Annual Water Sampling and
Analysis, Calendar Year 1999
RULISON Test Site Area
RIO BLANCO Test Site Area
FAULTLESS Test Site Area
SHOAL Test Site Area
GASBUGGY Test Site Area
GNOME Test Site Area
by
Max G. Davis
Prepared for the U.S. Department of Energy
under Interagency Agreement
DE-AI08-96NV11969
RADIATION AND INDOOR ENVIRONMENTS NATIONAL LABORATORY
OFFICE OF RADIATION AND INDOOR AIR
U.S. ENVIRONMENTAL PROTECTION AGENCY
P.O. BOX 98517
LAS VEGAS, NV 89193-8517
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402R99013
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NOTICE
The information in this document has been funded wholly or in part by the United States
Environmental Protection Agency (EPA) through Interagency Agreement (IAG) DE-AI08-96 NV
11969 from the United States Department of Energy (DOE). This document has been subjected
to the Agency's peer and administrative review, and it has been approved for publication as an
EPA document. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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ABSTRACT
The U. S. Environmental Protection Agency, Radiation and Indoor Environments National
Laboratory in Las Vegas, Nevada (R&IE) operates the radiological surveillance program
surrounding the Nevada Test Site (NTS) and, in addition, monitors former nuclear test areas in
Alaska, Colorado, Mississippi, Nevada, and New Mexico, each year under the Long Term
Hydrological Monitoring Program, or LTHMP. The LTHMP is designed to detect residual man-
made radionuclides in surface and ground water resulting from underground nuclear test
activities. This report describes the sampling and analysis of water samples collected from six
former nuclear test sites in three western states during 1999: Projects Rulison and Rio Blanco in
Colorado, Projects Shoal and Faultless in Nevada, and Projects Gasbuggy and Gnome in New
Mexico. Monitoring results for Alaska and Mississippi are reported separately.
Radiological results for 1999 are consistent with results from previous years, and no increase
was seen in either tritium concentrations or gamma-ray emitting radionuclides at any site.
Tritium levels at the sites are generally decreasing or stable, and are well below the National
Primary Drinking Water Standard for tritium of 20,000 pCi/L, with the exception of samples
from several deep wells adjacent to the nuclear cavity at the Gnome site. As in previous years,
the highest tritium value recorded for any sample, 4.85 x 107 pCi/L, was from one of these wells,
Well DD-1 (Project Gnome).
111
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w
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CONTENTS
Page
Notice ii
Abstract iii
Figures and Tables vi
Acronyms and Abbreviations vii
Acknowledgments viii
1.0 Introduction '. 1
2.0 Sample Analysis Procedures 1
2.1 Sampling at Project RULISON, Colorado 2
2.1.1 Water Analysis Results 4
2.1.2 Conclusions 5
2.2 Sampling at Project RIO BLANCO, Colorado 5
2.2.1 Water Analysis Results 5
2.2.2 Conclusions 5
2.3 Sampling at Project FAULTLESS, Nevada 8
2.3.1 Water Analysis Results 8
2.3.2 Conclusions 8
2.4 Sampling at Project SHOAL, Nevada 10
2.4.1 Water Analysis Results 10
2.4.2 Conclusions 12
2.5 Sampling at Project GASBUGGY, New Mexico 12
2.5.1 Water Analysis Results 13
2.5.2 Conclusions 13
2.6 Sampling at Project GNOME, New Mexico 15
2.6.1 Water Analysis Results 16
2.6.2 Conclusions 16
References 19
Glossary of Terms 20
Appendix 21
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FIGURES
Page
1. RULISON Site sampling locations for Junel999 3
2. RIO BLANCO Site sampling locations for Mayl999 6
3. FAULTLESS Site sampling locations for March 1999 9
4. SHOAL Site sampling locations for February 1999 1.1
5. GASBUGGY Site sampling locations for June 1999 14
6. GNOME Site sampling locations for June 1999 17
TABLES
Page
1. Analysis Results for Water Samples Collected at RULISON Site - June 1999 4
2. Analysis Results for Water Samples Collected at RIO BLANCO Site - May 1999 7
3. Analysis Results for Water Samples Collected at FAULTLESS Site - March 1999 10
4. Analysis Results for Water Samples Collected at SHOAL Site - February 1999 12
5. Analysis Results for Water Samples Collected at GASBUGGY Site - June 1999 15
6. Analysis Results for Water Samples Collected at GNOME Site - June 1999 18
VI
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ACRONYMS AND ABBREVIATIONS
AEC
DOE
DRI
RSL
EPA
DCG
g
3H+
3H
HpGe
IAG
keV
kg
kt
LTHMP
L
m
min
MDC
MeV
mL
Mt
ORIA
pCi/L
PHS
R&IE
SGZ
USGS
rr
U.S. Atomic Energy Commission
U.S. Department of Energy
Desert Research Institute
Radiation Sciences Laboratory
U.S. Environmental Protection Agency
Derived Concentration Guide (20,000 pCi/L for Tritium in Drinking Water)
gram
Enriched Tritium
Tritium
high purity germanium gamma detector
Interagency Agreement
kilo electron volts (one thousand electron volts)
kilogram, 1000 grams
kiloton (one thousand tons TNT equivalent)
Long-Term Hydrological Monitoring Program
liter
meter
minute
minimum detectable concentration
one million electron volts
milliliter (one thousandth of a liter)
megaton (one million tons TNT equivalent)
Office of Radiation and Indoor Air
picocuries per liter = 10"12 curies per liter = 1/1,000,000,000,000 curies per liter
U.S. Public Health Service
Radiation and Indoor Environments National Laboratory, Las Vegas, NV
surface ground zero
U.S. Geological Survey
International Technology Corp.
vn
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ACKNOWLEDGMENTS
The author would like to thank Rich Flotard, Rose Houston, Pat Honsa, Dennis Farmer, Brian
Moore, Betty Strickland, and the staff of the hydrological monitoring team, EPA, for their
dedication to quality and tireless work in the execution of the sampling and laboratory analysis
effort. The author would also like to thank Terry Mouck for her dedication and skill in word
processing and desktop publishing support which was crucial to the production of this report.
vm
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1.0 INTRODUCTION
Under an IAG with the DOE, the R&ffi, formerly Radiation and Sciences Laboratory (RSL),
Office of Radiation and Indoor Air (ORIA), EPA located in Las Vegas, NV, conducts a Long-
Term Hydrological Monitoring Program (LTHMP) to measure radioactivity concentrations in
water sources near the sites of former underground nuclear explosions. The results of the
LTHMP provide assurance that radioactive materials from the tests have not migrated into
drinking water supplies. This report presents the results for the samples collected in February,
May and June of 1999 around the following test site areas:
• Project RULISON Test Site, Garfield County, Colorado
• Project RIO BLANCO Test Site, Rio Blanco County, Colorado
• Project FAULTLESS Test Site, Nye County, Nevada
• Project SHOAL Test Site, Churchill County, Nevada
• Project GASBUGGY Test Site, Rio Arriba County, New Mexico
• Project GNOME Test Site, Eddy County, New Mexico
2.0 Sample Analysis
Radiochemical procedures used to analyze the samples collected for this report are described in
Johns, et al. (1979) and are summarized below (see Appendix for typical minimum detectable
concentration (MDC) values for gamma spectroscopy). These include standard methods to
identify natural and man-made gamma-emitting radionuclides, tritium, plutonium, strontium, and
uranium in water samples. Two types of tritium analyses were performed: conventional and
electrolytic enrichment. The enrichment method lowers the MDC from approximately 300
pCi/L to 5 pCi/L. The upper limit of activity of 700 - 800 pCi/L has been established for the
tritium enrichment method because sample cross contamination becomes a problem at higher
levels.
In late 1995, it was decided that a maximum of 25 percent of all samples collected would be
analyzed by the low-level enrichment method. This decision was based on the time required for
analysis, budgetary constraints, and an assessment of past results. Under the current sampling
and analysis protocol for the site, all samples are initially screened for tritium activity by the
conventional method and selected samples enriched. At this time, only sampling locations that
are in a position to show migration are selected for enrichment.
Sufficient sample is collected from new sampling locations to perform all routine analyses, and a
full-suite of other radiochemical determinations including assays for strontium, plutonium, and
uranium.
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Summary of Analytical Procedures
Type of
Analysis
Analytical
Equipment
Counting
Period (Min)
Analytical
Procedures
Sample
Size
Approximate
Detection Limit3
HpGe
Gammab
3H
HpGe detector -150
calibrated at 0.5 keV/
channel (0.04 to 2 MeV
range) individual detector.
Efficiencies ranging from
15 to 35%.
Automatic liquid
scintillation counter
3H+ Automatic liquid
Enrichment scintillation counter
300
300
Radionuclide concen-
tration quantified from
gamma spectral data
by online computer
program.
3.5L Varies with radionuclides
and detector used, if
counted to a MDC of
approx. 5 pCi/L for 137Cs.
Sample prepared by 5 -10 mL 300 to 700 pCi/L
distillation.
Sample concentrated 5 mL 5 pCi/L
by electrolysis followed
by distillation.
" The detection limit is defined as the smallest amount.of radioactivity that can be reliably detected, i.e.,
probability of Type I and Type II error at 5 percent each (DOE 1981).
b Gamma spectrometry using a high purity intrinsic germanium (HpGe) detector.
2.1 Sampling at Project RULISON, Colorado
History
Co-sponsored by the AEC and Austral Oil Company under the Plowshare Program, Project
RULISON was designed to stimulate natural gas recovery in the Mesa Verde formation. The
test, conducted near Grand Valley, Colorado on September 10, 1969, consisted of a 40-kt nuclear
explosive emplaced at a depth of 2,568 m (8,425 ft). Production testing began in 1970 and was
completed in April 1971. Cleanup was initiated in 1972, and the wells were plugged in 1976.
Some surface contamination resulted from decontamination of drilling equipment and fallout
from gas flaring. Contaminated soil was removed during the cleanup operations.
Sampling was conducted on May 18, 1999, from all sampling locations at Grand Valley and
Rulison, Colorado. Routine sampling locations are shown in Figure 1. Sampling included the
Grand Valley municipal drinking water supply springs, water supply wells for five local ranches,
and five sites in the vicinity of SGZ, including one test well, a surface-discharge spring and two
wells (RU-01 and RU-02) located at SGZ.
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Rothgery
Ranch
Grand Valley
City Springs
><
Grand Valley •*-'
Potter Ranch
Rulison
X™ Tim Jacobs Ranch
Gardner
Ranch Test Well
Hayward Ranch
\
•\ Battlement Creek
• Spring
N
Surface Ground Zero
I Water Sampling Locations
LOCATION MAP
Scale in Miles
0 5
Scale in Kilometers
GARFIELD
COUNTY
Figure 1. RULISON Site sampling locations for June 1999.
3
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2.1.1 Water Analysis Results
Tritium has never been observed in measurable concentrations in the Grand Valley City Springs.
All of the remaining sampling sites show detectable levels of tritium, which have generally
exhibited a stable or decreasing trend over the last two decades. The range of tritium activity in
1999 was from 30 ± 3.9 pCi/L at RU-1 to 76 ± 4.3 pCi/L at Lee Hayward Ranch (see Table 1).
All enriched values were less than 0.5 percent of the DCG (20,000 pCi/L). The detectable
tritium activities are consistent with values found in current precipitation and, perhaps, a small
residual component remaining from clean-up activities at the site. This is supported by Desert
Research Institute analysis, which indicates that most of the sampling locations at the RULISON
site are shallow, drawing water from the surficial aquifer, and therefore unlikely to become
contaminated by radionuclide migration from the Project RULISON cavity (Chapman and
Hokett, 1991).
Analysis Results for Water Samples Collected at RULISON Site - June 1999
TABLE 1
Sample
Location,
Battlement Creek
City Springs
David Gardner
CER Test Well
Lee Hayward Rn.
Potter Ranch
Wayne & Debra
Rothgery
Tim Jacobs
Spring 300 yds N.
ofGZ
Well RU-1
Well RU-2
Well RU-3
Collection
Date
1999
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
5/18/99
Enriched Tritium
.;PCi/L±2SD,*(Ml|©j);;
76 ±4.3 (4.8)
30 ± 3.9 (5.4)
Tritium00
lp£i/L±2SD (MDC)
29 ±135 (222)
8.6 ±135 (222)
67 ±136 (222)
-36 ± 134 (222)
180+138 (222)
84 ±136 (222)
-26 ±134 (222)
70 ±136 (222)
94 ±137 (222)
26 ±135 (222)
Gamma.Spectrometryb>
pCi/L (MDC)
ND (4.9)
ND (5.0)
ND (4.5)
ND (5.0)
ND (5.0)
ND (5.0)
ND (4.9)
ND (5.0)
ND (5.0)
ND (5.0)
ND (5.0)
ND (4.8)
(a) Indicate results are less than MDC (enriched or conventional method).
(b) Value in parenthesis represents "7Cs MDC (pCi/L).
ND Non-detected.
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2.1.2 Conclusions
Tritium concentrations in water samples collected onsite and offsite are consistent with those of
past studies at the RULISON Test Site. In general, the current level of tritium in shallow wells at
the RULISON site can not be distinguished from the rain-out of naturally produced tritium
augmented by, perhaps, a small amount of residual global "fallout tritium" remaining from
nuclear testing in the 1950s and 1960s. All routine samples were analyzed for presence of
gamma-ray emitting radionuclides. None were detected above the MDC (see Table 1, page 4).
2.2 Sampling at Project RIO BLANCO, Colorado
History
Project RIO BLANCO a joint government-industry test designed to stimulate natural gas flow
was conducted under the Plowshare Program. The test was conducted on May 17, 1973 at a
location between Rifle and Meeker Colorado. Three explosives with a total yield of 99 kt were
emplaced at 1,780-, 1,920-, and 2,040-m (5,840-, 6,299-, and 6,693-ft) depths in the Ft. Union
and Mesa Verde formations. Production testing continued until 1976 when cleanup and
restoration activities were completed. Tritiated water produced during testing was injected to
1,710 m (5,610 ft) in a nearby gas well.
Sampling was conducted on May 19-21, 1999. Sampling locations are shown in Figure 2. The
routine sampling locations included four springs, four surface, and five wells, three of which are
located near the cavity. At least two of the wells (Wells RB-D-01 and RB-D-03) were suitable
for monitoring because they were down gradient and would indicate possible migration of
radioactivity from the cavity. A new sampling location was added this year RB-W-01 (see
Figure 2).
2.2.1 Water Analysis Results
Gamma-ray spectral analysis results indicated that no man-made gamma-ray emitting
radionuclides were present in any offsite samples. None of the 15 samples collected were above
the MDC for enriched tritium (see Table 2, page 7).
2.2.2 Conclusions
Tritium concentrations in water samples collected onsite and offsite are consistent with those of
past studies at the RIO BLANCO Site. No radioactive materials attributable to the RIO
BLANCO test were detected in samples collected in the offsite areas during May 1999. All
samples were analyzed for presence of gamma-ray emitting radionuclides. None were detected
above the MDC.
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Johnson
Artesian Well
£/* •''/Fawn Cr. No. 1
CER-1K,
B-1 Equity
Camp
Brennan
Windmill
Fawn Cr.84001
Downstream
Fawn Cr.500' Downstream
RB-D-01
RB-D-03 i. 4
Fawn Cr.500'
Upstream
Fawn Cr.
Upstream
RB-S-03
RB-W-01
Fawn Cr. No. 3
Scale in Kilometers
RIO BLANCO COUNTY
GARFIELD COUNTY
LOCATION MAP
Surface Ground Zero
Water Sampling Locations
RIO BLANCO
COUNTY
Figure 2. RIO BLANCO Site sampling locations for May 1999.
6
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Analysis Results for Water Samples Collected at RIO BLANCO Site - May 1999
TABLE 2
Sample
Location
B-l Equity Camp
Brennan Windmill
CER #1 Black
Sulphur
CER #4 Black
Sulphur
Fawn Creek #1
Fawn Creek #3
Fawn Creek 500'
Upstream
Fawn Creek 6800'
Upstream
Fawn Creek 500'
Downstream
Fawn Creek 8400'
Downstream
Johnson Artesian
Well
Well RB-D-01
Well RB-D-03
Well RB-S-03
Well RB-W-01
Collection
Date .
5/19/99
5/19/99
5/19/99
5/19/99
5/20/99
5/20/99
5/20/99
5/20/99
5/22/99
5/22/99
5/19/99
5/19/99
5/21/99
5/21/99
5/21/99
Enriched Tritium
pCi/l;±2$D h,(MDC)
6.2 ± 3.2 (5.0)
2.7 ± 32 (a) (5.3)
1.3 ±2.8 (a) (4.6)
-0.73 ± 2.9 (a) (4.9)
2.5 ± 3.4 (a) (5.4)
Tritium(a)
pCi/L±2SD (MDC) ,
18 ±128 (210)
-28 ± 127 (210)
-32 ±127 (210)
-95 ± 125 (210)
9.6 ± 127 (210)
-86 ±125 (210)
-86+125 (210)
-32 ±127 (210)
18 ±128 (210)
-11 ±127 (210)
-22 ±127 (210)
18 + 128 (210)
Gamma Spectrometry01*
pCi/L (MDC)
ND (4.8)
ND (4.9)
ND (4.8)
ND (4.8)
ND (4.1)
ND (4.8)
ND (4.8)
ND (4.7)
ND (4.7)
ND (4.4)
ND (5.0)
ND (4.9)
ND (4.9)
ND (5.0)
ND (5.0)
(a) Indicate results are less than MDC (enriched or conventional method).
(b) Value in parenthesis represents '37Cs MDC (pCi/L).
ND Non-detected.
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2.3 Sampling at Project FAULTLESS, Nevada
History
Project FAULTLESS was a "calibration test" conducted on January 19, 1968, in a sparsely
populated area near Blue Jay Maintenance Station, Nevada. The test had a yield of less than 1
Mt and was designed to test the behavior of seismic waves and to determine the usefulness of the
site for high-yield tests. The emplacement depth was 975 m (3,200 ft). A surface crater was
formed, but as an irregular block along local faults rather than as a saucer-shaped depression.
The area is characterized by basin and range topography, with alluvium overlying tuffaceous
sediments. The working point of the test was in tuff. The groundwater flow is generally from
the highlands to the valley and through the valley to Twin Springs Ranch and Railroad Valley
(Chapman and Hokett, 1991).
Sampling was conducted on February 25 and March 10, 1999. Sampling locations are shown in
Figure 3. They include one spring and five wells of varying depths.
At least two wells (HTH-1 and HTH-2) are positioned to intercept migration from the test cavity,
should it occur (Chapman and Hokett, 1991). All samples yielded negligible gamma activity.
Enriched tritium concentrations were less than the MDC and less than 0.02 percent of the DCG.
These results were all consistent with results obtained in previous years. The consistently below-
MDC results for tritium indicate that, to date, migration into the sampled wells has not taken
place and no event-related radioactivity has entered area drinking water supplies.
2.3.1 Water Analysis Results
All gamma-ray spectral analysis results indicated that no man-made gamma-ray emitting
radionuclides were present above minimum detectable levels in any offsite samples. All tritium
results were below the MDC (see Table 3, page 10).
2.3.2 Conclusions
Tritium concentrations of water samples collected onsite and offsite are consistent with those of
past studies at the FAULTLESS Site. No gamma-ray emitting radionuclides were detected above
the MDC.
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HTH2
HTH1
I
I
,'x /
' — — -N
Hot Creek
Ranch
Six-Mile Well
Blue Jay
Maintenance
Station
SiteC
Complex
Surface Ground Zero
Water Sampling Locations
Scale in Miles
Scale in Kilometers
NYE
COUNTY
LOCATION MAP
Figure 3. FAULTLESS Site sampling locations for March 1999.
9
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Analysis Results for Water Samples Collected at FAULTLESS Site - February 1999.
TABLE 3
Sample
Location
Hot Creek Ranch
Spring
Blue Jay Maint
Station
Well HTH-1
Well HTH-2
Site C Complex
Six Mile
Collection
Date
2/25/99
2/28/99
3/10/99
2/25/99
2/25/99
2/25/99
Enriched Tritium'50
pCi/L±2SD (MDC)
-1.3 ±3.1 (5.1)
-1.2 ±3.9 (6.5)
-1.7 ±3.3 (5.4)
Tritium(a)
pCi/L±2SD (MDC)
6.2 ±127 (209)
78 ±127 (206)
-52 ±126 (278)
-10 ±126 (278)
Gamma Spectrometry(b)
pCi/L (MDC)
ND (4.9)
ND (3.1)
ND (3.4)
ND (4.9)
ND (4.9)
ND (4.9)
(a) Indicate results are less than MDC (enriched or conventional method).
(b) Value in parenthesis represents l37Cs MDC (pCi/L).
ND Non-detected.
2.4 Sampling at Project SHOAL, Nevada
History
Project SHOAL, a 12-kt nuclear test emplaced at 365 m (1,204 ft), was conducted on
October 26, 1963, in a sparsely populated area near Frenchman Station, Nevada, 28 miles
southeast of Fallen, Nevada. The test, a part of the Vela Uniform Program, was designed to
investigate detection of a nuclear detonation in an active earthquake zone. The working point
was in granite and no surface crater was created. The effluent released during drillback was
detected onsite only and consisted of 110 curies of 131Xe and 133Xe, and less than 1.0 curie of 131I.
Samples were collected on February 23 and 24, 1999. The sampling locations are shown in
Figure 4. Only eight of the nine routine locations were sampled. In 1997, four new wells were
added to the LTHMP at this site which are positioned near GZ. Sampling of these wells was
done in February 1999. Well HC-3 has drilling fluid in the well and will need to be reworked, it
will be sampled in 2000. Well HC-4 the pump was inoperative. The routine sampling locations
include one spring, one windmill, and seven wells of varying depths. At least one location, Well
HS-1, should intercept radioactivity migrating from the test cavity, if it occurs (Chapman and
Hokettl991).
2.4.1 Water Analysis Results
Gamma-ray spectral analysis results indicated that no man-made gamma-ray emitting
radionuclides were present in any samples above the MDC. Only one sampling location had a
tritium concentration barely above the MDC of 4.9 ± 30 pCi/L. Tritium concentration at all the
other locations were below the MDC (see Table 4, page 12).
10
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Fallon
HS-1
CHURCHILL COUNTY
^M ^H ^M ^^ ^M M ••• •
MINERAL COUNTY
To Scheelite Mine
N
Surface Ground Zero
Water Sampling Locations
LOCATION MAP
Scale in Miles
5 10
0 5 10 15
Scale in Kilometers
CHURCHILL
COUNTY
Figure 4. SHOAL Site sampling locations for February 1999.
11
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2.4.2 Conclusions
No radioactive materials attributable to the SHOAL nuclear test were detected in samples
collected in the offsite areas during 1999.
Analysis Results for Water Samples Collected at SHOAL Site - February 1999
TABLE 4
Sample
Location
Hunts Station
Flowing Well
Well H-2
Well H-3
Well HS-1
Well HC-1
Well HC-2
Well HC-3
Well HC-4
Collection
Date
2/23/99
2/23/99
2/23/99
2/23/99
2/23/99
2/24/99
2/24/99
2/24/99
2/24/99
'Enriched Tritium
pCi/L±2SD: (MDC)
0.25 ± 3.0 (a) (5.0)
4.9 ± 3.0 (4.8)
Tritium^
pCi/L ± 2 SD (MDC)
-89 ±125 (209)
27 ±127 (209)
-81 ± 125 (209)
14 ±127 (209)
56 ± 128 (209)
Gamma Spectrometry(b)
pGi/L (MDC)
ND (5.0)
ND . (5.0)
ND (5.0)
ND (3.5)
ND (3.3)
ND (5.0)
ND (4.9)
Not Sampled, drill
fluid in well
Not Sampled
(a) Indicate results are less than MDC (enriched or conventional method).
(b) Value in parenthesis represents l37Cs MDC (pCi/L).
ND Non-detected.
2.5 Sampling at Project GASBUGGY, New Mexico
History
Project GASBUGGY was a Plowshare Program test co-sponsored by the U.S. Government and
El Paso Natural Gas Co., conducted near Gobernador, New Mexico on December 10, 1967. A
nuclear explosive with a 29-kt yield was detonated at a depth of 1,290 m (4,240 ft) to stimulate a
low productivity natural gas reservoir. Production testing was completed in 1976 and restoration
activities were completed in July 1978.
The principal aquifers near the test site are the Ojo Alamo Sandstone, an aquifer containing non-
potable water located above the test cavity, and the San Jose formation and Nacimiento
formation.
12
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Both surficial aquifers contain potable water. The flow regime of the San Juan Basin is not well
known, although it is likely that the Ojo Alamo Sandstone discharges to the San Juan River 50
miles northwest of the Gasbuggy site. Hydrologic gradients in the vicinity are downward, but
upward gas migration is possible (Chapman and Hokett, 1991).
Annual sampling at Project GASBUGGY was completed during June 16-19, 1999. All of the
routine sampling locations were collected (see Figure 5). The Bixler Ranch has been deleted
from the routine sampling and is not accessible at this time. The Windmill 30.3.32.343 north was
collected this year after the well was fixed and returned to service.
2.5.1 Water Analysis Results
The Cedar Springs sampling site yielded enriched tritium activities of 33 ± 3.6 pCi/L which is
less than 0.5 percent of the DCG and similar to the range seen in previous years. Tritium samples
from the other locations were all below the average MDC, as was the concentration at the new
location (see Table 5, page 15).
Well EPNG 10-36 has yielded tritium activities between 100 and 560 pCi/L in each year since
1984, except in 1987. The sample collected in June 1999, yielded a tritium activity of 93 ± 4.6
pCi/L. The migration mechanism and route are not currently known, although an analysis by
Desert Research Institute indicated two feasible routes, one through the Printed Cliffs sandstones
and the other one through the Ojo Alamo sandstone, one of the principal aquifers in the region
(Chapman 1991). In either case, fractures extending from the cavity may be the primary or a
contributing mechanism. The proximity of the well to the test cavity suggests the possibility that
the activity increases may indicate migration from the test cavity.
All gamma-ray spectral analysis results indicated that no man-made gamma-ray emitting
radionuclides were present in any offsite samples above minimum detectable levels.
2.5.2 Conclusions
Tritium concentrations of water samples collected onsite and offsite are consistent with those of
past studies at the GASBUGGY Site.
13
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Bixler Ranch
To Blanco &
Gobernador
™ Pond N. of
Well 30.3.32.343N
Well 30.3.32.343N
La Jara Creek
Bubbling
Springs
Jicarilla Well 1
EPNG Well 0-36
Cedar Springs
M^^^H
Cave Springs
Lower Burro
10H Canyon
Arnold Ranch Spring
Arnold Ranch Well
Well 28.3.33.233S
LOCATION MAP
Surface Ground Zero
Water Sampling Locations
Scale in Miles
0 5
0 8
Scale in Kilometers
RIO
ARRIBA
COUNTY
NEW
MEXICO
Figure 5. GASBUGGY Site sampling locations for June 1999.
14
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Analysis Results for Water Samples Collected at GASBUGGY Site - June 1999
TABLE 6
Sample
Location
Arnold Ranch
Spring
Bubbling Springs
Cave Springs
Cedar Springs
La Jara Creek
Lower Burro
Canyon
Pond N. of Well
30.3.32.343
Well EPNG- 10-36
Jicarilla Well 1
Well 28.3.33.233
(South)
Well 30.3.32.343
(North)
Windmill #2
Arnold Ranch
Well
Collection
Date
6/19/99
6/18/99
6/18/99
6/18/99
6/17/99
6/18/99
6/18/99
6/18/99.
6/18/99
6/16/99
6/18/99
6/18/99
6/19/99
Enriched Tritium
pCi/L±2SD (MDC)
33 ± 3.6 (4.9)
43 ±4.6 (5.0)
Tritium00
pCi/L ± 2 SD (MDC)
-24 ±120 (231)
-4.0+121 (231)
36 ±3.5 (231)
-4.0 ±121 (231)
90 ±122 (231)
98 ±122 (231)
-92 ±138 (231)
-42 ±139 (231)
21 ±140 (231)
54 ±141 (231)
42 ±141 (231)
Gamma Spectrometry(b)
pCi/L (MDC)
ND (4.4)
ND (5.0)
ND (4.7)
ND (5.9)
ND (4.2)
ND (4.9)
ND (5.0)
ND (4.4)
ND (4.9)
ND (4.6)
ND (5.0)
ND (4.9)
ND (4.9)
(a) Indicate results are less than MDC (enriched or conventional method).
(b) Value in parenthesis represents 137Cs MDC (pCi/L).
ND Non-detected.
2.6 Sampling at Project GNOME, New Mexico
Project GNOME, conducted on December 10, 1961, near Carlsbad, New Mexico, was a
multipurpose test emplaced at a depth of 1,216 ft in the Salado salt formation. The explosive
yield was slightly-more-than 3-kt. Oil and gas are produced from the geologic units below the
working point. The overlying Rustler formation contains three water-bearing zones: brine
located at the boundary of the Rustler and Salado formations, the Culebra Dolomite which is
used for domestic and stock supplies, and the Magenta Dolomite which is above the zone of
saturation (Chapman and Hokett, 1991). The ground water flow is generally to the west and
southwest.
15
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Radioactive gases were accidentally vented following the test. In 1963, USGS conducted a tracer
study involving injection of 20 Ci tritium, 10 Ci 137Cs, 10 Ci 90Sr, and 4 Ci 131I in the Culebra
Dolomite zone; using Wells USGS 4 and 8. During remediation activities in 1968-69,
contaminated material was placed in the test cavity and the shaft up to within 7 ft of the surface.
More material was slurried into the cavity and drifts in 1979. A potential exists for discharge of
this slurry to the Culebra Dolomite and to Rustler-Salado brine. Potentially this may increase as
the salt around the cavity compresses, forcing contamination upward and distorting and cracking
the concrete stem and grout.
Annual sampling at Project GNOME was completed during May 1999. The routine sampling
sites, depicted in Figure 6, include ten monitoring wells in the vicinity of surface GZ; the
municipal supplies at Loving and Carlsbad, New Mexico.
2.6.1 Water Analysis Results
No tritium activity was detected in the Carlsbad municipal supply or the Loving Station well. An
analysis by Desert Research Institute (Chapman and Hokett, 1991) indicates that these sampling
locations, which are on the opposite side of the Pecos River from the Project GNOME site, are
not connected hydrologically to the site and, therefore, cannot become contaminated by Project
GNOME radionuclides.
Tritium results greater than the MDC were detected in water samples from four of the 12
sampling locations in the immediate vicinity of GZ. Tritium activities in wells DD-1, LRL-7,
USGS-4, and USGS-8 ranged from 4.85 x 107(DD-1) to 1.84 x 104 (LRL-7) pCi/L. Well DD-1
collects water from the test cavity; Well LRL-7 collects water from a sidedrift; and Wells USGS-
4 and USGS-8 were used in the radionuclide tracer study conducted by the USGS. None of these
wells are sources of potable water.
In addition to tritium, 137Cs and 90Sr concentrations were observed in samples from of Wells DD-
1, LRL-7, and USGS-8, while TOSr activity was detected in Well USGS-4 as in previous years
(see Table 7). No tritium was detected in the remaining sampling locations, including Well
USGS-1, which the DRI analysis (Chapman and Hokett 1991) indicated is positioned to detect
any migration of radioactivity from the cavity. All other tritium results were below the MDC.
2.6.2 Conclusion
No radioactive materials attributable to the GNOME Test were detected in samples collected in
the offsite areas during June of 1999.
16
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Carlsbad
Carlsbad
City |
Well?
I
N
PHS Well 9
PHSWelMO
Loving City
Well 2
PHS Well 6 •
• PHS Well 8
Surface Ground Zero
Water Sampling Locations
Scale in Miles
5
EDDY
COUNTY
0 5 10 15
Scale in Kilometers
LOCATION MAP
Figure 6. GNOME Site sampling locations for June 1999.
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Tritium Results for Water Samples Collected at GNOME Site - June 1999
TABLE 7
Sample
Location
Well 7 City
Well 2 City
PHS6
PHS8
PHS9
PHS 10
USGS Well 1
USGS Well 4
Well USGS 8
J. Mobley Ranch
Well DD-1
LRL-7
Collection
Date
5/22/99
5/25/99
5/22/99
5/24/99
5/24/99
5/24/99
5/22/99
5/23/99
6/23/99
5/24/99
5/24/99
5/23/99
iEnriched Tritium ,
pCi/L ± 2|SD;? |MDJS);;
-1.2 ±3.0 (a) (5.0)
3.0 ± 3.2 (a) (5.2)
Tritium
p,Ci/L ± 2 SD ..(MDC)
-4.18 ±146 (a) (251)
-337 ±147 (a) (251)
-372 ±147 (a) (251)
-110 ±151 (a) (251)
-58 ±151 (a) (251)
37 ±153 (a) (251)
1.15xl077±748 (251)
5.9xl04±549 (251)
4.85xl07 ±1.29xl05
(251)
1.84x10" ± 104 (251)
.fGammasSpectrornetry?0
fpqi/L "(MDC)
ND (4.7)
ND (4.7)
ND (4.5)
ND (4.8)
ND (4.7)
ND (4.1)
ND (4.3)
ND (4.1)
Cs-13775±13 (4.4)
ND (4.9)
Cs-137
6.9xl05± 1:0x10 5
Cs-137
34 + 8.1 (4.9)
(a) Indicate results are less than MDC (enriched or conventional method).
(b) Value in parenthesis represents 137Cs MDC (pCi/L).
ND Non-detected.
18
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REFERENCES
Chapman & Hockett, 1991. Evaluation ofGroundwater Monitoring at Off site Nuclear Test
Areas, Las Vegas, NV, Desert Research Institute, University of Nevada System, Report
DOE/NV/10845-07.
Code of Federal Regulations, Vol. 41, title 40, Part 141, July 9, 1976, National Interim Primary
Drinking Water Regulations.
A Guide for Environmental Radiological Surveillance at U.S. Dept. of Energy Installations, July
1981, Office of Operational Safety Report. Las Vegas, NV: U.S. Department of Energy;
DOE/EP-0023.
Johns, F., et al. 1979. Radiochemical and Analytical Procedures for Analysis of Environmental
Samples. Las Vegas, NV: U.S. Environmental Protection Agency; EMSL-LV-0539-17-1979.
Off site Environmental Monitoring Report Radiation Monitoring Around Nuclear Test Areas,
Calendar Year 1992. EPA 600/R-94/209.
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GLOSSARY OF TERMS
Background Radiation
The radiation in man's environment, including cosmic rays and radiation from naturally-
occurring and man-made radioactive elements, both outside and inside the bodies of humans and
animals. The usually quoted average individual exposure from background radiation is 125
millirem per year in mid-latitudes at sea level.
Curie (Ci)
The basic unit used to describe the rate of radioactive disintegration. The curie is equal to 37
billion disintegrations per second, which is the equivalent of 1 gram of radium. Named for Marie
and Pierre Curie who discovered radium in 1898. One microcurie (|iCi) is 0.000001 Ci.
Isotope
Atoms of the same element with different numbers of neutrons in the nuclei. Thus 12C, 13C, and
14C are isotopes of the element carbon, the numbers denoting the approximate atomic weights.
Isotopes have very nearly the same chemical properties, but have different physical properties
(for example 12C and 13C are stable, 14C is radioactive).
Enrichment Method
A method of electrolytic concentration that increases the sensitivity of the analysis of tritium in
water. This method is used for selected samples if the tritium concentration is less than 700
pCi/L.
Minimum Detectable Concentration (MDC)
The smallest amount of radioactivity that can be reliably detected with a probability of Type I
and Type n errors at 5 percent each (DOE 1981).
Offsite
Areas exclusive of the immediate Test Site Area.
Type I Error
The statistical error of accepting the presence of radioactivity when none is present. Sometimes
called alpha error.
Type II Error
The statistical error of failing to recognize the presence of radioactivity when it is present.
Sometimes called beta error.
20
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Appendix
Typical MDA Values for Gamma Spectroscopy
(100 minute count time)
Geometry*
Matrix
Volume
Isotope
Be-7
K-40
Gr-51
Mn-54
Co-57
Co-58
Fe-59
Co-60
Zn-65
Nb-95
Zr-95
Marinelli
Water
3.5 liter
MDA
4.56E+01
4.92E+01
5.88E+01
4.55E+01
9.65E+00
4.71E+00
1.07E+01
5.38E+00
1.24E+01
5.64E+00
9.06E+00
Model
Density
Units
Isotope
Ru-106
Sn-113
Sb-125
1-131
Ba-133
Cs-134
Cs-137
Ce-144
Eu-152
Ra-226
U-235
Am-241
430G
l.Og/ml
pCi/L.
MDA
4.76E+01
8.32E+00
1.65E+01
8.28E+00
9.16E+00
6.12E+00
6.43E+00
7.59E+01
2.86E+01
1.58E+01
1.01E+02
6.60E+01
Disclaimer
The MDA's provided are for background matrix samples presumed to contain no known analytes and no
decay time. All MDA's provided here are for one specific *Germanium detector and the geometry of
interest. The MDA's in no way should be used as a source of reference for determing MDA's for any
other type of detector. All gamma spectroscopy MDA's will vary with different types of shielding,
geometries, counting times and decay time of sample.
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