United States
Environmental Protection
Agency
Office of Radiation and
Indoor Air
Washington, DC 20460
EPA
August 1997
\>EPA Offsite Environmental
Monitoring Report
Radiation Monitoring Around
United States Nuclear Test
Areas, Calendar Year 1996
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Offsite Environmental Monitoring Report:
Radiation Monitoring Around United States
Nuclear Test Areas, Calendar Year 1996
Contributors:
Max G. Davis, Richard D. Flotard, Chris A. Fontana, Polly A. Huff,
Herb K. Maunu, Terry L. Mouck, Anita A. Mullen, Mark D. Sells,
and the Radiation and Indoor Environments National Laboratory
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 U.S. Environmental Protection Agency (EPA), through the Office of Air and Radiation (OAR), performed
the work described with funding received from the U.S. Department of Energy under interagency agreement
number RW89937611 -01 (EPA)/DE-AI08-96NV11969 (DOE). EPA funded the publication of this report. It has
been subjected to the Agency's peer review and has been approved as an EPA publication. Mention of trade
names or commercial products does not constitute endorsement or recommendation for use.
Subsequent to the completbn of this study an internal EPA reorganization resulted in a name change for some
organizational elements. The Radiation Sciences Laboratory- Las Vegas (RSL) is now the Office of Radiation
and Indoor Environments National Laboratory, Las Vegas (R&IE).
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Abstract
This report describes the Offsite Radiation Safety Program conducted during 1996 by the U. S. Environmental
Protection Agency's (EPAs), Office of Radiation and Indoor Air-Las Vegas, Radiation Science Laboratory. This
laboratory operated an environmental radiation monitoring program in the region surrounding the Nevada Test
Site (NTS) and at former test sites in Alaska, Colorado, Mississippi, Nevada, and New Mexico. The surveillance
program is designed to measure levels and trends of radioactivity, if present, in the environment surrounding
testing areas to ascertain whether current radiation levels and associated doses to the general public are in
compliance with existing radiation protection standards. The surveillance program additionally has the
responsibility to take action to protect the health and well being of the public in the event of any accidental
release of radioactive contaminants. Offsite levels of radiation and radioactivity are assessed by sampling milk,
water, and air; by deploying thermoluminescent dosimeters (TLDs); and using pressurized ionization chambers
(PICs).
No nuclear weapons testing was conducted in 1996 due to the continuing nuclear test moratorium. During this
period, R&IE personnel maintained readiness capability to provide direct monitoring support if testing were to
be resumed and ascertained compliance with applicable EPA, DOE, state, and federal regulations and
guidelines.
Comparison of the measurements and sample analysis results with background levels and with appropriate
standards and regulations indicated that there was no airborne radioactivity from diffusion or resuspension
detected by the various EPA monitoring networks surrounding the NTS. There was no indication of potential
migration of radioactivity to the off site area through groundwater and no radiation exposure above natural
background was received by the offsite population. All evaluated data were consistent with previous data
history. Using the EPAs CAP88-PC model and NTS radionuclide emissions and environmental monitoring
data, the calculated effective dose equivalent (EDE) to the maximally exposed individual offsite would have
been about 0.11 mrem. This value is less than two percent of the Federal dose limit prescribed for radionuclide
air emissions. The dose received from natural background radiation was about 144 mrem.
The offsite Environmental Monitoring Report: Radiation Monitoring Around United States Nuclear Test Areas,
Calendar Year 1994 and 1995 was not and will not be published. Please refer to the 1994 and 1995 Nevada
Test Site Annual Site Environmental Report, for data covering that time period.
Hi
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iv
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Contents
Notice ii
Abstract iii
Figures viii
Tables ix
Abbreviations, Acronyms, Units of Measure, and Conversions x
Acknowledgements xii
SECTION 1
1.0 Introduction 1
1.1 Program Summary and Conclusions 1
1.1.1 Thermoluminescent Dosimetry Program 1
1.1.2 Pressurized Ion Chamber 2
1.1.3 Air Surveillance Network 2
1.1.4 Milk 2
1.1.5 Long-Term Hydrological Monitoring Program 2
1.1.5.1 Nevada Test Site Monitoring 2
1.1.5.2 Offsite Monitoring in the Vicinity of the Nevada Test Site 2
1.1.5.3 LTHMP at Off-NTS Nuclear Device Test Locations 2
1.1.6 Dose Assessment 3
1.1.7 Hazardous Spill Center 3
1.2 Offsite Monitoring 3
1.3 Offsite Radiological Quality Assurance 3
1.4 Nonradiological Monitoring 4
SECTION 2
2.0 Description of the Nevada Test Site 5
2.1 Location 5
2.2 Climate 5
2.3 Hydrology 7
2.4 Regional Land Use 7
2.5 Population Distribution 10
SECTION 3
3.0 External Ambient Gamma Monitoring 11
3.1 Thermoluminescent Dosimetry Network 11
3.1.1 Design 11
3.1.2 Results of TLD Monitoring 11
3.1.3 Quality Assurance/Quality Control 13
3.1.4 Data Management 14
3.2 Pressurized Ion Chambers 14
3.2.1 Network Design 14
3.2.2 Procedures 14
3.2.3 Results 16
3.2.4 Quality Assurance/Quality Control 16
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Contents (continued)
SECTION 4
4.0 Atmospheric Monitoring 23
4.1 Air Surveillance Network 23
4.1.1 Design 23
4.1.2 Procedures 23
4.1.3 Results 23
4.1.4 Quality Assurance/Quality Control 25
SECTION 5
5.0 Milk 29
5.1 Milk Surveillance Network 29
5.1.1 Design 29
5.1.2 Procedures 29
5.1.3 Results 29
5.1.4 Quality Assurance/Quality Control 29
SECTION 6
6.0 Long-Term Hydrological Monitoring Program 32
6.1 Network Design 32
6.1.1 Sampling Locations 32
6.1.2 Sampling and Analysis Procedures 33
6.1.3 Quality Assurance/Quality Control Samples 33
6.1.4 Data Management and Analysis 34
6.2 Nevada Test Site Monitoring 34
6.3 Offsite Monitoring in the Vicinity of the Nevada Test Site 34
6.4 Hydrological Monitoring at Other Locations 37
6.4.1 Project FAULTLESS, Nevada 37
6.4.2 Project SHOAL, Nevada 37
6.4.3 Project RULISON, Colorado 39
6.4.4 Project RIO BLANCO, Colorado 39
6.4.5 Project GNOME, New Mexico 43
6.4.6 Project GASBUGGY, New Mexico 43
6.4.7 Project DRIBBLE, Mississippi 46
6.4.8 Amchitka Island, Alaska 46
6.5 SUMMARY '.'.'.'.'.'.'.'.'.'.'.'.'.'. 46
SECTION 7
7.0 Dose Assessment 61
7.1 Estimated Dose from Nevada Test Site Activity Data 61
7.2 Estimated Dose from Offsite Radiological Safety Program Monitoring Network
Data 62
7.3 Dose from Background Radiation 63
7.4 Summary 63
vi
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Contents (continued)
SECTION 8
8.0 Training Program 67
8.1 Emergency Response Training Program 67
8.2 Hazardous Materials Spill Center Support 68
SECTION 9
9.0 Sample Analysis Procedures 69
SECTION 10
10.0 Quality Assurance 71
10.1 Policy 71
10.2 Data Quality Objectives 71
10.2.1 Representativeness, Comparability, and Completeness Objective 71
10.2.2 Precision and Accuracy Objectives of Radioanalytical Analyses 72
10.2.3 Quality of Dose Estimates 72
10.3 Data Validation 72
10.4 Quality Assessment of 1996 Data 73
10.4.1 Completeness 74
10.4.2 Precision 75
10.4.3 Accuracy 76
10.4.4 Comparability 77
10.4.5 Representativeness 77
References 83
Glossary of Terms 85
Appendix (L0 Calculations) 87
VII
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Figures
Figure 2.1 Location of the Nevada Test Site 6
Figure 2.2 Ground water flow systems around the Nevada Test Site 8
Figure 2.3 General land use within 180 miles (300 km) of the Nevada Test Site 9
Figure 3.1 Location of TLD Fixed Stations and Personnel Monitoring Participants 12
Figure 3.2 Community Technical Liaison Program (CTLP) and PIC station locations 15
Figure 3.3 Monthly averages from each PIC Network station, 1996 18
Figure 4.1 Air Surveillance Network stations, 1996 24
Figure 5.1 Milk Surveillance Network stations, 1996 30
Figure 6.1 Long-Term Hydrological Monitoring Program sampling sites around the United
States 32
Figure 6.2 Wells on the Nevada Test Site included in the Long-Term Hydrological Monitoring
Program, 1996 36
Figure 6.3 Wells outside the Nevada Test Site included in the Long-Term Hydrological
Monitoring Program, 1996. 37
Figure 6.4 Long-Term Hydrological Monitoring Program sampling locations for Project
FAULTLESS, 1996 39
Figure 6.5 Long-Term Hydrological Monitoring Program sampling locations for Project
SHOAL, 1996 40
Figure 6.6 Long-Term Hydrological Monitoring Program sampling locations for Project
RULISON, 1996 41
Figure 6.7 Long-Term Hydrological Monitoring Program sampling locations for Project RIO
BLANCO, 1996 43
Figure 6.8 Long-Term Hydrological Monitoring Program sampling locations for Project
GNOME, 1996 44
Figure 6.9 Long-Term Hydrological Monitoring Program sampling locations for Project
GASBUGGY, 1996 46
Figure 6.10 Long-Term Hydrological Monitoring Program sampling locations for Project
DRIBBLE near ground zero, 1996 47
Figure 6.11 Long-Term Hydrological Monitoring Program sampling locations for Project
DRIBBLE towns and residences, 1996 48
Figure 6.12 Tritium result trends in Baxterville, MS, public drinking water supply, 1996 49
Figure 6.13 Tritium results in Well HM-S, Salmon Site, Project DRIBBLE, 1996 49
viii
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Tables
2.1 Characteristics of Climatic Types in Nevada (from Houghton et al., 1975) 7
3.1 Environmental Thermoluminescent Dosimetry Results, 1996 19
3.2 Personnel Thermoluminescent Dosimetry Results, 1996 21
3.3 Summary of Weekly Gamma Exposure Rates as Measured by Pressurized Ion Chambers,
1996 22
4.1 Gross Beta Results for the Offsite Air Surveillance Network, 1996 26
4.2 Gross Alpha Results for the Offsite Air Surveillance, 1996 27
4.3 Offsite High Volume Airborne Plutonium Concentrations, 1996 28
5.1 Offsite Milk Surveillance 90Sr Results, 1996 31
5.2 Summary of Radionuclides Detected in Milk Samples 31
6.1 Locations with Detectable Tritium and Man-Made Radioactivity in 1996 51
6.2 Summary of EPA Analytical Procedures, 1996 52
6.3 Typical MDA Values for Gamma Spectroscopy 52
6.4 Long-Term Hydrological Monitoring Program Summary of Tritium Results for Nevada Test
Site Network, 1996 ? 53
6.5 Long-Term Hydrological Monitoring Program Summary of Tritium Results for Wells near
the Nevada Test Site, 1996 54
6.6 Analysis Results for Water Samples Collected in June 1996 (RULISON) 56
6.7 Analysis Results for Water Samples Collected in June 1996 (RIO BLANCO) 57
6.8 Analysis Results for Water Samples Collected in June 1996 (FAULTLESS) 58
6.9 Analysis Results for Water Samples Collected in June 1996 (SHOAL) 58
6.10 Analysis Results for Water Samples Collected in June 1996 (GASBUGGY) 59
6.11 Analysis Results for Water Samples Collected in June 1996 (GNOME) 60
7.1 NTS Radionuclide Emissions, 1996 64
7.2 Summary of Effective Dose Equivalents from NTS Operations, 1996 65
7.3 Monitoring Networks Data used in Dose Calculations, 1996 65
7.4 Radionuclide Emissions on the NTS, 1996 66
9.1 Summary of Analytical Procedures 69
10.1 Data Completeness of Offsite Radiological Safety Program Networks 74
10.2 Precision Estimates for Duplicate Sampling, 1996 '. 76
10.3 Accuracy of Analysis from RADQA Performance Evaluation Study, 1996 79
10.4 Comparability of Analysis from RADQA Performace Evaluation Study, 1996 80
10.5 Accuracy of Analysis from DOE/EML Performace Evaluation Studies 81
10.6 Accuracy of Analysis from DOE/MAPEP PE Studies 82
ix
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Abbreviations, Acronyms, Units of Measure, and
Conversions
ABBREVIATIONS and ACRONYMS
AEC -- Atomic Energy Commission MQO
ALARA -- As Low as Reasonably Achievable MSL
All - Annual Limit on Intake MSN
ASN -- Air Surveillance Network NCRP
ANSI -- American National Standards
Institute NIST
ARL/SORD -- Air Resources Laboratory Special
Operations and Research Division NPDWR
BOG -- Bureau of Census
CEDE -- committed effective dose NFS
equivalent NTS
CFR -- Code of Federal Regulations NVLAP
CG -- Concentration Guide
CP-1 -- Control Point One ORSP
CTLP -- Community Technical Liaison
Program PHS
DAC ~ Derived Air Concentration PIC
DCG -- Derived Concentration Guide QA
DOE -- U.S. Department of Energy QC
DOELAP -- Department of Energy, ORIA
Laboratory Accreditation Program RAWS
DQO - data quality objective
DRI - Desert Research Institute RCRA
ECF ~ Element Correction Factor
EDE - Effective Dose Equivalent R&IE
EPA - U.S. Environmental Protection
Agency RWMS
FDA - Food and Drug Administration
GOES - Geostationary Operational S.D.
Environmental Satellite SGZ
GZ - Ground Zero SOP
HMC -- Hazardous Materials Center STDMS
HTO -- tritiated water
HpGe - High purity germanium TLD
lAGs - Interagency Agreements USGS
ICRP - International Commission on WSNSO
Radiological Protection
LTHMP - Long-Term Hydrological
Monitoring Program
MAPEP -- Mixed Analyte Performance
Evaluation Program
MDC -- minimum detectable concentration
MEI -- maximally exposed individual
measurement quality objective
mean sea level
Milk Surveillance Network
National Council on Radiation
Protection and Measurements
National Institute of Standards
and Technology
National Primary Drinking
Water Regulation
National Park Service
Nevada Test Site
National Voluntary Laboratory
Accreditation Program
Offsite Radiological Safety
Program
U.S. Public Health Service
pressurized ion chamber
quality assurance
quality control
Office of Radiation and Indoor Air
Remote Automatic Weather
Station
Resource Conservation and
Recovery Act
Radiation and Indoor Environments
National Laboratory- Las Vegas
Radioactive Waste Management
Site
standard deviation
Surface Ground Zero
standard operating procedure
Sample Tracking Data
Management System
thermoluminescent dosimetry
U.S. Geological Survey
Weather Service Nuclear Support
Office
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Abbreviations, Acronyms, Units of Measure, and
Conversions (continued)
UNITS OF MEASURE
Bq -- Becquerel, one disintegration per mo
second mR
C -- coulomb mrem
°C ~ degrees centigrade mSv
Ci - Curie pCi
cm --centimeter, 1/100 meter qt
eV -- electron volt R
°F -- degrees Fahrenheit rad
g -- gram rem
hr -- hour
keV -- one thousand electron volts Sv
kg -- kilogram, 1000 grams wk
km -- kilometer, 1000 meters yr
L -- liter uCi
m -- meter uR
MeV -- one million electron volts %
mg -- milligram, 10'3 gram ±
min ~ minute <
mL -- milliliter, 10'3 liter
-- month
-- milliroentgen, 10"3 roentgen
-- millirem, 10'3rem
-- millisievert, 10'3sievert
-- picocurie, 10'12 curie
-- quarter
-- roentgen
-- unit of absorbed dose, 100 ergs/g
- dose equivalent, the rad adjusted
for biological effect
-- sieved, equivalent to 100 rem
-- week
-- year
-- microcurie, 10~6 curie
-- microroentgen, 10'6 roentgen
-- percent
-- plus or minus
- less than
-- equal to
-- approximately equal to
-- greater than
PREFIXES CONVERSIONS
a
f
P
n
M
m
k
atto =
femto =
pico =
nano =
micro =
milli =
kilo =
10-18
10-is
10'12
10'9
10-*
10"3
103
Multiply
by
Concentrations
MCi/mL 10"
MCi/mL 10t2
To Obtain
pCi/L
pCi/m3
SI Units
rad
rem
pCi
mR/yr
10-2
10'2
3.7 x 10*
2.6x107
Gray (Gy=1 Joule/kg)
Sievert (Sv)
Becquerel (Bq)
Coulomb (C)/kg-yr
xi
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Acknowledgements
External peer reviews were provided by Dr. Norman Sunderland, Director, Environmental Health and Safety,
Utah State University (Logan, Utah). Internal reviewers, in addition to the authors, included Mark Doehnert,
Radiation and Protection Division, U.S. Environmental Protection Agency (Washington, DC), Polly Huff and Rich
Flotard, U.S. Environmental Protection Agency (Las Vegas, Nevada). The contributions of these reviewers in
production of this thai version of the 1996 annual report are gratefully acknowledged. Also, the authors would
like to thank Dr. Stuart C. Black for providing the offsfte dose calculations.
The authors would like to thank Jed Harrison for his advice and assistance in the coordination and preparation
of this report. We also want to thank the staff of the ORIA Radiation and Indoor Environments National
Laboratory-Las Vegas for collecting samples, maintaining equipment, interfacing with offsite residents, and for
analyzing the samples.
xii
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1.0 Introduction
The U.S. Atomic Energy Commission (AEC) used
the Nevada Test Site (NTS), between January 1951
and January 1975, for conducting nuclear weapons
tests, nuclear rocket engine development, nuclear
medicine studies, and for other nuclear and non-
nuclear experiments. Beginning in mid-January
1975, these activities became the responsibility of the
U.S. Energy Research and Development
Administration. Two years later this organization was
merged with other energy-related agencies to form
the U.S. Department of Energy (DOE).
Atmospheric weapons tests were conducted
periodically at the NTS from January 1951 through
October 1958, followed by a test moratorium which
was in effect until September 1961. Since then all
nuclear detonations at the NTS have been con-
ducted underground, with the expectation of con-
tainment, except the above-ground and shallow
underground tests of Operation Sunbeam and
cratering experiments conducted under the Plow-
share program between 1962 and 1968. In late
1992 a nuclear explosives test moratorium brought
an end to nuclear weapons testing and only
simulated readiness tests were conducted in 1996.
Prior to 1954, an offs'rte radiation surveillance
program was performed by personnel from the Los
Alamos Scientific Laboratory and the U.S. Army.
Beginning in 1954, and continuing through 1970, this
program was conducted by the U.S. Public Health
Service (PHS). When the U.S. Environmental
Protection Agency (EPA) was formed in December
1970, certain radiation responsibilities from several
Federal agencies were transferred to it, including the
Offsite Radiological Safety Program (ORSP) of the
PHS. From 1970 to 1995, the EPA Environmental
Monitoring Systems Laboratory-Las Vegas (EMSL-
LV) conducted the ORSP, both in Nevada and at
other U.S. nuclear test sites, under interagency
agreements (lAGs) with the DOE or its predecessor
agencies. Since that time, EPA's Office of Radiation
and Indoor Air, Radiation and Indoor Environments
National Laboratory-Las Vegas (R&IE) has
conducted a scaled down ORSP.
In 1996, the four major objectives of the ORSP were:
• Assuring the health and safety of the
people living near the NTS.
active contaminants in the vicinity of past
atomic testing areas.
• Maintaining readiness to resume nuclear
testing at some future date.
• Verifying compliance with applicable
radiation protection standards, guidelines,
and regulations.
Offsite levels of radiation and radioactivity are
assessed by gamma-ray measurements using
pressurized ion chambers (PICs) and thermolumi-
nescent dosimeters (TLDs); and by sampling air,
water, and milk.
1.1 Program Summary and
Conclusions
The primary functions of the ORSP are to conduct
routine environmental monitoring for radioactive
materials in areas potentially impacted by nuclear
tests and, when necessary, to implement actions to
protect the public from radiation exposure. Com-
ponents of the ORSP include surveillance networks
for air, and milk, exposure monitoring by
thermoluminescent dosimetry, and pressurized ion
chambers, and long-term hydrological monitoring of
wells and surface waters. In 1996, data from all
networks and monitoring activities indicated no
radiation directly attributable to current activities
conducted at the NTS. Therefore, protective actions
were not required. The following sections
summarize the ORSP activities for 1996.
1.1.1 Thermoluminescent
Dosimetry Program
In 1996, external exposure was monitored by a
network of thermoluminescent dosimeters (TLDs) at
49 fixed locations surrounding the NTS and by TLDs
worn by 25 offsite residents. No net exposures were
related to NTS activities. Neither administrative,
ALARA, nor regulatory investigation limits were
exceeded for any individual or fixed location
cumulative exposure. The range of exposures was
srnilarto those observed in other areas of the United
States and were slightly lower than those of the past.
Measuring and documenting levels and
trends of environmental radiation or radio-
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No radioactivity attributable to current NTS opera-
tions was detected by any of the monitoring net-
works. However, based on the releases reported by
NTS users, atmospheric dispersion model calcula-
tions (CAP88-PC) (EPA 1992) indicated that the
maximum potential effective dose equivalent to any
offsite individual would have been 0.11 mrem (1.1 x
10'3 mSv), and the dose to the population within 80
kilometers of the emission sites would have been
0.34 person-rem (3.4 x lO* person-Sv). The hypo-
thetical person receiving this dose was also exposed
to 144 mrem from normal background radiation.
Details of this program may be found in Section 3 of
this Report.
1.1.2 Pressurized Ion Chamber
Network
The Pressurized lonization Chamber (PIC) network
measures ambient gamma radiation exposure rates
on a near real-time basis. The 26 PICs deployed
around the NTS in 1996 showed no unexplained
deviations from background levels. These back-
ground exposures, ranging from 71 to 156 mR/yr
are within the U.S. background range and are con-
sistent with previous years' trends. Details of this
program may be found in Section 3 of this Report.
1.1.3 Air Surveillance Network
In 1996, the Air Surveillance Network (ASN) included
20 continuously operating sampling stations at
locations surrounding the NTS. In the majority of
cases, no gamma emitting radionuclides were
detected by gamma spectrometry (i.e., the results
were gamma-spectrum negligible). Naturally occur-
ring 7Be was the only radionuclide occasionally
detected. As in previous years, the majority of the
gross beta results exceeded the MDC. Analysis of
air samples for gross alpha showed results to be
either below or very slightly above (i.e. statistically
indistinguishable from) the MDC. The MDC for
239+24opu was exceeded for one high volume sample
from Rachel, NV. Details of the Atmospheric
Monitoring program may be found in Section 4 of this
Report.
1.1.4 Milk
Milk samples were collected from 11 Milk Surveil-
lance Network (MSN) stations in 1996. The average
total potassium concentration derived from 40K was
consistent with results obtained in previous years.
No man-made gamma-emitting radionuclides were
detected in any of the milk samples. Results of
analyses for 89Sr and 80Sr were similar to those ob-
tained in previous years. Neither increasing nor
decreasing trends were evident. Detailed discussion
of the collection and analysis of milk may be found in
Section 5 of this report.
1.1.5 Long-Term Hydrological
Monitoring Program
1.1.5.1 Nevada Test Site
Monitoring
Nineteen wells on the NTS or immediately outside its
borders on federally owned land were sampled. All
samples collected during 1996 were analyzed for
gamma-emitting radionuclides by gamma spectrom-
etry and for tritium by the conventional and/or the
enrichment method. No gamma-emitting radionu-
clides were detected. The highest tritium level,
detected in a sample from Well UE-5n (4.5 x 104
pCi/L), was less than 60% of the derived concentra-
tion guide for tritium. There were no indications that
migration from any test cavity is affecting any domes-
tic water supply.
1.1.5.2 Offsite Monitoring in the Vicinity of
the Nevada Test Site
These sampling locations represent drinking water
sources for rural residents and for communities in
the area. Sampling locations include 12 wells, nine
springs, and a surface water site. All the locations
are sampled quarterly or semiannually. Gamma
spectrometric analysis is completed on all samples.
No man-made gamma-emitting radionuclides were
detected. Tritium analysis is performed on a semian-
nual basis.
None of the 1996 samples analyzed for tritium using
the conventbnal method had results above the MDC.
Two that were analyzed for tritium by the enrichment
method showed detectable activity. These results
were felt to represent scavenged atmospheric tritium
by precipitation.
1.1.5.3 LTHMP at Off-NTS Nuclear
Device Test Locations
Annual sampling of surface and ground waters is
conducted at Projects SHOAL and FAULTLESS sites
in Nevada, Projects GASBUGGY and GNOME sites
in New Mexico, Projects RULISON and RIO
BLANCO sites in Colorado, and the Project DRIB-
BLE site in Mississippi. Routine biannual sampling
has not been conducted since 1993 at the Projects
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CANNIKIN, LONGSHOT, and MILROW sites on
Amchrtka Island, Alaska. Monitoring from well EPNG
10-36 at Project GASBUGGY contained tritium at a
concentration of 130± 5.2 pCi/L. The mechanism
and route of migration from the Project GASBUGGY
cavity is not currently known.
Details of the on-site, near NTS, and off-NTS
hydrological monitoring programs may be found in
Section 6 of this Report.
1.1.6 Dose Assessment
The extensive offsite environmental surveillance
system detailed in this report measured no radiation
exposures that could be attributed to recent NTS
activities. The potential Effective Dose Equivalent
(EDE) to the maximally exposed offsite resident was
calculated to be 0.015 mrem, using certain assump-
tions as all data were not available due to a decrease
of funding. Calculation with the EPA CAP88-PC
model, using estimated or calculated effluents from
the NTS, resulted in a maximum dose of 0.11 mrem
(1.1 X 10'3 mSv) to a hypothetical resident of
Springdale, NV located 14 km (nine mi) west of the
NTS boundary. Based on monitoring network data,
this dose is Calculated to be 0.005 mrem. This EDE
is about 5 percent of the dose obtained using the
CAP88-PC model. The calculated population dose
(collective effective dose equivalent (CEDE)) to the
approximately 32,210 residents living within 80 km
(50 mi) from each of the NTS airborne emission
sources was 0.34 person-rem (3.4 X 10~3 person-Sv).
Background radiation yielded a CEDE of 3,064
person-rem(30.6 person-Sv). Details of the dose
assessment calculations may be found in Section 7
of this Report.
1.1.7 Hazardous Spill Center
EPA participated on the control board for four series
of spill tests using 28 different chemicals conducted
at the HSC, located in Area 5 of the NTS. The
amounts used in the tests were so small that
boundary monitoring was not necessary.
Detailed discussion of R&IE-LV activities in support of
this facility may be found in Section 8 of this Report.
1.2 Offsite Monitoring
Under the terms of an Interagency Agreement
between DOE and EPA, the EPA R&IE conducts the
Offsite Radiation Safety Program (ORSP) in the
areas surrounding the NTS. The largest component
of R&IE's program is routine monitoring of potential
human exposure pathways. Another component is
public information.
As a result of the continuing moratorium on nuclear
weapons testing, only simulated tests were con-
ducted in 1996. Three simulated nuclear weapons
test readiness exercises and one non-proliferation
experiment using conventional (non-nuclear) explo-
sives were conducted at the NTS. For each one,
R&IE-LV senior personnel served on the Test Con-
troller's Scientific Advisory Panel and on the EPA
offsite radiological safety staff. To add as much
realism as possible to the exercises, actual meteoro-
logical conditions were used and data flow was
managed in the same manner as a real test. Rou-
tine offsite environmental radiation monitoring contin-
ued throughout 1996, as in past years.
Public information presentations provide a forum for
increasing public awareness of NTS activities, dis-
seminating radiation monitoring results, and address-
ing concerns of residents related to environmental
radiation and possible health effects. Community
Technical Liaison Program (CTLP) stations have
been established in prominent locations in a number
of offsite communities. The CTLP stations contain
samplers for several of the monitoring networks and
are managed by local residents. The University of
Utah and DRI are cooperators with EPA in the CTLP
The CTLP is discussed in Section 3.
Environmental monitoring networks, described in the
following subsections, measure radioactivity in air,
milk, and ground water. These networks monitor the
major potential pathways of radionuclide transfer to
man via inhalation, submersion, and ingestion.
Gamma radiation levels are continuously monitored
at selected locations using Reuter-Stokes pressur-
ized ion chambers (PICs) and Panasonic TLDs.
Atmospheric monitoring equipment includes both
high- and low volume air samplers. Milk is sampled
and analyzed annually. Ground water on and in the
vicinity of the NTS is monitored in the Long-Term
Hydrological Monitoring Program (LTHMP). Data
from these monitoring networks are used to calculate
an annual exposure dose to the offsite residents, as
described in Section 7.
1.3 Offsite Radiological
Quality Assurance
The policy of the EPA requires participation in a
centrally managed QA program by all EPA organi-
zational units involved in environmental data collec-
tion. The QA program developed by the R&IE for the
Offsite Radiological Safety Program (ORSP) meets
-------
all requirements of EPA policy, and also includes
applicable elements of the Department of Energy QA
requirements and regulations. The ORSP QA
program defines data quality objectives (DQOs),
which are statements of the quality of data a decision
maker needs to ensure that a decision based on
those data is defensible. Achieved data quality may
then be evaluated against these DQOs. In addition,
R&IE meets the EPA policy which states that all
decisions which are dependent on environmental
data must be supported by data of known quality.
EPA policy requires participation in a centrally man-
aged Quality Assurance Program by all EPA ele-
ments as well as those monitoring and measurement
efforts supported or mandated by contracts, regula-
tions, or other formalized agreements. The R&IE QA
policies and requirements are summarized in the
"Quality Management Plan" (EPA/R&IE 1996).
1.4 Nonradiological
Monitoring
R&IE also provides support for the HAZMAT Spill
Center( HSC) located at Frenchman Flat in Area 5 of
the NTS. The HSC was designed for safe research
on the handling, shipping, and storage of liquified
gaseous fuels and other hazardous liquids. The
R&IE provides a chemist to participate in meetings of
the Advisory Panel which reviews and approves all
programs prior to testing and maintains readiness for
monitoring emissions at the boundary of the NTS.
For those tests requiring monitoring, the R&IE per-
sonnel deploy air sampling sensors to detect any
offsite releases. No spills required monitoring in
1996 as such small amounts were released that they
would be far below the limit of detection for the R&IE
monitoring equipment at the edge of the NTS under
any reasonable scenario, including catastrophic
failure of the container in which the spill material is
stored.
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2.0 Description of the Nevada Test Site
The NTS, located in southern Nevada, was the
primary location for testing of nuclear explosives in
the continental U.S. from 1951 until the present
moratorium began. Historical testing has included
(1) atmospheric testing in the 1950s and early 1960s,
(2) underground testing in drilled vertical holes and
horizontal tunnels, (3) earth-cratering experiments,
and (4) open-air nuclear reactor and engine testing.
No nuclear tests were conducted in 1996. Limited
non-nuclear testing has included controlled spills of
hazardous material at the HAZMAT Spill Center.
Low-level radioactive and mixed waste disposal and
storage facilities for defense waste are also oper-
ated on the NTS.
The NTS environment is characterized by desert
valley and Great Basin mountain terrain and topogra-
phy, with a climate, flora, and fauna typical of the
southern Great Basin deserts. Restricted access
and extended wind transport times are notable
features of the remote location of the NTS and
adjacent U.S. Air Force lands. Also characteristic of
this area are the great depths to slow-moving
groundwaters and little or no surface water. These
features afford protection to the inhabitants of the
surrounding area from potential radiation exposures
as a result of releases of radioactivity or other con-
taminants from operations on the NTS. Population
density within 150 km of the NTS is only 0.5 persons
per square kilometer versus approximately 29
persons per square kilometer in the 48 contiguous
states. The predominant land use surrounding the
NTS is open range for livestock grazing with scat-
tered mining and recreational areas.
The EPA's Radiation and Indoor Environments
National Laboratory in Las Vegas, Nevada, conducts
hydrological studies at eight U.S. nuclear testing sites
in other states and two off the NTS in Nevada. The
last test conducted at any of these sites was in 1973
(Project RIO BLANCO in Colorado).
2.1 Location
The NTS is located in Nye County, Nevada, with its
southeast comer about 54 miles (90 km) northwest
of Las Vegas (Figure 2.1). It occupies an area of
about 1,350 square miles (3,750 square km), varies
from 28 to 35 miles (46 to 58 km) in width (east-
west) and from 49 to 55 miles (82 to 92 km) in length
(north-south). This area consists of large basins or
flats about 2,970 to 3,900 feet (900 to 1,200 m)
above mean sea level (MSL) surrounded by moun-
tain ranges rising from 5,940 to 7,590 feet (1,800 to
2,300 m) above mean sea level (MSL).
The NTS is surrounded on three sides by exclusion
areas, collectively named the Nellis Air Force Base
Range Complex, which provides a buffer zone
between the test areas and privately owned lands.
This buffer zone varies from 14 to 62 miles (24 to
104 km) between the test area and land that is open
to the public.
2.2 Climate
The climate of the NTS and surrounding area is
variable, due to its wide range in altitude and its
rugged terrain. Most of Nevada has a semi-arid
climate characterized as mid-latitude steppe.
Throughout the year, water is insufficient to support
the growth of common food crops without irrigation.
Climate may be classified by the types of vegetation
indigenous to an area. According to Nevada
Weather and Climate (Houghton et al., 1975), this
method of classification developed by Koppen is
further subdivided on the basis of "...seasonal distri-
bution of rainfall and the degree of summer heat or
writer cold." Table 2.1 summarizes the characteris-
tics of climatic types for Nevada.
According to Quiring (1968), the NTS average
annual precipitation ranges from about 4 inches (10
cm) at the lower elevations to around 10 inches (25
cm) at the higher elevations. During the winter
months, the plateaus may be snow-covered for a
period of several days or weeks. Snow is uncom-
mon on the flats. Temperatures vary considerably
with elevation, slope, and local air currents. The
average daily temperature ranges at the lower
altitudes are around 25 to 50°F (-4 to 10°C) in Janu-
ary and 55 to 95°F (13 to 35°C) in July, with extremes
of -15°F (-26°C) and 120°F (49 °C). Corresponding
temperatures on the plateaus are 25 to 35°F (-4 to
2°C) in January and 65 to 80°F (18 to 27°C) in July
with extremes of -30°F (-34°C) and 115°F (46°C).
The wind direction, as measured on a 98 ft (30 m)
tower at an observation station approximately 7 miles
-------
ADA | UTAH ' —•—•
100
0 SO 100 ISO
Scale in Kilometers
Figure 2.1 Location of the Nevada Test Site.
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Table 2.1 Characteristics of Climatic Types in Nevada (from Houghton et al. 1975)
Climate Type
Alpine tundra
Humid continental
Subhumid continental
Mid-latitude steppe
Mid-latitude desert
Low-latitude desert
Temperature
°F
Winter Summer
Oto15
(-18 to -9)
10 to 30
10 to 30
20 to 40
(-7 to 4)
20 to 40
(-7 to 4)
40 to 50
(4 to 10)
40 to 50
(4 to 10)
50 to 70
(10 to 21)
50 to 70
(10 to 21)
65 to 80
(18 to 27)
65 to 80
(18 to 27)
80 to 90
(27 to 32)
Annual
Precipitation
inches
(cm)
Total*
15 to 45
(38 to 11 4)
25 to 45
(64 to 11 4)
12 to 25
(30 to 64)
16 to 15
(15 to 38)
3 to 8
(8 to 20)
2 to 10
(5 to 25)
Snowfall
Medium to
heavy
Heavy
Moderate
Light to
moderate
Light
Negligible
Percent
Dominant of
Vegetation Area
Alpine meadows
Pine-fir forest
Pine or scrub
woodland
Sagebrush,
grass, scrub
Greasewood,
shadscale
Creosote bush
~
1
15
57
20
7
* Limits of annual precipitation overlap because of variations in temperature which affect the water balance.
(11 km) north-northwest of CP-1, is predominantly
northerly except during the months of May through
August when winds from the south-southwest pre-
dominate (Quiring, 1968). Because of the prevalent
mountain/valley winds in the basins, south to south-
west winds predominate during daylight hours of
most months. During the winter months, southerly
winds predominate slightly over northerly winds for a
few hours during the warmest part of the day. These
wind patterns may be quite different at other loca-
tions on the NTS because of local terrain effects and
differences in elevation.
2.3 Hydrology
Two major hydrologic systems shown in Figure 2.2
exist on the NTS (U.S. Energy Research and Devel-
opment Administration, 1977). Ground water in the
northwestern part of the NTS (the Pahute Mesa
area) flows at a rate of 6.6 to 600 feet (2 to 180 m)
per year to the south and southwest toward the Ash
Meadows discharge area in the Amargosa Desert.
Ground water to the east of the NTS moves from
north to south at a rate of not less than 6.6 feet (2 m)
nor greater than 730 feet (220 m) per year. Carbon-
14 analyses of this eastern ground water indicate that
the lower velocity is nearer the true value. At Mer-
cury Valley in the extreme southern part of the NTS,
the eastern ground water flow shifts to the southwest,
toward the Ash Meadows discharge area.
2.4 Regional Land Use
Figure 2.3 is a map of the off-NTS area showing a
wide variety of land uses, such as mining, camping,
fishing, and hunting within a 180-mile (300 km)
radius of the NTS operations control center at CP-1
(the location of CP-1 is shown on Figure 2.2). West
of the NTS, elevations range from 280 feet (85 m)
below MSL in Death Valley to 14,600 feet (4,420 m)
above MSL in the Sierra Nevada. Portions of two
major agricultural valleys (the Owens and San
Joaquin) are included. The areas south of the NTS
are more uniform since the Mojave Desert ecosys-
tem (mid-latitude desert) comprises most of this
portion of Nevada, California, and Arizona. The
areas east of the NTS are primarily mid-latitude
steppe with some of the older river valleys, such as
the Virgin River Valley and the Moapa Valley,
supporting irrigation for small-scale but intensive
-------
Pahute Mesa
Vranuie iviesa
Ground Water
System
Ash Meadows
Ground Water System
Mercury . .. _
»,. Indian Springs
^^^-^^^^^^^.
Flow Direction
Ground Water
System Boundaries
Silent Canyon
Caldera
Timber Mountain
Caldera
10 20 30 40
Scale in Kilometers
Figure 2.2 Ground water flow systems around the Nevada Test Site.
8
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r1—•—•—— .—.^._
\^i"-t——«—.—.—
Kmgman
LAKE
MOJAVE .
A
A Camping &
Recreational
Areas
D Hunting
• Fishing
O Mines
A Oil Fields
Lake Havasu
100
so 100 150
Scale in Kilometers
Figure 2.3. General land use within 180 miles (300 km) of the Nevada Test Site.
9
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farming of a variety of crops. Grazing is also com-
mon in this area, particularly to the northeast. The
area north of the NTS is also mid-latitude steppe,
where the major agricultural activity is grazing of
cattle and sheep. Minor agriculture, primarily the
growing of alfalfa hay, is found in this portion of
Nevada within 180 miles (300 km) of the CP-1.
Many of the residents have access to locally grown
fruits and vegetables.
Recreational areas lie in all directions around the
NTS and are used for such activities as hunting,
fishing, and camping. In general, the camping and
fishing sites to the northwest, north, and northeast of
the NTS are closed during winter months. Camping
and fishing locations to the southeast, south, and
southwest are utilized throughout the year. The peak
of the hunting season is from September through
January.
2.5 Population Distribution
The population of counties surrounding the NTS
based on the 1990 Bureau of Census (BOC) count
(DOC, 1990) is still fairly accurate although growth
has occurred in all parts of the state. Excluding
Clark County, which has grown tremendously since
the 1990 census and is the major population center
(approximately 1,000,000 in 1996), the population
density within a 90-mi (150-km) radius of the NTS is
about 0.9 persons per square mile (0.5 persons per
square kilometer). For comparison, the population
density of the 48 contiguous states was 76 persons
per square mile (29 persons per square kilometer)
(DOC, 1990). The estimated average population
density for Nevada in 1990 was 10.9 persons per
square mile (3.1 persons per square kilometer)
(DOC, 1986).
The offsite area within 48 miles (80 km) of CP-1 (the
primary area in which the dose commitment must be
determined for the purpose of this report) is predomi-
nantly rural. Several small communities are located
in the area, the largest being in Pahrump Valley.
Pahrump, a growing rural community with a popula-
tion of about 23,000 (Pahrump Times) in 1996, is
located 48 miles (80 km) south of CP-1. The small
residential community of Crystal, Nevada, also
located in the Pahrump Valley, is several miles north
of the town of Pahrump (Figure 2.2). The Amargosa
farm area, which has a population of about 950, is
located 30 miles (50 km) southwest of CP-1. The
largest town in the near offsite area is Beatty, which
has a population of about 1,500 and is located
approximately 39 miles (65 km) to the west of CP-1.
The Mojave Desert of California, which includes
Death Valley National Monument, lies along the
southwestern border of Nevada. The National Park
Service (NPS) estimated that the population within
the Monument boundaries ranges from a minimum
of 200 permanent residents during the summer
months to as many as 5,000 tourists, including
campers, on any particular day during the major
holiday periods in the winter months, and as many as
30,000 during "Death Valley Days" in November
(NPS, 1990). The largest populated area is the
Ridgecrest, California area, which has a population
of 27,725 and is located 114 miles (190 km) south-
west of the NTS. The next largest town is Barstow,
California, located 159 miles (265 km) south-south-
west of the NTS, with a 1990 population of 21,472.
The Owens Valley, where numerous small towns are
located, lies 30 miles (50 km) west of Death Valley.
The largest town in the Owens Valley is Bishop,
California, located 135 miles (225 km) west-north-
west of the NTS, with a population of 3,475 (DOC,
1990).
The extreme southwestern region of Utah is more
developed than the adjacent part of Nevada. The
largest community is St. George, located 132 miles
(220 km) east of the NTS, with a 1996 population
estimated at 40,000. The next largest town, Cedar
City, with a population of over 18,000, is located 168
miles (280 km) east-northeast of the NTS. The
extreme northwestern region of Arizona is mostly
range land except for that portion in the Lake Mead
Natbnal Recreation Area. In addition, several small
communities lie along the Colorado River.
The largest towns in the area are Bullhead City, 99
miles (165 km) south-southeast of the NTS, with a
1990 populatbn of 21,951 and Kingman, located 168
miles (280 km) southeast of the NTS, with a popula-
tion of 12,722 (DOC, 1990).
10
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3.0 External Ambient Gamma Monitoring
External ambient gamma radiation is measured by
the Thermoluminescent Dosimetry (TLD) Network
and also by the Pressurized Ion Chamber (PIC)
Network. The primary function of the two networks
is to detect changes in ambient gamma radiation. In
the absence of nuclear testing, ambient gamma
radiation rates naturally differ among locations since
rates vary with altitude (cosmic radiation) and with
radioactivity in the soil (terrestrial radiation). Ambient
gamma radiation will also vary slightly at a location
due to changes in weather patterns and other fac-
tors.
3.1 Thermoluminescent
Dosimetry Network
The primary purpose of the EPA R&IE-LV offsite
environmental dosimetry program is to establish
dose estimates to populations living in the areas
surrounding the NTS. This is accomplished by
developing baseline information regarding ambient
radiation levels from all radiation sources and looking
for any deviations from data trends. In addition to the
environmental TLD program, EPA deploys personnel
TLDs to Community Technical Liaison Program
(CTLP) station managers and their alternates, living
in areas surrounding the NTS. Information gathered
from this program would help identify possible
exposures to residents.
3.1.1 Design
The current EPA TLD program utilizes the Panasonic
Model UD-802 TLD for personnel monitoring and the
UD-814 TLD for environmental monitoring. Each
dosimeter is read using the Panasonic Model UD-
71OA automatic dosimeter reader.
The UD-802 TLD incorporates two elements of
Li2B4O7:Cu and two elements of CaSO4: Tm phos-
phors. The phosphors are behind approximately 17,
300, 300, and 1000 mg/cm2 of attenuation, respec-
tively. With the use of different phosphors and
f iltrations, a dose algorithm can be applied to ratios
of the different element responses. This process
defines the radiation type and energy and provides a
mechanism for assessing an absorbed dose equiva-
lent.
Environmental monitoring is accomplished using the
UD-814 TLD, which is made up of one element of
Li2B4O7:Cu and three elements of CaSO4:Tm. The
CaSO4:Tm elements are behind approximately 1000
mg/cm2 attenuation. An average of the corrected
values for elements two through four gives the total
exposure for each TLD. Two UD-814 TLDs are
deployed at each station per monitoring period.
In general terms, TLDs operate by trapping electrons
at an elevated energy state. After the collection
period, each TLD element is heated. When heat is
applied to the phosphor, the trapped electrons are
released and the energy differences between the
initial energies of the electrons and the energies at
the elevated state are given off in the form of pho-
tons. These photons are then collected using a
photomultiplier tube. The number of photons emit-
ted, and the resulting electrical signal, is proportional
to the initial deposited energy.
New computers and software were installed in 1996
to increase report options, and further hardware
upgrades will be completed in 1997.
3.1.2 Results of TLD Monitoring
ENVIRONMENTAL DATA:
In 1996, the TLD program consisted of 49 fixed
environmental monitoring stations and 25 offsite
personnel. Henderson and Boulder City, Nevada,
were added to the network in the fourth quarter.
Figure 3.1 shows the fixed environmental TLD
monitoring stations and the location of personnel
monitoring participants. Total annual exposures were
calculated by dividing each quarterly result by the
number of days representing each deployment
period. The quarterly daily rates were averaged to
obtain an annual daily average. If a deployment
period overlapped the beginning or end of the year a
daily rate was calculated, for that deployment period,
and multiplied by the number of days that fell within
1996. The total average daily rate was then multi-
plied by 365.25 to determine the total annual expo-
sure for each station.
There were 49 offsite environmental stations moni-
tored using TLDs. Figure 3.1 shows current fixed
environmental monitoring locations. Total annual
exposure for 1996 ranged from 59 mR (0.59 mSv)
per year at St. George, Utah, to 132 mR (1.3 mSv)
per year at Manhattan, Nevada, with a mean annual
exposure of 93 mR (0.93 mSv) per year for all oper-
11
-------
-------
ating locations. The next highest annual exposure
was 130 mR (1.3 mSv) per year at Queen City
Summit, Nevada. See Table 3.1 for 1996 results.
These results are consistent with those for 1995.
PERSONNEL DATA:
Twenty-five offsite residents, managers, and
alternates for the CTLP, were issued TLDs to moni-
tor their annual dose equivalent. Locations of per-
sonnel monitoring participants are also shown in
Figure 3.1 Annual whole body dose equivalents
ranged from a low of 48 mrem (0.48 mSv) to a high
of 125 mrem (1.2 mSv) with a mean of 96 mrem
(0.96 mSv) for all monitored personnel during 1996.
See Table 3.2 for 1996 results. These results are
similar to those for 1995.
3.1.3 Quality Assurance/
Quality Control
The following procedures assure that the TLD data
are of acceptable quality: Two calibration instru-
ments were available to support the program. One
is a TLD irradiator manufactured by Williston-Elin
housing a nominal 1.8 Ci 137Cs source. This irradi-
ator provides for automated irradiations of the TLDs.
The second calibration method used a nominal 10 Ci
137Cs well type irradiator. Unlike the Williston-Elin
irradiators, this well type does not provide automated
capabilities. TLD exposures accomplished with the
well type irradiator are monitored using a Victoreen
E-5000 precision electrometer whose calibration is
traceable to the National Institute of Standards and
Technology (NIST). The exposure rates of both
irradiators have been confirmed by measurement
using a precision electrometer which has a calibra-
tion traceable to NIST. Panasonic UD-802 dosime-
ters exposed by these irradiators are used to cali-
brate the TLD readers and to verify TLD reader
linearity. Control dosimeters of the same type as
field dosimeters (UD-802 or UD-814) are exposed
and read together with the field dosimeters. This
provides daily on-line process quality control checks
in the form of irradiated controls.
• For each read-out three irradiated control TLDs
are included that have been exposed to a nomi-
nal 200 mR. After the irradiated controls have
been read, the ratio of recorded exposure to
delivered exposure is calculated and recorded
for each of the four elements of the dosimeter.
This ratio is applied to all raw element readings
from field and unirradiated control dosimeters to
automatically compensate for reader variations.
Prior to being placed in service, element correc-
tion factors are determined for all dosimeters.
Whenever a dosimeter is read, the mean of the
three most recent correction factor determina-
tions is applied to each element to compensate
for normal variability (caused primarily by the
TLD manufacturing process) in individual dosim-
eter response.
In addition to irradiated control dosimeters, each
group of TLDs is accompanied by three unirradi-
ated control dosimeters during deployment and
during return. These unirradiated controls are
evaluated at the dosimetry laboratory to ensure
that the TLDs did not receive any excess dose
while either in transit or storage. The exposure
received while either in storage or transit is
typically negligible and thus is not subtracted.
An assessment of TLD data quality is based on
the assumption that exposures measured at a
fixed location will remain substantially constant
over an extended period of time. A number of
factors will combine to affect the certainty of
measurements. The total uncertainty of the
reported exposures is a combination of random
and systematic components. The random
component is primarily the statistical uncertainty
in the reading of the TLD elements themselves.
Based on repeated known exposures, this ran-
dom uncertainty for the calcium sulfate elements
used to determine exposure to fixed environmen-
tal stations is estimated to be approximately ± 3
to 5%. There are also several systematic com-
ponents of exposure uncertainty, including
energy-directional response, fading, calibration,
and exposures received while in storage. These
uncertainties are estimated according to estab-
lished statistical methods for propagation of
uncertainty.
Accuracy and reproducibility of TLD processing
of personnel dosimeters has been evaluated via
the Department of Energy Laboratory Accredita-
tion Program (DOELAP). This process conclud-
ed that procedures and practices utilized by the
EPA R&IE-LV TLD Laboratory comply with
standards published by the Department of
Energy. This evaluation includes three rounds of
blind performance testing over the range of 50
mrem to 500 rem and a comprehensive onsite
assessment by DOELAP site assessors.
13
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• The DOELAP accreditation process requires a
determination of the lower limit of detectability
and verification that the TLD readers exhibit
linear performance over the range included in
the performance testing program. The lower
limit of detectability (LD) for the R&IE-LV TLD
Laboratory has been calculated to be approxi-
mately 3 mrem above background at the 95%
confidence level. See Appendix A for LD calcula-
tions.
3.1.4 Data Management
The TLD data base resides on a Digital Equipment
Corporation Micro VAX II directly connected to the two
Panasonic TLD readers. Samples are tracked using
field data cards and an issue data base tracking
system incorporated into the reader control software.
Two major software packages are utilized by the
TLD network. The first, a proprietary package written
and supported by International Science Associates,
controls the TLD readers, tracks dosimeter perfor-
mance, completes necessary calculations to deter-
mine absorbed dose equivalent, performs automated
QA/QC functions, and generates raw data files and
reports. The second software package, locally
developed, maintains privacy act information and the
identifying data, generates reports in a number of
predefined formats, and provides archival storage of
TLD results.
3.2 Pressurized Ion Chambers
The Pressurized Ion Chamber (PIC) Network contin-
uously measures ambient gamma radiation exposure
rates, and because of its sensitivity, may detect low-
level exposures not detected by other monitoring
methods. The primary function of the PIC network is
to detect changes in ambient gamma radiation due
to anthropogenic activities. In the absence of anthro-
pogenic activities, ambient gamma radiation rates
naturally differ among locations as rates vary with
altitude (cosmic radiation) and with radioactivity in the
soil (terrestrial radiation). Ambient gamma radiation
also varies slightly within a location due to weather
patterns, i.e., snow changes the amount of radon-
Ihoron released by the soil and detected by the PICs.
3.2.1 Network Design
There are 26 PICs located in communities around
the NTS and one in Mississippi, which provide near
real-time estimates of gamma exposure rates. Two
new stations were added to the network in the fourth
quarter of 1996. They were Henderson and Boulder
City, Nevada. The PIC at Boulder City was vandal-
ized after only five days of data collection. Another
site in Boulder City is being proposed to prevent
future incidents. The locations of the PICs for stations
around the NTS are shown in Figure 3.2.
Because of the successful experience with the
Citizen's Monitoring Program during the purging of
the Three Mile Island containment in 1980, the
Community Radiation Monitoring Program (CRMP)
was begun. Because of reductions in the scope of
monitoring, the CRMP was changed to the CTLP. It
now consists of stations located in the states of
Nevada and Utah. In 1996, there were 15 stations
located in these two states. The CTLP is a
cooperative project of the DOE, EPA, and DRI.
The DOE/NV sponsors the program. The EPA
provides technical and scientific direction, maintains
the instrumentation and sampling equipment, ana-
lyzes the collected samples, and interprets and
reports the data. The DRI administers the program
by hiring the local station managers and alternates,
securing rights-of-way, providing utilities, and per-
forming additional quality assurance checks of the
data. Shown in Figure 3.2 are the locations of the
CTLP stations.
Each station is operated by a local resident. In most
cases, this resident is a high-school science teacher.
Samples are analyzed at the R&IE Laboratory.
Thirteen of the 15 CTLP stations have a low volume
air sampler, a tritium and noble gas sampler on
standby, and a TLD. The two stations recently setup
have no tritium or noble gas sampler. In addition, a
PIC and recorder for immediate readout of external
gamma exposure and a recording barograph are
located at the station. All of the equipment is
mounted on a stand at a prominent location in each
community. Residents may visit the stations and if
interested, they can check the data. Also, computer-
generated reports of the PIC data are issued monthly
by EPA for each station.
3.2.2 Procedures
The PIC Network utilizes Reuter-Stokes models
1011,1012, and 1013 PICs. The PIC is a spherical
shell filled with argon gas to a pressure 25 times that
of atmospheric. In the center of the chamber is a
spherical electrode with a charge opposite to the
outer shell. When gamma radiation penetrates the
sphere, fonizatfon of the gas occurs and the ions are
collected by the center electrode. The electrical
current generated is measured, and the intensity of
the radiation field is determined from the magnitude
of this current.
14
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I
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LAKE
Stone
Cabin Rn.
Nyala
Alamo
Delta*
Pio
Ca nte
I Milford
• Cedar City
i St. George
not
ARIZONA
Furnace Creek! "%• •" Overton<
Amargosa Center -TV Indian Springs
Pahrurrip % _ I/LAKE MEAD
>, Las
^ Vegas |
'•W Boulder City
*^ Henderson
•
N
\?
Community Technical Liaison Program (CTLP) (15)
Other PIC Locations) (11)
Scale in Miles
50
100
50 100 150
Scale in Kilometers
Figure 3.2 Community Technical Liaison Program (CTLP) and PIC station locations -1996
15
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Data are retrieved from the PICs shortly after mea-
surements are made. The near real-time telemetry-
based data retrieval is achieved by the connection of
each PIC to a data collection platform which collects
and transmits the data. Gamma exposure measure-
ments are transmitted via the Geostationary Opera-
tional Environmental Satellite (GOES) directly to a
receiver earth station at the NTS and from there to
the R&IE-LV by dedicated telephone line. Each
station routinely transmits data every four hours (i.e.,
4-hour average, 1-minute maximum, and 1-minute
minimum values) unless the gamma exposure rate
exceeds the currently established alarm threshold.
When the threshold is exceeded for two consecutive
1-minute intervals, the system goes into the alarm
mode and transmits a string of nine consecutive 1-
minute values every 2 to 15 minutes. Additionally,
the location and status (i.e..routine or alarm mode) of
each station are shown on a map in the control room
at the NTS and at R&IE-LV. Thus, the PIC Network
is able to provide immediate documentation of
radioactive cloud passage in the event of an acciden-
tal release of radioactivity.
The threshold limits are established at approximately
two times background for each station location.
These threshold values range from 16 uR/h for
Pahrump, Nevada, to 35 uR/h for Milford, Utah, and
Stone Cabin Ranch, Nevada. A significant improve-
ment was made to the network in 1993. In previous
years, 4-hour average, 1-minute minimum, and 1-
minute maximum values were the only values trans-
mitted every four hours. In 1993, the software at the
stations was upgraded to allow a string of 48 five-
minute averages to be transmitted every four hours.
In addition to telemetry retrieval, PIC data are also
recorded on magnetic tapes at 24 of the 27 EPA
stations and on magnetic cards for the other three
EPA stations. The magnetic tapes and cards, which
are collected monthly, provide a backup to the
telemetry data and are also useful for investigating
anomalies in the data are recorded in smaller incre-
ments of time (5-minute averages). The PICs also
contain a liquid crystal display, permitting interested
persons to monitor current readings.
The data are evaluated daily by R&IE-LV personnel.
Trends and anomalies are investigated and equip-
ment problems are identified and referred to field
personnel for correction. Monthly averages are
stored BI Lotus files on a personal computer. These
monthly averages are compiled from the 4-hour
averages from the telemetry data, when available,
and from the 5-minute averages from the magnetic
tapes or cards when the telemetry data are unavail-
able. Computer-generated reports of the PIC
monthly average data are issued monthly for posting
at each station. These reports indicate the current
month's average gamma exposure rate, the previous
month's averages, and the maximum and minimum
background levels in the U.S.
3.2.3 Results
Table 3.3 contains the number of monthly averages
available from each station and the maximum,
minimum, mean, standard deviation, and median of
the monthly averages. The mean ranged from 8.0
uR/hr at Pahrump, Nevada, to 17.7 uR/hr at
Tonopah, Nevada, or annual exposures from 71 to
156 mR (18 to 40 uC/kg). The table shows the total
mR/yr (calculation based on the mean of the monthly
averages) and the average gamma exposure rate for
each station. Background levels of environmental
gamma exposure rates in the U.S. (from the com-
bined effects of terrestrial and cosmic sources) vary
between 49 and 247 mR/yr (13 to 64 uC/kg-yr) (BEIR
III, 1980). The annual exposure levels observed at
each PIC station are well within these U.S. back-
ground levels. Figure 3.3 shows the distribution of
the monthly averages from each PIC station. The
horizontal lines extend from the mean value (•*) to
the minimum and maximum values. The vertical
lines are the approximate U. S. background range.
The data from Milford, Rachel, Twin Springs, and
Uhalde's Ranch stations show the greatest range
and the most variability. These data are within a few
tenths uR/hr from those of last year.
3.2.4 Quality Assurance/Quality
Control
General QA/QC guidelines for the PICs follow the
Quality Management Plan referenced on page 66
and are summarized as follows:
• Procedures for the operation, mainte-
nance, and calibration, of PIC equipment
and the data review, statistical analysis
and records are documented in approved
SOPs.
• Radiation monitoring specialists place a
radioactive source of a known exposure
on the PICs monthly to check the perfor-
mance of the units.
• Source check calibration and background
exposure rate data are evaluated monthly
and compared to historical values.
16
-------
• Data not transmitted via the telemetry
system due to equipment failure are
retrh/ed by reading mag tapes.
A data quality assessment of the PIC data is given in
Section 11, Quality Assurance.
17
-------
1
c
Alamo, NV
Amargosa Ctr., NV
Beatty, NV
Caliente, NV
Cedar City, NV
Complex 1, NV
Delta, UT
Furnace Creek, CA
Goldfield, NV
Indian Springs, NV
Las Vegas, NV
•B Medlin's Ranch, NV
ca
o Milford, UT
Nyala, NV
Overton, NV
Pahrump, NV
Pioche, NV
Rachel, NV
St. George, UT
Stone Cabin Ranch, NV
Terrell's Ranch, NV
Tonopah, NV
Twin Springs, NV
Uhalde's Ranch, NV
Natural Background ranges from about 4 to 28 uR/hr in the U.S
•I
Average Gamma Exposure Rate (uR/hr)
) 5 10 15 20 25 30
_
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
••
I I I I
H*
W
W
h*H
hH
hH
HH
W
hH
W
•-•—1
m
hH
r+H
H*
1H
H^
r*H
H
h^l
I*H
HH
H»-H
r*H
Figure 3.3 Monthly averages from each PIC Network station -1996
18
-------
Table 3.1 Environmental Thermoluminescent Dosimetry
Number
Station Name
Alamo, NV
Amargosa Center, NV
Austin, NV
Baker, CA
Barstow, CA
Beatty, NV
Bishop, CA
Blue Jay, NV
Boulder City, NV
Caliente, NV
Cedar City, UT
Coaldale, NV
Complex I, NV
Coyote Summit, NV
Delta, UT
Ely, NV
Eureka, NV
Gabbs, NV
Garrison, UT
Goldfield, NV
Groom Lake, NV
Henderson, NV
Hiko, NV
Indian Springs, NV
Las Vegas UNLV, NV
Lone Pine, CA
Lund, NV
Lund, UT
Manhattan, NV
Medlins Ranch, NV
Mesquite, NV
Milford, UT
Mina, NV
Moapa, NV
Nyala, NV
Overton, NV
Pahrump, NV
Results, 1996
of Days Daily Exposure (mR)
Deployed Min Max Mean
357
356
273
334
356
357
356
358
77
356
357
355
357
357
356
357
356
355
356
357
349
77
356
83
350
334
310
357
335
357
357
356
355
357
356
357
356
0.22
0.18
0.34
0.23
0.26
0.14
0.26
0.15
0.28
0.22
0.18
0.25
0.28
0.28
0.21
0.17
0.22
0.20
0.19
0.12
0.23
0.32
0.18
0.28
0.16
0.23
0.24
0.28
0.34
0.30
0.18
0.31
0.23
0.22
0.12
0.17
0.14
0.26
0.32
0.36
0.26
0.31
0.32
0.32
0.37
0.28
0.29
0.21
0.32
0.30
0.38
0.23
0.24
0.27
0.24
0.22
0.28
0.28
0.32
0.21
0.28
0.24
0.29
0.30
0.32
0.40
0.32
0.21
0.32
0.29
0.25
0.26
0.21
0.22
0.24
0.22
0.34
0.24
0.27
0.26
0.27
0.28
0.28
0.25
0.19
0.28
0.29
0.33
0.22
0.19
0.24
0.21
0.21
0.22
0.26
0.32
0.19
0.28
0.19
0.26
0.26
0.29
0.36
0.31
0.20
0.32
0.26
0.23
0.19
0.19
0.16
Total (mR)
Exposure
86
81
126
87
99
95
100
101
101
108
71
102
106
120
80
88
87
76
75
81
93
118
70
103
67
117
92
107
132
111
71
115
95
85
74
68
60
Continued
19
-------
Table 3.1 Environmental Thermoluminescent Dosimetry
Number
Results, 1996(Con't)
of Days Daily Exposure (mR)
Station Name
Pioche, NV
Queen City Summit, NV
Rachel, NV
Round Mountain, NV
St. George, UT
Stone Cabin, NV
Sunnyside, NV
Deployed Min
356 0.22
358 0.31
357 0.29
356 0.30
357 0.15
358 0.15
357 0.16
Tonopah Test Range, NV 357 0.16
Tonopah, NV
Twin Springs, NV
Uhaldes Ranch, NV
Warm Springs #1,NV
Minimum total exposure
Maximum total exposure
357 0.15
358 0.15
357 0.26
189 0.13
is 59 at St. George, UT
is 1 32 at Manhattan, NV
Max
0.25
0.35
0.32
0.34
0.19
0.33
0.19
0.34
0.33
0.33
0.33
0.27
Mean
0.23
0.34
0.31
0.32
0.16
0.26
0.17
0.29
0.27
0.26
0.30
0.20
Total (mR)
Exposure
105
130
111
116
59
98
61
105
101
95
109
75
Mean of total exposure is 93
* Based on 365.25 days
per year.
20
-------
Table 3.2 Personnel Thermoluminescent Dosimetry Results, 1 996
Location
022 Alamo, NV
028 Beatty, NV
040 Goldfield, NV
042 Tonopah, NV
045 St. George, UT
293 Pioche, NV
307 Mina, NV
336 Caliente, NV
344 Delta, UT
345 Delta, UT
346 Milford, UT
347 Milford, UT
348 Overton, NV
380 Amargosa Valley, NV
427 Alamo, NV
592 Alamo, NV
593 Cedar City, UT
594 St. George, UT
595 Las Vegas, NV
596 Las Vegas, NV
607 Tonopah, NV
608 Logandale, NV
610 Caliente, NV
621 Indian Springs, NV
651 Amargosa Valley, NV
Number
of Days
Worn
356
357
357
357
169
274
216
341
356
356
356
265
357
183
357
357
286
273
361
361
357
357
356
267
84
Daily
Deep
Exposure
Min
0.14
0.32
0.22
0.30
0.19
0.26
0.26
0.21
0.20
0.24
0.21
0.26
0.15
0.21
0.22
0.22
0.25
0.11
0.16
0.14
0.30
0.19
0.27
0.15
0.24
Max
0.30
0.37
0.33
0.34
0.22
0.34
0.31
0.29
0.27
0.28
0.36
0.36
0.21
0.24
0.32
0.29
0.32
0.19
0.40
0.30
0.36
0.21
0.38
0.30
0.24
Dose
(mrem)
Mean
0.23
0.35
0.28
0.32
0.20
0.31
0.29
0.25
0.23
0.26
0.29
0.30
0.19
0.23
0.26
0.26
0.28
0.15
0.27
0.22
0.34
0.20
0.32
0.21
0.24
Total
Annual
Exposure
85.2
125
101
117
74.0
111
99.7
91.1
84.9
95.1
107
109
71.0
81.8
93.0
94.8
104
48.8
90.4
76.1
124
74.9
116
76.5
86.9
Mean of total exposure is: 96.3mrem
Total data completeness: 98%
21
-------
Table 3.3 Summary of Gamma Exposure
Number of
Days Station
Station Reported Maximum
Alamo, NV
Amargosa Center, NV
Beatty, NV
Caliente, NV
Cedar City, UT
Complex 1, NV
Delta, UT
Furnace Creek, CA
Goldfield, NV
Indian Springs, NV
Las Vegas, NV
Medlin's Ranch, NV
Milford, UT
Nyala, NV
Overton, NV
Pahrump, NV
Pioche, NV
Rachel, NV
St. George, UT
Stone Cabin Ranch, NV
Terrell's Ranch, NV
Tonopah, NV
Twin Springs, NV
Uhalde's Ranch, NV
281
267
283
262
277
275
266
267
242
253
359
276
275
223
270
269
248
255
266
274
276
275
262
276
13.3
11.6
17.0
15.1
12.3
16.0
12.7
10.3
15.8
11.9
10.7
17.0
18.6
12.8
10.3
8.9
12.1
17.2
9.1
18.4
16.9
18.5
17.7
18.0
Rates as Measured by Pressurized Ion Chamber - 1 996
Gamma Exoosure Rate (uR/hrt
Minimum
12.1
10.5
15.9
13.6
10.8
14.5
11.2
9.1
14.4
10.8
8.7
15.8
17.0
11.3
9.2
7.9
10.8
15.9
7.9
16.9
15.7
17.1
15.7
16.6
Arithmetic
Mean
12.8
10.9
16.3
14.2
11.5
15.3
12.0
9.7
15.2
11.2
9.4
16.3
17.7
12.0
9.8
8.0
11.5
16.4
8.1
17.5
16.1
17.7
17.6
17.2
Standard
Deviation
1.08
0.73
1.08
0.48
0.83
0.86
0.71
0.64
1.16
1.06
0.16
0.68
0.93
0.21
0.62
0.41
2.03
1.37
0.75
1.22
0.84
1.22
1.0
0.73
Mean
Median mR/vr (uR/hr)
13.0
11.0
16.0
14.0
12.0
15.0
12.0
10.0
15.0
11.0
9.4
16.0
18.0
12.0
10.0
8.0
12.0
17.0
8.0
18.0
16.0
18.0
16.0
17.0
113
96
144
125
102
134
105
85
133
99
82
143
155
105
87
71
101
145
72
154
141
156
144
152
12.9
11.0
16.4
14.3
11.6
15.3
12.0
9.7
15.2
11.3
9.4
16.3
17.7
12.0
9.9
8.1
11.5
16.5
8.2
17.6
16.1
17.8
16.4
17.3
Note: Multiply uR/hr by 2.6 x 10'10 to obtain C • kg'1 • hr1
22
-------
4.0 Atmospheric Monitoring
The inhalation of radioactive airborne particles can
be a major pathway for human exposure to radiation.
The atmospheric monitoring networks are designed
to detect environmental radiation from NTS and non-
NTS activities. Data from atmospheric monitoring
can determine the concentration and source of
airborne radioactivity and can project the fallout
patterns and durations of exposure to man. The only
atmospheric monitoring network still operating is the
Air Surveillance Network (ASN). The ASN was de-
signed to monitor the areas within 350 kilometers
(220 miles) of the NTS.
Most of the data collected from the ASN fall below
the minimum detectable concentration (MDC).
Averages of data presented in this chapter were
calculated including measured results below MDCs.
All of the data collected from the atmospheric moni-
toring network reside on a VAX computer in the
Sample Tracking Data Management System
(STDMS).
4.1 Air Surveillance Network
4.1.1 Design
During 1996 the ASN consisted of 18 continuously
operating sampling stations. Two stations were
added during the fourth quarter to bring the total
number of stations to 20 (see Figure 4.1 for these
locations).
Each station is equipped with a low volume air
sampler to collect particulate radionuclides on fiber
filters and gaseous radioiodines in charcoal car-
tridges. The filters and charcoal cartridges receive
complete analyses at the R&IE-LV Radioanalysis
Laboratory. Duplicate air samples are collected from
two ASN stations each week. The duplicate sam-
plers operate at randomly selected stations continu-
ously for three months and are then moved to a new
location.
Six of the air sampling stations are equipped with
high volume air samplers that collect particulate
radionuclides on glass fiber filters. The filters are
analyzed by gamma spectrometry in the R&IE-LV
Radioanalysis Laboratory. The filters are then
composited by month and analyzed for plutonium
isotopes by wet chemistry methods. One duplicate
high volume sampler is co-located at a randomly
selected high volume sampling station and is moved
to a new location at the beginning of each quarter.
Duplicate samples are collected and analyzed by the
same methods as the routine samples.
4.1.2 Procedures
Low volume samplers collect airborne particulates at
each ASN station. The samples are collected as air
is drawn through 5 cm (2.1 in) diameter, glass-fiber
filters (prefliters) at a flow rate of about 100 m3 (2800
ft3) per day. Activated charcoal cartridges are placed
directly behind the filters to collect gaseous
radioiodines. Filters and cartridges are exchanged
after sampler operation periods of about one week
(approximately 560 m3 or 20,000 ft3). High volume
(hi-vol) samplers are located at selected stations
within the ASN. The hi-vol samplers collect airborne
particulates as air is drawn through an eight inch by
ten inch glass fiber filter at a rate of about 2000m3
(58,000 ft3) per day. The hi-vol filters are collected
monthly with a total volume of approximately 60,000
m3 (1,700,000 ft3).
Duplicate air samples are obtained weekly from
selected stations. Two low volume air samplers and
one high volume air sampler, which are identical to
the ASN station samplers, are rotated between ASN
stations quarterly. The results of the duplicate field
sample analyses are given in Chapter 8 as part of
the data quality assessment.
Prefilters and charcoal cartridges from low volume
samplers, and high volume filters are initially ana-
lyzed by high resolution gamma spectrometry. The
low volume prefilters are then analyzed for gross
alpha and gross beta activity. Analysis is performed
7 to 14 days after sample collection to allow time for
the decay of naturally occurring radon-thoron daugh-
ter products. Gross alpha/beta analysis is used to
detect trends in atmospheric radioactivity since it is
more sensitive than gamma spectrometry for this
purpose. High volume filters are submitted for wet
chemistry analysis for plutonium isotopes upon
completion of gamma spectrometry. Additional
^formation on the analytical procedures is provided
in Chapter 10.
4.1.3 Results
The ASN measures the major radionuclides which
could potentially be emitted from activities on the
NTS. Data from the ASN represents
23
-------
NEVADA
; PYRAMID
i LAKE
(
\
\
-------
the inhalation pathway component of radiation
exposure to the general public.
Gamma spectrometry was performed on all ASN low
and high volume samples. The majority of the
samples were gamma-spectrum negligible (i.e., no
gamma-emitting radionuclides detected). Naturally
occurring 7Be, averaging 2.5 x 10'13 uCi/mL, was de-
tected ocasionally by the low volume network of
samplers. Beryllium-7 was detected consistently by
the high volume sample method with average activity
of 2.4 x 10'13 uCi/mL. Alpha and beta low volume air
sample results were not included in data analysis if
they met one or more of the following criteria:
sampling duration of greater than 14 days, total
volume of less than 400 m3, average flow rate less
than 2.9 m%r or greater than 4.0 m3 /hr, or power
outage lasting more than one-third of sampling
interval length. All remaining results were used in
data analysis, including preparation of tables.
As in previous years, the gross beta results from the
low volume sampling network consistently exceeded
the analysis minimum detectable concentration
(MDC). The annual average gross beta activity was
1.42 x 10"H uCi/mL. Summary gross beta results for
the ASN are shown in Table 4.1.
Gross alpha analysis was performed on all low
volume network samples. The average annual gross
alpha activities were 1.32 x 10"16 uCi/mL. Summary
gross alpha results for the ASN are presented in
Table 4.2.
During the first three quarters of 1996, samples
collected at high volume sampling sites were
composited by month and analyzed for plutonium
isotopes. Starting with the last quarter of 1996, the
hi-vol samples were collected on a monthly basis to
improve the ease of sample preparation in the
laboratory. Due to a lower limit of detection for high
volume sampling and analysis methods, environ-
mental levels of plutonium were occasionally de-
tected at all six of the sampling sites. Plutonium
results for the high volume air sampling network are
presented in Table 4.3.
4.1.4 Quality Assurance/
Quality Control
General QA/QC guidelines for the ASN are as
follows:
• All field sampling and laboratory instru-
ments are calibrated and the date of cali-
bration is marked on a decal affixed to the
equipment.
• A file of calbration records, control charts,
and log books is maintained.
• Unique sample numbers are assigned.
• The laboratory supervisor approves all
analytical results before they are entered
into the permanent data base.
• Files of QA data, which includes raw
analytical data, intermediate calculations,
and review reports are maintained.
• Blanks are analyzed to verify the absence
of method interferences. These may be
caused by contaminants in solvents, and
reagents, on glassware, or introduced by
sample processing.
• Analytical accuracy is estimated with perfor-
mance evaluation samples. For the gamma
analysis of fiber filters, spiked samples
should be within ± 10% of the known value.
Gross beta analysis should be within ± 20%.
Plutonium analysis of internal spikes should
produce results within ± 20% of the known
value.
• The combined error due to both sampling
and analytical technique is estimated by
using replicates.
• An estimate of bias (the difference between
the value obtained and the true or reference
value) is determined by participating in
intercomparison studies.
Further discussion of the QA program and the data
quality assessment is given in Chapter 11.
25
-------
Table 4.1 Gross Beta Results for the Offsite Air Surveillance Network -1996
i_J
Sampling Location
Alamo, NV
Amargosa Center, NV
Beatty, NV
Boulder City, NV
Clark Station, NV
Stone Cabin Ranch
Goldfield, NV
Henderson, NV
Indian Springs, NV
Las Vegas, NV
Overton, NV
Pahrump, NV
Pioche, NV
Rachel, NV
Sunnyside, NV
Tonopah, NV
Twin Springs, NV
Fallini's Ranch
Cedar City, UT
Delta, UT
Milford, UT
St. George, UT
Mean MDC: 2.4 x10'15
Number
52
52
52
9
52
51
13
50
52
50
50
50
49
50
52
50
52
49
53
22
uCi/mL
Maximum Minimum
2.56
4.64
2.95
3.09
2.74
2.72
3.04
2.49
2.44
3.37
2.26
2.21
2.50
2.73
2.22
2.73
3.06
3.04
5.74
5.38
Standard
0.53
0.59
0.53
0.34
0.50
0.49
0.22
0.02
0.24
0.62
0.48
0.66
0.22
-0.05
0.48
0.26
0.18
0.22
0.19
0.66
Deviation of Mean
Arithmetic
Mean
1.4
1.6
1.5
1.4
1.5
1.4
1.5
1.3
1.3
1.5
1.4
1.4
1.4
1.4
1.3
1.6
1.2
1.5
1.5
1.8
MDC: 0.36
Standard
Deviation
0.47
0.65
0.48
0.87
0.48
0.52
0.88
0.49
0.44
0.58
0.47
0.44
0.49
0.51
0.41
0.56
0.61
0.88
0.82
1.0
x10'15uCi/mL
26
-------
Table 4.2 Gross Alpha Results for the Offsite Air Surveillance Network 1996
Concentration HO'15 uCi/mL [37 uBa/m3^
Sampling Location
Alamo, NV
Amargosa Center, NV
Beatty, NV
Boulder City, NV
Clark Station, NV
Stone Cabin Ranch
Goldfield, NV
Henderson, NV
Indian Springs, NV
Las Vegas, NV
Overton, NV
Pahrump, NV
Pioche, NV
Rachel, NV
Sunnyside, NV
Tonopah, NV
Twin Springs, NV
Fallini's Ranch
Cedar City, UT
Delta, UT
Milford, UT
St. George, UT
Number
52
52
52
9
52
51
13
50
52
50
50
49
49
50
52
50
52
49
53
22
Maximum
5.9
6.6
2.8
4.1
4.5
3.2
3.6
3.9
2.9
6.3
4.0
3.6
4.3
1.6
2.9
3.2
3.5
7.1
1.6
3.6
Minimum
0.4
0.0
0.2
1.3
0.5
0.2
0.8
0.2
0.2
-0.1
-0.2
-0.2
0.1
0.0
-0.3
-0.1
0.2
0.1
0.0
-0.2
Arithmetic
Mean
1.6
1.6
1.1
2.6
2.0
1.0
2.3
1.0
1.5
1.2
1.0
0.95
1.3
0.74
0.92
1.2
1.6
1.4
0.74
0.95
Standard
Deviation
0.94
1.1
0.64
1.0
0.72
0.60
0.84
0.70
0.74
1.1
0.81
0.66
0.98
0.43
0.56
0.77
0.78
1.2
0.43
0.66
Mean MDC: 7.7 x 10'1
Standard Deviation ot Mean MDC: 2.4 x 10'16 \iCVml
27
-------
Arithmetic Standard
Number Maximum Minimum Mean Deviation
Table 4.3 Offsite High Volume Airborne Plutonium Concentrations -1996
23BPu Concentration MO'18 Ci
Composite
Sampling Location
Alamo, NV
Amargosa Valley, NV
Goldfield, NV
Las Vegas, NV
Rachel, NV
Tonopah, NV
Mean of MDC: 0.73 x10'1VCi/mL
12
8
12
8
7
9
0.54
0.94
0.37
0.17
0.94
0.31
-0.09
-0.76
-0.05
-0.24
-0.76
-0.08
0.17
0.22
0.13
0.02
0.22
0.11
0.17
0.30
0.14
0.14
0.30
0.14
Std. Dev. of Mean MDC: 1.66 x10'1VCi/mL
Composite
Sampling Location
Alamo, NV
Amargosa Valley, NV
Goldfield, NV
Las Vegas, NV
Rachel, NV
Tonopah, NV
Mean of MDG: 0.52 x10'1VCi/mL
239+24op|| concentration MO'18
Arithmetic Standard
Number Maximum Minimum Mean Deviation
12
8
12
8
7
9
4.91
1.64
2.76
2.19
65.7
2.18
0.07
0.23
0.06
0.00
0.39
0.19
1.15
0.71
1.18
0.71
12.7
0.77
1.29
0.47
0.85
0.66
22.1
0.59
Std. Dev. of Mean MDC: 0.99 x10'1VCi/mL
DCG - Derived Concentration Guide established by DOE Order as 3 x 10'15 ,wCi/mL
28
-------
5.0 Milk
Ingestfon is one of the critical exposure pathways for
radionuclides to humans. Food crops may absorb
radionuclides from the soil in which they are grown.
Radionuclides may be found on the surface of fruits,
vegetables, or food crops. The source of these
radionuclides may be atmospheric deposition,
resuspensfon, or adhering particles of soil. Weather
patterns, especially precipitation, can affect soil
inventories of radionuclides. Grazing animals ingest
radionuclides which may have been deposited on
forage grasses and, while grazing, ingest soil which
could contain radionuclides.
These radionuclides may be transferred to milk.
Water is another significant ingestion transport
pathway of radionuclides to humans.
5.1 Milk Surveillance Network
Milk is an important source for evaluating potential
human exposures to radioactive material. It is one of
the most universally consumed foodstuffs and
certain radionuclides are readily traceable through
the chain from feed or forage to the consumer. This
is particularly true of radioiodine isotopes which,
when consumed by children, can cause significant
impairment of thyroid function. Because dairy
animals consume vegetation representing a large
area of ground cover and because many
radionuclides are transferred to milk, analysis of milk
samples may yield information on the deposition of
small amounts of radionuclides over a relatively
large area. The samples collected in July are from
animals consuming local feed. Accordingly, milk is
monitored by R&IE-LV through the Milk Surveillance
Network (MSN).
5.1.1 Design
The MSN includes commercial dairies and family-
owned milk cows and goats representing the major
milksheds within 186 mi (300 km) of the NTS. The
11 locations comprising the MSN at the beginning of
1996 and any changes are shown in Figure 5.1.
Samples were collected from only ten of these
locations because the Hafen Ranch in ivins, Utah,
was not milking during the collection period.
5.1.2 Procedures
Raw milk was collected hi 3.8-L (1-gal) cubitainers
from each MSN location in July and preserved with
formaldehyde. This network was designed to
monitor areas adjacent to the NTS, which could be
affected by a release of activity, as well as from
areas unlikely to be so affected.
All milk samples are analyzed by high-resolution
gamma-ray spectroscopy to detect gamma-ray
emitthg radionuclides. These samples are also ana-
lyzed for 89Sr and 80Sr by radiochemical separation
and beta counting (see Table 5.1).
5.1.3 Results
The average total potassium concentration derived
from naturally occurring 40K activity was 1.5 g/L for
samples analyzed by gamma spectrometry. All MSN
milk samples were analyzed for 89Sr and^Sr, and
the results are similar to those obtained in previous
years. The MSN network average values are shown
in Table 5.2 for 89Sr and MSr.
In conclusion, the MSN data is consistent with
previous years and is not indicative of increasing or
decreasing trends. No radioactivity directly related to
current NTS activities was evident.
5.1.4 Quality Assurance/Control
General QA/QC guidelines for the MSN are as
follows:
• Procedures for the operation, maintenance
and calibration of laboratory counting
equipment, the control and statistical
analysis of the samples and the data review
and records are documented in approved
SOPs.
• External and internal comparison studies
were performed and field and internal dupli-
cate samples were obtained for precision
and accuracy assessments.
• Analytical results are reviewed for
completeness and comparability.
• Trends are identified and potential risks to
humans and the environment are
determined based on the data. The data
quality assessment is given in Chapter 10.
29
-------
1
JTAH
I PYRAMID
LAKE
Austin<
Young Rn.H
0 Duckwater
• Bradshaw Rn.
v\
-^ Karen Epperlv
X» Tonopah^li
'V-
>, / COMPLEX
\
Ponderosa Dairy #14
Amargosa Valli
Ivins
David Hafen
Brent Jones
Dairy
IMIBMlrf
ARIZONA
Scale In Miles
50
hrurr
Pahrump Dairy
• Inyokern
Frances Jones Farm
• Hinkley
• Desert View Dairy
100
LftKE MEAD
6 so 100 150
Scale In Kilometers
• Milk
Sampling
Locations (11)
• Nearest Town
NOTE: When
sampling location
occurred in city or
town, the sampling
location symbol was
used for showing
both town and
sampling location.
Figure 5.1 Milk Surveillance Network stations -1996
30
-------
Table 5.1 Offsite Milk Surveillance 90Sr Results -1996
Concentration dO'10
Sampling Location
Hinkley, CA
Desert View Dairy
Inyokem, CA
Frances Jones Farm
Amargosa Valley, NV
Ponderosa Dairy #141
Austin, NV
Young's Ranch
Caliente, NV
June Cox Ranch
Duckwater, NV
Bradshaw's Ranch
Moapa, NV
Rockview Dairies
Pahrump, NV
Pahrump Dairy
Tonopah, NV
Karen Epperly
Cedar City, UT
Brent Jones Dairy
Mns, UT
David Hafen Dairy
* Sample lost in analysis.
** Currently not milking.
Number
1
1
0
1
0
1
1
1
1
1
0
Mean
2.1
0.9
Sample Lost*
2.6
Sample Lost* '
0.7
1.4
3.0
0.8
1.8
No Sample**
Table 5.2 Summary of
Radionuclides Detected in Milk Samples
Milk Surveillance Network
3H
89Sr
"Sr
No. of samples
(Network average
1996
Not analyzed
0(0.01)
0(0.63)
with results > MDC
concentration in pCi/L)
1995
0(37)
0(0.03)
0(0.61)
1994
0(85)
0(0.22)
2(0.44)
31
-------
6.0 Long-Term Hydrological Monitoring Program
One of the concerns of underground nuclear
weapons testing is the possibility of radionuclide
contamination of groundwaters. Since 1973,
underground nuclear weapons tests were conducted
only on the Nevada Test Site (NTS), but between
1961 and 1973, eleven tests were conducted in eight
other locations in the United States. The initial
ground and surface water monitoring program was
established by the U.S. Public Health Service
(USPHS) in the early 1950s. Pretest and post-test
monitoring for the locations off the NTS was
conducted by the USPHS, the U.S. Geological
Survey (USGS), and Teledyne Isotopes, Inc. In
1972, the Long-Term Hydrological Monitoring
Program (LTHMP) was established by the Nevada
Operations Office (NVO) of the Atomic Energy
Commission (AEC), a predecessor agency to DOE.
Through an interagency agreement between AEC
(later DOE) and EPA, responsibility for operation of
the LTHMP was assigned to the U.S. EPA's
Radiation and Indoor Environments National
Laboratory formerly the Environmental Monitoring
Systems Laboratory in Las Vegas, Nevada (EMSL-
LV). The LTHMP is only one component of the total
surface and ground water monitoring program
conducted under the auspices of DOE/NV.
The LTHMP conducts routine monitoring of specific
wells on the NTS and of wells, springs, and surface
waters in the offsite area around the NTS. In
addition, sampling for the LTHMP is conducted at
other locations in the U.S. where nuclear weapons
tests have been conducted. These locations include
sites in Nevada, Colorado, New Mexico, Mississippi,
and Alaska.
6.1 Network Design
The LTHMP was instituted because AEC (later
DOE/NV) acknowledged its responsibility for
obtaining and for disseminating data acquired from
all locations where nuclear devices have been
tested. The three objectives originally established for
the LTHMP were to:
• Assure public safety.
RioBlanco Site
Rulison Site
Shoal Site
Faultless Site
Nevada Test
Site
Gasbuggy Site
Long Shot Site
Mllrow Site
Cannikin Site
-\ ^
"•v^**"
Figure 6.1 Long-Term Hydrological Monitoring Program sampling sites around the United States.
32
-------
• Inform the public, news media, and
scientific community about any radiologi-
cal contamination.
• Document compliance with existing fed-
eral, state, and local antipollution require-
ments.
Another objective which has been incorporated into
the LTHMP is to, where possible, detect trends in
radionuclide activities which may be indicative of
migration from test cavities.
The primary radionuclide analyzed in the LTHMP is
tritium. As a product of nuclear weapons testing,
high levels of tritium are found in test cavities.
Because tritium can be incorporated into water
molecules, it is expected to be the first radionuclide
to migrate from a test cavity. Therefore, tritium
serves as an indicator of radionuclide migration.
Atmospheric tritium may also be deposited into
water, primarily by precipitation. Tritium from this
source is primarily found in surface waters, surficial
aquifers, and springs closely connected to surficial
aquifers.
6.1.1 Sampling Locations
In order to meet the objective of ensuring public
safety, R&IE-LV monitors drinking water supply wells
and springs around the NTS and in the vicinity of
surface ground zero (SGZ) at the other locations.
The majority of these sampling sites are privately
owned and participation in the LTHMP is voluntary.
Municipal drinking water supplies are also
represented. Regardless of the number of
individuals served by a particular water supply, the
National Primary Drinking Water Regulation1
(NPDWR) pertaining to radioactivity is used as the
compliance standard.2
All of the nuclear weapons tested at locations other
than the NTS were emplaced at depths of greater
than 1200 feet. Nuclear weapons tested on the NTS
are also emplaced at great depths, with the
exception of some shallow underground tests
conducted in the early 1960s. The drinking water
supply wells tap shallow aquifers and, consequently,
do not represent groundwater in the geologic strata
containing the test cavities. Therefore, wherever
possible, deep wells are included in the monitoring
program. These wells include some which were
drilled soon after a nuclear test specifically to monitor
activities in or near the test cavity and others which
can be considered only as "targets of opportunity;"
e.g., existing wells for which sampling permission has
been obtained. Most of the deep wells tap non-
potable water sources. Monitoring design standards,
such as those in the Resource Conservation and
Recovery Act (RCRA), did not become available until
long after the LTHMP deep wells had been drilled.
Cost has delayed emplacement of new wells,
although a program to drill more than 90 new wells
on the NTS was initiated in 1990. The sampling
locations not associated with the NTS are defined by
DOE as inactive hazardous waste sites and are
exempt from the RCRA monitoring design require-
ments. Table 6.1 is a listing of routine sampling
locations, on and offsite, where well water samples
contained tritium concentrations greater than 0.2
percent of the National Primary Drinking Water
Standards.
6.1.2 Sampling and Analysis
Procedures
The procedures for the analysis of samples collected
for this report were described by Johns, et al. (1979)
and are summarized in Table 6.2 (see Table 6.3 for
Typical MDA Values for Gamma Spectroscopy).
These procedures include gamma spectral analysis
and radiochemical analysis for tritium. The
procedures were based on standard methodology.
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 pCVL to 5 pCi/L An upper level of 700 pCi/L has
been established for use of 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,
89,8oSri 238,239*24opU) and uranjum jsotopes are deter-
mried. At least one of the one gallon samples from
each site is analyzed by gamma spectrometry. In
late 1995, because there was no indication of
migration and because of funding cutbacks, it was
decided that only 25% of tritium samples collected
would be analyzed by the enrichment method.
Sampling locations in a positron to show migration
are usually selected.
33
-------
6.1.3 Quality Assurance/Quality
Control Samples
Sample collection and analysis procedures are
described in standard operating procedures-(SOPs).
Data base management and data analysis activities
are described in the Quality Assurance Program Plan
(EPA, QAPP 1992).
• Use of standardized procedures ensures
comparability, of operations and data among
monitoring locations and across temporal
intervals.
• Annual data quality assessments of
precision, accuracy, and comparability are
based on the results of quality
assurance/quality control samples. The
data quality assessment results for 1996
are given in Section 8.0.
• Overall system precision is estimated from
the results of field duplicates. A field
duplicate is a second sample collected from
a sampling location immediately following
collection of the routine sample using
identical procedures.
• Field duplicates are collected from
sampling locations on the NTS and in the
vicinity of the NTS according to a schedule
established by the LTHMP Technical
Leader. Generally, all samples from the
other locations are collected in duplicate;
the second sample may be used as a
duplicate or may be used as a replacement
for the routine sample, if necessary.
• Accuracy is estimated from results of
intercomparison study samples. These
intercomparison study samples are spiked
samples (i.e., a water sample to which a
known amount of particular radionuclide(s)
have been added).
• Intercomparison study programs managed
by R&IE-LV and DOE's Environmental
Monitoring Laboratory (EML) both include
water matrix samples. The R&IE-LV
intercomparison study samples are also
used as an estimate of comparability.
Generally, sixty to more than 300
laboratories participate in a given
intercomparison study. Results for each
laboratory are reported, as are pooled
results (mean, standard deviation).
• Comparison of the R&IE-LV Radioanalysis
Laboratory results to the meari for all
laboratories provides an estimate of the
comparability of results.
In addition to the above described QA/QC samples
which are used in annual data quality assessments,
the Radioanalysis Laboratory employs a number of
internal QC samples and procedures to ensure data
quality on a day-to-day basis. Internal QC samples
include blanks, regular calibrations, matrix spike
samples, and duplicate analyses (gamma
spectroscopy only). If results of these internal QC
samples fall outside prescribed control limits,
analysis is stopped until the cause of the discrepant
data is found and resolved and corrective actions are
implemented.
6.1.4 Data Management and
Analysis
A bar code pilot program for the LTHMP was
completed in 1991, and was extremely successful.
It has been expanded to other monitoring networks.
Barcode labels are prepared prior to each sampling
excursion, based on the sampling schedule prepared
by the LTHMP Technical Leader. Upon receipt of
samples in Sample Control, the bar code label was
read and the information transferred into the Sample
Tracking Data Management System (STDMS), along
with information from the field data card.
Analysis data are entered into STDMS after they
have been generated and reviewed by the analyst
and Group Leader. Special software written in
Fortran (referred to as "Chemistry Programs") is
used for a majority of the radiochemical data
reduction. The Chemistry Programs are used for
calculating final data such as activity per unit volume,
MDC, and 2-sigma error terms. All hand-entered
data are checked for transcription errors. Once data
is entered and checked, they are transferred from a
"review" data base to a permanent data base, where
further changes may be made only by authorized
personnel.
Periodically, the assigned media expert reviews the
data base and checks for completeness of sample
collection, transcription errors, completion of sample
analysis and QA/QC samples, and accuracy of
information input. All discrepancies are resolved and
corrected. Once the data base is complete for a
given location, time series plots were generated.
Data review of the LTHMP is held with DOE and
Desert Research Institute (DRI) hydrology personnel.
The time series plots which indicated consistent data
trends are included as figures in the subsections
34
-------
which follow. The filled circles on the time series
plots represent the result values, the error bars
indicate ± one standard deviation of the result, and
the (x) represents the MDC value.
6.2 Nevada Test Site
Monitoring
The present sample locations on the NTS, or
immediately outside its borders on federally owned
land are shown in Figure 6.2. All sampling locations
are selected by DOE and primarily represent potable
water supplies. In 1995, sampling on the NTS was
modified so that EPA only samples wells without
pumps and, for Quality Assurance purposes, collects
samples from 10 percent of the potable wells
sampled by Bechtel Nevada. A total of 21 wells was
scheduled to be sampled, but only 19 wells were
sampled because the pumps were not working.
All samples were analyzed by gamma spectrometry
and for tritium. No gamma-emitting radionuclides
were detected in any of the NTS samples collected
in 1996. Summary results of tritium analyses are
given in Table 6.4. The highest average tritium
activity was 4.5 x 104 pCi/L (1,700 Bq/L) in a sample
from Well UE-5n. This activity is less than 60
percent of the DCG for tritium established in DOE
Order 5400.5 for comparison with the dose limit (4
mrem) in the National Primary Drinking Water
Regulations. Eight of the wells sampled yielded
tritium results greater than the minimum detectable
concentration (MDC). Well UE-7ns was routinely
sampled between 1978 and 1987 and sampling
began again in 1992. An increasing trend in tritium
activity was evident at the time sampling ceased in
1987. Recent results have shown a decrease from
those previous results, although the present result is
higher than results for 1995.
6.3 Offsite Monitoring In The
Vicinity Of The Nevada
Test Site
The monitoring sites in the area around the NTS are
shown in Figure 6.3. Most of the sampling locations
represent drinking water sources for rural residents
or public drinking water supplies for the communities
in the area. The sampling locations include 12 wells,
nine springs, and a surface water site. All of the
locations are sampled quarterly or semiannually.
Gamma spectrometric analyses are performed on
the samples when collected. No man-made
gamma-emitting radionuclides were detected in any
sample. Tritium analyses are performed on a
semiannual basis. Adaven Spring is the only site
which consistently shows detectable tritium activity.
The tritium activity in this spring represents
environmental levels that have been decreasing over
time. All results for this project for 1996 are shown
in Table 6.5.
6.4 Hydrological Monitoring At
Other United States
Nuclear Device Testing
Locations
In addition to the groundwater monitoring conducted
on and in the vicinity of the NTS, monitoring is
conducted under the LTHMP at sites of past nuclear
device testing in other parts of the United States to
ensure the safety of public drinking water supplies
and, where suitable sampling points are available, to
monitor any migration of radionuclides from the test
cavity. Annual sampling of surface and ground
waters is conducted at the Projects SHOAL and
FAULTLESS sites in Nevada, the Projects
GASBUGGY and GNOME sites in New Mexico, the
Projects RULISON and RIO BLANCO sites in
Colorado, and the Project DRIBBLE site in
Mississippi (for results, see Appendix A). Sampling
is normally conducted in odd numbered years on
Amchitka Island, Alaska, at the sites of Projects
CANNIKIN, LONG SHOT, and MILROW. Sampling
was not done last year due to lack of DOE funding.
The sampling procedure is the same as that used for
sites on the NTS and offsite areas (described in
Section 6.1.2), with the exception that two 3.8-L
samples are collected in cubitainers. The second
sample serves as a backup or as a duplicate
sample.
Because of the variability noted in past years in
samples obtained from the shallow monitoring wells
near Project DRIBBLE ground zero (GZ), the
sampling procedure was modified several years ago.
A second sample is taken after pumping for a
specified period of time or after the well has been
pumped dry and permitted to recharge. These
second samples may be more representative of
formation water, whereas the first samples may be
more indicative of recent area rainfall.
35
-------
Well P.M.
Exploratory
#1
= Not SampledThis Year
= Water Sampling Location
Well U3cn#-5
Test Well B
IT:
in
I
Water Well C
Well C-1
Water Well #4
Well UE-5N
'ell UE-5c
1
Well SB
Well 5C
Well Army #6A
Figure 6.2 Wells on the NTS Included in the LTHMP -1996
36
-------
Sharp's Ranch
Adaven Springs
Twin Springs Rn.
Tonopah City
Well,
I \HTTft Well 6 "
I Klondike Welt #2','" *
NELLIS AFB
RANGE COMPLEX
Coffers 11S/48-1dd
Beatty Well 12S/47E-7dbdB
Penoyer Culinary Well
• Crystal Springs
Alamo
City Well 4
N
Amargosa Valley" — _ -mi—,. „ •
WelM5S/50E-18cdc Fairbanks TTTndian Springs
•% • Springs Sewer Co. Well 1
*% H Crystal Pool
\ • Spring 17S/50E-14cac
\HWelM8S/51IE-7db
Furnace Creek
Supply Well #6
\.
V
I = Water Sampling Location
Scale In Miles
0 10 20 30 40
0 10 20 30 40 50 60
Scale in Kilometers
LOCATION MAP
Figure 6.3 Wells Outside the NTS Included in the LTHMP -1996
37
-------
6.4.1 Project FAULTLESS
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
(3,199 ft). A surface crater was created, but as an
irregular block along local faults rather than as a
saucer-shaped depression. The area is charac-
terized 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 and 7,1996, at
locations shown in Figure 6.4. Routine sampling
locations include one spring and five wells of varying
depths. The Bias Well was not sampled because the
ranch was closed and Six-Mile Well was not sampled
because the pump was removed. A new sampling
locatbn (site C Complex) was established to replace
the Bias Ranch Well. This site is approximately 8 mi
from Blue Jay Maintenance Station and is
approximately 20 mi from surface ground zero
(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.
These results are all consistent with results obtained
in previous years. The 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.
6.4.2 Project SHOAL
Project SHOAL, a 12-kt test emplaced at 365 m
(1,198 ft), was conducted on October 26,1963, in a
sparsely populated area near Frenchman Station,
Nevada. The test, 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. An effluent was released during
drillback but was detected onsite only and consisted
of 110 Ci of 131Xe and 133Xe, and less than 1.0 Ci of
1311
Samples were collected on March 4 and 5, 1996.
The sampling locations are shown in Figure 6.5.
Only five of the seven routine wells were sampled.
No sample was collected from Spring Windmill
because the pump was removed. No sample was
collected from Well H-2 because the well was locked
and no key was available to EPA until after sampling
was completed. This well will be sampled in the
1997 annual sampling. The routine sampling
locations include one spring, one windmill, and five
wells of varying depths. At least one location, Well
HS-1, should intercept radioactivity migrating from
the test cavity, should it occur (Chapman and Hokett,
1991).
Gamma-ray spectral analysis results indicated that
no man-made gamma-emitting radionuclides were
present in any samples above the MDC. All tritium
results were also below the MOC.
6.4.3 Project RULISON
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 June 4-7, 1996, with
collection of samples from eight out of nine wells in
the area of Grand Valley and Rulison, Colorado.
The spring 300 yards from SGZ was dry. Routine
sampling locatbns are shown in Figure 6.6, including
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 as part of the Remedial
Investigation and Feasibility Study. These wells will
be added to the LTHMP in 1998.
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.
38
-------
HTH2
HTH1
Hot Creek
Ranch
Six-Mile Well
Jim Bias Well
(Blue Jay Springs)
Blue Jay
Maintenance
Station
SiteC
Complex
W Surface Ground Zero
• Water Sampling Locations
D Not Sampled This Year
Scale in Kilometers
NYE
COUNTY
LOCATION MAP
Figure 6.4 LTHMP Sampling Locations for Project FAULTLESS -1996
39
-------
Fallon
HS-1
CHURCHILL COUNTY
•• ^m mm mm mm mm mm •
MINERAL COUNTY
N
Surface Ground Zero
Water Sampling Locations
Not Sampled This Year
LOCATION MAP
Scale In Miles
5 10
5 10 15
Scale in Kilometers
CHURCHILL
COUNTY
Figure 6.5 LTHMP Sampling Locations for Project SHOAL -1996
40
-------
Rothgery
Ranch
Grand Valley
City Springs
Grand Valley
Potter Ranch
Rulison
u
Gardner
Ranch Test Well
Tim Jacobs Ranch
1 i^B ^^ ^^
Hayward Ranch
\
•\ Battlement Creek
Spring
N
0 Surface Ground Zero
I Water Sampling Locations
D Not sampled this year
LOCATION MAP
Scale in Miles
0 5
0 8
Scale in Kilometers
GARFIELD
COUNTY
Figure 6.6 LTHMP Sampling Locations for Project RULISON -1996
41
-------
The range of tritium activity in 1996 was from 242 ±
140 pCi/L (9 Bq/L) at Battlement Creek, to 112 ± 6.9
pCi/L (4.1 Bq/L) at Lee Hayward Ranch. All values
were less than one percent of the DCG. The
detectable tritium activities were probably a result of
the high natural background in the area. This was
supported by the DRI 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
radionuclides arising from the Project RULISON
cavity (Chapman and Hokett, 1991). All samples
were analyzed for presence of gamma-ray emitting
radionuclides. None were detected above the MDC.
6.4.4 Project RIO BLANCO
Like Project RULISON, Project RIO BLANCO was a
joint government-industry test designed to stimulate
natural gas flow and 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 90 kt were emplaced at 1780-, 1920-, and
2040-m (5838-, 6229-, and 6689-ft) depths in the Ft.
Union and Mesa Verde formations. Production
testing continued to 1976 when cleanup and
restoratbn activities were completed. Tciliated water
produced during testing was injected to 1710 m
(5610 ft) in a nearby gas well.
Samples were collected June 6 and 7, 1996, from
the sampling sites shown in Figure 6.7. Only 13 of
the 14 routine wells were sampled. No sample was
collected from Brennan Windmill because the pump
was inoperable. The sample taken from CER #1;
was lost in transit. The routine sampling locations
included three springs and six wells. Three of the
wells are located near the cavity and at least two of
the wells (Wells RB-D-01 and RB-D-03) were
suitable for monitoring possible migration of
radioactivity from the cavity.
No radioactive materials attributable to the RIO
BLANCO test were detected in samples collected in
the offsite areas during June 1996. Three of the
eleven samples collected were above the MDC for
tritium and the rest were less than the MDC. The
tritium concentrations are well below 20,000 pCi/L
level defined in the EPA National Primary Drinking
Water Regulations (40 C.F.R. 141). All samples
were analyzed for presence of gamma-ray emitting
radionuclides, and none were detected. The tritium
concentrations were consistent with those collected
previously at this site.
6.4.5 Project GNOME
Project GNOME, conducted on December 10,1961,
near Carlsbad, New Mexico, was a multipurpose test
performed in a salt formation. A slightly more than
3-kt nuclear explosive was emplaced at 371 m (1217
ft) depth in the Salado salt formation. Radioactive
gases were unexpectedly vented during the test.
The USGS conducted a tracer study in 1963,
involving injection of 20 Ci 3H, 10 Ci 137Cs, 10 Ci 90Sr,
and 4Ci 131I (740, 370, 370 and 150 GBq,
respectively) into Well USGS-8 and pumping water
from Well USGS-4. During cleanup activities in
1968-69, contaminated material was placed in the
test cavity access well. More material was slurried
into the cavity and drifts in 1979.
Sampling at Project GNOME was conducted June
22-25,1996. The routine sampling sites, depicted in
Figure 6.8, include nine monitoring wells in the
vicinity of GZ and the municipal supplies at Loving
and Carlsbad, New Mexico. Stock tanks at wells
PHS 8, PHS 9, and PHS 10, were sampled at the
request of DOE. Tritium results from stock tank PHS
8 was greater than the MDC. The remaining two
were below the MDC.
Tritium results greater than the MDC were detected
in water samples from seven 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 x 103 pCi/L (185 Bq/L) in Well LRL-
7 to 6.8 x 107 pCi/L (2.5 MBq/L) in Well DD-1. Well
DD-1 collects water from the test cavity; Well LRL-7
collects water from a sidedrift; and Wells USGS-4
and -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 concentrations were
observed in samples from Wells DD-1 (7.29 x 10s ±
3.19 x 103), USGS 8 (6.8 ± 1.2) and LRL-7 (1.03 x
102 ±15) while 90 Sr activity was detected in Wells
DD - 1 (1.04 x 104 ± 1.43 x 103), LRL - 7 (
-------
Johnson
Artesian Wei
awn Cr. No. 1
B-1 Equity
Camp
Brennan
Windmill
Fawn Cr.8400'
Downstream
Fawn Cr.500' Downstream
RB-D-01
RB-D-03 >3
RG
Fawn Cr.5001
Upstream
Fawn Cr. 6800'
Upstream
Fawn Cr. No. 3
Scale in Kilometers
RIO BLANCO COUNTY
LOCATION MAP
Surface Ground Zero
• Water Sampling Locations
D Not Sampled This Year
RIO BLANCO
COUNTY
Figure 6.7 LTHMP Sampling Locations for Project RIO BLANCO -1996
43
-------
Carlsbad
Carlsbad
City |
Well?
obley
Ranch
USGS Wells
PHSWellQ
PHS Well 10
Loving City
Well 2
PHS Well 6 •
• PHS Well 8
N
Surface Ground Zero
Water Sampling Locations
Scale in Miles
5 10
0 5 10 15
Scale in Kilometers
EDDY
COUNTY
LOCATION MAP
Figure 6.8 LTHMP Sampling Locations for Project GNOME -1996
44
-------
6.4.6 Project GASBUGGY
Project GASBUGGY was a Plowshare Program test
co-sponsored by the U.S. Government and El Paso
Natural Gas. Conducted near Farmington, New
Mexico, on December 10, 1967, the test was
designed to stimulate a low productivity natural gas
reservoir. A nuclear explosive with a 29-kt yield was
emplaced at a depth of 1,290 m (4,240 ft).
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 nonpotable
water located above the test cavity and the San Jose
formation and Nacimiento formation, 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 mi northwest of the
GASBUGGY site. Hydrologic gradients in the vicinity
are downward, but upward gas migration is possible
(Chapman and Hokett, 1991).
Sampling at GASBUGGY was conducted during
June 1996. Only ten samples were collected at the
designated sampling locations shown in Figure 6.9.
The Bixfer Ranch has been sealed up and the pond
north of Well 30.3.32.343N was dry.
The three springs sampling sites yielded tritium
activities of 26 ± 4.3 pCi/L for Bubbling Springs, 43 ±
4.0 pCi/L for Cedar Springs, and 54 ± 6.2 pCi/L for
Cave Springs (0.96, 1.6, and 2.0 Bq/L, respectively),
which were 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 average MDC.
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
detectable tritium activities since 1984. The sample
collected in June 1996 contained tritium at a
concentration of 130 ± 5.2 pCi/L (4.8 Bq/L). The
migration mechanism and route is not currently
known, although an analysis by DRI 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. 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-emitting radionuclides
were present in any offsite samples. Tritium
concentrations of water samples collected onsite and
offsite are consistent with those of past studies at the
GASBUGGY site.
6.4.7 Project DRIBBLE
Project DRIBBLE was comprised of two nuclear and
two gas explosive tests, conducted in the SALMON
test site area of Mississippi under the Vela Uniform
Program. The purpose of Project DRIBBLE was to
study the effects of decoupling on seismic signals
produced by nuclear explosives tests. The first test,
SALMON, was a nuclear device with a yield of about
5 kt, detonated on October 22, 1964, at a depth of
826 m (2,710 ft). This test created the cavity used
for the subsequent tests, including STERLING, a
nuclear test conducted on Decembers, 1966, with a
yield of 380 tons, and the two gas explosions, DIODE
TUBE (on February 2, 1969) and HUMID WATER
(on April 19,1970). The ground surface and shallow
groundwater aquifers were contaminated by disposal
of drilling muds and fluids in surface pits. The
radioactive contamination was primarily limited to the
unsaturated zone and upper, nonpotable aquifers.
Shallow wells, labeled HMH wells on Figure 6.10,
have been added to the area near surface GZ to
monitor this contamination. In addition to the
monitoring wells near GZ, extensive sampling of
water wells is conducted in the nearby offsite area as
shown in Figure 6.11.
Of the twenty-eight wells that are sampled on the
SALMON test site, five regularly have tritium values
above those expected in surface water samples. In
the 52 samples collected from offsite sampling
locations, tritium activities ranged from less than the
MDC to 28 pCi/L (1.0 Bq/L), 0.02 percent of the
DCG. These results do not exceed the natural
tritium activity expected in rainwater in the area. In
general, results for each location were similar to
results obtained in previous years. Long-term
decreasing trends in tritium concentrations are
evident only for those locations that had detectable
tritium activity at the beginning of the LTHMP, such
as in the samples from the Baxterville City Well
depicted in Figure 6.12 and Well HM-S shown in
Figure 6.13.
Due to the high rainfall in the area, the normal
sampling procedure is modified for the shallow onsite
wells as described in Section 6.4. Of the 32
locations sampled onsite (20 sites sampled twice),
14 yielded tritium activities greater than the MDC in
either the first or second sample. Of these, eight
yielded results higher than normal background
(approximately 60 pCi/L [2.2 Bq/L]) as shown in
Table 6.1. The locations where the highest tritium
45
-------
To Dulce
Bixler Ranch D
D
Pond N. of
Well 30:3.32.343N
To Blanco &
Gobernador
Bubbling
Springs
EPNG Well 10-36
Cedar Springs •
Cave Springs •
La Jara Creek
Windmill 2 JicarillaWelM
Arnold Ranch
Lower Burro
Canyon
Well 28.3.33.233S
N
LOCATION MAP
® Surface Ground Zero
• Water Sampling Locations
D Wells not sampled
Scale in Miles
0 5
0 8
Scale In Kilometers
RIO
ARRIBA
COUNTY
Figure 6.9 LTHMP Sampling Locations for Project GASBUGGY -1996
46
-------
|WellHM-L2
^r
\ Half Moon
HMH-5 \Creek
\
Hunting Tatum
Club Well
~»-
Half \\
Moon \~~k-
Creek \ o,
Overflow \ -s
\o
\«
HMH-11
/
-9(
\
t
»
-4
IWell HT-2C
Surface Ground Zero
Water Sampling Locations
Scale in Feet
1000
2000
MIS!
0 100 200 300 400 500
Scale in Meters
LAMAR
COUNTY
LOCATION MAP
Figure 6.10 LTHMP Sampling Locations for Project DRIBBLE, Near Ground Zero -1996
47
-------
B. Dennis
M. Dennis
Columbia City Little Creek #1 -
Well 64B Lee Anderson -
Tim L. Bilbo -
Yancy Saucier
Philip Gi
Gil Ray's Crawfish Pond
G. Kelly
Lower Little
• •
Herman Gi
Howard Smith
E.J. Smith'
Howard •
Smith PonoT
Rita Moree
Sylvester Graham
Lee.L. Saul
Sau
Willie Burge
Joe Burge
Salt Dome Timber Co.
A.C.
Mills
Roy Mills
B. Hibley D. Napien m
Anderson's Pondf
B.R.
P.T. Lee
R.H. Anderson
E.Cox
W.H. Noble Jr.
G.W. Anderson
Noble's Pond
.L. Anderson Jr
r, i . j o — S. Powers
R.L. Anderson Sr
Regiria Anderson
Purvis City Well
-•-
G.Ray
D. Rushing
Ray Harttield
Ray Daniels•^WiDan|e|Jr.
Daniel's Rsh
Pond Well #2
Baxtetvllle
City Well
Lumberton
City Well 2
LAMAR
COUNTY
Surface Ground Zero
Water Sampling Locations
Salmon Test Area
01234
Scale In Kilometers
LOCATION MAP
Figure 6.11 LTHMP sampling Locations for Project DRIBBLE, towns and residences -1996
• 48
-------
100:
90-
80-
70-
5 60-
•& 50-
3
•c :
l- 40-
30-
20-
10-
0-
Baxtervilie, MS Public Drinking Water Supply
T
i % }
4 T
f tt
\ ^ T
1 1
T 1
J {
1 I
i * * M *
x x i x
x x xxx x
JAN73 JAN76 JAN79 JAN82 JAN85 JAN88 JAN91 JAN94 JAN97
Sample Collection Date
Figure 6.12 Tritium Results Trends in Baxterville, Public Drinking Water Supply -1996
Xs = MDC values for both figures.
Well HM-S, Salmon Site, Project DRIBBLE
Tritium vs Normal Tritium Decay
40000-
30000
20000
10000-
X X X X X XXX X
, , , , 1 1 1
JAN73 JAN76 JAN79 JAN82 JAN85 JAN88 JAN91 JAN94 JAN97
Sample Collection Date
Figure 6.13 Tritium Results in Well HM-S, SALMON Site, Project DRIBBLE -1996
49
-------
activities were measured generally correspond to
areas of known contamination. Decreasing trends
are evident for the wells where high tritium activities
have been found, such as Well HM-S depicted in
Figure 6.13. No tritium concentrations above normal
background values were detected in any offsrte
samples. Man-made gamma-ray emitting
radionuclides were not detected in any sample
collected in this study.
Results of sampling related to Project DRIBBLE are
discussed in greater detail in Onsite and Offsite
Environmental Monitoring Report, "Radiation
Monitoring around SALMON Test Site," Lamar
County, Mississippi, April 1996 (Davis 1996, available
from R&IE-LV).
6.4.8 AMCHITKA ISLAND, ALASKA
Sampling is normally conducted biannually on odd
years. The next sampling is scheduled for 1997.
6.5 Summary
None of the domestic water supplies monitored in the
LTHMP in 1996 yielded tritium activities of any health
concern. The greatest tritium activity measured in
any water body which has potential to be a drinking
water supply was less than one percent of the limit
prescribed by the NPDWRs. In general, surface
water and spring samples yielded tritium activities
greater than those observed in shallow domestic
wells in the same area. This is probably due to
scavenging of atmospheric tritium by precipitation.
Where suitable monitoring wells exist, there were no
indications that migration from any test cavity is
affecting any domestic water supply.
In most cases, monitoring wells also yielded no
radionuclide activity above the MDC. Exceptions
include wells into test cavities, wells monitoring
known areas of contamination, and one well at
GASBUGGY. Known areas of contamination exist at
Project GNOME where USGS conducted a tracer
study experiment, some areas onsite at Project
DRIBBLE, and a few surface areas near Project
LONG SHOT. The 1996 results for these monitoring
wells are consistent with decreasing trends observed
over time.
1. The NPDWR states that the sum of all beta/gamma emitter concentrations in drinking water cannot lead
to a dose exceeding 4 mrem/year, assuming a person were to drink two liters per day for a year (40 CFR
141). Assuming tritium to be the only radioactive contaminant yields a maximum allowable concentration of
2x104pCi/L.
2. The NPDWR applies only to public systems with at least 15 hookups or 25 users. Although many of the
drinking water supplies monitored in the LTHMP serve fewer users and are therefore exempt, the
regulations provide a frame of reference for any observed radionuclide activity.
50
-------
Table 6.1 Locations with Detectable Tritium and Man-Made Radioactivity in 1996 (a)
Concentration
Sampling Location Radionuclide x 1Q'9uCi/mL
NTS Onsite Network
Well PM-1 3H 200
Well UE-5n 3H 52,000*
Well UE-6d 3H 700
Well UE-7ns 3H 500
WellUE-18t 3H 200
Test Well B 3H 230
Project DRIBBLE, Mississippi (B)
WellHMH-1 3H 2,100
Well HMH-2 3H 230
WellHMH-5 3H 1,200
WellHM-L 3H 1,200
Well HM-S 3H 4,400
Half Moon Creek Overflow 3H 210
REECo Pit B 3H 240
REECo Pit C 3H 260
Project GNOME, New Mexico
WellDD-1 3H 6.8 x107
90Sr 10,000
137Cs 7.3 x 105
Well LRL-7 3H 5,300
90Sr 2.1
137Cs 100
Well USGS-4 3H 90,000
90Sr 3,500
137Cs <5.6
Well USGS-8 3H 77,000
90Sr 4,000
137Cs <6.8
(a) Only 3H concentrations greater than 0.2 percent of the 4 mrem DCG are shown {i.e., greater
than 1.6 x 10~7 |jCi/mL [160 pCi/L (6 Bq/L)]}. Detectable levels of other radioisotopes are
also shown.
Highest analytical result for Well UE-5n in 1996.
51
-------
Table 6.2 Summary of EPA Analytical Procedures - 1996
Type of Analytical Counting
Analysis Equipment Period (Mini
HpGe HpGe detector 100
Gamma*"1 calibrated at 0.5 keW
channel (0.04 to 2
MeV range) individual
detector efficiencies
ranging from 15 to
35 percent.
3H Automatic liquid 300
scintillation counter.
3H+ Automatic liquid 300
Enrichment scintillation counter.
Analytical
Procedures
Radionuclide concen-
tration quantified from
gamma spectral data
by online computer
program.
Sample Approximate
Size Detection L'mit(a)
3.5L Varies with radio-
nuclides and detector
used, see Table 6.3
below.
Sample prepared by
distillation.
Sample concentrated
by electrolysis followed
by distillation.
5-10 ml 300 to 700 pCi/L
250 ml 5 pCi/L
(a) 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.
Table 6.3 Typical MDA Values for Gamma Spectroscopy
All MDA values are computed for a water matrix sample (1.0 g/ml density) in a 3.5 Marinelli beaker geometry,
counted for 100 minutes on a Canbarra model 430G HpGe detector.
Isotope
MDA (pCi/L)
Isotope
MDA (pCi/L
Be-7
K-40
Cr-51
Mn-54
Co-57
Co-58
Fe-59
Co-60
Zn-65
Nb-95
Zr-95
45.6
49.2
58.8
45.5
9.65
4.71
10.7
5.38
12.4
5.64
9.06
Ru-106
Sn-113
Sb-125
1-131
Ba-133
Cs-134
Cs-137
Ce-144
Eu-152
Ra-226
U-235
Am-241
47.6
8.32
16.5
8.28
9.16
6.12
6.43
75.9
28.6
15.8
101
66.0
Disclaimer
The MDAs provided are for background matrix samples presumed to contain no known analytes and no
decay time. All MDAs provided here are for one specific high purity Germanium detector and the geometry
of interest. The MDAs in no way should be used as a source of reference for determining MDAs for any -
other type of detector. All gamma spectroscopy MDAs will vary with different types of shielding, geometries,
counting times, and decay time of sample.
52
-------
Table 6.4
Long-Term Hydrological Monitoring Program Summary of Tritium Results for Nevada
Test Site Network, 1996
Location
Tritium Concentration (pCi/L)
Arithmetic Mean
Number Maximum Minimum Mean 1 Sigma as %DCG
Mean
MDC
Test Well B
Test Well D
Well UE-6d
Well UE-6e
Well UE-7ns
WellUE-16f
WellUE-18r
WellUE-18t
Well 6A Army
Well HTH-1
Well PM-1
Well U3CN-5
Well UE-1c
WellUE-15d
Well HTH "F"
Well C-1
Well 1 Army
Well 5B
Well 5C
Well UE-5n
WellJ-13
1
1
2
2
2
1
2
1
2
1
1
230
38
724
190
496
8.1
230
220
3.3
-77
210
230
38
633
170
466
8.1
28
220
-1.3
-77
210
230
38
680
180
480
8.1
130
220
1.0
-77
210
70
70
180
67
160
1.7
67
3.5
0.35
70
3.1
0.26
-------
Table 6.5 Long-Term Hydrological Monitoring Program Summary of Tritium Results for Wells
near the NTS -1996
Tritium Concentration (pCi/L)
Location
Adaven
Adaven Spring
Alamo
Well 4 City
Ash Meadows
Crystal Pool
Fairbanks Spring
17S-50E-14cac
Well18S-51E-7db
Beatty
Low Level Waste Site
Tolicha Peak
11 S-48E-1dd Coffer's
12S-47E-7dbdCity
Younghans Ranch House Well 0
Boulder City
Lake Mead Intake
0
Clark Station
TTR Well 6 0
2
Goldfield
Klondike #2 Well 0
2
(a)
Number
of Samples'8'
2
2
1
1
3
1
2
0 •
1
1
1
1
1
3
1
3
1
3
1
1
/Veil 0
3
1
Max.
28
110
__
-
2.9
—
0.33
—
—
—
-
190
~
110
—
150
—
—
190
__
Min.
19
0
__
—
2.9
—
-1.1
—
—
—
—
._
0
...
0
—
38
—
—
-77
—
Mean
22
55
-2.3
39
-0.3
150
-0.8
0.8
0
1.0
39
6.2
94
-2.8
57
-0.6
110
-1.0
0
59
40
56
39
39
-38
48
% of Mean
1 s.d. DCG MDC
0.5
1.7
67
3.0
68
1.9
67
1.7
1.8
68
1.4
68
1.8
65
1.6
66
1.6
67
2.2
68
67
1.8
67
140
0.02
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
<0.01
NA
NA
NA
NA
NA
NA
NA
NA
0.04
5.1
220
10
220
6.3
210
5.8
5.8
220
4.3
220
5.9
220
5.4
220
5.4
220
7.5
220
220
4.9
NA 220
220
For each sample: 1st row is from enrichment analysis, 2nd row from conventional analysis.
Derived Concentration Guide (DCG) established by DOE Order as 90,000 pCi/L.
N/A Not applicable. Percent of concentration guide is not applicable because the result is less
than the MDC or the water is known to be nonpotable.
54
-------
Table 6.5 (Long-Term Hydrological Monitoring Program Summary of Tritium Results for Wells
near the NTS - 1996, con't.)
Location
Hiko
Crystal Springs
Indian Springs
Sewer Co. Well 1
Air Force Well 2
Lathrop Wells
15S-50E-18cdcCity
Nyala
Sharp's Ranch
Oasis Valley
Goss Springs
Rachel
Penoyer Culinary
Tonopah
City Well
Warm Springs
Twin Springs Ranch
Tritium Concentration (pCi/L)
Mean
Number
of Samples'8' Max. Min.
0
1
1
1
1
1
1
1
DRY
1
3
0
2
1
3
150
39
470
56
-19
56
-1.7
0
1.2
95
10
0.6
320
% of Mean
1 s.d. DCG MDC
3.1
68
1.4
67
66
1.3
67
NA
NA
NA
NA
NA
NA
10
220
0
2.6
0
-0.08
0
2.0
0
68
1.3
68
1.2
68
3.2
68
NA
NA
NA
NA
NA
NA
NA
220
4.3
220
4.0
220
10
220
4.8
210
NA 220
4.3
220
(a) For each sample: 1st row is from enrichment analysis, 2nd row from conventional analysis.
Derived Concentration Guide (DCG) established by DOE Order as 90,000 pCi/L.
N/A Not applicable. Percent of concentration guide is not applicable because the result is less
than the MDC or the water is known to be nonpotable.
55
-------
Table 6.6 Analysis Results for Water Samples Collected in June 1996.
RULISON Site
Sample. < '
Location
Battlement Creek
City Springs
Albert Gardner
CER Test Well
Lee Hayward Rn.
Potter Ranch
Wayne & Debra
Rothgery
Tim Jacobs
Spring 300 yds N.
ofGZ
Collection
Date
1996
6/04/96
6/05/96
6/04/96
6/04/96
6/04/96
6/04/96
6/04/96
6/04/96
6/07/96
Enriched Trium
pCR±aSD (MDC)
75 ± 4.7 (5.9)
112 ±6.9 (8.6)
Tritium
pC$MaSD (MOO)
242 ±140 (224)
-------
Table 6.7 Analysis Results for Water Samples Collected in June 1996.
RIO BLANCO Site
S&raplei f /--,
y)^ion:,',.\ -'I
B-1 Equity Camp
Brennan Windmill
CER #1 Black
Sulpher
CER #4 Black
Sulpher
Fawn Creek #1
Fawn Creek #3
Fawn Creek 500'
Upstream
Fawn Creek
6800'
Upstream
Fawn Creek 500'
Downstream
Fawn Creek
8400'
Downstream
Johnson Artesian
Well
Well RB-D-01
Well RB-D-03
Well RB-S-03
Colteetron
''Date
JM ,
6/06/96
6/06/96
6/06/96
6/06/96
6/06/96
6/06/96
6/06/96
6/06/96
6/06/96
6/06/96
6/06/96
6/07/96
6/06/96
6/07/96
Enriched Trittam
pCm,'*2SD (MDC)
47 ± 5.2 (7.2)
46 ± 4.7 (6.4)
32 ± 4.9 (7.0)
-------
Table 6.8 Analysis Results for Water Samples Collected in March 1996.
FAULTLESS Site
Sample
Location
Hot Creek Ranch
Spring
Blue Jay Maint
Station
Well HTH-1
Well HTH-2
Site C Base
Camp
ColtecUon
Date
1096
3/06/96
3/06/96
3/03-
07/96
3/03-
07/96
3/03-
07/96
Enriched Tritiora
pQH.*28D (MOO)
-------
Table 6.10 Analysis Results for Water Samples Collected in June 1996.
GASBUGGY Site
§&mpi# , -* . -
M*$!H$.'. .';...-.'x '
Arnold Ranch
Bbder Ranch
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
Collection
Date
1996
6/10/96
6/09/96
6/09/96
6/09/96
6/09/96
6/10/96
6/10/96
6/10/96
6/09/96
6/09/96
6/09/96
6/10/96
6/10/96
Enriched Tritium
P0W.*2SD (MDO)
26 ± 4.3 (6.2)
54 ± 6.2 (8.5)
43 ± 4.0 (5.6)
133 ±5.2 (5.2)
Tritium
pCtfUfcZSD
-------
Table 6.11 Tritium Results for Water Samples Collected in June 1996.
GNOME Site
Sarepte ; '
Location. ''''-,
Well 7 City
Well 2 City
PHS6
PHS8
PHS9
PHS10
USGS Well 1
USGS Well 4
Well USGS 8
J, Mobley Ranch
Well DD-1
LRL-7
Ooltectfon
Pate
tm-
6/13/96
6/13/96
6/14/96
6/14/96
6/14/96
6/14/96
6/13/96
6/15/96
6/15/96
6/14/96
6/15/96
6/15/96
Emicfisd Trfiom
pCi/L*2SD (MDC)
33 ± 4.7 (6.9)
7.8 ± 2.9 (4.5)
-------
7.0 Dose Assessment
There are several sources of possible radiation
exposure to the population of Nevada which were
monitored by EPA's offsite monitoring networks
during 1996. The pathways are:
• Background radiation due to natural sourc-
es such as cosmic radiation, natural radio-
activity in soil, and 7Be in air, and H in
water.
• Worldwide distributions of radioactivity, such
as 90Sr in milk, 85Kr in air, and plutonium in
soil.
• Airborne emissions and radioactive liquid
discharges to onsite containment ponds.
7.1 Estimated Dose From
Nevada Test Site Activity
Data
The potential EDE to the offsite population due to
NTS activities is estimated annually. Two methods
are used to estimate the EDE to residents in the
offsite area in order to determine the community
potentially most impacted by airborne releases of
radioactivity from the NTS. In the first method,
effluent release estimates, based on monitoring data
or calculated resuspensbn of deposited radioactivity,
and meteorological data are used as inputs to EPA's
CAP88-PC model which then produces estimated
EDEs. The second method entails using data from
the Offsite Radiological Safety Program (ORSP) with
documented assumptions and conversion factors to
calculate the committed effective dose equivalent
(CEDE). The latter method provides an estimate of
the EDE to a hypothetical individual continuously
present outdoors at the location of interest that
hcludes both NTS emissions and worldwide fallout.
In addition, a collective EDE is calculated by the first
method for the total offsite population residing within
80 km (50 mi) of each of the NTS emission sources.
Background radiation measurements are used to
provide a comparison with the calculated EDEs. In
the absence of detectable releases of radiation from
the NTS, the Pressurized Ion Chamber (PIC)
network provides a measurement of background
gamma radiation in the offsite area.
The extensive offsite environmental surveillance
system operated around the NTS by EPA R&IE-LV
measured no radiation exposures attributed to recent
NTS operations. However, using onsite emission
measurements, estimates provided by U.S.
Department of Energy (DOE) and calculated
resuspension data as input to the EPA's CAP88-PC
model, a potential effective dose equivalent (EDE) to
the maximally exposed individual (MEI) was
calculated to be 0.11 mrem (1.1 x 10"3 mSv) to a
hypothetical resident of Springdale, NV, located 58
km (36 mi) west-northwest of Control Point 1 (CP-1),
on the NTS. The calculated population dose
(collective EDE) to the approximately 32,210
residents living within 80 km (50 mi) from each of the
NTS airborne emission sources was 0.34
person-rem (3.4 x 10'3 person-Sv). Monitoring
network data indicated a 1996 exposure to the MEI of
144 mrem (1.44 mSv) from normal background
radiation. The calculated dose to this individual from
worldwide distributions of radioactivity as measured
from surveillance networks was 0.023 mrem (2.3 x
10"4 mSv). These maximum dose estimates,
excluding background, are less than one percent of
the most restrictive standard.
Onsite source emission measurements, as provided
by DOE, are listed in Table 7.1, and include tritium,
radioactive noble gases, and plutonium. These are
estimates of releases made at the point of origin.
Meteorological data collected by the Air Resources
Laboratory Special Operations and Research
Division, (ARL/SORD) were used to construct wind
roses and stability arrays for the following areas:
Mercury, Area 12, Area 20, Yucca Flat, and the
Radioactive Waste Management Site (RWMS) in
Area 5. A calculation of estimated dose from NTS
effluents was performed using EPA's CAP88-PC
model (EPA 1992). The results of the model
indicated that the hypothetical individual with the
maximum calculated dose from airborne NTS
radioactivity would reside at Springdale, Nevada, 58
km (36 mi) west-northwest of CP-1. The maximum
dose to that individual could have been 0.1 mrem
(1 x 10'3 mSv). For comparison, data from the PIC
monitoring network indicated a 1996 dose of 144
mrem (1.44 mSv) from background gamma radiation
occurring in that area. The population living within a
radius of 80 km (50 mi) from the airborne sources on
the NTS was estimated to be 32,210 individuals,
based on 1995 population data. The collective
population dose within 80 km (50 mi) from each of
these sources was calculated to be 0.3 person-rem
(3 x 10"3 person-Sv). Activity concentrations in air
that would cause these calculated doses are much
61
-------
higher than actually detected by the offsite
monitoring network. For example, 0.107 mrem of
the calculated EDE to the MEI is due to plutonium.
The annual average plutonium concentration in air
that would cause this EDE is 4.1 x10-17uCi/mL This
is about 20 times the annual average plutonium in air
measured in Goldfield (nearest community) of 0.19
x 10'17 uCi/mL (Chapter 4, Table 4.3). Table 7.2
summarizes the annual contributions to the EDEs
due to 1996 NTS operations as calculated by use of
CAP88-PC and the radionuclides listed in Table 7.1.
Input data for the CAP88-PC model included
meteorological data from ARL/SORD and effluent
release data calculated from monitoring results and
from resuspension estimates. These release data
are known to be estimates and the meteorological
data are mesoscale; e.g., representative of an area
approximately 40 km (25 mi) or less around the point
of collection. However, these data are considered
sufficient for model input, primarily because the
model itself is not designed for complex terrain such
as that on and around the NTS. Errors introduced by
the use of the effluent and meteorological data are
small compared to the errors inherent in the model.
The model results are considered overestimates of
the dose to offsite residents. This has been
confirmed by comparison with the offsite monitoring
results.
7.2 Estimated Dose From
ORSP Monitoring Network
Data
Potential CEDEs to individuals may be estimated
from the concentrations of radioactivity, as measured
by the EPA monitoring networks during 1996. Actual
results obtained in analysis are used; the majority of
which are less than the reported minimum detectable
concentration (MDC). No krypton or tritium in air
data were collected offsite, so the onsite krypton for
this year, and an average value for previous year's
offsite tritium were used. No vegetable or animal
samples were collected in 1996, so calculations for
these intakes were not done.
Data quality objectives for precision and accuracy
are, by necessity, less stringent for values near the
MDC, so confidence intervals around the input data
are broad. The concentrations of radioactivity
detected by the monitoring networks and used in the
calculation of potential CEDEs are shown in Table
7.3.
The concentrations given in Table 7.3 are expressed
in terms of activity per unit volume. These
concentrations are converted to a dose by using the
assumptbns and dose conversion factors described
below. The dose conversion factors assume
continuous presence at a fixed location and no loss
of radioactivity in storage or handling of ingested
materials.
• Adult respiration rate = 8,400 m3/yr (2.3 x 104
Lttay [ICRP 1975]).
• Milk intake for a 10-year old child = 164 L/yr
(ICRP 1975).
• Water consumption for adult-reference man =
2 L/day (approximately 1,900 mL/day [ICRP
1975]).
The CEDE conversion factors are derived from
EPA-520/1-88-020 (Federal Guidance Report No.
11). Those used here are:
• 3H: 6.4x10'8mrem/pCi(ingestionor
inhalation).
• 7Be2.6x10'7mrem/pCi
(inhalation).
• e°Sr: 1.4x10-4mrem/pCi(ingestion).
• 85Kr: 1.5x10-smrem/yr/pCi/m3
(submersion).
f 238,239+240pu.
3.7 x 10"4 mrem/pCi (ingestion).
3.1 x 10'1 mrem/pCi (inhalation).
The algorithm for the dose calculation is:
• (concentration) x (assumption in volume/unit
time) x (CEDE conversion factors) = CEDE
As an example calculation, the following is the result
of breathing tritium in air concentration of 0.2 pCi/m3:
• (2 x 10 -1 pCi/m3) x (8400 m3/yr) x (6.4 x 1O'8
mrem/pCi) = 1.1 x 10'4 mrem/yr
However, in calculating the inhalation CEDE from 3H,
the value is increased by 50 percent to account for
absorption through the skin (ICRP, 1975). The total
dose in one year, therefore, is 1.1 x 10-" x 1.5 = 2.4
x 10"4 mrem/ yr. Dose calculations from ORSP data
are summarized in Table 7.3.
62
-------
The individual CEDEs, from the various pathways,
added together give a total of 0.015 mrem/yr. Total
EDEs can be calculated based on different
combinations of data. If the interest was in just one
area, for example, the concentrations from those
stations closest to that area could be substituted into
the equations used here.
In 1996, because of budget cuts and the standby
status of nuclear device testing, samples of game
animals and garden vegetables were not collected.
Also, the noble gas and tritium sampling network was
discontinued in the offsite locations, and the air
sampling network was reduced. In order to calculate
an EDE for a resident of Springdale, the MEI from
the CAP88-PC operation, it is necessary to make
some assumptions. The NTS average krypton-85
concentration is representative of statewide levels;
tritium in air does not change significantly from year
to year; and, because Goldfield has the nearest air
sampler to Springdale, its plutonium concentration is
used to calculate the EDE.
7.3 Dose from Background
Radiation
In addition to external radiation exposure due to
cosmic rays and gamma radiation from naturally
occurring radionuclides in soil (e.g., 40K, U, and Th
and their progeny), there is a contribution from 7Be
that is formed in the atmosphere by cosmic ray
interactions with oxygen and nitrogen. The annual
average 7Be concentration measured by the offsite
surveillance network was 0.24 pCi/m3. With a dose
conversion factor for inhalation of 2.6 x 10~7
mrem/pCi, and a breathing volume of 8,400 m3/yr,
this equates to a dose of 5.2 x 10"4 mrem as
calculated in Table 7.3. This is a negligible quantity
when compared with the PIC network measurements
that vary from 73 to 156 mR/year, depending on
location.
7.4 Summary
The offsite environmental surveillance system
operated around the NTS by EPA's R&IE-LV
detected no radiological exposures that could be
attributed to recent NTS operations, but a calculated
EDE of 0.015 mrem can be obtained, if certain
assumptions are made, as shown in Table 7.2.
Calculation with the CAP88-PC model, using
estimated or calculated effluents from the NTS
during 1996, resulted in a maximum dose of 0.11
mrem (1.1 x 10'3 mSv) to a hypothetical resident of
Springdale, Nevada, 14 km (9 mi) west of the NTS
boundary. Based on monitoring network data, this
dose is calculated to be 0.005 mrem. This latter
EDE is about 5 percent of the dose obtained from
CAP88-PC calculation. This maximum dose
estimate is less than one percent of the International
Commission on Radiological Protection (ICRP)
recommendation that an annual EDE for the general
public not exceed 100 mrem/yr (ICRP 1985). The
calculated population dose (collective EDE) to the
approximately 32,210 residents living within 80 km
(50 mi) of each of the NTS airborne emission
sources was 0.34 person-rem (3.4 x 10'3 person-Sv).
Background radiation yielded a CEDE of 3,064
person-rem (30.6 person-Sv).
Data from the PIC gamma monitoring indicated a
1996 dose of 144 mrem from background gamma
radiation measured in the Springdale area. The
CEDE calculated from the monitoring networks or
the model, as discussed above, is a negligible
amount by comparison. The uncertainty (2o) for the
PIC measurement at the 144 mrem exposure level
is approximately five percent. Extrapolating to the
calculated annual exposure at Springdale, Nevada,
yields a total uncertainty of approximately 7 mrem
which is greater than either of the calculated EDEs.
Because the estimated dose from NTS activities is
less than 1 mrem (the lowest level for which Data
Quality Objectives (DQOs) are defined, as given in
Chapter 10) no conclusions can be made regarding
the achieved data quality as compared to the DQOs
for this insignificant dose.
63
-------
05
Table 7.1 NTS Radionuclide Emissions -1996
Onsite Liquid Discharges
Containment
Ponds
Area 12, E Tunnel
Area 20, Well ER-20-5
Area 20, Well ER-20-6
TOTAL
Airborne Effluent Releases
Facility Name
(Airborne Releases)
Areas 3 and 9(c)
Area 5, RWMS(d)
Atlas Facility*
SEDAN Crater(d)
Other Areas'0'
TOTAL
3d
1.1 xlO1
1.1x102
8.2x10°
1.3x10*
3.5 x ID'1
5.2X10-3
1.4x10*
1.2x10-°
Curies(a)
4.4 xlO'5 1.5xlO'3
Curies(a)
137C
4.4 x10'5 1.5X1Q-3 3.4X10-6
3.4 x 10-*
0.036
0.28
(a) Multiply by 3.7 x 1010 to obtain Bq. Calculated releases from laboratory spills and losses are included in Table 7 4
(b) In the form of treated water vapor, primarily HTO.
(c) Resuspension f rom known surface deposits.
(d) Calculated from air sampler data.
239+240pu
2.7x10's
2.7 x10'5
-------
Table 7.2 Summary of Effective Dose Equivalents from NTS Operations -1996
Dose
Location
NESHAP(e>
Standard
Percentage
of NESHAP
Background
Percentage of
Background
Maximum EDE at
NTS Boundary""
0.12 mrem
(1.2x10-3mSv)
Site boundary 40 km
WNW of NTS CP-1
10 mrem peryr
(0.1 mSv peryr)
1.2
144 mrem
(1.44 mSv)
0.08
Maximum EDE to
an Individual""
0.11 mrem
(1.1x10'3mSv)
Springdale, NV 58 km
WNW of NTS CP-1
10mrem peryr
(0.1 mSv peryr)
1.1
144 mrem
(1.44 mSv)
0.08
Collective EDE to
Population within 80 km
of the NTS Sources
0.34 person-rem
32,210 people within
80 km of NTS Sources
3064 person-rem
(30.6 person-Sv)
0.011
(a) The maximum boundary dose is to a hypothetical individual who remains in the open continuously during the
year at the NTS boundary located 40 km (25 mi) west-northwest from CP-1.
(b) The maximum individual dose is to a person outside the NTS boundary at a residence where the highest
dose-rate occurs as calculated by CAP88-PC (Version 1.0) using NTS effluents listed in Table 6.1 and
assuming all tritiated water input to the Area 12 containment ponds was evaporated.
(c) National Emission Standards for Hazardous Air Pollutants.
Table 7.3 Monitoring Networks Data used in Dose Calculations - 1 996
Medium
Meat
Milk
Radionuclide
9oSr
3H
Drinking Water 3H
Vegetables
Air
TOTAL (Air =
(a) Units are
(b) Units are
3H
7Be
239+240 pu
= 5.5 X10-3, Liquids
pCi/L and Bq/L.
oCi/m3 and Ba/m3.
Concentration
0.63 (a)
(0.023)
0
0.71 "»
(0.026)
0.2°"
(0.007)
0.24 <"'
(0.010)
25.2 w
(0.93)
1.7x10-S(b)
(6.3X10-8)
= 9.7 x10'3) = 1.5x10
MremWear Comment
Not collected this year
9.7 x 1 0"3 Concentration is the average
of all network results
0 Not Analyzed
3.3 x 1 0"5 Concentration is the average
from wells in the area
Not collected this year
1 .6 x 1 0"" Concentration is average
network result (1 994 data)
5.2x10"" Annual average for
Goldfield, Nevada
3.8 x 1 0'" NTS network average
4.4 x 1 0"3 Annual average for Goldfield
"2 mrem/yr
65
-------
Table 7.4 Radionuclide Emissions on the NTS - 1996(a)
Radionuclide Half-life (year) Quantity Released (Ci) <"'
Airborne Releases:
3H 12.35 <°>0.35
10.72 0.019
24065. (c)0.28
Containment Ponds:
3H 12.35
-------
8.0 Training Program
Proper and efficient performance of radiological
health functions by qualified personnel is required to
ensure protection from radiological hazards. The
purpose of the training program is to provide well-
trained, qualified personnel to safely and efficiently
perform their assigned duties at a predetermined
level of expertise.
8.1 Emergency Response
Training Program
Emergency response training is essential to maintain
a cadre of personnel who are qualified to perform
approved radiological health and field monitoring
practices. The training program includes: tracking
training requirements; maintaining training records;
developing in-house training; and documenting
personnel qualifications and accomplishments.
Systematic determination of job functions promotes
consistent training activities and develops or
.improves knowledge, skills and abilities that can be
utilized in the work environment.
In 1996, the EPA ORIA/R&IE National Laboratory in
Las Vegas (R&IE-LV) supported DOE by instructing
or co-instructing radiological training courses for
state and local emergency responders nationwide.
One such program is the Transportation Emergency
Training for Radiological Assistance (TETRA);
another is the Federal Radiological Monitoring and
Assessment Center (FRMAC). TETRA training
includes railway simulated accidents known as
TETRA/RAIL; an intensive course in radiological
emergency response called Radiological Emergency
Operations (REO) at the Nevada Test Site (NTS);
and Radiological Emergency Response for Local
Responders (RETLR). FRMAC training is given at
drills and exercises in the form of classroom and
hands-on training followed by a drill or exercise
involving field monitoring practical experience
simulating an actual emergency response scenario.
In addition, R&IE-LV supports other emergency
response needs. Several personnel are trained in
the Radiological Assistance Program (RAP).
Radiation field monitors are required to complete an
initial 40 hr. Hazardous Waste Site Operations and
Emergency Response (HAZWOPER) (29 CFR
1910.120) with 8 hour annual refreshers course and
complete a RAP training class, plus maintain
respirator fit qualification to be on the RAP team. In
February, three R&IE-LV personnel attended a
Transportation Emergency Training for Response
Assistance (TTT), train-the-trainer course in Idaho
Falls, ID. This course prepared the students to
become trainers of trainers in the specific area of
transportation emergency response along
transportation corridors.
Co-instructed Training Courses -1996
Course Name
RETLR
TETRA/RAIL
REO
REO
REO
RETLR
Location
Columbia, SC
Pueblo, CO
NTS, NV
NTS, NV
NTS, NV
Charleston, SC
Dates
June 12-20
June 24-28
May 6-10
May 25-29
March 4-8
August 20-23
EPA Co-instructors Provided
(D
(4)
(9)
(9)
(9)
(1)
67
-------
Emergency Response
Course Name
RAP
Radiological Field
Team Leader Class
Field Instrument
for the Detection
of Low Energy
Radiation (FIDLER)
Class
FRMAC Readiness
Class
8-hr. HAZWOPER
Refresher
Handshake II
FRMAC Readiness
Class
FRMAC Readiness
Class
Operational Radiation
Protection
Classes Attended -1996
Location Dates
Ft. Smith, AK January 24-28
Las Vegas, NV March 12-14
(R&IE sponsored)
Las Vegas, NV April 9-10
(R&IE sponsored)
Las Vegas, NV April 15-17
(R&IE sponsored)
Las Vegas, NV May 3
(EPA sponsored)
Savannah River Site, SC May 13-17
Las Vegas, NV June 10-12
(R&IE sponsored)
Las Vegas, NV July 8-10
(R&IE sponsored)
Bechtel, NV December 2-6
8.2 Hazardous Materials Spill
Center Support
The Hazardous Materials Spill Center (formerly the
Liquified Gaseous Fuels Spill Test Facility) is located
at Frenchman Flat in Area 5 of the Nevada Test Site.
Originally completed in 1986, the HAZMAT Spill
Center was designed for safety research on the
handling, shipping, and storage of liquified gaseous
fuels and other hazardous liquids. Early research
was aimed at understanding the physics of spill
dispersion, spill effects mitigation, and clean-up
technology. More recently the Center has been used
by industry for conducting tests on protective
clothing, to give hands-on spill mitigation experience
to industrial emergency response workers, and to
test a variety of sensors designed to detect airborne
hazardous materials. Organizations conducting tests
range from the Federal government, and
corporations, to foreign governments working in co-
operation with the U.S. Government. The facility is
completely supported by user fees paid by the
organizations conducting the tests.
The HAZMAT Spill Center has the advantages of
being located far from populated areas, inside of a
secure facility, and subjected to well characterized
and predictable meteorological conditions. The EPA
provides a chemist to participate in meetings of the
Advisory Panel which reviews and approves all
programs prior to testing and maintains a readiness
for monitoring emissions at the boundary of the NTS.
Recent spills have involved such small amounts of
material that monitoring at the boundary was not
justified. Dispersion models show that even a
catastrophic release of the entire supply of the test
materials would not be measurable at the test site
boundary. Four spill programs were conducted in
1996. These included a U.S. Navy incinerator test,
testing a variety of laser sensors, and a spill
mitigation workshop conducted by an industrial user.
68
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9.0 Sample Analysis Procedures
The procedures for analyzing samples collected for this report are described in Radiochemical and Analytical
Procedures for Analysis of Environmental Samples (Johns, 1979) and are summarized in Table 9.1 and (see
Table 6.2 page 52). These include gamma analysis, gross beta on air filters, strontium, tritium, plutonium, and
noble gas analyses. These procedures outline standard methods used to perform given analytical procedures.
Table 9.1 Summary of Analytical Procedures
Type of Analytical Counting Analytical
Analysis Equipment Period (min) Procedures
HpGe
Gamma6
Gross alpha
and beta on
air filters
'"••"Sr
"H
HpGe 60 - Air charcoal
detector- cartridges and
calibrated at individual air
0.5 keV/ filters.
channel 100 - milk, water,
(0.04 to 2 suspended solids.
meV range)
Individual
detector
efficiencies
ranging from
15 to 35%.
Low-level end 30
windows, gas
flow pro-
portional
counter with a
5-cm diameter
window.
Low 50
background
thin-window,
gas-flow,
proportional
counter.
Automatic 150-300
liquid
scintillation
counter
with output
printer.
Radionuclide concen-
tration quantified from
gamma spectral data
by online computer
program.
Samples are
counted after decay
of naturally occurring
radionuclides.
Chemical separation
by ion exchange.
Separated sample
counted succes-
sively; activity calcu-
lated by simulta-
neous solution of
equations.
Sample prepared by
distillation.
Sample
Size
1.0L&3.5L -
routine liquids.
560 m° - low-
volume air
filters.
10,000m3-
high-volume air
filters.
560m'
1.0 L- milk
or water.
4 to lOmLfor
water.
Approximate
Detection Limit"-"
Cs-137, routine
liquids; 5 x 10-" uCi/mL
(1.8x10-' Bq/L). Also
see Table 6.3, page 52.
Low-volume air filters:
5 x 10'" uCi/mL
(1.8x10*Bq/m3),
High-volume air filters;
5 x 10'" uCi/mL
(1.8x10*Bq/ma).
alpha 8.0 x10-'euCi/mL
(3.0x10-5Bq/m3)
beta- 2.5 x 10'IS uCi/mL
(9.25x10*Bq/m3)
"Sr: 5x10-'uCi/mL
(1.85x10-'Bq/L)
MSr: 2x10-"uCi/mL .
(7.4 x10'2 Bq/L)
300 to 700 x
10-* pCi/mL
(11-MBq/L)°
Continued
69
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Table 9.1 (Summary of Analytical Procedures, cont.)
Type of
Analysis
*H Enrichment
(LTHMP
samples)
2M.239t240p..
Analytical Counting
Equipment Period (min)
Automatic 300
liquid
scintillation
counter
with output
printer.
Alpha 1,000
spectrometer
with silicon
surface
barrier
detectors
operated in
vacuum
chambers.
Analytical
Procedures
Sample concen-
trated by electrolysis
followed by
distillation.
Water sample, or
acid-digested filter
separated by ion
exchange and electro-
plated on stainless
steel planchet.
Sample
Size
250 ml -
water.
1.0 L- water.
5,000 to
10,000 m" - air.
Approximate
Detection Limif
10 x10" pCi/mL
(3.7x10-' Bq/L)
238Pu: 0.08x10-°
uCi/mL (2.9x10"
Bq/L).
239*240 pu. Q 04
x10*uCi/mL(1.5x
10"3 Bq/L.) -water.
MaPu: 5x10'17
(1.9X10*
239*240 py.
10x10-'rpCi/mL-
air filters.
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 (DOE81).
Gamma spectrometry using a high purity intrinsic germanium (HpGe) detector.
Depending on sample type.
70
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10.0 Quality Assurance
10.1 Policy
One of the major goals of the EPA is to ensure that
all agency decisions which are dependent on
environmental data are supported by data of known
quality. EPA Order 5360.1, "Policy and Program
Requirements to Implement the Quality Assurance
Program" requires participation in a QA Program by
all EPA organizational units involved in
environmental data collection. This policy further
requires participation hi a centrally managed QA Pro-
gram by all EPA Laboratories, Program Offices,
Regional Offices, and those monitoring and mea-
surement efforts supported or mandated through
contracts, regulations, or other formalized agree-
ments.
The QA policies and requirements of EPA's R&IE-LV
are summarized in the Quality Management Plan
(R&IE, draft 1997). Policies and requirements
specific to the ORSP are documented in the Quality
Assurance Program Plan for the Nuclear Radiation
Assessment Division Offsite Radiation Safety
Program (EPA, 1992, under revision). The
requirements of these documents establish a
framework for consistency in the continuing appli-
cation of quality assurance standards and
procedures in support of the ORSP- Administrative
and technical procedures based on these QA
requirements are maintained in appropriate manuals
or are described in SOPs. It is R&IE policy that
personnel adhere to the requirements of the QA Plan
and all SOPs applicable to their duties to ensure that
all environmental radiation monitoring data collected
by R&IE in support of the ORSP are of adequate
quality and properly documented for use by the DOE,
EPA, and other interested parties.
10.2 Data Quality Objectives
Data quality objectives (DQOs) are statements of the
quality of data a decision maker needs to ensure that
a decision based on that data is defensible. Data
quality objectives are defined in terms of represent-
ativeness, comparability, completeness, precision,
and accuracy. Representativeness and compara-
bility are generally qualitative assessments while
completeness, precision, and accuracy may be
quantitatively assessed. In the ORSP, represent-
ativeness, comparability, and completeness objec-
tives are defined for each monitoring network.
Precision and accuracy are defined for each analysis
type or radionuclide.
Achieved data quality is monitored continuously
through internal QC checks and procedures. In
addition to the internal QC procedures, R&IE
participates in external intercomparison programs.
One such intercomparison program is managed and
operated by a group within EPA/CRD-LV. These
external performance audits are conducted as
described in and according to the schedule con-
tained in "Environmental Radioactivity Laboratory
Intercomparison Studies Program" (EPA, 1992a).
The analytical laboratory also participates in the DOE
Environmental Measurements Laboratory (EML)
Quality Assurance Program in which real or synthetic
environmental samples that have been prepared and
thoroughly analyzed are distributed to participating
laboratories. The R&IE laboratory also began
participation in the DOE Mixed Analyte Performance
Evaluation Program (MAPEP) during 1996. External
Dosimetry is accredited every two years. In 1996 the
program was accredited under the Department of
Energy Accreditation Program (DOELAP).
Accreditation includes performance testing as well as
an on-site assessment. The R&IE External
Dosimetry Program is currently seeking National
Voluntary Laboratory Accreditation Program
(NVLAP) accreditation, which will also include
performance testing and an on-site assessment.
10.2.1 Representativeness, Compa-
rability, and Completeness
Objectives
Representativeness is defined as "the degree to
which the data accurately and precisely represent a
characteristic of a parameter, variation of a property,
a process characteristic, or an operation condition"
(Stanley and Vemer, 1985). In the ORSP,
representativeness may be considered to be the
degree to'which the collected samples represent the
radionuclide activity concentrations in the offsite
environment. Collection of samples representative
of pathways to human exposure as well as direct
measurement of offsite resident exposure through
the TLD monitoring programs provides assurance of
the representativeness of the calculated exposures.
Comparability is defined as "the confidence with
which one data set can be compared to another"
(Stanley and Vemer, 1985). Comparability of data is
assured by use of SOPs for sample collection,
71
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handling, and analysis; use of standard reporting
units; and use of standardized procedures for data
analysis and interpretation. In addition, another
aspect of comparability is examined through long-
term comparison and trend analysis of various
radionuclide activity concentrations, and TLD, and
PIC data. Use of SOPs, maintained under a
document control system, is an important component
of comparability, ensuring that all personnel conform
to a unified, consistent set of procedures.
Completeness is defined as "a measure of the
amount of data collected from a measurement
process compared to the amount that was expected
to be obtained under the conditions of measurement"
(Stanley and Vemer, 1985). Data may be lost due to
instrument malfunction, sample destruction, loss in
shipping or analysis, analytical error, or unavailability
of samples. Additional data values may be deleted
due to unacceptable precision, accuracy, or
detection limit or as the result of application of
statistical outlier tests. The completeness objective
for all networks except the LTHMP is 90%. The
completeness objective for the LTHMP is 80%; a
lower objective has been established because dry
wells or access restrictions occasionally preclude
sample collection.
10.2.2 Precision and Accuracy
Objectives of Radioanalytical
Analyses
Measurements of sample volumes should be
accurate to ± 5% for aqueous samples (water and
milk) and to ± 10% for air and soil samples. The
sensitivity of radiochemical and gamma spectro-
metric analyses must allow no more than a 5% risk
of either a false negative or false positive value.
Precision to a 95% confidence interval, monitored
through analysis of duplicate and blind samples,
must be within ± 10% for activities greater than 10
times the minimum detectable concentration (MDC)
and ± 30% for activities greater than the MDC but
less than 10 times the MDC. There are no precision
requirements for activity concentrations below the
MDC, which by definition cannot be distinguished
from background at the 95% confidence level.
Control limits for accuracy, monitored with matrix
spike samples, are required to be no greater than ±
20% for all gross alpha, gross beta, and gamma
spectrometric analyses, depending upon the media
type.
At concentrations greater than 10 times the MDC,
precision is required to be within ± 10% for:
• Conventional Tritium Analyses
• Uranium
• Thorium (all media)
• Strontium
and within ± 20% for:
• Enriched Tritium Analyses
• Strontium (in milk)
• Plutonium.
At concentrations less than 10 times the MDC, both
precision and accuracy are expressed in absolute
units, not to exceed 30% of the MDC for all analyses
and all media types.
10.2.3 Quality of Dose Estimates
The allowable uncertainty of the effective dose
equivalent to any human receptor is ± 0.1 mrem
annually. This uncertainty objective is based solely
upon the precision and accuracy of the data
produced from the surveillance networks and
parameter uncertainties does not apply to uncertain-
ties in the model used, effluent release data received
from DOE, or dose conversion factors. Generally,
effective dose equivalents must have an accuracy
(bias) of no greater than 50% for annual doses
greater than or equal to 1 mrem but less than 5
mrem and no greater than 10% for annual doses
greater than or equal to 5 mrem.
10.3 Data Validation
Data validation is defined as "A systematic process
for reviewing a body of data against a set of criteria
to provide assurance that the data are adequate for
their intended use." Data validation consists of data
editing, screening, checking, auditing, verification,
certification, and review (Stanley et al; 1983). Data
validation procedures are documented in SOPs. All
data are reviewed and checked at various steps in
the collection, analysis, and reporting processes.
The first level of data review consists of sample
tracking; e.g., that all samples planned to be
collected are collected or reasons for noncollection
are documented; that all collected samples are
delivered to Sample Control and are entered into the
appropriate data base management system; and that
all entered information is accurate. Next, analytical
data are reviewed by the analyst and by the
laboratory supervisor. Checks at this stage include
verifying that all samples received from Sample
Control have been analyzed or reasons for
nonanalysis have been documented; that data are
72
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•'reasonable" (e.g., within expected range), and that
instrumentation operational checks indicate the
analysis instrument is within permissible tolerances.
Discrepancies indicating collection instrument
malfunction are reported to the R&IE Center for
Environmental Restoration and Emergency
Response (CERMER). Analytical discrepancies are
resolved; individual samples or sample batches may
be reanalyzed if required.
Raw data are reviewed by a designated media
expert. A number of checks are made at this level,
including:
1. Completeness - all samples scheduled to
be collected have, in fact, been collected
and analyzed or the data base contains
documentation explaining the reasons for
noncollection or nonanalysis.
2. Transcription errors - checks are made of
all manually entered information to ensure
that the information contained in the data
base is accurate.
3. Quality control data - field and analytical
duplicate, audit sample, and matrix blank
data are checked to ensure that the col-
lection and analytical processes are within
specified QC tolerances.
4. Analysis schedules - lists of samples
awaiting analysis are generated and
checked against normal analysis sched-
ules to identify backlogs in analysis or data
entry.
5. Unidentified malfunctions - sample results
and diagnostic graphics of sample results
are reviewed for reasonableness. Condi-
tions indicative of instrument malfunction
are reported to CERMER/CRQA.
Once the data base has been validated, the data are
compared to the DQOs. Completeness, accuracy,
and precision statistics are calculated. The achieved
quality of the data is reported at least annually. If
data fail to meet one or more of the established
DQOs, the data may still be used in data analysis;
however, the data and any interpretive results are to
be qualified.
All sample results exceeding the natural background
activity range are investigated. If data are found to
be associated with a non-environmental condition,
such as a check of the instrument using a calibration
source, the data are flagged and are not included in
calculations. Only data verified to be associated with
a non-environmental condition are flagged; all other
data are used in calculation of averages and other
statistics, even if the condition is traced to a source
other than the NTS (for example, higher-than-normal
activities were observed for several radionuclides
following the Chernobyl accident). When activities
exceeding the expected range are observed for one
network, the data for the other networks at the same
location are checked. For example, higher-than-nor-
mal-range PIC values are compared to data ob-
tained by the air or TLD samplers at the same
location.
Data are also compared to previous years' data for
the same location using trend analysis techniques.
Other statistical procedures may be employed as
warranted to permit interpretation of current data as
compared to past data. Trend analysis is made
possible due to the length of the sampling history,
which in some cases is 30 years or longer.
Data from the offsite networks are used, along with
NTS source emission estimates prepared by DOE, to
calculate or estimate annual committed effective
dose equivalents to offsite residents. Surveillance
network data are the primary tools for the dose
calculations. Additionally, EPA's CAP88-PC model
(EPA, 1992) is used with local meteorological data to
predict doses to offsite residents from NTS source
term estimates. An assessment of the uncertainty of
the dose estimate is made and reported with the
estimate.
10.4 Quality Assessment Of 1996
Data
Data quality assessment is associated with the
regular QA and QC practices within the radio-
analytical laboratory. The analytical QC plan,
documented in SOPs, describes specific procedures
used to demonstrate that data are within prescribed
requirements for accuracy and precision. Duplicate
samples are collected or prepared and analyzed in
the exact manner as the regular samples for that
particular type .of analysis. Data obtained from
duplicate analyses are used for determining the
degree of precision for each individual analysis.
Accuracy is assessed by comparison of data from
spiked samples with the "true" or accepted values.
Spiked samples are either in-house laboratory
blanks spiked with known amounts of radionuclides,
or QC samples prepared by other organizations in
which data are compared between several
laboratories and assessed for accuracy.
73
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Table 10.1 Data Completeness of Offsite Radiological Safety Program Networks
Network
Number of
Sampling
Locations
Total Samples
Possible
Valid Samples
Collected
Percent
Completeness
LTHMP«" 271
Low-volume Air 20
High-volume Air 6
Milk Surveillance 10
PIC 24(0>
Environmental TLD 49
Personnel TLD 25
479
6,745 days*'
1,993 days
10
8,760 days
17,897 days
9,011 days
468
6,440
1673
9
6,477
17,537
8,831
97.8
95.5
83.9
90.0
73.9(d)
98.0
96.9
(a) The Data Quality Objectives (DQO) for completeness for monitoring networks summarized in this table
are 90 percent.
(b) Continuous samplers with samples collected at intervals of approximately one week. Days used as
units to account for differences in sample interval length.
(c) Continuous samplers with data summarized on a weekly basis.
(d) Satellite telemetry data only, does not include backup data systems.
(*) Data for three quarters.
Achieved data quality statistics are compiled on a
quarterly and annual basis. This data quality
assessment is performed as part of the process of
data validation, described in Section 10.3. The
following subsections describe the achieved data
quality for 1996.
10.4.1 Completeness
Completeness is calculated as:
%C = (-1) x 100
n
where:
%C = percent completeness
V = number of measurementsjudgedvalid
n = total number of measurements
The percent completeness of the 1996 data is given
in Table 10.1. Reasons for sample loss include
instrument malfunction, inability to gain site access,
monitoring technician error, or laboratory error.
The achieved completeness of over 97 percent for
the LTHMP exceeds the DQO of 80 percent.
Overall completeness for the routine Air Surveillance
Network low volume samples was greater than 95
percent, exceeding the DQO of 90 percent.
Individually, seventeen of twenty stations exceeded
95 percent data recovery and nine stations achieved
completeness of 100 percent. Plutonium analyses,
conducted on composited filters from six high volume
samplers at selected air stations, were over 83
percent complete, falling below the DQO of 90
percent due to equipment failures and difficulty
obtaniing replacement parts for new systems. Three
of the six stations achieved completeness greater
than 90 percent.
Overall sample completion for the MSN was equal to
the DQO of 90 percent. Many of the milk sampling
locations consist of family-owned cows or goats that
can provide milk only when the animal is lactating.,
74
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Ninety-one percent of the total possible number of
samples were collected from ten ranches (see
Figure 4.1). Annual means for these locations,
individually, cannot be considered to be represent-
ative of the year. However, milk collected in July is
representative of cows grazing on pasture or fed
green chop which represent the typical food chain
for those areas. The Hafen Ranch in Ivins, UT was
not sampled as they were not milking during the
collection period and there was no alternate
sampling site in the area.
The achieved completeness of over 76 percent for
the PIC Network fails to meet the DQO of 90
percent. This completeness value represents
satellite telemetry data only, which is used for
reporting purposes. Gaps in the satellite
transmissions are filled by data from the magnetic
tape or card media. The redundant data systems
used in the PIC Network (i.e., magnetic tape or card
data acquisition systems) are responsible for high
rates of recovery of the collected data, and are
stored electronically for reference.
10.4.2 Precision
Precision is monitored through analysis of duplicate
samples. Field duplicates (i.e., a second sample
collected at the same place and time and under the
same conditions as the routine sample) are collected
in the ASN, LTHMP, and MSN. For the ASN, a
duplicate sampler is collocated with the routine
sampler at randomly selected sites for a period of
three months to provide the field duplicate. A total of
two samplers are used for low volume sample
duplicates and one sampler is used for a duplicate
high volume sample. The duplicate samplers are
moved to randomly selected sampling sites
throughout the year. Approximately ten percent of
samples submitted to the laboratory are analyzed
twice for intra laboratory comparison whenever
possible. In lieu of field duplicates, precision for the
PICs is determined by the variance of measurements
over a specific time interval when only background
activities are being measured. Precision may also be
determined from repeated analyses of routine or
laboratory spiked samples. The spiked QC samples
are generally not blind to the analyst; i.e., the analyst
both recognizes the sample as a QC sample and
knows the expected (theoretical) activity of the
sample.
Precision is expressed as percent relative standard
deviation (%RSD), also known as coefficient of
variation, and is calculated by:
%RSD - (
Std-
mean
x 100
The precision or %RSD (also called Coefficient of
Variation) is not reported for duplicate pairs in which
one or both results are less than the MDC of the
analysis. For most analyses, the Measurement
Quality Objectives (MQOs) for precision are defined
for two ranges: values greater than or equal to the
MDC but less than ten times the MOC and values
equal to or greater than ten times the MDC. The
%RSDs is partially dependent on statistical counting
uncertainty so it is expected to be more variable for
duplicate analyses of samples with low activities.
From duplicate samples collected and analyzed
throughout the year, the %RSD was calculated for
various types of analyses and sampling media. The
results of these calculations are shown in Table 10.2.
Samples not meeting the precision MQO were low
activity, air particulate samples in which 7Be was
detected. The precision data for all other analyses
were well within their respective MQOs. The R&IE
data presented in Table 10.2 includes only those
duplicate pairs that exceeded the minimum
detectable concentration (MDC).
A total of 161 low volume duplicate pairs was
analyzed for gross alpha and gross beta. Field
duplicates account for sixty-nine of the samples and
ninety-two were laboratory duplicates.
A total of 84 duplicate pairs exceeded the analysis
MDC for gross alpha. Twenty-six of these were field
duplicates and fifty-eight were laboratory duplicates.
Of the field duplicates, ten of the twenty-six exceeded
the MQO of 30 percent for samples greater than
MDC but less than ten times MDC. One of the field
duplicate samples exceeded ten times the MDC and
the RSD for that sample was zero percent. Of the
fifty-eight laboratory duplicates, nineteen exceeded
the MQO of thirty percent. None of the laboratory
duplicates were greater than ten times the MDC.
Sixty-seven of the sixty-nine field duplicates
exceeded the analysis MDC for gross beta. Of
these, three were greater than ten times the MDC.
The average RSD for the pairs greater than ten times
MDC was 13.2 percent, exceeding the MQO of 10
percent for samples greater than ten times MDC. All
three samples had RSDs of less than 15 percent.
75
-------
Table 10.2 Precision Estimates from Duplicate Sampling, 1996
Analysis Type
Gross Alpha
Gross Beta
Gamma Spectroscopy (low-vol 7Be)
Gamma Spectrometry (hi-vol 7Be)
Tritium in Water (enriched)
Tritium in Water (unenriched)
Number of duplicate
Analysis > MDC
85
156
25
11
12
2
Estimated Precision,
%RSD
28.8
16.9
31.4
46.8
7.9
26.2
The average RSD for the sixty-four pairs greater than
MDC but less than ten times MDC was 19.9 percent,
well below the MQO of thirty percent for the analysis.
Ten of the sixty-four samples exceeded the MQO. Of
ninety-two laboratory duplicate pairs, five were
greater than ten times the MDC. The average RSD
for these five samples was 3.5 percent with all
samples less than the MQO of 10 percent. Eighty-
four samples were greater than the MDC but less
than ten times MDC for the analysis. The average
RSD for this group of samples was 15.5 percent, well
below the MQO of 30 percent. Eight of the samples
exceeded the MQO value/Be was detectable on 25
low volume duplicate pairs. Eleven were field
duplicates and 14 were laboratory duplicates. The
average RSD of 31.4 percent is above the precision
MQO of 30 percent for samples above MDC and
less than ten times MDC. Of the eleven field
duplicates, the average RSD was 29.8 percent which
meets the MQO. The average RSD for the
laboratory duplicates was 32.7 percent. Eight
duplicate pairs from the field samples and 11 of the
duplicate pairs from the laboratory samples were
less than the MQO of 30 percent. High volume
duplicate pairs where 7Be was detected did not meet
the MQO. The average of 11 samples was 46.8
percent. Four of the eleven samples met the MQO
of 30 percent.
Forty-two duplicate pairs were analyzed for tritium
using the unenriched method. Of the 42 samples
analyzed, two were above the MDC for the analysis.
The average RSD for these two samples was 26.2
percent which meets the MQO for this type of
analysis. A total of 25 samples was analyzed for
tritium using the enrichment method. Five of the
duplicate pairs were above ten times MDC for the
analysis with an average RSD of 7.1 percent, within
the MQO of 10 percent for the analysis. Seven
duplicate pairs were greater than MDC and less than
ten times MDC, with RSD of 8.6 percent which is well
within the MQO of 20 percent for this type of analysis.
10.4.3 Accuracy
The accuracy of all analyses is controlled through
the use of NIST-traceable standards for instrument
calibrations. Internal checks of instrument accuracy
may be periodically performed, using spiked matrix
samples. These internal QC procedures are the only
control of accuracy for Pressurized Ion Chambers.
For spectroscopic and radiochemical analyses, an
independent measurement of accuracy is provided
by participation in intercomparison studies using
samples of known activities. The EPA R&IE-LV
Radioanalysis Laboratory participates in three such
intercomparison studies.
In the EPA CRD/RADOA Intercomparison Study
program, samples of known activities of selected
radfonuclides are sent to participating laboratories on
a set schedule throughout the year. Water, milk, and
air filters are used as the matrices for these samples.
Results from all participating laboratories are
compiled and statistics computed comparing each
laboratory's results to the known value and to the
mean of all laboratories. The comparison to the
known value provides an independent assessment of
accuracy for each participating laboratory.
Table 10.3 presents accuracy (referred to therein as
Percent Bias) results for these intercomparison
studies. Comparison of results among all partici-
pating laboratories provides a measure of compa-
rability, discussed in Section 10.4.4. Approximately
70 to 290 laboratories participate in any given
intercomparison study. Accuracy, as percent
difference or percent bias is calculated by:
76
-------
%BIAS =
100
Where:
%BIAS = Percent bias
Cm = Measured Sample Activity
Ca = Known Sample Activity
The other intercomparison studies in which the EPA
R&IE-LV Radioanalysis Laboratory participates are
the semiannual DOE QA Program conducted by
EML in New York, NY. and the DOE Mixed Analyte
Performance Evaluation Program (MAPEP).
Approximately 20 laboratories participate in the EML
performance evaluation program. The MAPEP
program evaluates the performance of
approximately forty laboratories. Sample matrices
for both of these programs include water, air filters,
vegetation, and soil. Results for these performance
audit samples are given in Tables 10.5 and 10.6.
One of the two EML studies for 1996 was reported
outside of acceptable limits for gamma spectroscopy
in both air and water matrices. Follow-up
investigation established a volume data entry error in
both cases. Corrective actions were implemented.
In addition to use of irradiated control samples in the
processing of TLDs, DOELAP and NVLAP both
monitor accuracy as part of their accreditation
program. As with the intercomparison studies,
samples of known activity are submitted as single
blind samples. The designation "single blind"
indicates the analyst recognizes the sample as being
other than a routine sample, but does not know the
concentration or activity contained in the sample.
Individual results are not provided to the participant
laboratories by DOELAP or NVLAP; issuance of the
accreditation certificate indicates that acceptable
accuracy reproducfoil'rty has been achieved as part of
the performance testing process and that an onsite
independent review has indicated conformance with
established accreditation standards.
10.4.4 Comparability
The EPA Performance Evaluation Program provides
results to each laboratory participating in each study
that includes a grand average for all values,
excluding outliers.
A normalized deviation statistic compares each
laboratory's result (mean of three replicates) to the
known value and to the grand average. If the value
of this statistic (in multiples of standard normal
deviate, unitless) lies between control limits of -3 and
+3, the accuracy (deviation from known value) or
comparability (deviation from grand average) is within
normal statistical variation. Table 10.4 displays data
from the 1996 intercomparison studies for all
variables measured. There were five instances in
which the EPA R&IE-LV Radioanalysis Laboratory
results deviated from the grand average by more
than three standard normal deviate units. All of
these were gamma spectrometry analyses of the
June gamma in water intercomparison study sample.
After investigation of the error in the reported data for
this sample, it was found that the initial dilution of the
sample had been improperly performed. The
sample data was recalculated by the laboratory
using the proper values for dilution which provided
satisfactory analytical results for 4 of the 5 analytes
in question. All other analyses were within three
standard normal deviate units of the grand mean.
This indicates acceptable comparability of the
Radioanalysis Laboratory with the 70 to 290
laboratories participating in the EPA Intercomparison
Study Program.
10.4.5 Representativeness
Representativeness cannot be evaluated quantita-
tively. Rather, it is a qualitative assessment of the
ability of the sample to model the objectives of the
program. The primary objective of the ORSP is to
protect the health and safety of the offsite residents.
Therefore, the DQO of representativeness is met if
the samples are representative of the radiation
exposure of the resident population. Monitoring
stations are located in population centers. Siting
criteria specific to radiation sensors are not available
for many of the instruments used. Existing siting
criteria developed for other pollutants are applied to
the ORSP sensors as available. For example, siting
criteria for the placement of air sampler inlets are
contained in Prevention of Significant Deterioration
guidance documents (EPA, 1976). Inlets for the air
samplers at the ORSP stations have been evaluated
against these criteria and, in most cases, meet the
siting requirements. Guidance or requirements for
handling, shipping, and storage of radioactivity
samples are followed in program operations and
documented in SOPs. Standard analytical method-
ology is used and guidance on the holding times for
samples, sample processing, and results
calculations are followed and documented in SOPs.
77
-------
In the LTHMP, the primary objectives are protection
of drinking water supplies and monitoring of any
potential cavity migration. Sampling locations are
primary "targets of opportunity", i.e., the sampling
locations are primarily wells developed for purposes
other than radioactivity monitoring. Guidance or
requirements developed for Comprehensive
Environmental Response, Compensation, and
Liability Act and Resource Conservation Recovery
Act regarding the number and location of monitoring
wells have not been applied to the LTHMP sampling
sites. In spite of these limitations, the samples are
representative of the first objective, protection of
drinking water supplies. At all of the LTHMP
monitoring areas, on and around the NTS, all
potentially impacted drinking water supplies are
monitored, as are many supply sources with virtually
no potential to be impacted by radioactivity resulting
from past or present nuclear weapons testing. The
sampling network at some locations is not optimal for
achieving the second objective, monitoring of any
migration of radionuclides from the test cavities. An
evaluation conducted by DRI describes, in detail, the
monitoring locations for each LTHMP location and
the strengths and weaknesses of each monitoring
network (Chapman and Hokett, 1991). Corrective
actions are dependent upon DOE funding of new
wells. This evaluation is cited in the discussion of the
LTHMP data in Section 6.
78
-------
Table 10.3 Accuracy of Analysis from RADQA Performance Evaluation Study, 1996
Known Value EPA Average Percent
Nuclide Month (pCi/IJ fpCi/L) Bias
Water Performance Evaluation Studies
Alpha Jan 12.1 13.3 8.3
Alpha Apr(a) 74.8 71.3 -4.7
Alpha Jul 24.4 24.0 -1.6
Alpha Oct 10.3 12.4 16.9
Alpha Oct(a) 59.1 58.5 1.0
Beta Jan 7.0 12.8 -82.9
Beta Apr(a) 167 162 -3.2
Beta . Jul 44.8 51.5 13.0
Beta Oct 34.6 37.5 8.4
Beta Oct(a) 112 111 -0.4
3H Mar 22002 21311 -3.1
3H Aug 10879 10805 -0.7
80Co Jun 99.0 869 778
60Co Oct(a) 15.0 15.7 4.7
60Co Nov 44.0 44.0 0.0
65Zn Jun 300 2801 834
65Zn Nov 35.0 37.7 7.2
89Sr Jul 25.0 24.0 4.0
89Sr Oct(a) 10.0 12.3 23.0
e°Sr Jul 12.0 12.0 0.0
BOSr Oct(a) 25.0 24.0 -4.0
131I Feb 67.0 77.0 14.9
131I Oct 27.0 26.3 -2.6
133Ba Jun 745 6289 744
133Ba Nov 64.0 58.0 -10.3
134Cs Jun 79.0 648 720
134Cs Oct(a) 20.0 21.7 8.5
134Cs Nov 11.0 12.7 15.5
137Cs Jun 197 1761 794
137Cs Oct(a) 30.0 33.7 12.3
137Cs Nov 19.0 19.7 3.7
U,Nat, Apr(a) 58.4 54.9 -6.0
U'Nat> Jun 20.2 20.8 3.0
U(Na" Sep 10.1 10.2 1.0
U(Na" Oct(a) 40.9 38.3 -6.4
U(Na" Dec 5.0 5.0 0.0
(a) Sample from Blind Performance Evaluation (PE) Study
79
-------
Table 1 0.4 Comparability of Analysis from RADQA Performance Evaluation Study, 1 996
Nuclide
Month
Known
Value
(pCi/L)
EPA
Average
(DCi/U
Grand
Average
(pCi/L)
Expected
Precision
Normalized
Dev. of EPA
Average from
Grand Average
Normalized
Dev. of EPA
Average from
Known Value
Water Performance Evaluation Studies
Alpha
Alpha
Alpha
Alpha
Alpha
Beta
Beta
Beta
Beta
Beta
3H
3H
60Co
e°Co
60Co
6SZn
85Zn
89Sr
89Sr
90Sr
90S|.
1311
1311
133Ba
133Ba
134Cs
134Cs
134Cs
137Cs
137Cs
137Cs
u
Ij(Nal)
(j(Nat)
(J(Nat)
Jj(Nat)
Jan
Apr(a)
Jul
Oct
Oct(a)
Jan
Apr(a)
Jul
Oct
Oct(a>
Mar
Aug
Jun
Oct(a)
Nov
Jun
Nov
Jul
Oct(a)
Jul
Oct(a)
Feb
Oct
Jun
Nov
Jun
Oct(a>
Nov
Jun
Oct(a)
Nov
Apr(a)
Jun
Sep
Oct(a)
Dec
12.1
74.8
24.4
10.3
59.1
7.0
167
44.8
34.6
112
22002
10879
99.0
15.0
44.0
300
35.0
25.0
10.0
12.0
25.0
67.0
27.0
745
64.0
79.0
20.0
11.0
197
30.0
19.0
58.4
20.2
10.1
40.9
5.0
13.3
71.3
24.0
12.4
58.5
12.8
162
51.5
37.5
111
21311
10805
869
15.7
44.0
2801
37.7
24.0
12.3
12.0
24.0
77.0
26.3
6289
58.0
648
21.7
12.7
1761
33.7
19.7
54.9
20.8
10.2
38.3
5.0
11.9
68.7
19.7
8.9
59.9
8.5
159
44.4
35.3
108
21573
10591
98.1
15.2
44.5
309
36.1
23.9
10.4
11.8
23.7
68.5
27.6
720
61.4
72.9
18.5
10.6
201
30.5
20.4
55.5
19.9
10.0
39.4
5.1
5.0
18.7
6.1
5.0
14.8
5.0
25.0
5.0
5.0
16.8
2200
1088
5.0
5.0
5.0
30.0
5.0
5.0
5.0
5.0
5.0
7.0
6.0
75.0
6.0
5.0
5.0
5.0
10.0
5.0
5.0
5.8
3.0
3.0
4.1
3.0
0.47
0.24
1.24
1.21
-0.17
1.48
0.20
2.47
0.76
0.37
-0.21
0.34
267
0.15
-0.19
144
0.55
0.04
0.68
0.07
0.11
2.09
-0.37
129
-0.98
199
1.11
0.71
270
1.10
-0.24
-0.20
0.54
0.12
-0.46
-0.08
0.40
-0.32
-0.10
0.72
-0.07
2.00
-0.37
2.32
0.99
-0.05
-0.54
-0.12
267
0.23
0.00
144
0.92
-0.35
0.81
0.00
-0.35
2.47
-0.19
128
-1.73
197
0.58
0.58
271
1.27
0.23
-1.06
0.37
0.08
-1.08
0.00
(a) Sample from Blind Performance Evaluation (PE) Study
80
-------
Table 10.5 Accuracy of Analysis from
Nuclide Month
Air Intercomparison Studies
MMn March
54Mn September
67Co March
"Co September
60Co March
60Co September
106Ru March
106Ru September
125Sb March
125Sb September
134Cs March
134Cs September
137Cs March
137Cs September
144Ce March
238Pu March
238Pu September
23BPu March
Soil Intercomparison Studies
90Sr March
238Pu March
238Pu September
239Pu March
238Pu September
Vegetation Intercomparison Studies
90Sr March
90Sr September
239Pu March
239Pu September
Water Intercomparison Studies
3H March
3H September
54Mn March
S4Mn September
60Co March
60Co September
DOE/EML Performance
Evaluation
EML Value EPA Value
3.44
6.35
8.90
14.8
29.5
8.64
11.6
10.8
9.78
10.8
14.7
10.8
6.64
8.52
33.3
0.09
0.118
0.093
1340.
43.0
1.13
9.23
21.8
1300.
1390.
9.82
1.96
251.
587.
38.4
60.5
32.8
61.1
3.24
9.23
7.71
21.1
29.8
12.2
11.3
14.8
9.35
14.6
14.4
15.3
6.19
11.2
26.9
0.093
0.122
0.099
1.22
42.2
0.79
8.99
21.1
1.15
129.
8.75
2.22
222.
492.
45.4
9.45
36.1
9.28
Studies
Percent
Bias
-5.81
45.4
-13.4
42.6
1.02
41.2
2.59
27.0
-4.40
35.2
-2.04
41.7
-6.78
31.5
19.2
3.33
3.39
6.45
-99.9
-1.86
-30.1
-2.60
-3.21
-99.9
-90.7
-10.9
13.3
-11.6
-16.2
18.2
-84.4
10.1
-84.8
81
-------
Table 10.5 Accuracy of Analysis from DOE/EML PE Studies (Con't)
Percent
Nuclide
Month
EML Value
EPA Value
e°Sr March 1.45
90Sr September 2.71
137Cs March 38.3
137Cs September 89.5
234U March 0.274
234U September 0.480
238U March 0.275
238U September 0.480
238Pu March 0.982
238Pu September 1.91
239Pu March 0.772
239Pu September 0.840
1.29
3.12
46.1
13.4
0.329
0.489
0.313
0.484
0.990
1.92
0.778
0.851
-11.0
15.1
20.4
-85.0
20.1
1.88
13.8
-0.83
0.81
0.52
-0.78
1.31
Table 10.6. Accuracy of Analysis from DOE/MAPEP PE Studies
Result Ref. Mean Std. Bias
(Bq/L) Unc. Value Result Dev. [%]
Cesium-137
57.1 3.6 58.77 55.47 3.54 -5.62
57.9 3.5
51.4 3.2
Cobalt-57
93.8 4.1 92.38 91.37 4.39 -1.10
94.0 4.1
86.3 3.8
Manganese-54
103.9 5.5 99.08 103.6 6.56 4.56
110 5.5
96.9 3.8
Plutonium-238
1.69 .061 1.83 1.74 0.05 -4.79
1.71 .061
1.78 .062
Plutonium-239
1.29 .048 1.34 1.29 0.01 -4.02
1 .28 0.46
1.30 .047
Strontium-90
13.8 0.48 15.69 13.20 1.13 -15.87
13.9 0.41
11.9 0.88
Mean
Flag Uncert.
A 3.43
A 3.83
A 4.93
A 0.06
A 0.05
A 0.59
Uncert.
Flag
L
L
L
L
L
Flags:
A = Mean result is acceptable (Bias <= 20%)
W = Mean result Is acceptable with a warning (20% < Bias <= 30%)
N = Mean result is not acceptable (Bias > 30%)
L = Mean uncertainty potentially too low (for Informational purposes only)
H = Mean uncertainty potentially too high (for informational purposes only)
82
-------
References
Bureau of the Census, 1990, Population Count
Pursuant to Public Law 94-171. Department of
Commerce, Washington, D.C. DOC90
Bureau of Census, 1986. 1986 Population and 1985
Per Capita Income Estimates for Counties and
Incorporated Places, Publication Number P-26. U.S.
Department of Commerce, Washington, D.C.
DOC86
Chapman, J.B. and S.L. Hokett, 1991, Evaluation of
Groundwater Monitoring at Off site Nuclear Test
Areas, DOE Nevada Field Office Report
DO E/NV/10845-07, Las Vegas, NV. CHA 1991
Code of Federal Regulations, 1988. Drinking Water
Regulations, Title 40, part 141, Washington D.C.
CFR88
Committee on the Biological Effects of Ionizing
Radiation 1980. The Effects on Populations of
Exposure to Low Levels of Ionizing Radiation.
National Academy Press, Washington, D.C. BEIR80
Davis, Max, 1996. Annual Water Monitoring on and
around the SALMON Test Site Area, Lamar County,
Mississippi, April 1996, U.S. Environmental
Protection Agency Report EPA 420-R-96-019, Las
Vegas, NV. DAV1996
Houghton, J.G., C.M. Sakamoto, R.O. Gifford, 1975.
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Johns, F., 1979. Radiochemical and Analytical
Procedures for Analysis of Environmental Samples,
U.S. Environmental Protection Agency, Las Vegas,
Nevada, Report EMSL-LV-0539-17-1979, Las
Vegas, NV. JOH 1979
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cites population growth for Pahrump in 1996.
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Measurement, 1989. Screening Techniques for
Determining Compliance with Environmental
Standards: Releases of Radionuclides to the
Atmosphere, NCRP Commentary No 3. Washington
D.C. NCRP89
National Park Service, 1990. Personal
Communication from Supervisor Park Ranger,
R.Hopkins, Death Valley Nation Monument, Death
Valley, CA. NPS90
Quiring, R.E., 1968, Climatological Data, Nevada
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ESSA Research Laboratory Report ERLTM-ARL-7,
Las Vegas, NV. QUI1968
Stanley, T.W. and S.S. Vemer, 1975, The U.S.
Environmental Protection Agency's Quality
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(eds.), Quality Assurance for Environmental
Measurements, ASTM STP-865, Philadelphia, PA.
STA1985
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Specifications for Preparing Quality Assurance
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Protection Agency, Office of Research and
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U.S. Department of Agriculture. Nevada 1994
Agricultural Statistics. Carson City, Nevada.
U.S. Energy Research and Development
Administration, 1977. Final Environmental Impact
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U.S. Environmental Protection Agency. 1976.
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U.S. Environmental Protection Agency, 1996, Quality
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Utah Agricultural Statistics 1994, Utah Department of
Agriculture Annual Report. State Statistical Division,
Salt Lake City, Utah.
84
-------
Glossary of Terms
Definitions of terms given here are modified from the U.S. Nuclear Regulatory Commission Glossary of
terms (NRC81).
alpha Positively charged moving particles
particles (a) identical with the nuclei of helium
atoms. They penetrate tissues to
usually less than 0.1mm (1/250 inch) curie (Ci)
but create dense ionization and
heavy absorbed doses along these
short tracks.
background The radiation in man's natural envir-
radiation onment, including cosmic rays and
radiation from the naturally radioac-
tive elements, both outside and inside
the bodies of humans and animals. dosimeter
It is also called natural radiation. The
usually quoted average individual
exposure from background radiation
is 125 millirem per year in duplicate
midlatitudes at sea level.
becquerel A unit, in the International System
(Bq) of Units, of measurement of radio-
activity equal to one nuclear trans-
formation per second.
beta A charged particle emitted from a half-life
particle (/?) nucleus during radioactive decay,
with a mass equal to 1/837 that of a
proton. A positively charged beta
particle is called a positron. Large
amounts of beta radiation may cause
skin bums, and beta emitters are
harmful if they enter the body. Beta ionization
particles are easily stopped by a thin
sheet of metal or plastic.
Committed The summation of Dose Equivalents
Effective to specific organs or tissues that
Dose would be received from an intake of
Equivalent radioactive material by an individual
during a 50-year period following the ionization
intake, multiplied by the appropriate chamber
weighting factor.
cosmic Penetrating ionizing radiation, both
radiation particulate and electromagnetic, isotope
originating in space. Secondary cos-
mic rays, formed by interactions in
the earth's atmosphere, account for
about 45 to 50 millirem of the 125
millirem background radiation that an
average individual receives in a year.
The basic unit used to describe the
rate of radioactive disintegration. The
curie is equal to 37 billion disintegra-
tions per second, which is approxi-
mately the rate of decay of 1 gram of
radium; named for Marie and Pierre
Curie, who discovered radium in
1898.
A portable instrument for measuring
and registering the total accumulated
dose of ionizing radiation.
A second aliquot of a sample which is
approximately equal in mass or vol-
ume to the first aliquot and is ana-
lyzed for the sample parameters.
The laboratory performs duplicate
analyses to evaluate the precision of
an analysis.
The time in which half the atoms of a
particular radioactive substance disin-
tegrate to another nuclear form.
Measured half-lives vary from mil-
lionths of a second to billions of
years. Also called physical half-life.
The process of creating ions
(charged particles) by adding one or
more electrons to, or removing one
or more electrons from, atoms or
molecules. High temperatures, elec-
trical discharges, nuclear radiation,
and X-rays can cause ionization.
An instrument that detects and mea-
sures ionizing radiation by measuring
the electrical current that flows when
radiation ionizes gas in a chamber.
One of two or more atoms with the
same number of protons, but differ-
ent numbers of neutrons in their nu-
clei. Thus, 12C, 13C, and 14C are iso-
topes of the element carbon, the
numbers denoting the approximate
85
-------
atomic weights. Isotopes have very
nearly the same chemical properties,
but often different physical properties
(for example, 13C and14C are radio-
active).
matrix spike An aliquot of a sample which is
spiked with a known concentration of
the analyte of interest. The purpose
of analyzing this type of sample is to
evaluate the effect of the sample
matrix upon the analytical methodol-
ogy.
method blank A method blank is a volume of de-
mineralized water for liquid samples,
or an appropriate solid matrix for
soil/sediment samples, carried
through the entire analytical proce-
dure. The volume or weight of the
blank must be approximately equal to
the volume or weight of the sample
processed. Analysis of the blank
verifies that method interferences
caused by contaminants in solvents,
reagents, on glassware, and other
sample processing hardware are
known and minimized.
minimum The smallest amount of radioactivity
detectable that can be reliably detected with a
concentration probability of Type I and Type II
(MDC) error at five percent each (DOE81).
millirem A one-thousandth part of a rem.
(mrem) (See rem.)
milliroentgen A one-thousandth part of a roent-
(mR) gen. (See roentgen.)
personnel
monitoring
picocurie
(pCi)
The determination of the degree of
radioactive contamination on individ-
uals using survey meters, or the de-
termination of radiation dosage re-
ceived by means of internal or exter-
nal dosimetry methods.
One trillionth part of a curie.
quality factor The factor by which the absorbed
dose is to be multiplied to obtain a
quantity that expresses, on a com-
mon scale for all ionizing radiations,
the biological damage to exposed
persons. It is used because some
types of radiation, such as alpha
particles, are more biologically dam-
aging than other types.
rad Acronym for radiation absorbed dose.
The basic unit of absorbed dose of
radiation. A dose of one rad means
the absorption of 100 ergs (a small
but measurable amount of energy)
per gram of absorbing material.
radioisotope An unstable isotope of an element
that decays or disintegrates sponta-
neously, emitting radiation.
radionuclide A radioisotope.
rem Acronym for roentgen equivalent
man. The unit of dose of any ionizing
radiation that produces the same
biological effect as a unit of absorbed
dose of ordinary X-rays. (See quality
factor.)
roentgen (R) A unit of exposure in air to ionizing
radiation. It is that amount in air of
gamma or X-rays required to produce
ions carrying one electrostatic unit of
electrical charge in one cubic centi-
meter of dry air under standard con-
ditions. Named after Wilhelm Roent-
gen, German scientist who discov-
ered X-rays in 1895.
Sieved (Sv) A unit, in the International System of
Units (SI), of dose equivalent which is
equal to one joule per kilogram (1 Sv
equals 100 rem).
terrestrial The portion of natural radiation
(background) that is emitted by natu-
rally occurring radiation radioactive
materials in the earth.
tritium A radioactive isotope of hydrogen that
decays by beta emission. It's half-life
is about 12.5 years.
86
-------
Appendix
(LD Calculations)
Determination of L
Accomplished upon the addition of a new
dosimeter type to the program. Once
completed, this test is not normally repeated.
Two methods are acceptable for accomplishing
the task.
Method #1 : At least 1 0 dosimeters for irradiation
per category, plus 10 dosimeters for background
evaluation, for each dosimeter design, are
selected from the routine processed pool of
dosimeters. The dosimeters are placed in an
unshielded environment for a time sufficient to
obtain an unirradiated background signal typical
for routine processed dosimeters. At least 10
dosimeters are irradiated for each category to a
dose significantly greater (e.g., 500 mrem) than
the estimated lower limit of detectability. Both
the irradiated and unirradiated dosimeters are
processed and evaluated. The following
quantities are calculated:
H. =
H1 =
s =
0 ~*
S, =
Mean evaluated dose equivalent values
for unirradiated dosimeters.
Mean evaluated dose equivalent values
for irradiated dosimeters.
Associated standard deviation of
unirradiated dosimeters dose equivalent
values.
Associated standard deviation of
irradiated dosimeters dose equivalent
values.
The dosimeter readings are processed through
the standard dose algorithms without truncation
or distortion (i.e., readings are not rounded to
zero). If a background is subtracted, negative
values are retained for the calculation of S0. The
algorithms for the calculation of shallow and/or
deep dose equivalent are used to calculate H0
and H1f depending on the category test
specifications. The lower limit of detection, LD is
then calculated as follows:
n
Xio
Where:
s, =
£ (*„ -
n-l i=
«, —
n ,-=
XB = Unirradiated dosimeter values.
X, = Irradiated dosimeter values.
Method # 1 - Lower Limit of Detectability Determination
Where:
tp = The t distribution for n - 1 degrees of
freedom and a p value of 0.95.
H'0 = The average of the unirradiated
dosimeter values without subtracting a
background signal.
• Method #2: If NAVLAP performance testing was
completed within six months of this study, then
the values of B and S may be used to calculate
[1.75 X S/(1 + B)] which may be used in place of
tpS/H, in the above equation. Only one set of
unirradiated dosimeters is required to determine
LD using this method.
The above equation is based on the desire
to minimize both false negative and false
positive results. All values below the
detection threshold should be set to zero.
87
-------
For example, LS0 for p = 0.95 is an estimate
of the detection threshold allowing 5% false
positive values. For the lower limit of
detection false negative values are also
minimized. For p = 0.95, the probability of
no more than 5% false positive and false
negative values provides a lower limit of
detection of:
Where:
S0 = The standard deviation of unirradiated
dosimeters.
tp0 and tpD depend on the number of dosimeters
used to estimate S0 and SD, respectively.
The above equation is an estimate of the
relationship:
Lower Limit of Detectability Determination -
Two methods of calculation are considered
acceptable and are detailed in this document. This
Determination uses the data obtained from a 6-
month fade study conducted with both UD-802
(personnel) and UD-814 (environmental) dosimeters.
In each case, the following calculation is
accomplished to determine lower limit of
detectability:
tfS0
Vs.
Where:
onand
OD = The true standard deviations.
The abscissa of the standard normal
distribution below which the total relative
area under the curve is P.
The aD value is composed of the fluctuation of
the background (o~0) and the fluctuation inherent
in the readout process. If o/H, is the relative
standard deviation at high doses, then
a.
— (f-B
TT I X V
H\
Where:
LD =
and solving for LD
S, =
H0 =
H'n=
H, =
LD =
Lower limit of detectability.
The t distribution for n - 1 degrees of
freedom and a p value of 0.95.
Associated standard deviation of
unirradiated dosimeter dose equivalent
values.
Associated standard deviation of
irradiated dosimeter dose equivalent
values.
Mean evaluated dose equivalent values
for unirradiated dosimeters.
The average of the unirradiated
dosimeter values without subtracting a
background signal.
Mean evaluated dose equivalent values
for irradiated dosimeters.
Calculation for Personnel dosimeters:
|U1 I
/L— H.
PH,
Method #2 - Lower Limit of Detectability Determination
2 [2.262 x 0.583
LD =
( 2.262 x 15.014
" { 174.05
•r
LD = 3.01 mR; (for UD 802s)
3.425]
Using tp for Kp and S for o, the final equation in
Method #1 is obtained. If tp0 is not equal to tp D,
the formula for LD is not exact, but should be a
close approximation
detectability.
of the lower limit of
2 [2.571 x 0.983 * f (2.571) 5'039 V 1.033]
1 f 2.571 x
( 168.33
: 5.039V
.33 j
88
-------
LD = 5.10 mR; (for UD814s, CaSO< elements
only)
Similarly LD = 44.73 mR (for UD814s,
elements only)
Where:
Tp = 12.706
S, = 19.315
S0 = 2.081
H0 = 4.5
H, = 163.300
89
------- |