United States
Environmental Protection
Agency
Office of Radiation Programs
Eastern Environmental
Radiation Facility
P.O. Box
Montgomery AL 38109
EPA-52G/S-78-G11
September 1978
Radiation
\
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This report has by the Office of Programs, U.S. Environmental Protection
Agency for publication. of trade or products
endorsement or for use.
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EPA-52Q/5-78-011
SUPPLEMENTARY RADIOLOGICAL MEASUREMENTS
A T THE MAXEY FLA TS RADIO A CTIVE
WASTE BURIAL SITE -1976 - 1977
Richard L. Blanchard *
Daniel M. Montgomery f
Harry E. Kolde $
Gerald L. Gels *
September 1978
* U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Radiation Programs
Eastern Environmental Radiation Facility
P. O. Box 3009
Montgomery, Alabama 36109
t U.S. NUCLEAR REGULATORY COMMISSION
Region II
230 Peachtree Street, N.W.
Suite 1217
Atlanta, Georgia 30303
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Environmental Monitoring and Support Laboratory
26 West St. Clair
Cincinnati, Ohio 45268
This study was conducted while the authors were located as Oar's Radiochemisiry and Nuclear Engineering Branch,
Cincinnati, Ohio, now located in Montgomery, Alabama,
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FOREWORD
The Office of Radiation Programs (ORP) of the Environmental Protection Agency (EPA) carries out a
national program designed to evaluate population exposure to ionizing and nonionizing radiation and to
prepare Federal radiation protection guidance and generally applicable environmental standards necessary
to protect the environment and public health. In order to carry out this responsibility, EPA has performed
field studies at nuclear facilities and sites. These field studies have required the development of means for
identifying and quantifying any released radionuclides, as well as the methodology for evaluating facility
discharge pathways and environmental transport,
Within ORP, radioactive waste management has been assigned a high priority, and requires
participation and cooperation with several State and Federal agencies. This report is one of a series directed
at a specific EPA task to establish environmental radiation protection criteria and standards for
management and disposal of low-level radioactive wastes, based in part on environmental pathways and
radiation exposure levels. Other reports, recommendations and State assistance projects are being
developed and executed to fulfill EPA obligations in the management and disposal of all types of
radioactive wastes, including high-level wastes, low-level wastes, transuranium-contaminated wastes,
uranium mill tailings, naturally-occurring radioactive wastes, and wastes from decommissioned nuclear
facilities.
This report discusses radiological measurements made at the Maxey Flats Radioactive Waste burial
site by the Radiochemistry and Nuclear Engineering Branch, Cincinnati, Ohio (now located at the Eastern
Environmental Radiation Facility in Montgomery, Alabama), The measurements were made at the request
of the ORP Technology Assessment Division to support EPA's program to obtain data on the effectiveness
of current land burial methods and processes, and on the environmental impact of existing commercial
burial sites. The measurements also furnished technical support requested by (and obtained in cooperation
with) the Kentucky Department for Human Resources.
The report also furnished supplementary data to a previously published report, "Radiological
Measurement at the Maxey Flats Radioactive Waste Burial Site," (EP A-520/ 5-16/ 020), which was used as
the basis of this study. Measurements performed during this latter study period provide additional
information on evaporator stack effluents, lateral movement of radionuclides through the soil zone in the
trench and surface drainage areas, solubility of radionuclides in test-well samples, and radioactivity in
indigenous foods. The results verify the earlier conclusion that no significant public health hazard presently
exists in the Maxey Flats area. However, the potential long-range impact of these contaminants is still not
certain and will probably depend partly upon future custodial practices at the site.
It not the intent of studies to ascertain the relative significance of suggested mechanisms by
which radioactivity could migrate from the burial trenches, Hydrogeological studies being conducted by the
U.S. Geological Survey concurrent with further radiological measurements may provide information on
this, as well as furnish data useful in predicting the future impact of the burial site on the surrounding
environment. Information obtained and surveillance methodologies developed at the Maxey Flats site will
be utilized in planning and conducting similar studies under consideration at other commercial burial sites.
111
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Review comments were received from the Nuclear Regulatory Commission, the Energy Research and
Development Administration, the U.S. Geological Survey, several State laboratories, the Oak Ridge
National Laboratory, the Kentucky Department for Human Resources, and the Nuclear Engineering
Company, Inc. They were found to be very useful in the final editing of this report.
Additional comments on this report would be appreciated.They should be sent to the Director,
Technology Assessment Division (ANR-459), Office of Radiation Programs, Environmental Protection
Agency, 401 M Street, SW, Washington, DC 20460.
W. D. Rowe.Ph.D,
Deputy Assistant Administrator
for Radiation Programs (ANR-458)
IV
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CONTENTS
Page
I, INTRODUCTION ., 1
2. ON-SITE MEASUREMENTS 3
2.1 Auger Sampling and Analysis . , 3
2.2 Auger Samples From the Trench Area 4
2,3 Site Drainage Samples 4
2.4 Test-Well Sample Particle-Size Distribution .. 10
3. ENVIRONMENTAL 13
3.1 Sampling and Analysis 13
3.2 Radionuclides in Tomatoes 13
3.3 Radionuelides in Milk 17
4. EVAPORATOR STUDY , ,20
4.1 Introduction 20
4.2 Sample Collection 20
4,3 Radionuelide Analysis .,,....,,,.,,,.,.. .21
4,4 Results and Discussion 21
4,4,1 Carbon-14 concentrations in leaehate holding tasks 21
4.4,2 Radionuelide concentrations in evaporator stack effluent and discharge rates 22
4,4,3 Decontamination factors of the evaporator ....,.,. 22
5, SUMMARY ,,..,..,.... 29
6. REFERENCES 31
APPENDICES
1. Acknowledgements .32
2. 14C Dose Computation 33
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Tables
Page
2,1 Gamma Spectral and Plutonium Analyses of Auger Samples - November 1976 6
2.2 Radionuclides in Trench Water (pCi/1) and Buried in the Trenches (Ci) Hear the
Auger Holes , 7
2.3 Radionuclide Concentrations in Auger Samples Near Site Boundary, November 8, 1976 9
2.4 Particle-Size Distribution of Radionuclides in Test Well-SE , 12
2.5 Radionuclides in Water from Trench No. 37 and Water and Sediment from Test Well 8E.... 12
3.1 Sampling Locations Near Maxey Flats Burial Site 15
3.2 Radionuclide Concentrations in Tomatoes 16
3.3 A Comparison of the 1975 and 1976 Average Tritium Concentrations in Tomatoes
and Milk 17
3,4 Radionuclides in Milk and Cow's Drinking Water , 19
4.1 Evaporator Stack Effluent Sampling Data 20
4.2 Concentrations of !4C in Samples of Trench Leachate From Various Tanks, as of
May 19, 1977 , 21
4.3 Radionuclide Concentrations in Evaporator Stack Effluent, Tests 18-20, jiCi/ml of Air
or Water ..,...._. ,. 24
4.4 Radionuclide Concentrations in Evaporator Stack Effluent, Tests 21 and 22, juCi/ml of Air
or Water 25
4.5 Gaseous I4C in Samples of Evaporator Stack Effluent , 26
4.6 Radionuclide Discharge Rates From Evaporator Stack During Tests 18-22 26
4.7 Concentrations of Radionuclides in Evaporator Input Samples 27
4.8 Decontamination Factors of Waste Processing System 28
Figures
Page
2.1 Locations of the Four Piezometer Wells on the Burial Site Around Which Auger Samples
| Were Taken and Analyzed for Radioactivity 5
2.2 Locations of Auger Samples Taken in Site Drainage Pathways and Test Well No. 8E
With Depth 8
2.3 Sedimentation Apparatus , 11
3.1 Milk and Vegetable Sampling Locations 14
VI
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L INTRODUCTION
A radiological study was conducted during 1974-1975 by the U.S. Environmental Protection
Agency (USEPA) at the Maxey Flats radioactive waste burial site near Morehead, Kentucky. The
objectives of this study were to:
a. Identify and measure radionuclides in the evaporator effluents discharged to the atmosphere, and
determine decontamination factors of the evaporator system for the principal radionuclides.
b. Measure the radionuclide content of selected aquatic and terrestrial samples to identify potential
pathways and, possibly, the critical pathways to man.
c. Measure radionuclides in selected environmental and test-well samples to support and supplement
Kentucky Department for Human Resources (KDHR) measurements.
A detailed report of the EPA study with a description of the burial site and its operation was published
in 1976.(1) It is assumed that the reader is familiar with this report. Copies may be obtained from the
Eastern Environmental Radiation Facility (EERF), United States Environmental Protection Agency,
P. O. Box 3009, Montgomery, Alabama 36109.
The 1974-1975 EPA study at Maxey Flats revealed small quantities of radionuclides outside the burial
trenches in the surrounding streams that drain the site and in sediment from the test wells. Although 15
radionuclides were identified in evaporator stack effluent, only tritium was discharged at a rate of possible
significance. The observed maximum discharge rate of tritium was 1.9 x 103 /uCi/sec. Radiochemical
analyses of well water, fresh vegetables grown near the site and milk revealed only tritium in excess of
ambient levels. Consumption of these foods by the nearby population was estimated to result in radiation
doses of less than 1 mrem/yr. It was concluded that the burial site did not at the time present a significant
public health hazard.
Results of the study strongly indicated precipitation run-off from the site surface to be the major
mechanism of transport of radioactivity from the burial site to nearby streams. However, questions regard-
ing the future importance of other transport pathways, the mechanism by which radioactivity, particularly
plutonium isotopes, migrates to the test wells that surround the trench area, and the contribution of evapo-
rator discharges to site surface contamination remained essentially unanswered. Suggested projects for
further study to provide information on these and other questions were:(l)
1. Determine the extent to which subsurface migration of radionuclides through fissure systems in the
rocks and lateral migration through the soil zone contribute radioactivity to the surrounding
streams. The U.S. Geological Survey (USGS) is presently studying the subsurface hydrology at the
site to provide information on these pathways.(2)
2. Determine the mechanism by which radioactivity, particularly plutonium isotopes, migrates to the
test wells that surround the trench area. Although plutonium is generally considered to be essen-
tially immobile in a soil matrix, its mobility may be enhanced by a number of complex
mechanisms. Brookhaven National Laboratory (BNL) is presently studying the chemical reactions
that occur in the buried wastes.(3,4)
3. Determine the total quantity of radioactivity that leaves the burial site and is transported down
Rock Lick Creek each year.
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4. Determine the quantity of I4C in evaporator stack discharges — there are approximately 2.5 x 104 Ci
of I4C buried at the site (5) — and improve the measurements of the decontamination factors (DF)
determined earlier for cesium and plutonium in the evaporator,
5. Verify food chain dose estimates to the surrounding population.
6. Determine radionuclide concentrations in air outside the fence-line to verify dose estimates from
evaporator effluents, and determine the contribution of washout from the plume to surface water
contamination.
7, Determine present levels of environmental radioactivity to compare with those of 1974-1975 to
ascertain the effects of the improved waste management practices at the burial site.
Although it was not feasible for this laboratory to investigate all items listed above, the studies that
were conducted during 1976 and 1977 have produced additional information regarding evaporator effluents
and radioactivity on the site:
1. Analysis of auger samples taken from the top of the Main East Wash, the principal surface-water
run-off passage on the site, to obtain a profile of radionuclide concentrations with depth,
2. Analysis of auger samples obtained in the trench area to detect possible lateral migration of radio-
activity through the soil zone.
3. Analysis of filtered water and sized particles from a test well to provide information regarding the
physico-chemical properties of plutonium in these wells.
4. Analyses of additional milk and fresh vegetable samples from the area to determine if previously
estimated food pathway dose estimates had changed.
5. Analyses of both input and effluent samples from the evaporator for radionuclides, including 14C
which was not measured earlier, to obtain improved measurements of the decontamination factors
and estimates of the quantities discharged to the atmosphere.
Further studies are presently being conducted at the Maxey Flats site by the Eastern
Environmental Radiation Facility (EERF), USEPA, and will be reported later. Information obtained in
these studies should be useful in assessing the environmental impact of low-level radioactive waste burial
sites and assist in setting criteria for site selection, a fundamental responsibility of the Office of Radiation
Programs, USEPA.
These supplementary measurements were performed by the Radiochemistry and Nuclear
Engineering Branch, Cincinnati, Ohio, with the support of the Technology Assessment Division, ORP,
USEPA, and the Radiation and Product Safety Branch, KDHR. Assisting the investigators were indi-
viduals, listed in Appendix 1, from the KDHR, the U.S. Geological Survey, the U.S. Environmental
Protection Agency, and the Nuclear Engineering Company.
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2, ON-SITE MEASUREMENTS
Although efforts were primarily directed to the evaluation of dose to individuals in the vicinity of the
burial site determination of the critical exposure pathways, some work was initiated to provide data in
support of studies to evaluate the extent or potential of subsurface movement of radioactivity from the
trenches.
It is recognized that a realistic evaluation of the suitability of the site or its long term radiological im-
pact would require extensive hydrogeologicai studies. Our efforts were limited to the radiochemical
analyses of auger samples and the determination of radioactivity with various sized particles
from a test-well sample. The auger samples were from site drainage pathways and the trench area. Holes
were augered in the trench area at locations selected for future drilling of piezometer wells to ensure that the
wells would not intercept burial trenches. These samples provided the opportunity to examine sub-
surface samples for evidence of lateral movement of radioactivity from the trenches. Samples front the
drainage areas were taken to investigate the possible transport of radioactivity in the shallow soil zone,
Since the Main East Wash was shown to be a major pathway for radioactivity leaving the site via surface-
water run~off,(l) it was of interest to determine the relative importance of subsurface transport in the shal-
low soil zone.
Previous work showed that plutonium activity in test-well water samples was associated with partieu-
late materiai(l) If the source of plutonium in the test wells is from subsurface movement from the trenches,
it is important to determine the transport mechanism. Characterization of the physico-chemical properties
of plutonium in the wells will be an important contribution to the determination of the transport mechanism
and, as mentioned previously, this work is in progress,(3,4) Our work was limited to determining the
particle-size distribution of plutonium and to measure gamma-ray-emitting isotopes detected in a test well.
Although it is recognized that these data are of limited value alone, they are presented so that they will be
available to other investigators.
2.1 Auger Sampling and Analysis
Samples were obtained by USGS personnel with a 6-in-diameter power auger mounted on the back of
a truck.* Prior to augering, approximately 1 m of topsoil was removed with a backhoe to prevent contami-
nation of the holes with surface soil. Augering was performed vertically from the bottom of these holes. The
maximum augering depth was approximately 5 m and was usually limited to less than 5 m because the auger
bit could not penetrate a sandstone bed underlying the site at that depth, The earthen were collected
at the bottom of the 1-m hole after auger cuttings had risen from the cutting bit along the auger stem.
Samples were obtained over various depth intervals ranging from 30 to 45 cm. Although this method was
rather crude with poor depth resolution, cross-contamination of samples was judged by the authors not to
be significant.
The samples were oven dried to constant weight at 110° C and sieved-through a No, 10 mesh screen,
Four-hundred-gram samples were analyzed for gamma-ray emitting radionuclides by gamma spectroscopy
with an 85-cm3 Ge(Li) detector. Ten-gram samples were analyzed for plutonium isotopes using the radio-
chemical procedure previously outlined.(l)
All augering depths given in this report are referenced to ground level.
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2,2 Auger Samples From the Trench Area
The locations selected for four piezometer wells are shown in Figure 2,1, Four holes were augered
around two of the well sites, UB-1 and UB-2, and three holes were augered around the other sites, UB-3 and
UB-4. At UB-1 and UB-2, the four holes formed the corners of squares with the proposed drilling sites at the
centers. At UB-3 and UB-4, the three holes formed the corners of triangles with the proposed drilling sites at
the centers,
The concentration of radionuelides detected in the samples are given in Table 2.1 The samples con-
sisted of regolith (rock which has been weathered "in place") and alluvium. The results, in general, show
only low-level contamination, primarily *°Co and 137Cs, Plutonium analyses often selected auger samples
also indicated low-level plutonium contamination. The highest radionuclide concentrations were observed
in UB-1-4 and UB-3-1, IE UB-1-4, the concentrations were much greater at the 1,5 -1.8 m depth interval
compared to the 3 - 3.5 m interval. The radionuclide concentrations in the samples from UB-3-1 also
decreased with depth, but not so dramatically. It should be noted that in all cases the radioactivity levels
were quite low in regard to a public health hazard, but did indicate that contamination from some source
had occurred.
These data are of value without additional hydrogeological information. However, the higher
levels at the shallow depths suggest that surface contamination may be responsible for most of the radio-
activity observed. Some of the material augered may have actually been compacted fill material used for
capping the trenches. Hence, lateral migration from the trenches to these locations and depths is not signifi-
cant, This is further evident from a comparison of the auger sample measurements with the quantities
reported to be buried in the trenches adjacent to the augering sites and in the water removed from these
trenehes,(3,6) The concentration of dissolved radionuclides measured in water from two nearby trenches
and the quantities estimated to have been buried in five nearby trenches are given in Table 2.2. It is recog-
nized that the radioactivity inventory from which the latter was extracted may not be totally accurate, (6)
but it is the best available data. Considering the very large quantities present in close proximity to the coring
sites, the very small amounts observed in the auger indicate that if lateral migration of radionuclides
from the trenches occurs, it is very slow. However, these observations do not preclude the possibility of sub-
surface migration from the trenches through fissure systems in the rocks at other locations on the site or at a
greater depth than was sampled.
2,3 Site Drainage Samples
Auger samples were taken in the site drainage pathways to the east and south of the site allocations
shown in Figure 2.2. The two locations to the east were in the Main East Wash and are designated as the
North Channel and South Channel.
Surface samples were collected before removing the upper 1 m of soil with a baekhoe. In the Main East
Wash, auger samples were collected from depths of 1 m to 5 m. At the southern boundary of the site,
inability of the auger to penetrate a sandstone bed limited the sampling depth to 0.8 m below ground level
(No hole was dug with a baekhoe at this site, and augering commenced at ground level),
The results of the radionuclide analyses, presented in Table 2.3, show that *°Co and * "Cs were the only
non-naturally-occurring gamma-ray-emitters in samples down to 1 m, Plutonium isotopes were detected at
depths greater than 1 m, but the concentrations were substantially lower than samples from the top ! m. The
decrease in radionuclide concentrations with depth, plus the presence of alluvial gravel, sand, and silt to
depths of 1 m in the Main East Wash suggested that the radionuclides in this interval were probably asso-
ciated with the sediment deposited from surface run-off or surface run-off infiltrating the shallow alluvium.
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Evaporator
21 L
15
36
10 15 11S
19S
r^Qi
f
17L
16L
14L
UB-3
*
UB-4
35
41
32
13L
18
20
23
30
24
25
29
28
.27
Figure 2.1. Locations of the Four Piezometer Wells on the Burial Site Around Which Auger Samples Were Taken
and Analyzed for Radioactivity.
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Table 2 .1
Gamma Spectral and Plutonium Analyses of Auger Samples - November 1976
Sample
UB-1-2
UB-1-2
UB-1-3
UB-1-3
UB-1-4
UB-1-4
UB-2-1
UB-2-1
UB-2-2
UB-2-2
UB-2-3
UB-2-3
UB-2-3
UB-2-4
UB-2-4
UB-3-1
UB-3-1
UB-3-2
UB-3-2
UB-3-3
UB-3-3
UB-4-1
UB-4-1
UB-4-2
UB-4-2
UB-4-3
UB-4-3
Depth*
(m)
1.5-1.8
3.0-3.4
1.5-1.8
3.0-3.5
1.5-1.8
3.0-3.5
1.5-1.8
2.7-3.0
1.5-1.8
2.7-3.0
1.5-1.8
3.0-3.4
4.6
1.5-1.8
2.7-3.0
1.5-1.8
2.7-3.0
1.5-1.8
2.7-3.5
1.5-1.8
2.9-3.0
1.5-1.8
2.7-3.0
1.5-1.8
2.7-2.9
1.5-1.8
2.9-3.5
60Co
0.1210.03
0.16 ±0.07
<0.06
<0.06
1.5 ±0.1
0.17 ±0.06
0.13+0.06
<0.06
0.04 ±0.02
<0.06
<0.03
<0.06
<0.06
0.37 ±0.07
0.11+0.06
3.7 ±0.1
1.4 ±0.1
0.25+0.06
0.30 + 0.06
0.13 + 0.06
0.10 ±0.06
0.04+0.02
0.03+0.02
0.16+0.04
0.22 ±0.06
<0.05
0.10+0.05
'"Cs
0.14+0.05
<0.05
0.11+0.04
<0.06
2.27 ±0.06
0.12 ±0.05
0.20+0.07
<0.06
0.12 + 0.02
<0.06
<0.03
<0.06
<0.06
0.66 ±0.07
0.12+0.06
0.14+0.07
0.10+0.07
0.22+0.05
0.08+0.05
<0.04
<0.04
0.12+0.02
<0.02
0,06
<0.06
<0.05
0.08+0.05
22*Ra
2.3 + 0.9
2.6 ±0.8
3.1+0.6
1.9+1.0
3.8+0.2
2.9+0.9
3.0 ±1.0
2.5+0.8
3.0 + 0.3
3.0+1.0
2.6+0,2
3,3 + 0.8
2.6 + 0.8
2.0 + 0.9
1.3+0.8
2.2+0.9
2.7 ±0.8
2.6 ±1.0
2.5+0.7
2.4+0.4
3.6 ±0.9
2.7 ±0.3
2.1+0.4
2.3 ±0.7
2.7+0.9
2.3 ±0.9
2.5 + 0.7
2»pu** 239Pu**
2.6 ±0.2 0.17 ±0.02
0.15 +0.02 0.008 ±0.003
0.008 ±0.002 <0.002
0.020+0,004 0.002 ±0,001
0.004 ±0.002 0.003 ±0.002
0.14 ±0.02 0.012 ±0.003
0.05 ±0.01 0.007 ±'0,002
0.05 ±0.01 0.003 ±0.002
0.050 + 0.003 0.0014 ±0.0005
<0.06 <0.003
* Depth below ground level.
** Only 10 samples were analyzed for plutonium.
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Figure 2.2. Locations of Auger Samples Taken in Site Drainage Pathways and Test Well No. 8E With Depth.
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Table 2.2
Radionuclides in Trench Water (pCi/l) and Buried in (he Trenches (Ci)
Near the Auger Holes (3,6)
Radionuelide Form
3H Water
Buried
6BCo Water
Buried
'°Sr Water
Buried
I37Cs Water
Buried
»«pu Water
Buried
B9Pu Water
Buried
Pu-X Water
Buried
Trench
IIS
NR
'5,5 x IO3
NR
6,0 x I(T
NR
'8.5x 10a
NR
5,7 x IO2
NR
NR
NR
6.4 x 101
NR
1.6 x 10'
Trench
15
NR
3,1 x iO2
NR
2.0 x IO1
NR
8.6 xlO1
NR
2.3 x IO2
NR
NR
NR
2.2 x IO1
JWI
NR
Trench
19S
6.9 x IO7
2.8 x 10*
/ J * IO3
1.5 x IO4
2.rf x l(f
1.8 x IO2
5,2 x /O3
1.2 x 102
1,7 x 10s
2.2 x 10"'
NR
1.3 x 10 2
NR
1.8 x 10'
Trench
32'
JW?
1.2 x 101
NR
3.4 x 10s
j¥S
4,0 x IO1
MR
2.0 x IO2
NR
1,2 x IO4
NR
5.0 x 1C2
M«
4.3 x IO2
Trench
35
2.0 x IO9
2.2' x 102
4.7 x IO2
' 2.8x10*
1.2x10*
2.1x10°
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Table 2,3
Radionuclide Concentrations in Auger Samples near Site Boundary, November 8, 1976
DeptKm
Surface
I m
1.5 - 1.8
3.0 - 3.3
4,5 - 5,0
Surface
i m
1.5- 1.8
3.0 - 3.6
4,5 - 5.0
Surface
0.75
"Co
0.29 ± 0,04
0.48 ± 0.03
<0.03
<0.03
<0.03
0.20 + 0.03
0,02 ± 0.01
<0.01
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The absence of *°Co and ' 37Cs and the very low plutonium concentrations at depths greater than i m suggest
that subsurface migration of radionuclides in the shallow soil zone has not occurred at this location and
depth. Since this location is approximately 30 m from the nearest trench, these data do not imply that sub-
surface migration has not occurred at distances closer to the trenches. However, these data strongly indicate
that the source of radioactivity in the Main East Wash, t-hrprimary aqueous pathway by which radioactivity
leaves the site, is surface run-off-and not lateral migration in the shallow soil lone at depths to 5 m,
2.4 Test-Well Sample Particle-Size Distribution
Test-well samples were collected on June 27.1976, for particle-size determination. The initial intent
was to make particle-size determinations on samples from all wells that had previously been shown to con-
tain radioaetivity.(l) However, the process was so laborious and time consuming that available resources
limited this investigation to one well sample, a 3,7 liter water sample with suspended sediments from well
8-E. The test well location with depth in meters is shown in Figure 2,2, Previous analyses had shown that
samples from this test well contained the highest plutonium concentration of all wells sampled,
The fractionation and harvesting of particles from the test-well water sample were accomplished using
a sedimentation method and by wet sieving of the sediment particles.(7) Particles with diameters greater
than 53 jum were first collected by wet sieving using a 270-mesh screen. The sedimentation procedure that
followed involved repeated gravitational settling and decantation to a fixed depth in a large graduated
cylinder until a good separation was achieved. The rate of settling of the particles was assumed to be
governed by Stoke's Law which is applicable for particles of nearly spherical shape. The fall velocity for par-
ticles with a density of 2.65 g/cm3 is given by:
V =
/« (2,1)
where V is the velocity in cm/sec, d is the particle diameter in mm, and $ is the dynamic viscosity of the fluid
in poise (fi = 0.009358 for water at 23° C).
Initially a gross separation was made by allowing 3,7 liters of the water-sediment mature to settle for 3
days to remove most particles from the water. Since some smaller particles (assumed to be less than 2 /J.M) do
not settle, the decanted liquid was filtered through 0,45 pm membrane liters. These filters were saved to be
included with the 0,45-5 fim fraction. The filtrate was then evaporated to 400 ml for radiochemical analysis.
The paniculate material was wet sieved through a 270-mesh screen to collect all particles with diam-
eters greater than 53 fan. Distilled water was used for wet sieving and for all subsequent steps in the settling
procedure when additional water was needed.
The material which had passed through the sieve (< 53 pm diameter) was placed in the settling cylinder
(See Figure 2.3) to separate the smaller particle size groups: 0.45 - 5 /utm, 5 - 20 pm and 20 - 53 jura. The set-
tling cylinder was a 500-cc graduated cylinder with the top cut off just below the pouring lip so that a rubber
stopper could be inserted for shaking the solution to suspend the particles. A glass siphon was used with a
peristaltic (sigmamotor) pump as shown in Figure 2.3. After shaking the sample to suspend all particles and
the appropriate settling time was achieved, the liquid containing the desired sized particles was removed by
pumping into the receiving vessel,
10
-------
Receiving
Vessel
Figure 2,3. Sedimentation Apparatus,
The particles in the smallest diameter range (0,45 - 5 /an) were separated first. The time required for
5-fitn. particles to settle the distaneejiwas obtained using the fall velocity computed by Equation 2.1. After
suspending the particles in the cylinder and the fall time had elapsed, the liquid in the cylinder was pumped
to the receiving vessel, This liquid represents a sample from which all particles greater than 5 jum have been
removed. The liquid collected in the receiving vessel was then filtered through 0.45 faa filters to collect par-
ticles in the 0.45 - 5 fim range. The filtrate was returned to the settling cylinder and the process repeated until
the yield of particulate material, determined by weighing the filters, was negligible. This process was re-
peated for the other particle-size groups with appropriate settling times for the specific particle diameters,
The filters from the various particle-size groups were composited for analysis. The analyses included
gamma-ray spectroscopy and plutonium separations. The results, presented in Table 2.4, show the presence
of "Co, 137Cs, mPut 239Pu, and naturally-occurring 226Ra.
The radioactivity was primarily associated with the particulate material, as indicated by the absence of
detectable quantities of *°Co and lwCs and the very low concentrations of plutonium in the filtrate. (Par-
ticles with diameters less than 0.45 f*m are considered to be in solution.) The highest radionuclide concentra-
tions were found in the 0.45 - 5 ism particle-size range. This may be indicative of the higher ion-exchange
capacity of the smaller particles (this is commonly observed with ions associated with sediment). However,
this conclusion cannot be confirmed in this case because neither ion-exchange capacity measurements nor
chemical species analysis were performed,
Radkmuelides were measured in water from trench No. 37 in April 19?6.(3) This trench, approxi-
mately 100 m from test well 8E, is the nearest one for which data on dissolved radionuclide concentrations
are available. In Table 2.5 are listed the soluble radionuciide concentrations measured in the water from
trench No. 3? and in the June 1976 test-well sample, A direct comparison is difficult because the actual
source of radionuclides found in the test well has not been established and essentially all of the radio-
nuclides, except 3H, were associated with particulate matter. However, it is apparent that if the radio-
nuelides observed in test-well samples originated in the trenches, considerable dilution occurs during their
movement to the test wells.
11
-------
2.4
Particle-Size Distribution of Radionuclides in Test Well-SE
Particle size
(microns)
0,45 - 5
5 -20
20 -53
>53
Filtrate*
Radionuclide Concentration, pCi/g (dry weight)
Concentration
(g/1) 60Co 1J7Cs 226Ra • 2S8Pu 2MPu
0.29 3.810.4 2.2 ±0,4 30 + 8 14.9 ±0,9 0.23 ±0.05
0.96 0.7 + 0.1 1.7 + 0.2 20 + 6 9.0 ±0.5 0.20 ±0.03
1.05 1.1 ±0.03 0.8 + 0,4 12 + 3 5.7 ±0,8 0.16 ±0.02
0.23 2+1 2 ±1 <4G 9,3 +0.1 0.14 +0.05
<0.8 <0.8 <20 0.04 ±0,02 <0.008
*Radionuclide concentration of filtrate is pCi/1,
± values are 2a uncertainties based on counting error.
Table 2.5
Radionuclides in Water from Trench No. 37 and
Water and Sediment from Test Well SE
(pa/I)
Radionuclide
3H
"Co
»Sr
U4Cs
137Cs
238Pu
Trench No. 37 (3)
l.lxlO7
5.0 x 10*
1.9 x 10}
1.7 x I03
9 J x 10J
1.8 x 10"
Test Well 8E
Filtrate
3.5 x 102
<8 x 10"'
NA
ND
<8 x 10"'
4 x 10~2
Sediment
NA
3.4 x 10°
NA
ND
3.6 x 10°
2.1 x 101
The trench water sample was collected ia April 1976 and measured for dissolved radionuelides.
Except for 3H, all detectable radioactivity in the test-well sample was associated with sediments;
not in solution.
NA Not analyzed.
ND Not detected.
12
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3. ENVIRONMENTAL MEASUREMENTS
The purposes of additional environmental measurements were to provide data for the dose to
individuals from food pathways to determine if radionuclide levels are increasing or decreasing. Meas-
urements were limited to tomatoes from local gardens and milk from local dairies.* The drinking water
pathway for individuals near the site, shown earlier to be an important pathway, was not investigated since it
is routinely evaluated by the KDHR.(l)
5.1 Sampling and Analysis
Tomato were collected at 5 locations near the site on August 9,1976, and September 1,1976.
The sampling locations are shown in Figure 3.1 and listed in Table 3.1. In addition, tomatoes from
Aberdeen, Ohio, were collected for background. Aberdeen is approximately 48 km north of the site and
would not be affected by the Maxey Flats operations or any other nuclear facility,
Radiochemical analyses were performed for 3H as HTO, MC and gamma-ray emitters. Sample prepa-
ration and radioassay procedures were the same as previously reported.(I) Carbon-14 analyses were per-
formed on three samples collected August 9,1976. The procedure for 14C involved combustion of the freeze-
dried residue to CO2, conversion of COa to benzene, and liquid scintillation counting.
Milk samples were collected during three periods: June 30 - July 1,1976, August 9-10,1976, and
September 1-2,1976. In addition to the locations sampled during the 1974 - 1975 study, another commer-
cial dairy farm near the site (Location 54) and a background location were included. The dairy at location 54
is approximately 1.2 km south of the site. In contrast to the other milk sampling locations, this one does not
receive run-off from-the burial site via Rock Lick Creek. The main source of drinking water for the cows
here is a shallow farm pond which is recharged primarily from nearby surface-water run-off. The back-
ground location (BG) was a commercial dairy approximately 30 km north of the site. Cows* drinking water
was also collected at sampling locations for 3H analysis,
Milk samples were analyzed for 3H, 90Sr, and gamma-ray emitters. Two milk samples were also
analyzed for 14C by benzene synthesis of the milk solids and liquid scintillation counting. The radiochemieal
procedures for the of milk are given in the 1974 - 1975 report(l)
3.2 Radionuclides in Tomatoes
Radionuclide concentrations measured in tomatoes are given in Table 3,2, Tritium was the only
radionuclide attributed to releases from the disposal site and, considering that the site locations are isolated
from site drainage, the evaporator is the source, Carbon-14 concentrations were consistent with back-
ground levels.(9) The highest 3H concentration was 6.5 x 103 pCi/kg at location 41 on August 9, 1976.
Tomatoes from this location also contained the highest 3H levels during 1975, The range of concentrations
in tomatoes at the various sites were not significantly different from those observed the previous year (See
Table 3.3), Some variability is expected as a result of differences in the quantity of 3H released and climatic
conditions,
These results confirm the earlier observation that the potential radiation exposure to individuals con-
suming vegetables from gardens near the burial site is very smalL(l) The potential maximum whole body
dose was computed to be about 0,01 mrem/yr,
* Cucumbers were observed earlier to contain about twice the 3H concentration as tomatoes, 7.9 x 104
pCi/kg and 3,2 x 104 pCi/kg, respectively.(1) However, since it is estimated that the average adult con-
sumes 40 g/d of tomatoes and only 3.5 g/d of cucumbers,(8) tomatoes will be the principal vegetable in the
food pathway. The availability of samples was also greater for tomatoes.
13
-------
km
Figure 3.1. Milk and Vegetable Sampling Locations.
-------
Table 3,1
Sampling Locations near Maxey Flats Burial Site
Site
number Location
41 Residence on Rock Lick Creek Road, approximately 1,7 km west of Rt. 158.
43 Residence on Rock Lick Creek Road, approximately 3,2 km west of Rt. 158,
44 Residence approximately 2.2 km north-northeast of site and approximately 0.3 km south
of Rt. 32.
46 Dairy farm on Rock Lick Creek Road, approximately 0.3 km east of Rt. 158.
r
47 Dairy farm on Markwell Road, approximately 3.1 km south-southwest of the site,
48 " Residence southwest of the intersection of the site access road with Maxey Flats Road,
f
51 Residence on Maxey Flats Road, approximately 1.1 km east of the site access road.
54 Dairy farm on Randall Hill Road, approximately 1.2 km south of site.
15
-------
Table 3.2
'Radionuclide Concentration in Tomatoes
Sampling
Date
8/9/76
8/9/76
8/9/76
8/9/76
8/9/76
8/9/76
9/1/76
9/1/76
9/1/76
9/1/76
9/1/76
9/1/76
Location
(Table 3.1)
41
43
44
48
51
AB
41
43
44
48
51
AB
pCi/1 (tissue water)
2.4 ± 0.3(3)
0.7 '± 0.3(3)
1.3 ±0.2(3)
6,9 ± 0.2(3}
2.4 ± 0,2(3)
<0.2(3)
3.7 ± 0.2(3)
0.6 ±0.3(3)
1.1 ±0.2(3)
4.5 ± 0.3(3)
2.0 ± 0.4(3)
<0.2(3)
3H
pCi/kg (fresh weight)
2.2 ± 0.3(3)
0.7 ± 0.3(3)
1.2 ±0.2(3)
6,5 ± 0.2(3)
2,3 ± 0.2(3)
<0.2(3)
3.4 ± 0.2(3)
0.6 ± 0.3(3)
1.0 ± 0.2(3)
4.3 ± 0.3(3)
1,9 ± 0.4(3)
<0.2(3)
_,4C
dpm/« C
NA
NA
NA
18.2 ± 0.6
19.5 ± 0.8
19,0 ± 0.8
NA
' NA
NA
NA
NA
NA
Gamma-Ray Emitters
pCi/kg (fresh weight)
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AB Background location at Aberdeen, Ohio,
NA Not analyzed.
ND Not detected; typical detection limits were 60Co - 8 pCi/kg, '"Cs - 8 pCi/kg.
± Values are 2tr uncertainties based on counting error.
Exponents of 10 are indicated by numbers in parentheses.
-------
Table 33
A Comparison of the 1975 and 1976 Average
Tritium Concentrations in Tomatoes and Milk
Location No. 1975 1976
Tomatoes, pCi/ kj (fresh weight)
41 4.0 (3) 2.8 (3)
44 1.0 (3) 1.1 (3)
48 5,3 (3) 5.4 (3)
51 1.8 (3) 2,1 (3)
Milk. pCi/1
41 6.5 (3) 2.5 (3)
46 2.6 (3) 1,7 (3)
47 1.3 (3) 5.0 (2)
Exponents of 10 arc indicated by numbers in parentheses.
3.3 RadionucHdes in Milk
The results of the milk analyses are presented in Table 3,4. Tritium is the only radionuclide in the
taken near the site (Locations 41,46,47, and 54) which can be unambiguously attributed to releases
from the disposal site. The highest concentration observed during this reporting period was 3.6 x 1GJ pCi/1
at Location 41 on August 7,1976, compared to 6.5 x 103 pCi/1 at the same location on August 27,1975. An
additional sampling station (Location 54) showed 3H contamination which was somewhat lower than the
levels observed in milk from cows receiving their water from Rock Lick Creek. The source of 3H ingested by
cows at Location 54 is from atmospheric rather than aqueous releases. Since the JH levels in the
cows* drinking water is similar to the milk, the most likely pathway for JH at Location 54 is from the depo-
sition of 3H discharged from the evaporator stack to the pond. For cows pastured along Rock Lick Creek
(Locations 41,46, and 47), the principal source of 3H in the creek is surface-water run-off from the burial
site, which is partly or completely due to site-surface contamination. The tritium concentrations in milk
from cows pastured along Rock Lick Creek in 1976 are about one-half those observed in milk at the
locations during the 1974 -1975 study (See Table 3,3). This reduction may be due to better operating pro-
cedures implemented at the burial site which have resulted in less ground surface contamination.
17
-------
The 90Sr levels in milk varied from 3 to 7 pCi/1. Although the concentrations in milk produced near the
burial site ranged above those in the background samples, they were not significantly higher and could not
be distinguished from atmospheric fallout from weapons testing. No gamma-ray emitters, aside from
naturally-occurring 40K, were detected in any milk samples. The 07Cs concentrations were below the mini-
mum detectable level, 8 pCi/L
The 14C levels in milk were 18 and 19.§dpm/g carbon at Locations 41 and 46, respectively. These levels
are consistent with ambient levels of 14C throughout the country, 15-20 dpm/g carbon,(9)
The dose associated with the ingestion of 3H in milk was estimated from the concentrations measured
at Location 41. These data were used because the highest 3H concentrations occurred here, arid the milk is
consumed by the residents. The average 3H concentration of milk for three sampling dates was 2,5 x 103
pCi/1. Assuminga daily intake of 1 liter and a dose conversion factor of 6.2 x 1G~3 (mrem/ yr)-s-(pCi/ day), the
associated whole body dose to an adult 0.2 mrem/year.
18
-------
Table 3,4
Radionuclides in Milk and Cow's Drinking Water
Date
6/30/76
7/01/76
7/01/76
7/01/76
7/01/76
8/09/76
8/10/76
8/10/76
8/09/76
8/09/76
8/09/76
9/01/76
9/02/76
9/01/76
9/02/76
9/02/76
6/30/76
7/01/76
S/09/76
1/09/76
9/01/76
9/01/76
Location
41
46
47
54
MH
41
46
47
54
MH
CIN
41
46
47
54
BG
46
54
46
54
46
54
3H
nwlfir
J.VJL **-/V
2.3 ± 0,2 (3)
1.9 ± 0.2 (3)
0,6 ±0.1 (3)
1,3 ± 0.2 (3)
0.4 ±0.1 (3)
3.6 ± 0.2 (3)
1.6 ± 0.2 (3)
0.4 ± 0.1 (3)
0.5 ±0.1 (3)
0.2 ±0.1 (3)
<0.2 (3)
1.6 ± 0.1 (3)
1.6 ±0.1 (3)
0.5 ±0.1 (3)
0.7 + 0.1(3)
<0.2 (3)
Cow's Drinking Water
3.3 ± 0.2 (3)
1.6 ± 0.2 (3)
2.7 ± 0,2 (3)
1.0 + 0.2(3)
2.6 ± 0.2 (3)
1.0 ± 0.2 (3)
14C*
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
18.0 ± 0.6
19.8 ± 0.6
NA
NA
NA
NA
NA
NA
NA
NA
NA
MSr
. 5 + 2
7±2
3 + 1
5 + 2
3±1
NA
5± 1
6+ 1
7±2
4+1
NA
6 + 2
5± 1
2 + 1
6±2
3+1
NA
NA
NA
NA
NA
NA
* I4C concentration is dpm/gram stable carbon.
± Values are 2-a uncertainties based on counting error,
MH Morehead Dairy, CIN - Cincinnati dairy; BO - background location.
NA Not analyzed.
Exponents of 10 are indicated by numbers in parentheses.
19
-------
4. EVAPORATOR STUDY
4.1 Introduction
During the period of this report, two series of tests were performed to supplement previous studies of
airborne radioactivity discharges from the evaporation of trench leachate. Tests nos. 18, 19, and 20 were
conducted on September 1 and 2,1976, and tests nos, 21 and 22 on May 18 and 19,1977. Table 4,1 provides
details of sampling periods, sample volumes and composition of the leachate being evaporated,
Since the previous report,(I) evaporator-operation has been modified. Trench leachate awaiting pro-
cessing is now stored in 10 large holding tanks that are housed in an aluminum building with an excavated
earthen floor. Of greatest significance, operation of the evaporator was reduced from a 24-hour to an 8-hour
per day, 5-day per week schedule on August 30, 1976. This, of coarse, lessens the amount of radioactivity
discharged to the atmosphere as well as the radiation dose contribution to the surrounding population that
was calculated on an annual basis in the previous report,{l)
4,2 Sample Collection
The stack effluent sampling system remained similar to that used in the previous tests.(l) During
tests nos. 21 and 22, however, a gas collection bottle was inserted momentarily after the air fi her to withdraw
grab samples of effluent gas. Before entering the 1,75-liter evacuated metal bottle, the gas passed through a
silica gel bed to remove residual moisture. Sampling required less than one minute, at the times indicated in
Table 4.1,
Nine of the ieachate holding tanks (tank E was empty at the time} were sampled on May 19,1977, to
determine 14C concentration levels. The samples consisted of 250-mI aliquots obtained at the midpoint of
the leachate level in the tanks. These measurements provided the first data on MC contents in trench leachate
at Maxey Flats.
Table 4.1
Evaporator Stack Effluent Sampling Data
Test
No
18
19
20
21
22
*
**
Date
9/01/76
9/01/76
9/02/76
5/18/77
5/19/77
Remaining 50 percent
Sarnnles obtained for
Period
(hrs.)
0921-1121
1318-1519
0924-1125
1418-1555**
0935-1123**
of feed consisted
f"! Has analvsis w
Sampling
Duration
(min.)
120
120
120
90
104
of dilution water,
/ere obtained at 14."
Evaporator
feed
(amount, %)
Tank J{50)*
Tank J(50)*
Tank J(50)*
A(15), F(85)
Tanks A(15), F(85)
!8 and 1511 hrs. durinff 1
Samp|e_
air (m3)
2.52
2,52
2.52
1.93
2.14
"est 21 and at 103
volumes
water (liters)
2.88
2,66
2.85
1.94
2.18
Oand 11 22 hrs.
during Test 22,
20
-------
1.3 Radionuclide Analysis
Water collected from stack effluent was subsequently passed through 0.45-jum membrane filters,
Radionuclides present in the filtered water or on the membrane and glass fiber air filters were measured by
gamma-ray spectrometry using Ge(Li) detectors or specific radiochemieal techniques, as described in the
previous report,(l)
Carbon-14 in the stack effluent was analyzed by placing the sample fractions in a closed distillation
apparatus along with an oxidizing agent and acid,(10) Air was bubbled slowly through the sample and heat
ivas applied to transfer CO2 into a flask containing a basic CaClj solution. The collected CaCOs was centri-
fuged, washed, weighed, and placed on a toluene solution for analysis by liquid scintillation counting,
Carbon-14 as CCh or other gaseous forms (CH.t, CO, etc,) was determined by mixing an aliquot of the
sampled gas with relatively pure COa and CH,» carrier gases. The mixture was passed through a train consist-
ing of a bubbler containing Ba(OH)a to collect "COi, a palladium sponge catalyst heated to 550 ° C for oxi-
dation of other carbon gases, and a second bubbler containing Ba(OH)2.(l 1) The 14C activity of the BaCOs
produced in the-bubblers was measured by liquid scintillation counting,
4.4 Results and Discussion
4.4.1 Carbon-14 concentrations in teachate holding tanks. Concentrations of I4C in the holding
tanks as of May 19, 1977, are given in Table 4.2. Concentrations vary from approxi-
mately 4 x 10~s to 8 x 1Q~5 jLtCi/ml of leachate. (The relative amounts of 14C in soluble or insoluble forms
were not determined at this time). Assuming that each of the tanks contained the same amount of liquid, the
overall average !4C concentration was, at this time, 1,9 x 1CT5 /iCi/ml.
Table 4,2
Concentrations of 14C in Samples of Trench Leachate
From Various Tanks, as of May 19, 1977
Holding Tank
A
B
C
D
E
F
G
H
I
J
Concentration
8.3 ±0,1 x 1(T6
3.9 ± 0.1 x 10"6
6.6 ±0.1 x HT6
4.8 ± 0.02 x 10~5
Tank empty
4,3 ±0.1 x 10"*
7.8 ± 0.03 x 10"5
4.2 ± 0.1 x 10~6
4.6 ± 0.1 x 10"6
1.7 ± 0.02 x 10~5
21
-------
4,4.2 Radiamtclide concentrations in evaporator stack effluent and discharge rates. As before, H,
*°Co and IS7Cs were observed In samples from each of the five tests, as indicated in Tables 4.3 and 4,4.
Tritium was again the predominant radionuclide in terms of relative concentration, ranging up to
2.2 pCi/ml. Strontium-90 was observed in all sample sets analyzed, as was plutonium, Cobalt-58 was ob-
served in stack effluent for the first time (tests 18 and 19).
Effluent samples from tests 18 to 21 were analyzed for 14C since no data on its discharge were available,
The radionuclide was present in every sample fraction analyzed, and at highest concentration in the dis-
solved solids of the filtered water samples,
Gaseous !4C was observed in only one of the four gas samples obtained in May 19??, as shown in
Table 4.5. It was present only in the form of COj and at an amount slightly above the minimum detectable
level.
Radionuclide discharge rates from the evaporator stack during the five recent tests, calculated as de-
scribed in the previous report,(l) are presented in Table 4.6. As observed previously, most effluent radio-
activity was contributed by 3H and at many magnitudes above that of any other radionuclide!
4.43 Decontamination factors of the evaporator. During the effluent measurements, samples of
entering the evaporator system were obtained to determine plant decontamination factors (DPs)
for 14C, *°Co, 1J7Cs, 2JIPu and 23SPu, DF's the effectiveness of the entire treatment system in remov-
ing radionuclides, other than 3H, the waste liquid before discharge to the atmosphere. DF values were
calculated by the method described in Section 2,6,6 of the previous reportf!)
For test no, 20, leachate from tank J was sampled at the point where the liquid enters the first settling
tank at 1355 hours, September 1,1976. (This liquid was held overnight in the settling tank for processing the
following morning.) A sample of the water used for dilution of the leachate was obtained at the same point at
1335 hours, September 1, 1976. For test no. 21, a sample of tank A input was collected at 1300 hours,
May 19, 1977, and of tank F» which was being mixed with tank A leachate, at 0937 hours on the date. It
should be noted that data from the two input samples are being applied to effluent measurements from
test no. 21, which occurred on the afternoon of May 18.
Concentrations of 14C, MCo, mCs, 2J8Pu and "*Pu found in the input samples are given in Table 4.7.
Carbon-14 in the suspended solids fraction of two sample sets was not measurable since the membrane
filters were used previously for other analyses, Plutonium analyses were not performed on samples from
tanks A and F.
DF's derived from these data are listed in Table 4.8, The values vary for the different tests, and are in
general lower than those reported in the previous report.(l) This variation the complexity of the
total treatment system. The measured DF values may be influenced by the chemical composition of the in-
coming which affects the flocculating process, the resuspension and settling time of the floe, and re-
sidual radioactivity that remains in the particularly in the settling tanks, from previous processed
batches. The DF value determined for 238Pu is more precise than that for 239Pu, since the concentrations of
the latter in the effluent sample fractions (see Table 4,3) were determined near or below minimum detectable
levels. The average DF for plutonium given by four previous measurements was 5 x 1Q5.{1)
22
-------
The radiation dose to the limiting receptor* (0,8 km NNE of the evaporator) due to the atmospheric
discharge of 14C from the evaporator is estimated to be 1 x 1Q~4 mrem/yr to the lung (insoluble) and 2 x 1Q~7
mrem/ yr to the GI tract (soluble). (This computation is described in Appendix B.) Since nearly all of the I4C
in the effluent was in soluble form, the latter dose is the more applicable, although both are insignificant.
Tritium remains the critical radionuclide. However, since the operation has been reduced to a 40 hr per week
schedule, the dose from *H to the limiting receptor has been decreased to about 0.8 rorem/yr,(l) The d.ose
rate from all other measured radionuclides was less than 0.1 mrem/yr.
* The limiting receptor is defined as that person(s) who resides near the site and is most likely to receive the
highest dose from operations of the facility.
23
-------
Table 4.3
Radionuclide Concentrations in Evaporator Stack Effluent,
Tests 18-20, ttCi/ml of Air or Water
Sample
Radionuclide Type*
3H W
"C A
W
F
58Co A
W
F
«°Co A
W
F
"Sr A
W
F
!34Cs A
i W
F
117 C» ' A
W
F
2MPu A
W
F
2"Pu A
W
F
* Sample types; A - air filter; W -
water sample was passed.
± Values indicate analytical error at
ND Not detectable.
NA Not analyzed.
18
8.42 ± 0.01 x 1CT2
1.7 ±0,2 x 10~u
1.3 ±0.2 x 10""7
2,3 ± 0,3 x 1G~5
7 + 2 x 10""
ND
ND
3,3 ± 0.9 x 10" °
3+1 x 10~8
2+1 x 10"*
1.9 ± 0,4 x 1C12
5.3 ± 0.3 x 1G~S
7.0 ± 0,5 x 10~8
1.9 ±0,5 x 1(T12
2 ± 1 x 10~8
ND
1.7 ±0.1 x KT11
1.1 ±0.1 x 10"1
ND
3.3 ± 0.5 x 10~IJ
1.7 + 0,2 x KT9
6,2 ± 0,4' x 10~10
ND
ND
ND
water passed through 0.45-^m
2-er confidence level.
Test No,
19
6.77 ± 0,01 x 10"3
NA
3.0 ± 0.3 x 10"7
NA
2.7 ± 0.5 x 10"12
5 ±2 x 10"s
1,1 +0.4 x 10"'
6,6 + 0.8 x 10^12
1.1 ±0.2 xHT7
3,0 ± 0,6 x 10**
2.4 ± 0.3 x 10""'
8.8 + 0.4 x 10"*
7+4 x 10~10
4.0 ± 0,7 x 10"12
1,5 ± 0.2 x 10"T
ND
3.1' ±0.1 xIO"11
7.9 ± 0,3 x 10""7
6+3 x 10T10
2.6 ± 0,2 x 10"12
2,0 ±0.1 x 10"8
1.6 ±0.1 x 10"*
5 ± 2 x 10"14
3.2 ± OJ x 10"10
1.7 + 0.3 x 10"m
membrane filters; F -
• 20
6.62 ± 0.01 x 10^2
2.2 ±0.2 x 10""
1.0 ± 0.2 x 10"f
1,2 ± 0.3 x 10"*
ND
ND
ND
2,4 ± 0.6 x 10H2
4+1 x 10"8
1.9 ± 0.4 x 10"*
1.3 ± 0,3 x 10""12
5.4 ±0,3 x 10^*
2,2 ± 0.4 x 10"*
2.6 ± 0,5 x 10""
2+1 x 10~*
ND
2,0 ±0.1 x 1Q~U
1.4 ± 0,2 x 10"7
1.1 ±0,3 xIO"9
2,9 ± 0,7 x 10"""
4.5 ±0.4 xIO"'
1.1 +0.1 x 10"*
ND
5 ±3 x 10HI
WD
0.45-jnm filters through which
24
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Table 4.4
Radionuclide Concentrations in Evaporator Stack
Effluent, Tests 21 and 22, nCijml of Air or Water
Radionuclide
^H
"C
60Co
134Cs
137Cs
Sample Type*
W
A
W
F
A
W
F
A
W
F
A
W
F
1.14
3.0
3.0
5.7
2.2
1,4
1.1
8
6
±
+
±
±
±
+
±
±
±
Test No.
21
0.01
0
.3 xKT"
0,1 xlO""7
0
0
0
0
1
1
.3 xMT9
.2 x «r»
.2 x 10"T
.2 xlO"8
x 10-"
x 10"'
ND
4.2
3.2
8
±
±
±
0
0
2
.1 xlO"10
.1 x 1Q-*
xlfl-*
22
2.22 ± 0.01
NA
NA
NA
8 ±1
8 ±1
6 ±2
2.4 ±0.8
2 ±1
ND
1.6 ±0.1
1.8 ±0.1
5 ±2
x W10
xlO"8
x 10"9
x 10""12
xlO"8
x i
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Table 4,5
Gaseous uCin Samples of Evaporator
Stack Effluent, fid/ml
I4C Concentration
Test No, Sample
21 1 1.6
21 2
22 1
22 2
Table 4.6
CG2
± 0,4 x 1(TS
<4 x 10"9
<4 x ICT*
<1 x 10'*
Non-COa
<4xlG~9
<3xlO"9
<4x!{T*
<8xlO"*
Radionuctide Discharge Rates from Evaporator
Stack during Tests
(pCi/sec)
18-22
Test No,
Radionuclide 18 19
3H 7,8 ( 1) 5.7 ( 1)
14C 1.2 (-4) 2.5 (-4)
58Co 6 (-7) 4.9 (-5)
MCo 3.6 (-5) 1.0 (-4)
90Sr 5.6 (-5) 7.7 (-5)
134Cs 2 (-5) 2,0 (-5)
mCs 1.2 (-4) 7.0 (-4)
BiPu 2.4 (-6) 3.3 (-5)
339Pu ND 4,5 (-7)
20 21
6,0 ( 1) 9.5 ( 2)
9.2 (-5) 2,5 (-4)
ND ND
3.6 (-5) 1.4 (-4)
5.1 (-5) NA
2 (-5) 6 (-5)
1,4 (-4) 3,0 (-3)
5.4 (-6) NA
6 (-8) NA
22
1.8 ( 3)
NA
ND
7.4 (-5)
NA
2 (-5)
1.6 (-3)
NA
NA
Exponents of 10 are indicated by numbers in parentheses.
NA Not analyzed.
ND Not detectable.
26
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Table 4.7
Concentrations of Radionuclides in Evaporator
Input Samples
(pd/ml)
Liquid Source Radionuelide
Tank J MC
"Co
137CS
238Pu
239Pu
Dilution Water 14C
"Co
I37Cs
23-p,
239Pu
Tank A 14C
MCo
137Cs
Tank F 14C
"Co
137Cs
Dissolved Solids
4.5 ±0.1 xlO~*
2.0 ±0.2 xlQ"6
• 2.0 ± 0,2 x 10"*
9,3 ± 0.7 x 10"*
4.7 ± 1.3 x 10"s
< 5 x 10 "s
1.3 ±0.3 xlO"7
8.5 ±2.8 xHT8
2.7 ±0.1 xlO"7
2.0 ±0.7 xlO"9
1.2 ± 0.04 x 10"5
L3±0.02x IO"5
4.7 ±0.1 xlO"*
5.9 ± 0.2 x IO"6
1.5 ±0.1 xlO"6
1,1 ±0.01 xlO"s
Suspended Solids
NA
6.3 ± 0.2 x IO"7
1.0 + 0.1 xlO^6
3.5 ± 0.02 x IO"5
1.9 ±0,3 xlO"7
NA
4.9 ±0,2 xlO"7
8.6 ± 1.0 x IO"8
5.8 ± 0.3 x 10"7
6,7 ±1.0 x IO"9
5.0 ±0.1 xlO"7
5.2 ± 0,3 x 10"'
5.3 ± 1.8 x 10"*
6.6 + 0,3 xlO"8
6.3 + 0.3 xlO"7
2.9 ±0.2 xlO"7
± Values indicate analytical error at 2-cr confidence level.
NA Not analyzed.
27
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Table 4.8
Decontamination Factors of Waste Processing System
Test No,
RadionucHde 19 20 21 22
14C - 22 23
"Co 11 40 - 41
B7Cs 3 13 - 5
238Pu - 3670
239Pu - 1710
28
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5. SUMMARY
A4ditional measurements were conducted on-site and in the environment of the Maxey Flats radio-
active waste burial site near Morehead, Kentucky, These measurements, somewhat limited in scope and
number, were for the purpose of supplementing data acquired during 1974-1975 and published in 1977. The
objectives of these measurements, the results, and interpretations are discussed below,
1. Additional samples of vegetables (tomatoes) and milk, determined during the 1974-1975 study as
the most significant foods for the potential exposure of people living near the site, were analyzed.
Results confirmed the earlier observations that 3H is the only measurable radionuclide present and
that the radiation dose resulting from consuming these foods is very low. The observation that 3H
levels in milk from cows drinking Rock'Lick Creek water were lower in 1976 than in 1975 indicates
that levels of radioactivity in surface run-off from the site has decreased, No difference in "H levels
in tomatoes was observed between 1974-1975 and 1976. This was expected since the source of the
SH was the evaporator which operated in a similar fashion during both study periods. Evaporator
operation was not reduced to 40 hr/wk until August 30, 1976, the end of the tomato growing
season and sampling period.
2, Low-level contamination of land surfaces with 3H resulting from evaporator operations will con-
tinue for as long as this means is necessary to dispose of accumulated trench water. Since its incep-
tion in 1973, more than 2.6 million gallons (1 x IG7 liters) of trench water containing an estimated
average of 1 x 109pCi/lof3Hhavebeenprocessed,(12) Thus, the quantity of 3H discharged by the
evaporator probably exceeds 10,000 curies. During August 1976, the evaporator operation was re-
duced from a 24-hr/day, 5-day/wk schedule to an 8-hr/day, 5-day/wk schedule. This curtailed
operation should result in lower annual discharges of JH,
3. Thirteen auger-cutting samples obtained from holes augered to depths of 1.5 to 3.5 m below
ground level in the vicinity of trenches 10,15,35,41, US and 19S contained only small quantities
of radioactivity that decreased sharply with depth. The observed radioactivity was probably due to
surface contamination. The ground surface in the sampling area had been disturbed to some extent
by burial operations, which probably explains the existence of some radioactivity at 2 to 3 m
depths. It is doubtful that any significant amount of the radioactivity observed can be attributed to
subsurface migration from the near-by trenches. However, this does not discount the possible oc-
currence of deeper subsurface movement of radioactivity from the trenches through fissure
systems in the underlying rocks.
4. A test well sample was examined to determine what fraction of the plutonium present was asso-
ciated with particulate matter and the of the particles on which it attached. The results in-
dicated that essentially all of the radioactivity (> 99,8%) was associated with particulate matter,
with the smallest particle-size fraction containing the highest concentration. These data indicate
that if this radioactivity, particularly plutonium, originated in the trenches, it was transported to
the test wells through fissures in the rock attached to particles or possibly as a mobile organic com-
plex which for some reason was destroyed immediately upon reaching the test well. If the latter is
true, it is surprising that at least some plutonium is not present in the soluble fraction. Also, the
agent responsible for breaking down the organic plutonium complex is unknown. Test-well water
should be analyzed for evidence of organic compounds that have been observed in trench water.
These include numerous aliphatic and aromatic acids, alcohols, ketones, esters and ethers.(3)
Another possibility is that test-well sediment may be contaminated by large volumes of water, con-
taining radionuclides at concentrations below detectable levels, that percolate through rock inter-
sected by the well.
29
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5. Concentration of radionuelides in evaporator effluent and leachate input to the evaporator system
were measured on five occasions in 1976 and 1977. The objectives of these measurements were to
improve the DF values previously determined and to include 14C which was not previously meas-
ured. The DF's were variable and generally lower than those previously measured. Recom-
mended DFs for use in estimating stack effluent concentrations are given below. DFs deter-
mined in Test 6 and the two l37Cs values of less than one (Tests 16and 17) were neglected in arriving
at these suggested values (See Table 2.12 of reference 1).
I4C = 22 MSr = 250 B4?137Cs = 40
*°Co = 90 106Ru = 80 238Pu = 1.5 x 10s
6. The radiation dose resulting from atmospheric discharges of UC was insignificant, less than 0.001
mrem/yr to the lung and GI tract. It is apparent that 1H is the critical radionuclide in evaporator
effluent, delivering an estimated 0,8 mrem/yr (total body) to the limiting receptor, assuming the
40-hr/wk operating schedule continues, AH other radionuelides discharged, including plutonium,
contribute less than 0.1 mrem/yr to the limiting receptor,
7, The results of four years of study, although limited in scope, described in this and the previous re-
port,(l) verify with little question that individuals in the vicinity of the Maxey Flats burial
site are not exposed significantly to radiation from the burial site. Considering the small radiation
doses computed from measurements made during these studies and the limited population in-
volved, no apparent health effects can be expected. However, to better understand other aspects of
shallow burial of radioactivity and to gain an insight into the potential long-term impact of this
and similar burial sites, necessary for establishing criteria for setting appropriate radiation stand-
ards, the following additional short-term projects are suggested;
a. Evaluate the significance of 14C emanating as from buried wastes.
b. Measure external gamma-ray radiation on and off site,
c. Measure evaporator plume depletion during rainfall and ground-level 3H concentrations
beneath the plume at various distances and relate these measurements to available atmos-
pheric transport models,
d. Repeat surface water/sediment sampling to ascertain changes in radionuclide distri-
bution with time.
e. Determine if organics prevalent in trench leachate are present in test-well water.
In addition, a continuous water sampling station installed on Rock Lick Creek at the USGS gaug-
ing station would provide data to estimate the quantity of radioactivity leaving the burkl site via
the aqueous pathway.
30
-------
6.
1. Montgomery, D, M., Kolde, H, E, and Blanchard, R. L., "Radiological
Measurements at the Maxey Flats Radioactive Waste Burial Site - 1974 to 1975,"
U.S. Environmental Protection Agency Report, EPA-520/5-76/020 (1976).
2, Zehner, H. H,, U.S. Geological Survey, Louisville, Kentucky, in preparation,
3, Colombo, P., Weiss, A. J, and Francis, A, J,."Evaluation of Isotope Migration -
Land Burial Water Chemistry of Commercially Operated Low-Level Radioactive
Waste Disposal Sites," Quarterly Progress Reports, April - June, July - September,
October - December 1976, BNL - NUREG-S0623, 50666, and 50670 (1977).
4, Colombo, P. and Neilson, R. M., "Properties of Radioactive Wastes and Waste
Containers," Quarterly Project Report, January - March 1977, BNL - NUREG-50692
(1977).
5, Gat, UM Thomas, J. D, and Clark, D., "Radioactive Waste Inventory of the Maxey
Flats Nuclear Waste Burial Site," Health Pays. 30, 281 (1976).
6. Gat, U., "Nuclear Low-Level Waste Burial Site Inventory Evaluation," to be pub-
lished.
7, "Methods of Soil Analysis (Part 1)," Agronomy Monograph No, 9, American
Society of Agronomy, Inc., Madison, Wisconsin, 545-574 (1965).
8. National Economic Analysis Division, U.S. Department of Agriculture, "Food
Consumption, Prices and Expenditures," Supplement for 1975 to Agricultural
Economic Report AER 138, (Jan. 1977),
9. Office of Radiation Programs, U.S. Environmental Protection Agency, "Carbon-14 in Total Diet and
Milk, 1972-1973," Rad. Health Data Rept ]4, 679 (1973),
10. Krieger, H, L. and Gold, S., "Procedures for Radiochemical Analysis of Nuclear Reactor Aqueous
Solutions," U.S. Environmental Protection Agency Report, Environmental Monitoring Series,
EPA-R4-73-014 (1973),
1L Gold, S., "Analysis of Carbon-14 and Tritium in Reactor Stack Gas," U.S. Environmental Protection
Agency Report, Environmental Monitoring Series, EPA-600/4-75-011 (1975).
12. Dames and Moore, "Assessment of the Levels, Potential Origins and Transport Routes of Radio-
activity Measured in the Vicinity of the Maxey Rats Low-Level Radioactive Waste Burial Site," A
Report for the Dept. of Finance and Administration, Commonwealth of Kentucky (1977).
31
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APPENDIX!. ACKNOWLEDGEMENTS
This report includes contributions from the staff of the Radiochemistry and Nuclear Engineering
Branch, USEPA. Staff members who assisted in the study or the preparation of the report were:
Charlotte S, Andress Seymour Gold Eleanor R. Martin
William J. Averett Betty J. Jacobs James B. Moore
Annette B. Fannin Jasper W, Kearney Ellery D, Savage
George W. Frishkorn Herman L. Krieger
The continued assistance of John Razor, Nuclear Engineering Company; David T, Clark, Kentucky
Department for Human Resources; and Harold H, Zehner, U.S. Geological Survey, in the collection of
samples is gratefully acknowledged. The continued cooperation and support of Charles Hardin, Kentucky
Department for Human Resources, and G. Lewis Meyer, USEPA, during the course of the study are also
appreciated.
32
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APPENDIX 2. I4C COMPUTATION
The annual radiation dose from 14C in evaporator effluent to the limiting receptor is
given by:
Dose (mrem/yr) = 8.4 x 106 (DCF) ( af)/4,
where,
DCF = dose conversion factor [taken from Killough and McKay (1)]
Soluble form - 1.07 x 10~4 rem/jstCi to the Gl tract,
Insoluble form - 5,94 x IG"2 rem/^tCi to the tang,
4 = adjusts the dose to a 40 hr/wk discharge
X = ground-level air concentration of I4C at the site of the limiting receptor, given by
3,3 x 10"* Q-(2) Q is the evaporator discharge rate, and given by:
Q = C x FR/DF,
where,
C = average I4C concentration in the holding tanks; assumed to be 1.9 x 10"5 /jCi/ml.
FR = feed rate to the evaporator stack; 284 ml/sec.
DF = decontamination factor; assumed to be 22.
See Appendices 4 and S of previous report for further details.(2)
1. Killough, O. G. and McKay, L. R,, "A Method for Calculating Radiation Doses from Radioactivity
Released to the Environment," Oak Ridge National Laboratory Report, ORNL4992 (UG-41) (1976),
2. See reference 1.
;33;
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TECHNICAL DATA
(PleaK read Instructions on the reverse before completing}
1. REPORT NO,
EPA-520/5-78-Oil
4, TITLE AND SUBTITLE
Supplementary Radiological Measurements at
the Maxey Flats Radioactive Waste Burial
Site - 1976 - 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8, PERFORMING ORGANIZATION REPOBT NO,
Richard L. Blanehard,. Daniel M, Montgomery,
Harry 1. Kolde, Gerald L. Gels
9, PERFORMING ORGANIZATION NAME AND ADDRESS
Eastern Environmental Radiation Facility
P, 0. Box 3009
Montgomery, Alabama 36109
12, SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Radiation Programs
3, RECIPIENT'S ACCESSION NO,
5. REPORT DATE
September 1978
10, PROGRAM ELEMENT NO.
11, CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVSflED
Final
14, SPONSORING AGENCY CODE
SPA/200/03
15, SUPPLEMENTARY NOTES
16. ABSTRACT
Additional radiological measurements were performed during 1976 and 1977 at the Maxey Flats
radioactive waste burial site. These supplement data collected during 1974 and 1975 reported in EPA-
520/5-76/020.
Evaporator effluents were investigated further to better define quantities of radionuclides discharged
to the atmosphere and improve decontamination factors assigned to the principal radionuclides observed in
the evaporator feed; 3H5 14C, "Co, mCs» 23SPu, and 239Pu,
Qn-site measurements included soil sample profiles taken to a maximum depth of 3,5 m from the trench
area and from withia the main washes east and south of the site. These measurements provided additional
information on the near-surface lateral movement of radioactivity. Radiochemical analysis of a test-well
sample showed that all measurable radioactivity was associated with the sediment in the well the highest
specific radioactivity was associated with the smaller particles (< 5
Milk and vegetables were again sampled from a number of nearby farms. As previously reported,
tritium was the only radionuclide measured in these foods above ambient levels, although concentrations
were less than in similar samples collected during the earlier study,
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Environmental Radioactivity
Radioactive Waste Disposal
Shallow Land Burial
b, IDENTIFIERS/OPEN ENDED TERMS
Radiation Surveys
Environmental trans-
port
Low level waste
disposal
c. COSATI Field/Group
1806
1807
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Release to public
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Unclassified
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3 "2
•3
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Dnclasalf I e*A
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EPA Form 2220-1 (Rev. 4— /7)
PREVIOUS EDITION is OBSOLETE"
-------
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Environmental Protection
Agency
Office of Radiation Programs
Eastern Environmental
Radiation Facility
P.O. Box 3009
Montgomery AL 36109
Official Business
Penalty lor Private Use S300
Postage and
Fees Paid
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