SEPA
United States
Environmental Protection
Agency
Office of Radiation and
Indoor Air
Washington, DC 20460
EPA
June 1997
EPA-402-R-97-010
Annual Water Sampling
and Analysis Calendar Year 1996;
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
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Annual Water Sampling and
Analysis Calendar Year 1996:
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-A108-91 NV 10963
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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NOTICE
The information in this document has been funded wholly or in part by the United States
Environmental Protection Agency (EP A) through Interagency Agreement (lAG) DE-A108-91
NV 10963 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 EP A document. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
n
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ABSTRACT
In this report the annual water sampling for the Long-Term Hydrological Monitoring Program
(LTHMP) conducted during 1996 by the Environmental Protection Agency's (EPA's) Radiation
and Indoor Environments National Laboratory-Las Vegas (R&IE), Office of Radiation and
Indoor Air will be described. This laboratory operates an environmental radiation monitoring
program in the region surrounding the Nevada Test Site (NTS) and at former test sites in
Colorado, Nevada, and New Mexico. The LTHMP program is designed to detect any
radioactivity that may be related to previous nuclear testing activities. Although tritium initially
seeped from two of the offsite tests, the tritium levels in wells at both these sites are decreasing
and were well below the National Primary Drinking Water Regulation levels.
The analytical results are given and all samples were analyzed for the presence of gamma-ray
emitting radionuclides, none was detected above the minimum detectable activity.
ill
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IV
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CONTENTS
Pa~e
Notice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Abstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. iii
Figures and Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. vi
Acronyms and Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. viii
1.0 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
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 .........................7
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
v
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FIGURES
Pa~e
1. RULISON Site sampling locations for June 1996 ................................. 3
2. RIO BLANCO Site sampling locations for June 1996 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. FAULTLESS Site sampling locations for March 1996 .............................9
4. SHOAL Site sampling locations for March 1996 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. GASBUGGY Site sampling locations for June 1996 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6. GNOME Site sampling locations for June 1996 ................................. 17
TABLES
Pa~e
1. RULISON Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. RIO BLANCO Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. FAULTLESS Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. SHOAL Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. GASBUGGY Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6. GNOME Site. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
VI
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ABC
DOE
RSL
EPA
DCG
g
3H+
3H
HpGe
keV
kg
kt
LTHMP
L
m
mm
MDC
MeV
mL
ORIA
pCi/L
PHS
R&IE
SGZ
USGS
ACRONYMS AND ABBREVIATIONS
Atomic Energy Commission
Department of Energy
Radiation Sciences Laboratory
Environmental Protection Agency
Derived Concentration Guide
gram
Enriched Tritium
Tritium
high purity germanium gamma detector
kilo electron volts = thousand electron volts
kilo gram, 1000 grams
kiloton (TNT equivalent)
Long- Term Hydrological Monitoring Program
liter
meter
minute
mhrimum detectable concentration
million electron volts
milliliter = one thousandth of a liter
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
surface ground zero
U.S. Geological Survey
vn
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ACKNOWLEDGMENTS
The author would like to acknowledge Donald James, Julius Barth, Dennis Farmer, and the staff
of the hydrolo gical monitoring group, EP A, 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.
V1ll
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1.0 INTRODUCTION
Under an lAG with the U.S. Department of Energy (DOE), the Radiation and Indoor
Environments National Laboratory (R&IE), formerly Radiation and Sciences Laboratory (RSL),
Office of Radiation and Indoor Air (ORIA), ofthe U.S. Environmental Protection Agency (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 underground nuclear
explosions. The results of the L THMP 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 March and June of 1996 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 Procedures
The procedures for the analysis of samples collected for this report were described by Johns, et al.
(1979) and are summarized below (see Appendbc for Typical MDA Values for Gamma
Spectroscopy). These include gamma spectral analysis and radiochemical analysis for tritium.
The procedures were based on standard methodology for given analytical procedures. Two
methods for tritium analysis were performed: conventional and electrolytic enrichment. The
samples are initially analyzed by the conventional method. If the tritium result is less than 700
pCi/L, selected samples are analyzed by the electrolytic enrichment method which lowers the
minimum detectable concentration (MDC) from approximately 300 pCi/L to 5 pCi/L. An upper
level of 700 pCi/L has been established for the tritium enrichment method. Sample cross
contamination becomes a problem at higher ranges.
For wells with operating pumps, the samples are collected at the nearest convenient outlet. If the
well has no pump, a truck-mounted sampling unit is used. With this unit it is possible to collect
three-liter samples from wells as deep as 1,800 meters (5,900 ft). At the normal sample collection
sites, the pH, conductivity, water temperature, and sampling depth is measured and recorded
when the sample is collected.
The first time samples are collected from a well, 3H, 89,90Sr, 238, 239+240pU, and uranium isotopes are
determined. At least one of the one gallon samples from each site is analyzed by gamma
spectrometry. In late 1995, it was decided that only 25% of tritium samples collected would be
analyzed by the enrichment method. Sampling locations in a position to show migration are
usually selected.
1
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Summary of Analytical Procedures
Type of Analytical Counting Analytical Sample Approximate
Analysis Equipment Period (Min) Procedures Size Detection Limit"
HpGe HpGe detector 100 Radionuclide concen- 3.5L See Table in Appendix.
Gammab calibrated at 0.5 keV/ tration quantified from
channel (0.04 to 2 MeV gamma spectral data by
range) individual detector. online computer program.
Efficiencies ranging from
15 to 35%.
3H Automatic liquid 300 Sample prepared by 5 to 10 mL 300 to 700 pCiIL
scintillation counter distillation.
3H+ Automatic liquid 300 Sample concentrated by 250 mL 5 pCiIL
Enrichment scintillation counter 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
Cosponsored by the ABC 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 in June 1996, with collection of eight samples out of nine wells in the
area of Grand Valley and Rulison, Colorado. The spring 300 yards from SGZ was dry. 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 three sites in the vicinity of
SGZ, including one test well, a surface-discharge spring which was dry and a surface sampling
location on Battlement Creek. Seven new monitoring wells were completed at the RULISON
Site in 1995. These wells will be added to the Long-Term Hydrological Monitoring Program.
The EP A was sampling these wells for BTEX, THP diesel, and RCRA metals. The samples were
sent to Quanterra Laboratory in Missouri. After the samples were analyzed, the results were sent
to IT Corp, where the report of those measurements are compiled for DOE.
2
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@
I
~
I
Rothgery
Ranch
Grand Valley
City Springs
~
,-""
,.-
I
-.. I
Rulison..J /
-- -...;
---,,' I
,
J.!. - - - - - ,. Tim Jacobs Ranch
I \ 8 Hayward Ranch
,I ,
8 I 8' Battlement Creek
Gardner CER. ~
Ranch Test Well w Spring
8
~
N
LOCATION MAP
8 Surlace Ground Zero
I Water Sampling Locations
D Not sampled this year
Scale in Miles
o 5
..-~
Scale in Kilometers
i1illill.:111111111ill
GARFIELD
COUNTY
o
8
Figure 1. RULISON Site sampling locations for June 1996.
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
1996 was from 242 :t 140 pCYL at Battlement Creek, to 112:t 6.9 pCYL at Lee Hayward Ranch
(see Table 1). All values were less than one percent ofthe DCG. The detectable tritium activities
were probably a result of the high natural background in the area. This was supported by the
Desert Research Institute analysis, which indicated that most of the sampling locations were
shallow, drawing water from the surficial aquifer which was unlikely to become contaminated by
any radio nuclides arising from the Project RULISON cavity (Chapman and Hokett, 1991).
Table 1. Analysis Results for Water Samples Collected in June 1996.
II~i~l~
Battlement Creek
City Springs
Albert Gardner
CER Test Well
Lee Hayward Rn.
Potter Ranch
Wayne & Debra
Rothgery
Tim Jacobs
Spring 300 yds N.
ofGZ
RULISON Site
.... .
..... .....
..... .
......... ..""
..... .
(t9~t~#Qi{ .. ........ ...... ................. . .
iF~~ .~r:~~~~~q»
........ ... ... ......... ".', ... "."','
....... ..., ... . ... .. ... .. ..... ..
P' . . ... .
r##iii& .. <.. ..... ... .. ... ... .."G~.$P.t%~9f9iitY..
.pCiIL~ZSb/{~)..".. ..pCiJt."..(tVIDCX..
6/04/96
6/05/96
6/04/96
6/04/96 75 :f:4.7 (5.9)
6/04/96 112 :f: 6.9 (8.6)
6/04/96
6/04/96
6/04/96
6/07/96
242:f: 140
(224)
(244)
(5.7)
(5.9)
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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 Rille 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 in June 1996. Sampling locations are shown in Figure 2. Only 13 of the
14 routine wells were sampled. No sample was collected from Brennan Windmill because the
windmill was inoperable. The bottle containing the sample taken from CER #1 was broken in
transit. The routine sampling locations included three springs and six surface wells. Three of the
wells are located near the cavity and at least two ofthe 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.
2.2.1 Water Analysis Results
Gamma-ray spectral analysis results indicated that no man-made gamma-ray emitting
radio nuclides were present in any offsite samples. Three of the eleven samples collected were
above the MDC for 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 June 1996. The tritium concentrations are well below 20,000 pOlL
level defined in the EPA National Primary Drinking Water Regulations (40CFR141). All samples
were analyzed for presence of gamma-ray emitting radionuclides.
5
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Scale in Miles
o
I
5
.
8
~
o
Scale in Kilometers
RIO BLANCO COUNTY
./
.,'
GARFIELD COUNTY
-------------------------------
~
N
.;.:.::::::
;-
8 Surface Ground Zero
. Water Sampling Locations
o Not Sampled This Year
Figure 2. RIO BLANCO Site sampling locations for June 1996.
6
LOCATION MAP
RIO BLANCO
COUNTY
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Table 2. Analysis Results for Water Samples Collected in June 1996.
RIO BLANCO Site
:.:.... .?>:::<:.............. .::CoHeytion .:.. ........... ...... .
......... ....~......../. «MPc)
B-1 Equity Camp 6/06/96 47:1: 5.2 (7.2) ND (5.5)
Brennan Windmill 6/06/96 No Sample
inoperable
CER#l Black 6/06/96 Sample lost in transit
Sulpher
CER #4 Black 6/06/96 46 :1:4.7 (6.4) ND (5.2)
Sulpher
Fawn Creek #1 6/06/96
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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 March 6 - 7, 1996. Sampling locations are shown in Figure 3.
Routine sampling locations include one spring and five wells of varying depths. The Bias Well
was not sampled because the ranch was closed and at the Six Mile Well because the pump was
removed. A new sampling location was established to replace the shallow wells at Bias Ranch
and the Six Mile Well. The site C complex is a very deep well and is approximately twenty miles
from SGZ.
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.
Tritium concentrations were less than the MDC and less than 0.01 percent of the DCG (shown in
the Table on page 9). 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
radio nuclides were present 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.
All samples were analyzed for presence of gamma-ray emitting radionuclides. None were
detected above the MDC.
8
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I
~
~ HTH2
,- HTH 1
,
I
I
J
~~I
~ I
~
I ~ I
I ~~ I
~ ,
, ~-,- ~~ I
r ,--, ~ \
I ',~~ \
I ',~~ \
Hot Creek I 0 \
Ranch I Six-Mile Well
I
I
I
I
I
,
,
I
I
I
I
I
I
I
I
I
I
,
I
I
~
N
o
Jim Bias Well
(Blue Jay Springs)
Site C
Complex
Blue Jay
Maintenance
Station
8 Surface Ground Zero
. Water Sampling Locations
o Not Sampled This Year
Scale in Miles
o
I
5
~
o
5
Scale in Kilometers
Figure 3. FAULTLESS Site sampling locations for March 1996.
9
10
LOCATION MAP
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Table 3. Analysis Results for Water Samples Collected in March 1996.
FAULTLESS Site
"
:«> " .,"""...... .,..,CD,',.,',..,...o,.a:'..',.'..~",.,..,l,..,ec,..,.,.,'."..,,:,~~# """','" ,',',','..,.........",.:..,. ' ' .., ",' ,',', '" ",.."", ,,"""
~.,.', .. "":'..'.."'.>J9%..<~1i\'~btiUi~cr .~g&~i~b(Mrjait~~s~~I~
Hot Creek Ranch 3/06/96
-------
,
,
(J..'
01,- , ,
00 ,
~,
?).
----
o Spring
Windmill
Flowing Well .
H-3.
Hunt's Station.
o H-2
o
. HS-1
. Smith/James
Spring
,
,
, , CHURCHILL COUNTY
--------------------------------_1
MINERAL COUNTY
~
N
Scale in Miles
o 5
~
10
~
15
8 Surface Ground Zero
. Water Sampling Locations
o Not Sampled This Year
o
5
10
Scale in Kilometers
Figure 4. SHOAL Site sampling locations for March 1996.
11
LOCATION MAP
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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 March of 1996. Tritium, when detected, is compared t~ the
National Primary Drinking Water Regulations (40CFR141) which list tritium at 20,000 pCi/L for
human consumption.
All samples were analyzed for presence of gamma-ray emitting radio nuclides. None were
detected above the MDC.
Table 4. Analysis Results for Water Samples Collected in March 1996.
SHOAL Site
/:: ?3I1~~m': .~r;tii~~~~~} .~g:;:2SP ;~Sp~=r:
saii .t ...(MDd<
.. . HJ 9%
Hunts Station 3/04/96
-------
both surficial aquifers containing 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 ofthe Gasbuggy site. Hydrologic gradients in the vicinity are downward, but
upward gas migration is possible (Chapman and Hokett, 1991).
Annual sampling at Project GAS BUGGY was completed during June 1996. Only ten samples
were collected at the Truckee sampling locations (see Figure 5). The Bixler Ranch has been
sealed up and is inaccessible at this time. The pond north ofWe1l30.3.32.343N was dry.
2.5.1 Water Analysis Results
The three springs sampling sites yielded tritium activities of 26 :t 4.3 pCiIL for Bubbling Springs,
Cedar Springs 43 :t 4.0 pCiIL, and 54 :t 6.2 pCiIL for Cave Springs, which was less than 0.2
percent of the DCG and similar to the range seen in previous years. Tritium samples from the
three shallow wells were all below the MDC (see Table 5, page 15).
Well EPNG 10-36 yielded tritium activities between 100 and 560 pCiIL in each year since 1984,
except in 1987. The sample collected in 1996, yielded a tritium activity of 133 :t 5.2 pCiIL. The
migration mechanism and route is 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 principle aquifers in the region (Chapman 1991) in
either case, fractures extending from the cavity may be the primary or a contributing mechanism.
All gamma-ray spectral analysis results indicated that no man-made gamma-ray emitting
radio nuclides were present in any offsite samples.
2.5.2 Conclusions
Tritium concentrations of water samples collected onsite and offsite are consistent with those of
past studies at the GASBUGGY Site.
Well EPNG 10-36, a gas well located 132 m (435 ft) northwest of the test cavity with a sampling
depth of approximately 1,100 m (3,600 ft), has yielded tritium activities between 100 and 560
pCiIL in each year since 1984, except 1987. The proximity of the well to the test cavity suggests
the possibility that the activity increases may indicate migration from the test cavity. The sample
collected in June yielded a tritium activity of 133 :t 5.2 pCiIL (MDC 5.2). All samples were
analyzed for presence of gamma-ray emitting radionuclides.
13
-------
o Pond N. of
Well 30.3.32.343N
Bixler Ranch 0
. La Jara Creek
EPNG Well 1 0-36 ~
Cedar Springs.
Cave Springs.
.
Windmill 2
.
Jicarilla Well 1
Arnold Ranch.
Lower Burro .
Canyon
.
N
.
Well 28.3.33.233S
LOCATION MAP
8 Suriace Ground Zero
. Water Sampling Locations
o Wells not sampled
Scale in Miles
o 5
..-~
::;:;:;:;:::
.
o
8
Scale in Kilometers
Figure 5. GASBUGGY Site sampling locations for June 1996.
14
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Table 5. Analysis Results for Water Samples Collected in June 1996.
GASBUGGY Site
.....<) " "" .. .:.
.C911cCtipn .1<
Ilill;""? ."".. .,.. . . .. ......... ... ......... . .
. . ....... . . .. .
....... .... . ,......... ...
. .. . ....... .......
u~;~~ ....../(. ~r~!i~~~(~} ' ....... O~~$pe~tiotriei&:
. Trijiqiif u . ..... ............, .
:}\::..:. . .pGi/Lj; 4 SD .:. " ..........
(MDC). pOlL> .CMDQ ...
Arnold Ranch 6/1 0/96
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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 l37Cs, 10 Ci 90Sr, and 4 Ci 1311 in the cu1ebra. . .
Dolomite zone; wells USGS 4 and 8 were used for this tracer study. During remediation actIVItIes
in 1968-69, contaminated material was placed in the test cavity and 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. This potent~al m~y
increase as the salt around the cavity will compress, forcing contamination upward and dlStortmg
and cracking the concrete stem and grout.
Annual sampling at Project GNOME was completed during June 1996. The routine sampling
sites, depicted in Figure 6, include nine monitoring wells in the vicinity of surface GZ, the
municipal supplies at Loving and Carlsbad, New Mexico, and the Pecos River Pumping Station
well. No detectable tritium activity was detected in the Carlsbad municipal supply or the Pecos
River Pumping Station well. An analysis by Desert Research Institute (Chapman and Hokett,
1991) indicates that this sampling location, on the opposite side of the Pecos River from the
Project GNOME site, is not connected hydrologically to the site and, therefore, cannot become
contaminated by Project GNOME radionuclides.
2.6.1 Water Analysis Results
Tritium results greater than the MDC were detected in water samples from two of the nine
sampling locations in the immediate vicinity of GZ. Tritium activities in wells DD-1, LRL-7,
USGS-4, and USGS-8 ranged from 5.32E+o3:!:: 214 to 6.79E+o7 pCiIL in Well DD-l. Well DD-1
is the test cavity, Well LRL-7 samples a sidedrift, and wells USGS-4 and -8 were used in the
radio nuclide tracer study conducted by the USGS. Wells PH-6 and PH-8 had concentrations of
33.0 :!:: 4.7 and 7.8 :!:: 2.9 pCiIL, which are consistent or below those of surface water. No tritium
was detected in the remaining Project GNOME samples, including Well USGS-I, which is
possibly positioned to best detect nuclide migration from the test cavity, should it occur
(Chapman and Hokett, 1991). In addition to tritium, l37Cs concentrations of 1.29E+05 :!:: 7.07E+04
pCi/L to 6.8:!:: 1.2 pCiIL were observed in samples from wells DD-1, LRL-7, and USGS-8, while
90Sr activity ranging from 1.04E+04 :!:: 143 pCiIL to 3.98E+03 :!:: 23 pCiIL was detected in wells DD-
1, USGS-4 and USGS-8. Samples from these four wells were analyzed for plutonium isotopes
and results were less than the MDC in all cases (see Table 6, page 18). Ofthe wells analyzed for
the presence of 90Sr, three had concentrations exceeding the MDC values. The three wells were
USGS-4 (3.53E+03 :!:: 23), USGS-8 (3.98E+o3 :!:: 23), and DD-1 (1.04E+04 :!:: 1.43E+03) pCi/L,
respectively. The samples from wells DD-1, LRL-7, and USGS-4 indicate a decreasing trend for
all detectable radio nuclides when compared to results of previous years.
2.6.2 Conclusion
No radioactive materials attributable to the GNOME Test were detected in samples collected in
the offsite areas during June of 1996. The tritium concentrations are well below 20,000 pCiIL
level defmed in the EPA National Primary Drinking Water Regulations (40CFR141).
16
-------
Carls bad
City
Well? .
Carls bad
.
Loving City
Well 2
~
N
PHS Well 6 .
PHS Well 9 .
.
PHS Well 10
. PHS Well 8
8 Surface Ground Zero
. Water Sampling Locations
o
10
15
.........................,..,..
.......................""",
...............,...............
......,..",.........",."",
"""""""""'N""e"W"""""""""""'.'.'
........... ...........
i::::::::::::~_::::i:::::::::::
rt
EDDY
COUNTY
Scale in Miles
o 5 10
~
5
Scale in Kilometers
Figure 6. GNOME Site sampling locations for June 1996.
17
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Table 6. Tritium Results for Water Samples Collected in June 1996.
~t~:>:'" ::":';:::::::::":::::." ,...::.:>:;.;.:. .... .......
,<.,.....' .:.< ,.... ..(;66~9~)
"<..... .g~t~',""""'"
'>J996,',
GNOME Site
. .... ..... ....... . ........ '"
. '.',",,", ",",',"","" ',,"""" .. .. ',',','" " ,'.. ,',', ,',. ,",
.... """"'"'''''' n. ....
... ...... .
............. ....
. ,...,.;8..... imC:h~qT1...ritt.~Um.....'. < ,. ",.
....''','p~Ct.l,''iIL?~u.<,m. .'-<..".. .2: ....S'..D.',;.'...'..'.:.::. :.\....+1i:AI'V"\.'.'.:..>.'."..'" ',','..":sOp~.Ltr:.'m...'e'>.. .t;r..'.'y'''..'.' ..'.'.....(':MD.'... ..'. ',. '."C". 'i..:..:.......
,pQilL+ ~$P.trv1Dq > ~ W~""'J ""'v I
Well 7 City 6/13/96
Well 2 City 6/13/96
PHS 6 6/14/96
PHS 8 6/14/96
PHS 9 6/14/96
PHS 10 6/14/96
USGS WeIll 6/13/96
USGS Well 4 6/15/96
Well USGS 8 6/15/96
33 :t 4.7
(6.9)
(4.5)
7.8 :t 2.9
-------
REFERENCES
Chapman & Hockett, 1991. Evaluation of Groundwater Monitoring at Offsite Nuclear Test
Areas, Las Vegas, NV, Desert Research Institute, University of Nevada System, Report
DOE/NV1l0845-07.
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.
Offsite Environmental Monitoring Report Radiation Monitoring Around Nuclear Test Areas,
Calendar Year 1992. EPA 600/R-94/209.
19
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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 (flCi) 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 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 II errors at 5 percent each (DOE 1981).
Offsite
Areas exclusive of the immediate RULISON Test Site Area.
Type I Error
The statistical error of accepting the presence of radioactivity when none is present. Sometimes
called alpha error.
Type n 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
Marinelli
Water
3.5 liter
MDA
Model 430G
Density 1.0 g/ml
Units pCi/L
Isotope MDA
Ru-106 4.76E+01
Sn-113 8.32E+00
Sb-125 1. 65E+0 1
1-131 8.28E+00
Ba-133 9. 16E+00
Cs-134 6. 12E+00
Cs-137 6.43E+00
Ce-l44 7.59E+01
Eu-152 2. 86E+0 1
Ra-226 1.58E+01
U-235 1.01E+02
Am-241 6.60E+01
Be-7
K-40
Cr-51
Mn-54
Co-57
Co-58
Fe-59
Co-60
Zn-65
Nb-95
Zr-95
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+0 1
5.64E+00
9.06E+00
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 *Gennanium 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.
21
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