
and (4) in a sample associated with evaporator plume discharges.
Primary conclusions which may be drawn from the hydrogeolgical
and radiological information include:
- Pu and other radionuclides have been leached or released from the
wastes to form a Pu-contaminated leachate.
50
-------
- There is Pu contaminantion in and around the Maxey Flats burial
site.
<. t ,
'.)..' , . • „'<••
- Pu has migrated or moved from the trenches and the site possibly
via several pathways including; surface transport, interflow, subsur-
face movement, and atmospheric fallout.
- Samples collected in similar locations as the Pu samples
contained H-3, Co-60, Sr-89, Sr-90, Cs-134, and Cs-137, in
concentrations greater than background or fallout, indicating that
other radioactive contaminants are moving or migrating also; thus
tending to confirm the conclusion that Pu is migrating.
- Contamination from other sources such as spills from routine
operations, spills during trench dewatering, the use of contami-
nated fill, and cross-contamination during the sampling has been
reported or suggested. After careful review, it has been
concluded that the contamination from these other reported
sources does not significantly alter the data from the KDHR's
"6-month" study or the basic conclusions concerning the potential
for migration of Pu via the water pathways.
- There is insufficient radiological and hydrogeological information
to estimate in what form, in what quantity, or at what rate Pu is
migrating.
Conclusions of a more general nature which can be drawn from
experience and data from Maxey Flats follow:
- According to many technical references, Pu normally does not
move through the soil and subsurface more than a few centimeters,
yet at Maxey Flats, it has been detected tens and hundreds of
meters from the trenches.
- The burial site was expected to retain the buried Pu for its hazard-
ous lifetime, but Pu has migrated from the site in less than 10
years.
- If 100% retention of a waste for its hazardous lifetime is the goal
of shallow land disposal, continued burial of Pu (and other radio-
nuclides) in humid climates using present waste forms, containers
and trench construction methods will not achieve the goal.
51
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[1] Clark, D. T., A History and Preliminary Inventory Report on the
Kentucky Radioactive Waste Disposal Site, Radiation Data and
Reports 14 7 (1973) 573.
[2] Kentucky Department for Human Resources, Six Month Study of
Radiation Concentrations and Transport Mechanisms at the Maxey
Flats Area of Fleming County, Kentucky, open file report, (1974)
[3] Montgomery, D., USEPA, Radiochemical and Nuclear Engineering
Branch-Cincinnati, personal communication (1975).
[4] U.S. Atomic Energy Commission, 10CFR Part 20, Transuranic
Waste Disposal, Proposed Standards for Protection Against Rad-
iation, Federal Register 39 178 (1974).
[6] Clark, D., Kentucky Department for Human Resources, personal
communication (1975).
[7] Nuclear Engineering Company Inc., Preliminary Comments on
"Preliminary Data on the Occurrence of Transuranium Nuclides
in the Environment at the Radioactive Waste Burial Site, Maxey
Flats, Kentucky, submitted to EPA December 1975.
[8] Kolde, H. Evaportor Study at the Maxey Flats Radioactive Waste Dis-
posal Site, (study in progress, preliminiary report available), USEPA,
Radioachemistry and Nuclear Engineering Facility, Cincinnati, Ohio,
Quarterly Reports, October-December 1974, April-June 1975.
[9] Montomery, D., Preliminary Environmental Pathway Study of the
Maxey Flats Radioactive Waste Disposal Site, (study in progress,
preliminary reports available), USEPA, Radioachemistry and
Nuclear Engineering Facility Cincinnati, Ohio, Quarterly Reports,
October-December 1974, January-March 1975, April-June 1975.
[10] Kentucky Department for Human Resources, Radioactive Waste Burial
Ground Field Test, Maxey Flats, Kentucky, report in progress.
[11] Palmquist, W. N., Jr., Hall, F. R., Reconnaissance of Ground-
Water Resources in the Blue Grass Region, Kentucky, U.S. Geologi-
cal Survey Water-Supply Paper 1533 (1961).
[12] U.S. Geological Survey, The National Atlas of the United States
(1970).
52
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[13] McDowell, R. C., Peck, J. H., and Mytton, J. W., Geologic Map
of the Plummers Landing Quadrangle, Fleming and Rowan Counties,
Kentucky, U.S. Geological Survey Map GQ-964 (1971).
; i
[14] Papadopulos, S. S. and Winograd, I. J., Storage of Low-Level Radio-
active Wastes in the Ground: Hydrogeologic and Hydrochemical
Factors with an Appendix on the Maxey Flats, Kentucky, Radioactive
Waste Storage Site: Current Knowledge and Data Needs for a Quantita-
tive Hydrogeologic Evaluation, USEPA Rpt. 520/3-74-009 (1974).
[15] Walker, I. R., Geologic and Hydrologic Evaluation of Proposed Site
for Burial of Solid Radioactive Wastes Northwest of Morehead,
Fleming County, Kentucky, unpublished report (1962).
[16] Hopkins, H., U.S. Geological Survey, written communication, (1962).
[17] Zehner, H. H., U.S. Geological Survey, personal communication
(1975).
[18] EMCON Associates, Project 108-52, unpublished report (1973).
[19] Zehner, H. H., Preliminary Hydrogeological Evaluation of the
Maxey Flats Radioactive Waste Disposal Site, (study in progress),
U. S. Geological Survey.
[20] U.S. Geological Survey, Study of Principles and Processes of .: <
Migration of Radioactive Contaminants at Maxey Flats Burial
Facility, in planning.
[21] Kentucky Service and Technology Commission, Preliminary Report:
Technical Summary of the Maxey Flats Radioactive Waste Material
Disposal Site, prepared by a special subcommittee of the Kentucky
Science and Technology Advisory Council (1971).
[22] Prairie, R., Preparation of Radioactive Waste Inventory System for
Maxey Flats for Operational Status, Southwest Ohio Regional
Computer Center, report in progress.
[23] U.S. Atomic Energy Agency, Environmental Statement for the
Liquid Metal Fast Breeder Reactor Program, WASH-1535 (1975).
[24] Morton, R. J., Land Burial of Solid Radioactive Wastes: Study of
Commercial Operations and Facilities, U.S. Atomic Energy
Commission. WASH-1143 (1968). ,
53
-------
[25] Sill, G. W., Puphal, K. W., and Hindman, F. D., Simultaneous
determination of alpha-emitting nuclides of radium through californium
in soil, Analytical Chemistry £6 (1974) 1725.
[26] Harley, John, H., HASL Procedures Manual, USAEC Report, HASL-
300 (1972).
[27] Strong, A., Lieberman, R., USEPA, unpublished report (1975).
[28] Miller, C. R., Providing Numerical Guidance for the Restoration
and Use of Land Contaminated with Transuranium Elements, USEPA,
open file report (1975).
[29] Sill, C. W., USER DA Health Services Laboratory, Idaho Falls,
personal communication (1975).
[30] Smith, A. E., Nuclear Reactivity Evaluations of 211b - Z- 9 Enclosed
Trench, USAEC Report ARH-2915 (1973).
[31] Christenson, C. W., and Thomas, R. G., "Movement of Plutonium
through Los Alamos Tuff, "in Second Ground Disposal of Radioactive
Wastes Conference, Chalk River, Canada, USAEC report, TID-7628
(1961).
[32] McCullough, J., EMCON Associates, personal communication
(1974).
[33] Keys, Scott, U.S. Geological Survey, unpublished report (1975).
[34] Kaufman, R. F., U.S. Environmental Protection Agency, written
.communication, (1976).
[35] Reichert, S. O., Radionuclides in groundwater at the Savannah River
Plant waste disposal facilities. Journal of Geophysical Research 67
11 (1962) 4363. —
[36] Fenimore, J. W., Land burial of solid radioactive waste during a
10-year period, Health Physics 10 (1964) 239.
[37] Krey, P. W., Hardy, E. P., Plutonium in Soil Around the Rocky
Flats Plant, USAEC Report HASL-235 (1970).
[38] McClendon, H. R., Soil Monitoring for plutonium at the Savannah
River Plant, Health Physics £8 (1975) 347.
54
-------
[39] Finder, J. E., Smith, M. M., McClendon, H. R., Boni, A. L.,
Horton, J. H., and Corey, J. C., "A Field Study of Obtain Plutonium
Contents of Old Field Vegetation and Soil under Humid Climatic .
Conditions", Proceedings, Radioecology Symposium, Corvallis,
Oregon (1975).
[40] Romney, E. M., Mork, H. M,, Larsen, K. H., Persistence of
plutonium in soil, plants and small mammal, Health Physics 22
(1970)487. .
[41] Francis, C. W., Plutonium mobility in soil and uptake in plants:
a review, J. Environ. Quality, 2 1 (1973) 67.
[42] Price, K. R., A review of transuranic elements in soils, plants,
and animals, J. Environ. Quality, 2_\ (1973) 62.
[43] Hajek, B. F., Plutonium and Amerioium Mobility on Soils, USAEC
Report BNWL-cc-925 (1966),
i •
[44] Rhodes, D. W.» Asorption'of plutonium by soil, Soil Science
84(1967)465.
[45] Wilson, D. O. and Cline, J. F. Removal of plutonium-239, tungsten-
185, and lead-210 from soils, Nature 209 (1966) 941.
[46] Christenson, C. W,. Fowler, E. B.,. Johnson, G. L., Rex E. G.,
and Virgil, F. A., Soil adsorption of radioactive waste at Los
Alamos, Sewage and Industrial Wastes 3£ (1958) 1478.
[47] Knoll, K. C. Reactions of Organic Wasteg and Soils, USAEC report
BNWL-860 (1969).
[48] Neubold, P., Absorption of Plutonium-239 by Plants, GB Agr. Res.
Council, ARCRL-10 (1963),
[49] Neubold, P., Mercer, E. R., Absorption by Plutonium-239 by
Plants, GB Agr. Res. Council, ARCRL-8 (1962)
[50] Rediske, J. H., Cline J. F., and Selders, A. A., The Adsorption
of Fission Products by Plants, USAEC Report HW-36734 (1955) 17.
[51] Hale, V. Q. and Wallace, A., Effects of chelates on uptake of some
of heavy metal radionuclides from soil by bush beans, Soil Science
109 (1970) 26.
55
-------
[52] Cera, F., Geochemical Behavior of Long-Lived Radioactive Wastes,
USAEC Report ORNL-TM-4481 (1975).
[53] Haxo, H. E., Monthly Progress Report No. 12, Matrecon, Inc.,
Oakland, California, unpublished report (1975). , ,
[54] USEPA, Summary Report: Gas and Leachate From Land Disposal
of Municipal Solid Waste, open file report (1974).
[55] Matuzsek, John, New York Department of Health, personal communi-
cation (1975).
[56] New york Department of Environmental Conservation - New York
Energy Research Development Agency - USEPA, Preliminary
Evaluation of Radio-Contaminant Migration at the Radioactive Waste
Burial Facility, West Valley, New York, (a joint report, in
preparation).
[57] Duguid, J. O., Status Report on Radioactivity Movement from Burial
Grounds in Melton and Bethel Valleys. USERDA Report ORNL-5017,
(1975).
[58] U.S. Energy Research Development Agency, press release dated
February (1976).
[59] Gat, U., Radioactive Waste Inventory System, USEPA, Unpublished
Report (1974).
56
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APPENDIX A
CROSS-CONTAMINATION QF SOIL SAMpLES BY USING DIRTY
CORING DEVICE
Could significant Pu contamination of the soil samples collected by
the KDHR have resulted from cross-contamination by residue left in the
coring device from a previous contaminated sample? And if so, what
would be the maximum concentrations of Pu transferred into the new
sample?
Cross-contamination of a new sample by residues from previous
samples certainly is possible if the coring device is not thoroughly
cleaned between uses. It is not expected, however, that the amount of
residue carried forward from the previous sample would be greater than
several thousandths or several hundredths of the total volume of the
coring device. If a residue in this amount were carried forward, it
would be thoroughly mixed with the new sample during the sample pre-
paration process prior to analysis and would therefore be diluted to
several thousandths or hundredths of its original concentration.
Let us take the example of the three cores taken from the same core
hole at Trench 26 (see Figure 9). Core No. 139 had a Pu-238 concen-
tration of 4. 75 dpm/g; if this contamination resulted from a small
amount of residue the left in the coring device, the average concentration
of Pu-238 in the previous sample should have ranged from 950 to 240
dpm/g if the new sample were contaminated by a residue carried forward
in the coring device equal to 5/1000ths to 2/100ths of the volume of the new
sample. Yet if we examine all of the soil cores collected at Maxey Flats,
the highest concentration of Pu-238 detected was 20 dpm/g or less than
I/10th of that required to produce the contamination observed in No. 139.
Using a similar calculation for Core No. 140, the next deeper core, we
can assume that the Pu-238 concentration in the preceeding core was
4. 75 dpm/g. If we again assume that 5/1000ths to 2/100ths of Core No.
139 was carried forward to NO. 140, the average concentation of Pu-238
contributed by No. 139 to No. 140 would range from 0.024 to 0.095 dpm/g.
Yet the concentration found in Core No. 140 was 13.30 dpm/g or almost
three times greater than the concentration of Pu-238 found in No. 139.
Again, making similar calculations for Core No. 141, the next deeper
core from the same core hole, we know that the Pu-238 concentrations
in the two preceeding cores were 4. 75 and 13. 30 dpm/g respectively.
Therefore, again assuming that 5/1 OOOths to 2/lOOths of Core No. 140
(13. 30 dpm/g) was carried forward to Core No. 141, the average con-
centration of Pu-238 contributed by No. 140 would range from 0. 067 to
0. 27 dpm/g. Yet the concentration of Pu-238 found in No. 141 was 4. 04
dpm/g. Similar observations can be made about the core samples
collected near Trenches 33L, No. 7 and No. 10. Clearly, the dilution
57
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one should expect has not occurred if the contamination in the core
samples in the trench area is due to the use of a dirty or contaminated
coring device.
It seems clear that generally to the author, the higher surface con-
centations of Pu-238 which would be required to cause significant contam-
ination of the "6-month" samples were not found at Maxey Flats. And on
a detailed basis, such as examining the mechanics and sequence of
sampling as at Trench 26, the concentrations of Pu-238 actually are too
low to be the source of significant cross-contamination.
58
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APPENDIX B
CROSS-CONTAMINATION OF WELL SAMPLES BY USING DIRTY
SAMPLING DEVICE (BAILElTT~
Could the concentrations of Pu-239 in the samples from the E-Series
wells be the result of cross-contamination from a dirty sampler? It is
possible that some contamination may have been transferred to a new
sample if the bailer used to collect the sample was not thoroughly washed?
No, it does not seem probable that all of the Pu detected in the samples
collected, from the wells was caused by cross-contamination from a dirty
bailer for the following reasons:
(1) The concentrations of Pu-238 and ratios of Pu-238/239 in samples
from the wells were significantly higher than the average of those found in
surface soil and soil core samples collected around the site. It is believed
that the sampling process and sample preparation would tend to cause
significant dilution of Pu-238 transferred by comtaminated residue from
one well into the sample of another well. First, let us make a very
conservative assumption that the contaminated residue which was trans-
ferred into the sample might make up as much as 10 to 25 percent by
volume of the new sample to bring the new sample up to the concentration
reported. * If 10 percent contaminated residue were introduced, it would
have to have Pu-238 concentrations of 86, 66-75, and 220-330 dpm/g
respectively in samples from Wells 3E, 6E, and HE to raise the Pu-238
concentrations in the samples from the wells up to the levels reported.
It seems more reasonable, in fact, to assume that no more than a trace
or several tenths of one precent by volume of contaminated residue would
remain in the bailer from a sample collected from a previous well, if
any at all remained. In this latter case the contaminant would have had
to have a Pu-238 concentration of 4, 000-16, 000 dpm/g to raise the samples
from the wells to the levels reported. Only one of the surface soil and soil
core samples had a concentration of Pu-238 greater than 40 dpm/g and only
two had concentrations of 20 dpm/g or greater.
* This estimate is based on the following reasoning and using sample 1616
from Well 3E which had a Pu-238 concentration of 8. 6 dpm/g: (1) the new
sample from the well would make up 75% by volume of the totsd sample
arid have a Pu-238 concentration of 0 dpm/g; (2) the contaminated residue
would make up 25% by volume of the total sample and would haive a Pu-238
concentration of 34.4 dpm/g; (3) the 25% residue and 75% new sample would
be thoroughly mixed; and (4) the total sample would come out with a Pu-238
concentration of 8. 6 dpm/g.
59
-------
Therefore, one can reasonably conclude that there is not an obvious
place where surface concentrations of Pu-238 were sufficiently high to
serve as a source for contaminating the bailer, if the bailer contained
an unreasonably high amount of contaminant such as 10 to 25 percent.
One could almost say that there is not even a place where surface concen-
trations of Pu-238 were sufficiently high to serve as a source for con-
taminating the bailer if the bailer transferred 50, 75, or even 100
percent of the suspended solids forward to the next well.
2. Samples collected from the E-Series wells by NECO and by EPA's
RNEB also contained Pu-238 and Pu-239 in concentrations greater than
background. The author has assumed that NECO collected their samples
from the wells in such a manner as to not cross-contaminate their
samples but this has not been discussed with NECO. The author has,
however, discussed the sampling techniques used by RNEB and is
confident that cross-contamination of RNEB samples is not a significant
problem. A detailed description of sampling method used by RNEB will
be included in Montgomery's pathways study [9].
3. If we look at all of the analyses which are available for the E-
Series wells, we find that for 9 out of 9 wells, the Pu-238/239
ratio was greater than 20; for 8 out of 9, the Pu-238/239 ratio was
greater than 25; for 6 out of 9, the Pu-238/239 ratio was greater
than 30; the mean or average ratio for 20 samples was approximately
3; the median ratio was 33; and the range was 0. 7 to 71. 7. Again,
the author concludes that there is no well-defined place or area at
land surface where the bailer could pick up contamination with
Pu-238/239 ratios such as seen in the E-Series wells.
If we look for a surface source area for contamination which has
Pu-238/239 ratios similar to the ratios found in the E-Series wells,
only at the east end of Trench 26 were ratios above 20 found. In all
other cases, the Pu-238/239 ratios of surface soil and soil cores samples
were less than 16.4. The Pu-238/239 ratios of 75 percent E-Series well
samples were higher than 20. The author is of the opinion that the chances
of transferring contaminants from the Trench 26 area individually into each
of the wells (3E, 6E, and HE) are extremely low because there is no obvious
or simple way for the bailer to pick up the contamination.
4. The author believes that "the preponderance of evidence" supports
the hypothesis that cross-contamination of samples by a dirty bailer did
not contribute significantly to the Pu contamination seen in the E-Series
wells. At this time, there are 20 analyses of suspended solids from the
E-Series wells; of these, 20 out of 20 samples were definitely contaminated
with Pu from a source other than fallout. These samples were collected
from nine different wells (IE, 2E,. 3E, 6E, 8E, 10E, HE, and 12E) by
60
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three different organizations (NEGO, KDHR, and RNEB) and were analyzed
by four different labs (AEC HSL, Radiation Management, LFE Labs, and
EPA RNEB). The author cannot see how this many organizations and
laboratories could have made mistakes with all of the samples collected.
5. Four samples had Pu contamination in the soluble portion of the
sample. Cross-contamination of the liquid portion of a sample by a dirty
bailer does not seem possible from a materials balance point of view. In
collecting the samples, all of the water is poured out of the bailer after
each sample is collected from the well. Even if the bailer is not rinsed
and wiped dry before the next sample is collected, only a few drops will
remain in the bailer to contaminate the next sample. If, for instance, as
much as 10 ml would have had to have been 2890 dpm/ml for this amount
to raise the concentration of Pu-238 to 28. 9 dpm/ml in the sample collected
from well 3 E if there was no contamination in the well to begin with. And
this would require that the 10 ml of highly concentrated contaminated liquid
would not be flushed from the bailer when the bailer was immersed in the
well water, or else it would be diluted below a point which would give the
concentration necessary to yield 28. 9 dpm/ml Pu-238. These circum-
stances seem highly unlikely to the author.
6. The following radionuclides were also found in the E--Series wells:
H-3, Co-60, Sr-89, Sr-90, Cs-134, and Cs-137. The presence of these
radionuclides tends to support that migration of radionuclides through the
subsurface has occurred. Further, tritium is a radionuclide which cannot
be transferred by cross-contamination in a dirty bailer in great concen-
trations because its transfer would be restricted to the water remaining
in the bailer and as discussed above no more than 10 ml should be carried
forward from one well to the next.
61
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Appendix C. Concentration of Pu-258 and Pv.i-.259 and ratio of Pu-238 to Pu-239 Ln suspended solids/sediments
and soluble portions of water samples collected from test wells at Maxey l:lats burial facility
NJ
Wei
1
Number ; Date
IE
2E
3E
3E
3E
3E
3E
6E
6E
6E
6E
6E
6E
8E
8E
8E
10E
10E
HE
HE
HE
HE
HE
HE
12E
13E
4-30-75
9-11-75
2-1S-74
(1) ;7-9-74
'8-8-74
11-8-74
4-30-75
;2-4-74
!5-8-74
6 -,11-7451-10--
™ 8-6-74
ai-8-74
U-30-75
11-8-74
(!) 4-30-75
:8-15-75
9-17-511-8-74
.4-30-75
:2-18-74
'5-8-74
!ll-8-74
;12-8-74
'4-30-75
:8-15-75
:4-30-75
4-30-75
Inso
Pu-238
(DPM/G)
6.4+0.4
25.8+1.3
8.6+0.7
18.2+1.8
-0-
3.2+0.2
1.3+0.1
7.5+0.5
6.0+0.6
75 4.3+1.6
-0-
-0-
0.18+0.04
-0-
33.3+2.0
-0-
20.6+1.5
8.2+0.7
33+2
22 + 2
2.0^0.1
4.3+1 .1
O.Sb+0.09
-0-
lb.2+0.9
!(•>. " + 0.9
luble
Pu-239
(DPM/G)
0.18+0.07
0.6+0.09
0.12+0.0009
< 0.4
-0-
0.09+0.02
0.03+0.015
0.22+0.03
0.19+0.04
<6.0
-0-
-0-
<0.013
-0-
1.2+0.09
-0-
<0.2
<1.3
0.59+0.07
0.47+0.07
0.07+0.022 ;
<0.72
0.1+0.01
-0-
0.64+0.13
n 75+0 11
Pu-238/239
(Ratio)
35.6
43.0
71.7
>41.0
-0-
36 . 3
40.0
34.1
31.6
^0.7
-0-
-0-
13.3
-0-
27.8
-0-
46.5
6.2
55.9
46.8
30.7
N
^6.0
7.8
-0-
25.2
22.1
Pu-238
(DPM/L)
-0-
<0.02
-0-
28.9+5.1
4.6+0.47
6.7+0.9
<0.15
-0-
-0-
-0-
<1.1
<8
-0-
<0.4
<0.04
<0 . 34
<0.9
<0.15
-0-
.-0-
-0-
-0-
<0.1
<0.555
<0.06
-0-
Soluble
Pu-239
(DPM/L)
-0-
<0.01
-0-
<2 .2
<0.1
<0.7
<0.15
-0-
-0-
-0-
<0.2
<12
-0-
1.7+0.7
<0.04
<0.34
3.3+1.6
<0.1
-0-
-0-
-0-
-0-
<0.1
<0.555
<0.06
-0-
Pu-238/239;
(Ratio)
fc_
-0-
-0-
-0-
>13
^20.9
^^
>10.0
-0-
-0-
-0-
-0-
-0-
-0-
-0-
<0.3
-0-
-0-
0.3
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
Laboratory
F.PA-RN'EB
FPA-RNEB
AEC-HSL
Radiation Management
Teledyne Isotopes
LFE
EPA-RNEB
AEC-HSL
AEC-HSL
Radiation Management
Teledyne Isotopes
LFE
EPA-RNEB
LFE
EPA-RNEB
EPA-RNEB
LFE
EPA-RNEB
AEC-HSL
AEC-HSL
LFE
Radiation Management
EPA-RNEB
Radiation Management
EPA-RNEB
EPA-RNEB
(1) Total sample; insoluble plus soluble.
-------
APPENDIX D
EPA RESPONSES TO THE REVIEW COMMENTS OF THE ENERGY RESEARCH
DEVELOPMENT AGENCY ON, "PRELIMINARY DATA ON THE OCCURRENCE"OF
TRANSURANIUM NUCLIDES IN THE ENVIRONMENT AT THE RADIOACTIVE
WASTE BURIAL SITE, MAXEY FLATS, KENTUCKY."
1. The results of studies mentioned on page 11 should be
included in the report.
Response: Preliminary drafts of the EPA studies are expected
to be available in March. A high priority will be given to their
review and they will be issued as soon as possible.
2. A statistically sound basis should be used to distinguish
between background radioactivity and that attributable to burial
ground operations.
Response: The significance of ERDA's comment is appreciated but
is clearly beyond the scope of the present report. EPA will confer with
ERDA on what it considers a statistically sound basis for distinguishing
between background radioactivity and that attributable to burial ground
operations. For the purpose of this paper, concentrations for Pu-238
and Pu-239 were conservatively set well above general regional background
levels so that there would be as little question as to whether the Pu
detected in a sample represented contamination from fallout or contamina-
tion from the wastes buried at the site. It is our opinion that the
follow-on papers mentioned in response to question No. 1 above would be
the appropriate place for determining what the .background levels are.
This must be done for a broad spectrum of other radionuclides which
have moved or have the potential to move from the site.
3. Some estimate should be provided of the fraction of Pu
originally in the wastes which has moved.
Response: Insufficient information is presently available to make
the estimate requested. The inventory of radioactivity in the form
kept by NECO is inadequate to determine what isotopes, where and how
much Pu has been buried at Maxey Flats in any useful form for scientific
studies at the site.
It is hoped that the computer-based radioactive waste inventory
system which EPA has been developing in cooperation with the State will
give us this capability. It may be necessary to investigate individual
invoices with the producer of the waste to finally determine the extent
of the problem. On the other side, a knowledge of the movement of water
63
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through the hydrogeologic .framework- at Maxey Flats together w-ith
an understanding of how Pu and the other radionuclides buried therein
interact with the geologic formations are also required to make the.
requested calculations. In brief, we don't know what's buried at
the site or understand the hydrogeological/geochemical system it is
buried in. EPA believes such information is needed and that the
studies to obtain this information should be performed.
4. It should be pointed; out that each trench and the waste
buried therein has a unique inventory of Pu in a unique waste matrix
and is therefore a unique source term.
Response: ERDA is correct on this matter and the paper has been
modified appropriately. We feel, however, that as these leachates
migrate downward into the deeper subsurface formations, they will be
subject to mixing, dispersion and dilution within the various perched
and regional water bearing formations. The end result may well be the
discharge of contaminated groundwater with a somewhat averaged composi-
tion but possibly with several subgroups.
5. Some perspective should be provided in the report on the extent
to which plutonium movement that has been observed poses a current or
possible future hazard.
Response: We can only say that the migration and movement from the
site is apparently not causing any health hazard at the present time.
Insufficient information is available to make an estimate of the .
situation which may exist in the future.
6. The term "migration" is variously used in the paper to describe
different mechanisms of movement. To avoid the resultant ambiguity
and possible misunderstanding, the term should be used as it usually is
in this, field, i.e., to mean movement through soil. It should not be
used to mean all mechanisms of transport.
Response: The use of "migration" throughout the paper has been
reviewed and changed so far as practical without changing the meaning
or intent of the paper.
7. The statement on the top of page 24 should .not be underlined.
Underscoring the possibility that "...Pu may be-migrating from the
trenches via the subsurface pathway" (page 24) adds emphasis that is
not warranted by the data presented in the paper.
64
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Response: The underline has been removed.
8. Units (dpm/g) and estimates of error should be given
in Table 1.
Response: These editorial comments were rejected. The reader
can make a rough estimate of the error of analysis for the soil and
soil core samples by looking at the estimated error for the suspended
solids analyses in Appendix C.
9. Surface and subsurface sample data should be presented
separately to avoid misunderstanding and misinterpretation.
Response: These editorial comments were rejected. The data are
separated for interpretation purposes in Table 1 into what the author
considers surface samples (I.e.', ON-SITE and OFF-SITE) and! subsurface
samples (i.e., SOIL CORE and TEST WELL).
10. Probable errors in Pu-238/Pu-239 ratios should be reported.
Response: There are several methods for calculating the probable
error for a ratio of two values each of which has its own estimated
error of analysis. However, it is the author's opinion that no one of
these methods is satisfactory to all statisticians or for all purposes.
Therefore, the author prefers to furnish the estimated error of
analysis for the basic data and let the reader determine the probable
errors in the Pu-238/Pu-239 ratios as he wishes.
11. An estimate should be provided of the amount of Pu in the
large mobile source term mentioned oh page 30. If some quantitative
estimate cannot be inferred from the data, the statement should" be
deleted.
Response: There is insufficient information on the source term
of Pu buried at' Maxey Flats. • However, based on a preliminary review
of the computer-based inventory data, the total source term of Pu-238
and Pu-239 might run as high as 200-300 kg. As a bare minimum, we
know that 80 kg Pu-239 have been buried at the site. This is a large
source term; however, the mobile fraction is unknown.
65
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12. Beginning on page-25 in section 7, the discussion of
information presented in reference 34-42 should be improved to better
represent the findings of the authors.
Response: The discussion reflects the author's understanding
of the references..
13. The projected burial growth rates for volumes of wastes and
quantities of special nuclear material, indicated by the arrows in
Figure 5, page 35, are at odds with the plotted data, which show a
steady decrease since 1972. The arrows should be eliminated or
modified appropriately.
Response: Both the text and the title of Figure 5 state that
projections shown were based on the information available as of 1972,
the period of time when authorities from the KDHR became concerned
about the water in the trenches and the phenomenal growth of waste
volume and special nuclear material being buried at Maxey Flats. The
author showed all of the detail available as a service to the reader.
14. If any additional data on Pu analyses on Maxey Flats environ-
mental samples is available and pertinent, it should be added to the
report.
Response: Additional Pu analyses which are available will be
published in the studies mentioned in response to comment No. 1.
15. References to documents which are not readily available,
particularly personal communications, should be eliminated.
Response: The intent is to indicate the source of additional
relevant information. In some cases, personal communications were
the only source of information.
16. According to Figure 7, sample 124 was an off-site sample;
therefore, the data for sample 124 in Table 1 should be listed with
the off-site samples. Also, the Pu-238/Pu-239 ratio for this sample
should be corrected.
Response: The Pu-238/Pu-239 ratio for sample No. 124 has been.
corrected.Tn regards to ERDA's comment concerning No. 124 being an
off-site sample, it falls well within the basic off-site sample
description of, "close in to the buried area."
66
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17. As is recognized in the table and elsewhere in the text,
the paper presents only preliminary data. It is essential, there-
fore, that a clear distinction be made between results, conclusions
based on results, and speculations offered in the absence of
definitive information. In this regard, a number of conclusions are
misleading or are not supported by the data presented in the paper. The
following are examples:
A. The conclusion on page 31 regarding confirmation of Pu
movement provided by measurements of other radionuclides is not
supported.
Response (17A): The author feels that finding the other radio-
nuclides in the monitoring wells does tend to confirm the migration
of Pu, since these others act as multiple tracers.
B. The data indicate that Pu has been detected some distance
from the trenches. However, these preliminary data do not warrant the
implication that the many technical references which conclude that Pu
does not move very far "through the soil and subsurface" are incorrect.
Therefore, the observation that Pu is not supposed to move (migrate)
etc., should be removed from the conclusions.
Response (17B): It is the feeling of many authorities that plutonium
does not "move" very far through the soil and subsurface rocks. In this
case, however, plutonium was found in 20 out of 20 samples available from
nine wells and in 14 out of 14 soil cores. If the hypotheses presented
in this paper to explain the movement of plutonium are correct, then
under certain sets of conditions, the statement needs to be amplified
to recognize that plutonium may not be held by the soil and rocks under
all possible conditions. We suggest, therefore, that a more careful
statement needs to be made about migration through the soil than has
been the case until today.
C. The last conclusion on page 31 should be deleted since it is
not supported by the limited nature of the survey and the resulting
preliminary data.
Response (17C) : Additional data has been added to the text which
the author feels supports this conclusion.
67
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D. The conclusion on page 31 beginning "Other modes of
contamination..." should state which of the water pathways are
supported by the data in the text.
Response (17D): This statement has been modified.
68
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APPENDIX I-
lil'A RESPONSES TO THE REVIEW COMMENTS OF THE NUCLEAR REGULATORY
COMMISSION ON, "PRELIMINARY DATA ON THE OCCURRENCE OF TRANS-
URANIUM NUCLIDES IN THE ENVIRONMENT AT THE RADIOACTIVE WASTE BURIAL
SITE, MAXEY FLATS, KENTUCKY."
1. The paper fails to give adequate emphasis to the public
health significance of the data and conclusions presented. Public
health significance is referenced in only two sentences on pages 1
and 4.
Response: The fact that health authorities and scientists from
the State of Kentucky, the Nuclear Regulatory Commission, and EPA
have all advised that the levels of plutonium detected in the environ-
ment at Maxey Flats do not constitute a health hazard at this time
has been given prominent coverage in both the Foreword and in the
text.
The immediate public health significance of the possible migra-
tion of Pu at Maxey was not relevant to the point of the paper. The
main issues in the paper are that: (1) Pu and other radionuclides are
out of the trenches and (2) Pu may be migrating via the water pathways,
2. The paper does not give recognition to the fact that the
Maxey Flats burial ground has been under a program of continuing
evaluation since the time it was licensed.
Response: We recognize that the regulatory agencies, i.e., the
State of Kentucky and NRC have had a continuing interest. The report
itself is based on a specific period of time and did not attempt to
evaluate the regulatory aspects of waste management, which is properly
the responsibility of those regulatory agencies.
3. The paper is based on data collected by Kentucky during the
period 11/73 to 5/74. There is little or no new data presented in
the paper. Kentucky has been collecting and analyzing samples since
conclusion of the 6-month study in May of 1974. Also, the EPA and
USGS have been conducting research studies of the site. Preliminary
results of these studies and longer term environmental monitoring
data may support or deny certain of the paper's conclusions.
Response: We recognize the paper is limited in time, and remedial
improvements made since May of 1974 have been recognized. Completion
of preliminary drafts of EPA, USGS, and KDHR site investigations is
expected in March 1976. Making these studies publicly available has
69
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been given a high priority. They will be forwarded to NECO, NRC,
ERDA, and KDHR, for comment as soon as the drafts are available and
will be published as soon as their review is completed. EPA plans
to keep the review time short and issue these reports as soon as
practicable because of the widespread interest in their content.
4. The first three objectives of the paper have already been
accomplished and presented in the Kentucky 6-month report. Also, it
appears desirable to attempt the fourth objective using only six
months of data, when, as indicated in the paper, additional data is
available.
Response: Delay of the paper until all of the facts and all of
the studies were completed was, of course, possible. However, it is
believed that presentation of the paper at San Francisco at a
symposium convened specifically to present new findings on transuranium
nuclides in the environment was particularly appropriate. Now that the
paper is common knowledge and will be publicly available in the proceed-
ings of the symposium, EPA cannot justify withholding its release.
The interpretations presented in the paper were presented for public
review, comment, and criticism.
5. As the title suggests, the paper is preliminary in nature since
it presents several specific and general conclusions concerning pathways
for the migration of plutonium based on data which the author concedes
equally support or do not rule out other "possibilities." We believe
that before predicting the future effectiveness of Maxey Flats burial
ground, the degree to which site operations and each pathway is
contributing to the radioactivity detected off-site should be determined.
Response: We concur with the need for additional information on
pathways contributing radioactivity detected off-site. However, the
extended period of time that may be required to gather this information
makes it impracticable to include such information in this
edition. We still believe that the information in the existing report
will be of interest to those concerned with the problem of possible
plutonium migration through the soil. In answer to the entire problem
of shallow land burial, site operations will be addressed on a
continuing basis as the information is gathered by EPA and the other
agencies.
70
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6. The paper speaks of plutonium migration by any.of four modes;
(!)•• surface runoff, (2) interflow, (3) subsurface interflow, and,..,,.
(4) atmospheric dispersion. .We .believe use of the term migration '.'.
should be limited to discussion .of the movement of the material, through
the soil (interflow) and underlying geologic formations (subsurface ,
flow). Surface runoff carrying contamination from site operations
and evaporator fallout are contributing radioactivity to the local
environment which makes it difficult to determine to what extent
radioactivity has migrated or is continuing to migrate via the inter-
flow and subsurface flow modes.
Response: The use of "migration" throughout the paper has been
reviewed and changed so far as practicable.
General Comment: EPA may want to consider a second overview
paper which takes into consideration the shortcomings of this paper.
Such a paper could summarize the current status of the various evaluation
activities being conducted at the site, present longer term trend data,
current monitoring data, discuss the public health significance of the
data, evaluate the effect of the improved water management program and
discuss the critical pathways contributing radioactivity to the local
environment in terms of the recent data. We believe such an overview
summary could provide a useful reference document for those agencies
and parties having responsibilities while still serving to focus
attention on a situation that merits continued monitoring and study.
Response: EPA already plans to publish additional reports concern-
ing the Maxey Flats burial site. These reports will present longer
term trend data, current monitoring data, discuss the potential public
health significance, hydrogeology, and discuss the critical pathways
contributing radioactivity to the local environment. We do not, how-
ever, have any information on the effects of the .improved water manage-
ment program.
General Comment: The paper'.s closing conclusion notes that the
goal of waste disposal sites, i.e., 100 percent retention of wastes
for their hazardous lifetime, is not being achieved. It is our
opinion that 100 percent retention is not a realistic goal. It is
doubtful that a site could be found that would not permit some releases
albeit small. Disposal sites should be selected and operated in such a
way as to minimize releases to off-site areas. We agree that criteria
for evaluating releases of radioactivity from commercial burial grounds
should be defined to assist in determining the acceptability of existing
and future disposal sites and disposal practices.
71
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Response: EPA's underlying philosophy is that waste management
means containment of radioactive materials until they have decayed to
innocous levels. The objective is to minimize exposure to>.-present
and future populations and to avoid dilution into the biosphere. Con-
tainment may involve burial, 'storage, or some other form of assuring
that dispersion into the biosphere does not take place.
EPA believes this philosophy is consistent w-ith the criteria
under which burial sites, such as Maxey Flats, were initially licensed.
This criteria was spelled out in the draft environmental impact state-
ment for the Liquid Metal Fast Breeder Reactor (WASH-1535) as "The
basic objective of shallow land burial is the confinement of radioactive
materials on the site over the periods of time the wastes remain a
hazard. Site evaluation and field studies should provide reasonable
assurances that this objective will be met."(l) In addition, the same
criteria can be found in the draft Generic Environmental Statement
Mixed Oxide Fuel (WASH-1337) and the Draft Environmental Statement for
the Uranium Fuel Cycle (WASH-1248).
The Task Force on Radioactive Waste Management of the Conference
of State Radiation Control Program Directors; in its 1974 Annual Report
to the Conference stated: "Authorization to operate a commercial land
burial facility is based on an analysis of the nature and location of
potentially affected facilities; of the site topographical, geographical,
meteorological, and hydrological characteristics; and of groundwater
and surface water use in the general area which must demonstrate that
buried radioactive waste will not migrate from the site."(2)
EPA believes that the development and verification of environmentally
acceptable techniques for disposal and long-term containment of low-level
radioactive wastes is a significant problem that needs to be solved
soon. EPA is optimistic that this problem can be solved. However, a
number of actions may be required to achieve this goal including:
development of criteria for selection and evaluation of sites; limit-
ing the quantities of certain radionuclides allowed to be buried, based
on half lives and relative biological hazards; segregation of waste at
the source; new packaging or containerization requirements; more
selective choice of sites; and additional operational controls at the
sites themselves.
EPA intends to pursue a program to develop minimal acceptability
criteria in terms of environmental barriers, and also to address ths
problems related to monitoring around sites, and the development of
action levels that may be necessary to protect man and his environment.
EPA intends to carry out this program in cooperation with the other
agencies involved.
72
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