United Slates National Air and EPA 520'5-91 -004
Environmental Protection Radiation Environmental Laboratory
Agency
Ollice ol Radiation Programs
xvEPA
Radiation
Radiological Surveys of Naval
Facilities in the New London Harbor
and on the Thames River,
Connecticut
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EPA 520/5-91-004
Radiological Surveys of Naval Facilities
in New London Harbor and on the
Thames River, Connecticut
Mark O. Semler
and
Richard L. Blanchard
National Air and Radiation Environmental Laboratory
1504 Avenue A
Montgomery, Alabama 36115—2601
December 1991
U.S. Environmental Protection Agency
Office of Radiation Programs
401 M Street, S.W.
Washington, D.C. 20460
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TABLE OF CONTENTS
List of Figures v
List of Tables v
Preface ix
Introduction 1
Characteristics of the Harbor, Thames River, and
the Environs 3
Survey and Analytical Methods 5
Results and Discussion 14
Conclusions 29
References 31
Appendix A: Description of Samples Collected 34
Appendix B: Concentration of Cobalt-60 in Individual
Sediment Samples 37
Appendix C: Concentration of Radionuclides in
Sediment Core Samples 39
Appendix D: Local Gamma Exposure Rate Survey 42
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LIST OF FIGURES
Figure
1. New London, Connecticut Harbor and Thames River .... 10
2. Electric Boat Sediment Sampling Sites 11
3. New London Submarine Base Sediment Sampling Sites. . . 12
4. State Pier and Sound Signature Facility Sediment
Sampling Sites 13
5. Electric Boat Core, Water and Biota Sampling Sites . . 21
6. New London Submarine Base Core, Water, and Biota
Sampling Sites 22
LIST OF TABLES
Table
1. Summary of Samples Collected 9
2. Summary of Radionuclide Concentrations in Sediment
Samples 16
3. Comparison of Co-60 Concentrations in Sediment
Samples Collected in 1972 and 1989 18
4. Summary of the Co—60 Concentrations in Sediment
Core Samples ..... 19
5. Description of Biota Samples 25
6. Summary of Gamma-Ray Exposure Rates 27
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PREFACE
The Office of Radiation Programs identifies and evaluates
environmental public health impacts of both natural and man-made
radiation sources. The National Air and Radiation Environmental
Laboratory (NAREL), formerly the Eastern Environmental Radiation
Facility (EERF), is a fully integrated participant with other
components of the Office in these efforts. The Laboratory provides
comprehensive capability for evaluating radiation sources through
planning and conducting environmental studies, nationwide
surveillance, and laboratory analysis. The NAREL also provides
special analytical support for Environmental Protection Agency
Regional Offices and other federal government agencies, as
requested, as well as technical assistance to the radiological
health programs of state and local health departments.
This report presents results of the surveys conducted by NAREL
personnel to assess levels of environmental radioactivity resulting
from maintenance and operation of nuclear-powered warships at the
New London Submarine Base (NLSB), General Dynamics Electric Boat
Division, Sound Signature Facility, and the State Pier, all located
within New London, Connecticut, Harbor on the Thames River. The
purpose of the survey was to determine if activities related to
IX
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nuclear-powered warships resulted in release of radionuclides which
may contribute to significant population exposure or contamination
of the environment.
Readers of our reports are encouraged to bring comments,
omissions, or errors to our attention.
^X/flxuw -J- ^yU"i^o/-v\CUvv—-
Sam T. Windham, Director
National Air and Radiation
Environmental Laboratory
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INTRODUCTION
Since 1963, the National Air and Radiation Environmental
Laboratory (NAREL), formerly the Eastern Environmental Radiation
Facility (EERF), U.S. Environmental Protection Agency (USEPA), in
cooperation with U.S. Naval Sea Systems Command (NAVSEA), has
surveyed facilities serving nuclear-powered warships on the
Atlantic and Pacific coasts and the Gulf of Mexico. These surveys
assess whether construction, maintenance, overhaul, or refueling of
nuclear-powered warships have created elevated levels of
radioactivity. The surveys emphasize sampling those areas and
pathways that could expose the public.
In 1984, NAVSEA requested that the USEPA again survey all
active facilities servicing nuclear-powered warships. In 1989, the
USEPA conducted a radiological survey of New London, Connecticut,
Harbor and the Thames River, focusing on the action facilities
servicing nuclear—powered warships, in order to determine if
nuclear ship activity has contributed to detectable quantities of
radioactivity to the environment. Measurements and sampling were
primarily conducted in the environs of the New London Submarine
Base (NLSB), General Dynamics Electric Boat Division (Electric
Boat), Sound Signature Facility, and the State Pier.
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This survey was a follow—up of two previous surveys conducted
in the same areas during July 1966 (Ca66) and July 1972 (Wi73).
Cobalt-60 was the predominant non-naturally occurring radionuclide
observed during both surveys. Concentrations in sediment samples
collected by dredge (0-10 cm depth into the sediment) during the
1972 Groton Harbor survey ranged from 0.2 to 26 pCi/g dry
weight, with an average of 2.9 pCi/g. The Cobalt—60 concentrations
in sediment samples collected during the 1972 survey from locations
that duplicated those of the 1966 survey had decreased by a factor
of about 30. This decrease was attributed to a reduction in
radioactivity discharged to the harbor, radioactive decay (half-
life of Co-60 is 5.27 years) and natural sedimentation. Much of
the Cobalt-60 remaining was found at a depth of 15 cm to 20 cm in
the sediment (Wi73), indicating that it did not result from
operations of the early 1970's.
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CHARACTERISTICS OF THE HARBOR, THAMES RIVER, AND THE ENVIRONS
The Thames River is a tidal estuary arising at the confluence
of the Yantic and Shetucket Rivers, approximately 24 km (15 miles)
north of the Groton—New London Harbor area. The river varies in
width from 0.21 km (0.13 miles) to a maximum of 1.82 km (1.13
miles) where it empties into Long Island Sound. The mean tidal
range of the river at New London is 76 cm (2.5 feet).
The bottom sediment is characterized mainly by mud, gravel,
and sand. Because of silting, maintenance dredging is required in
the channel and in the areas adjacent to the piers. Between the
1966 and 1972 surveys, dredging had been done in an area adjacent
to pier 17 and the marine railway at the NLSB and in the area north
of the State Pier. Dredging continued in the Thames River during
the 1980's, primarily to accommodate the greater draft of the
Trident class submarine. However, according to General Dynamics
personnel, no recent dredging has been performed around the piers,
only in the Thames River Channel. Some changes have occurred since
the 1972 survey that are noteworthy. The North Yard at Electric
Boat has been expanded to include the Land Level Facility and
Building 260, and finger pier B has been removed. At the NLSB,
piers 18 through 24 have been replaced with piers 31, 32, and 33.
A new facility, the Sound Signature Facility, has been added south
3
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of the State Pier at Fort Trumball. Personal communications with
local authorities indicated no commercial fishing is done in the
Groton—New London Harbor area, although sport fishing and power and
sail boating are popular, and a ferry boat operates out of New
London. There appeared to be no swimming in the harbor area. The
two principal population centers in the vicinity are Groton, with
about 9,000 people, and New London with about 250,000 people (1980
census).
Both Groton and New London obtain their city water supplies
from reservoirs fed by surface streams. The harbor area is
industrialized with essentially no agriculture along the shore.
The major industries in the harbor area are the New London
Submarine Base, General Dynamics Electric Boat Division, the U.S.
Coast Guard Academy, and Charles Pfizer and Sons.
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SURVEY AND ANALYTICAL METHODS
Personnel from the General Dynamics Radiological Control Group
accompanied the NAREL team during surveys of the four facilities.
They provided information on those sampling sites where
radioactivity associated with Naval nuclear propulsion plants/ if
it were present, would most likely be detected. Extensive sediment
sampling was conducted in the pier and dock areas where nuclear
warships were being or had been serviced. Sampling procedures and
locations were also selected so that comparisons could be made with
the data obtained in the 1972 survey. Locations of vessels and
additions and changes in the piers and docks prevented resurveying
some locations used in 1972. Public access or recreational areas
and public drinking water supplies in the vicinity of the Naval
facilities were also surveyed for radioactivity.
Cobalt—60 is the predominant radioisotope one would find in
environmental media if radioactivity were present as a result of
Naval nuclear propulsion plant operations (Ca66, Wi73, Se88);
therefore, environmental sampling focused on detecting this
radioisotope. The Co-60 content in all samples was determined by
gamma—ray spectroscopy. Water samples were also analyzed for
tritium since this radionuclide is known to be produced in the
coolant of light-water nuclear reactors.
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As stated above, if radioactivity were released as a result of
Naval nuclear propulsion plant operations, it would be detected as
Co—60 in the sediment. Radionuclides tend to accumulate in the
sediment over time, which enables detection of events that may have
occurred in the past. A standard Peterson dredge was used to
sample approximately the top 10 centimeters of sediment. Eighty-
five sediment samples were collected from around the four locations
surveyed. At the laboratory these samples were dried, ground to a
fine powder, placed in 400 cm3 sample counting containers, and
counted on intrinsic germanium detectors for 1000 minutes. The
minimum detectable activity for Co-60 in this geometry is
approximately 0.01 picocuries per gram (pCi/g).
Sediment core samples are useful in determining the vertical
distribution of radioactivity in harbor bottom sediment. If
radioactive material were present from past operations and
subsequently covered with sediment, the radioactivity might be
detected in the core samples. Seven core samples were taken with
3.8 cm diameter plastic tubes housed in a mechanical coring tool.
The cores were frozen and sectioned into 2.5 cm lengths. The
individual sections were freeze—dried and counted on intrinsic
germanium detectors for 1000 minutes to determine the gamma-ray
emitting radioisotopes. The minimum detectable activity for Co-60
in this geometry is approximately 0.1 pCi/g.
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Water samples were collected at ten sites. The surface water
samples were grab samples. The drinking water samples, collected
from taps, represent the water supplies for Groton and New London,
Connecticut, and the New London Submarine Base. One liter water
samples were analyzed for gamma-ray emitters, especially Co-60, on
intrinsic germanium detectors. The minimum detectable level for
Co—60 in this geometry is 5 picocuries per liter (pCi/L) . The
water samples were also analyzed for tritium. The tritium found in
reactor coolant systems is in oxide form and chemically
indistinguishable from water; therefore, it does not accumulate in
marine life or on the harbor floor (Ma88). The minimum detectable
level for tritium is 200 pCi/L with the analytical procedure used.
Aquatic biota samples were collected at six sites by divers.
These samples were divided for analysis as follows: fish — muscle
only; lobster — meat only; crab — whole animal; mussels, clams,
conch, and oysters — meats; starfish, sea cucumber, and sea urchin
— analyzed whole; and vegetation (kelp and sea lettuce). The
biota samples were dried, ground to a fine powder, and counted on
intrinsic germanium detectors for 1000 minutes. The counting
geometry was determined by the amount of sample available; the
minimum detectable level for Co-60 is 0.01 pCi/g for a 400 cm3
sample and 0.1 pCi/g for a 40 cm3 sample.
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Gamma .radiation measurements were made with pressurized
ionization chambers or portable scintillation survey instruments
that were calibrated with the pressurized ionization chambers.
Measurements were made at all sites in the pier and dock areas
where the majority of the sediment samples were collected and along
the security restricted area boundaries at Electric Boat and the
NLSB. Public access and recreation areas in the vicinity of the
NLSB were surveyed with portable scintillation survey instruments,
as were the shores of the Thames River.
Sampling sites are shown on maps of New London Harbor and the
Thames River, New London Submarine Base, Electric Boat, Sound
Signature Facility, and the State Pier in Figures 1 through 6. A
summary of the samples collected from the four sites is presented
in Table 1. Sample types collected at each sampling location are
detailed in Appendix A.
8
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TABLE 1
Summary of Samples Collected
Sampling
Facility Sites
Number of Samples
Water Sediment Cores Biota
River/Harbor 8
Sound Signature
Facility
New London
Submarine Base 36
Electric Boat 33
State Pier 8
TOTAL 88
8
0
5
5
_0
10
34
32
_8
85
0
0
10
12
3
4
0. _P_
7 22
NOTE: See Appendix A for a listing of all samples collected at
each sampling location.
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Figure 1
STATE PIER
j
NEW LONDON
<
SOUND SIGNATURE FACILITY
1-95 BRIDGE
GROTON
i
1
KM
1. New London, Connecticut Harbor and Thames River
10
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0.05 0.1
KM
h
ri,
!• '
NORTH YARD
PRIVATE
SOUTH YARD
NUCLEAR
REPAIR
FACILITY
GUARD TOWER
BUOY#13
THAMES RIVER
RED
MARKER
2. Electric Boat Sediment Sampling Sites
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"I
H-
uq
2
n
CD
0 0.1 0.2
KM
USS
NAUTILUS
MEMORIAL
DEPENDENTS
MARINA
NR-1
COMPOUND
• "3
3. New London Submarine Base Sediment Sampling Sites
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Figure 4
t
i
0 0.1 0.2
KM
SOUND SIGNATURE FACILITY
4. State Pier and Sound Signature Facility Sediment Sampling Sites
13
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RESULTS AND DISCUSSION
Sediment Samples
Eighty—five sediment samples were Collected from around the
four locations surveyed and from the harbor and river. The
sampling locations are shown in: Figure I, The Thames River and
New London Harbor; Figure 2, Electric Boat; Figure 3, the NLSB;
and Figure 4, the State Pier and the Sound Signature Facility. A
summary of the radionuclide concentrations measured in the sediment
samples is presented in Table 2. Traces of Co—60 were observed in
all samples collected. The Co-60 concentrations in individual
samples are provided in Appendix B. The presence of the Co—60 in
the sediment of these locations is the result of past Co-60
releases from nuclear-powered warships. The Cs-137 observed in the
sediments can be attributed to fallout from previous atmospheric
nuclear tests, and the other radionuclides detected are naturally
occurring.
The Co—60 concentrations vary widely between samples;
however, the average concentrations at the four sites are similar,
ranging from 0.14 pCi/g at the NLSB to 0.26 pCi/g at the State
Pier. The average Co-60 concentration of all samples collected is
0.18 pCi/g.
14
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Background sediment samples were collected from three
locations upriver (North) of the Navy facilities (see sites 39, 40,
and 41 in Figure 1) . Low concentrations of Co—60 were observed in
sediment samples from upriver locations during the 1972 survey,
indicating that small quantities of Co-60 have moved upriver.
Considering that the background samples were collected only from
about 1.2 km to 4.5 km north of the NLSB, the radioactivity
observed upriver probably resulted from tidal movements generating
currents that had swept sediments short distances upriver. Also,
the lower concentrations measured in sediments out of the facility
confines in the harbor and river were probably the result of faster
currents and dredging activities. The average upriver background
concentration observed during this survey, 0.02 pCi/g, is
significantly less than for the 1972 survey, consistent with the
expected decrease due to radioactive decay and sedimentation. It
also indicates that no Co-60 has been released since the 1972
survey.
15
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TABLE 2
Summary of Radionuclide Concentrations
in Sediment Samplesa'b/c
Radionuclide
Electric
Boat
Submarine
Base
State
Pier
No. of Samples
K-40
Cs-137
Co-60
Ra-226
Th-232
32
19(13-20)
0.13(0.02-0.69)
0.20(0.06-0.65)
1.6 (1.2-2.1)
0.84(0.71-1.00)
34
17(10-20)
0.17(0.03-0.35)
0.14(0.01-0.23)
1.5(0.86-1.8)
0.77(0.52-1.19)
8
17(16-18)
0.13(0.10-0.16)
0.26(0.16-0.60)
1.5(1.2-1.8)
0.77(0.68-0.89)
Radionuclide
Sound Signature
Facility
Harbor/
River
Background*3
No. of Samples
K-40
Cs-137
Co-60
Ra-226
Th-232
16(14-19)
0.10(0.09-0.11)
0.16(0.08-0.20)
1.3(1.0-1.5)
0.69(0.57-0.77)
5 3
17(13-19) 14(11-15)
0.13(0.03-0.29) 0.10(0.02-0.24)
0.06(0.02-0.11) 0.02(<.01-0.03)
1.6(0.9-1.9) 1.3(1.0-1.7)
0.96(0.85-1.03) 0.80(0.63-0.90)
Concentrations are pCi/g dry weight.
''Mean concentrations are given with the range shown in parentheses.
"Approximate 2-sigma counting errors are: K-40 (3%); Cs-137 (20%);
Co-60 (30% for concentrations less than 0.1 pCi/g); Ra-226 (20%);
and Th-232 (10%).
dSampling sites 39, 40, and 41 are considered background sites (see
Figure 1).
16
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Cobalt-60 was observed in sediment samples collected during
previous surveys of these facilities in 1966 and 1972. An attempt
was made during this recent survey to collect some sediment samples
from the same sites used in 1972. Although changes in piers and
docks since the last survey, as well as conditions that existed
during this survey, made this task difficult, twelve sampling sites
were duplicated. The results obtained in 1989 are compared in
Table 3 with measurements made in 1972. Significant decreases in
the Co-60 concentration have occurred at all sites. A seven to
eight fold decrease in the Co-60 concentration has occurred in
sediments at the NLSB, which is about the decrease that would
result from radioactive decay in the 17-year period since the last
survey with no subsequent Co-60 added. A greater decrease is
observed to have occurred in sediments at the Electric Boat area
and the State Pier (25 to 30 fold), which may be the result of
sedimentation in addition to radioactive decay.
17
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TABLE 3
Comparison of Co—60 Concentrations
in Sediment Samples Collected in 1972 and 1989.
Co-60 Concentration,
Sampling Location pCi/g dry weight
1989 1972 1989 1972
49
48
50
55
59
46
48
43
52
51
New London Submarine Base
0.18
0.18
0.19
0.18
0.21
1.5
1.9
1.3
1.4
1.0
Average Concentrations 0.19 1.4
Electric Boat
13
21
22
23
25
85
87
25
31
30
33
32
Average
8
12
Average
Concentrations
State
Concentrations
0
0
0
0
0
0
.23
.20
.39
.34
.16
.26
1
2
2
9
26
8
.1
.5
.5
.3
.1
.3
Pier
0
0
0
.16
.22
.19
4
5
4
.0
.5
.8
Although Co-60 was observed in sediment at the Navy
facilities/ the concentrations present are very small, and have
continued to decrease with time at a rate equal to or greater than
the decay rate of Co—60. The small and decreasing quantities of
18
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Co-60 in the harbor sediments pose no radiological impact to the
area.
Sediment Core Samples
Sediment core samples were collected at seven sites: four
samples from the aquatic environs of Electric Boat (Figure 5) and
three samples from the NLSB (Figure 6) . Traces of Co-60 were
detected throughout the cores in all samples. A summary of the Co-
60 concentrations measured in the core samples is presented in
Table 4, and the results for each depth increment (2.5 cm) are
reported in Appendix C.
TABLE 4
Summary of the Co-60 Concentrations in
Sediment Core Samples3
Sample
Location1*
Total
Depth, cm
Co-60 Concentration,
pCi/g dry weight0
Range Average
Electric Boat
8
15
21
26
28
43
15
13
0
0
0
0
.07-0
.10-0
.05-0
.07-0
.18
.19
.12
.07
0.
0.
0.
0.
13
15
09
07
New London Submarine Base
48
52
65
25
18
13
0
0
0
.14-0
.21-0
.23-0
.37
.31
.36
0.
0.
0.
23
25
28
aSee Appendix C for detailed analytical results.
bSee Figures 5 and 6 for sampling locations.
19
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°Analytical uncertainties in the results are about 75% for
concentrations between 0.1 and 0.2 pCi/g, and 35% for
concentrations greater than 0.2 pCi/g.
20
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PRIVATE
PIER
0 0.05 0.1
KM
NORTH YARD
SOUTH YARD
NUCLEAR
REPAIR
FACILITY
GUARD TOWER
d
h
(D
BUOY#13
THAMES RIVER
AREA SAMPLED BY DIVERS FOR AQUATIC BIOTA
CORE SAMPLE
WATER SAMPLE
RED
MARKER
5. Electric Boat Core, Water and Biota Sampling Sites
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"I
1'
•Q
d
n
(D
o
0.1
KM
0.2
USS
NAUTILUS
MEMORIAL
ISJ
rv.
DEPENDENTS
MARINA
6. New London Submarine Base Core, Water and Biota Sampling Sites
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Cobalt-60 concentrations in the core samples from the NLSB
were about twice those measured in samples from Electric Boat (0.2
versus 0.1 pCi/g); however, the difference is probably not
significant considering the variability of Co-60 concentrations in
the sediment and the few samples obtained. No significant
variation in concentration with depth was observed in cores from
Electric Boat. The maximum concentration of 0.37 pCi/g at a depth
of about 18 cm was observed in the core from the NLSB at sampling
location 48 (see Appendix C), however, this concentration cannot be
related to any particular occurence and indicates the Co—60 is not
the result of current operations. The other radionuclides observed
in the core samples are Cs-137, which is attributed to fallout from
previous atmospheric nuclear tests, and K—40, Ra-226, and Th—232,
which are naturally occurring radionuclides.
Water Samples
Surface water samples were collected at seven sites: sites 2,
16, 21, and 31 at Electric Boat and sites 46, 51, and 72 at the
NLSB. No radioactivity associated with nuclear-powered warships
was detected in any of the water samples by the gamma-ray analysis.
Tritium concentrations were below the limit of detection, 200
pCi/L. Drinking water samples were collected from Groton (site
28), New London (site 29), and the NLSB (site 88). No detectable
23
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gamma-ray activity was observed in any of the drinking water
samples, and the tritium concentrations were below the detectable
level.
Biota Samples
Twenty-two biota samples were analyzed from six locations (see
Figures 5 and 6). A list of the samples from each site that were
analyzed for gamma-ray emitting radionuclides is provided in Table
5. The small concentrations of Co-60, less than 0.1 pCi/g dry
weight, measured in samples of kelp, sea lettuce, and starfish from
Electric Boat and kelp, sea lettuce, and sea cucumber from the NLSB
may be due to sediment adhering to the surface of these biota
samples. Cobalt-60 was not detected in any edible seafoods. Some
samples contained small traces of Cs-137 and Th-232.
24
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TABLE 5
Description of Biota Samples
Site Location3 Samples Analyzed
Electric Boat
North Area, Site 1 Clams & Mussels
Starfish
Lobster & Conch
Kelp
Middle Area, Site 2 Lobster
Starfish & Sea Urchin
Kelp
South Area, Site 3 Lobster & Crab
Starfish
Mussels
Sea Lettuce
Kelp
Submarine Base
North Area, Site 1 Flounder
Lobster & Mussels
Kelp & Sea Lettuce
Starfish
Middle Area, Site 2 Starfish & Mussels
Lobster
Mussels & Conch
South Area, Site 3 Lobster
Starfish, Mussels, Conch
Kelp & Sea Cucumber
aSee Figures 5 and 6 for these sampling locations.
25
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GAMMA RADIATION MEASUREMENTS
Gamma radiation measurements were taken at the sediment
sampling sites/ north of the State Docks (to represent background),
along the Electric Boat and NLSB restricted area boundaries, and
along each shoreline of the Thames River. The shoreline surveys
extended from Jupiter Point on Long Island Sound to Hurlbut Road in
Gales Ferry, Connecticut, on the east shore and from Ocean Beach
Park on Long Island Sound to Powerhouse Road near Uncasville,
Connecticut, on the west shore. In addition, a few radiation
measurements were made in areas accessible to the public on the
NLSB. Radiation measurements at the sediment sampling sites were
performed with pressurized ionization chambers, while land surveys
were conducted with portable scintillation survey instruments that
had been calibrated with the pressurized ionization chambers. A
summary of the gamma ray exposure measurements is presented in
Table 6. Individual exposure rates measured during the land
surveys are presented in Appendix D.
26
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TABLE 6
Summary of Gamma-Ray Exposure Rates
Gamma—Ray Exposure Rates, i/R/hr
Location of Survey Average Range
Harbor Sampling Sites
Electric Boat 4.3 3.4-5.2
New London Submarine Base 6.9 3.2-8.5
Background 4.1 3.8-4.6
Restricted Area Boundary at Electric Boat 4.0 3.5-4.8
Restricted Area Boundary at Submarine Base 3.9 3.2-4.6
Shoreline Survey*
East Shoreline 8.2 3-12
West Shoreline 8.1 3-11
New London Submarine Base - Land
Marine shoreline
near Bldg 181 & 387 11 10-12
Lower base shoreline 8.2 6-10
Golf Course, greens 1-3 16 15-19
aSee Appendix D for individual exposure measurements.
All gamma—ray exposure measurements made in accessible
locations over water in the harbor reflect background exposure
rates. The exposure rate measurements made in the harbor are lower
than those taken on land because of the shielding afforded by the
water.
The exposure rates along the two shorelines of the Thames
River are very similar and within the expected background range for
that area, 3 //R/hr to 12 //R/hr (EPA 89) . A description of the
27
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areas surveyed is given in Appendix D. Measurements taken on the
NLSB in areas accessible to the public ranged from 6 fJR/tir to 19
A*R/hr. The slightly elevated measurements over those taken along
the shoreline are attributed to natural terrestrial radiation or
areas where rock high in granite content was used as fill (Se88,
Sm87, Wi87).
28
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CONCLUSIONS
The radiological surveys of the Naval Facilities on the Thames
River at Groton and New London, Connecticut, provide the basis for
the following conclusions:
1. Trace quantities of Co-60 remain in the sediment at all
locations investigated; however, the concentrations have
significantly decreased since the earlier two surveys and
represent no radiological impact to the environment or
individuals living or working in the area.
2. Sediment samples that duplicated samples obtained in 1972
contained 8—30 times less Co—60 than the earlier samples,
indicating that radioactive decay and sedimentation is
naturally reducing the Co—60 levels in surface sediments and
that no significant releases of Co-60 have occurred in recent
years.
3. No Co-60 was detected in any edible aquatic species.
4. All seven sediment core samples contained low levels of Co-60.
The maximum concentration observed was 0.37 pCi/g at a depth
of about 18 cm, but this cannot be related to any particular
occurrence and indicates the Co—60 is not the result of
current operations.
29
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CONCLUSIONS — Continued
5. Water samples contained no detectable levels of radioactivity
other than those occurring naturally.
6. Gamma-ray measurements did not detect any increased radiation
exposure to the public above natural background levels.
7. Based on these surveys, current practices regarding nuclear-
powered warship operations have resulted in no increase in
radioactivity that would result in significant population
exposure or contamination of the environment.
30
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REFERENCES
B176 Blanchard, R.L., et. al. 1976. Radiological Surveillance
Studies at the Oyster Creek BtfR Nuclear Generating
Station. EPA-520/5-76-003. Washington, D.C.:
U.S. Environmental Protection Agency, Office of
Radiation Programs.
Ca66 Cahill, D.F., Breakfield, W.D., and McCurry, D.C., 1966.
Radiological Survey of the Thames River, Connecticut,
and Environs. Southeastern Radiological Health
Laboratory Technical Report, July/August, 1966.
Ca87 Callis, R.S., 1987. Radiological Survey of the Pearl
Harbor Naval Shipyard and ^Environs, Honolulu, Hawaii.
EPA 520/5-87-010. Washington,
D.'C. :
U.S. Environmental Protection Agency, Office of
Radiation Programs.
EPA89 U.S. Environmental Protection Agency, 1989. Environmental
Radiation Data, Report 58, April - June 1989.
EPA 520/5-89-034. Washington, D.C.:
U.S. Environmental Protection Agency, Office of
Radiation Programs.
31
-------
REFERENCES — Continued
EPA90a U.S. Environmental Protection Agency, 1990. Environmental
Radiation Data: Report 59 (July - September 1989).
EPA 520/5-90-003. Washington D.C.: U.S. Environmental
Protection Agency, Office of Radiation Programs.
EPA90b U.S. Environmental Protection Agency, 1990. U.S.
Environmental Radiation Data: Report 60 (October -
December 1989). EPA 520/5-90-018. Washington, D.C. :
U.S. Environmental Protection Agency, Office of
Radiation Programs.
Ma88 Mangeno, J.J., Steele, J.M., and Poletti, L.F., 1988.
Environmental Monitoring and Disposal of Radioactive
Wastes from U.S. Naval Nuclear Powered Ships and Their
Support Facilities. Naval Sea Systems Command Report,
NT-88-1.
Se88 Semler, M.O. and Blanchard, R.L., 1988. Radiological
Survey of San Diego Bay". EPA 520/5-88-019.
Washington, D.C.: U.S. Environmental Protection
Agency, Office of Radiation Programs.
Sen88 Sensintaffar, E.L. and Blanchard, R.L., 1988.
Radiological Survey of the Norfolk Naval Station, the
Norfolk Naval Shipyard, and Newport News Shipbuilding.
EPA 520/5-88-017. Washington, D.C.:
U.S. Environmental Protection Agency, Office of
Radiation Programs.
32
-------
REFERENCES — Continued
Sm87 Smith, J.M., 1987. Radiological Survey of Charleston
Naval Base and Shipyard and the Charleston Naval
Weapons Station. EPA 520/5-87-009. Washington, D.C. :
U.S. Environmental Protection Agency, Office of
Radiation Programs.
Wi73 Windhan, S.T. and Phillips, C.R., 1973. Radiological
Survey of New London Harbor, Thames River,
Connecticut, and Environs. Radiation Data Report 14,
No. 11, 659-666, November, 1973.
Wi87 Windham, S.T., 1987. Radiological Survey of Kings Bay
Submarine Support Facility. EPA 520/5-87-008.
Washington, B.C.: U.S. Environmental Protection
Agency, Office of Radiation Programs.
33
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APPENDIX A
Description of Samples Collected
Facility/Site No.
Samples Collected
Electric Boat
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
30
31
32
33
34
Sediment
Sediment,
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment,
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment, Core,
Sediment,
Sediment
Sediment
Sediment
Sediment
Sediment, Core,
Surface Water
Sediment
Sediment
Sediment
Sediment
Sediment,
Sediment
Drinking Water
Sediment
Sediment,
Sediment
Sediment
Sediment
Surface Water
Core, Biota3
Biota8
Surface Water
Core, Biota8
Surface Water
34
-------
APPENDIX A — Continued
Description of Samples Collected
Facility/Site No.
Samples Collected
Thames River
35
36
37
38
39
40
41
75
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
New London Submarine Base
29
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
Drinking water
Sediment
Sediment
Sediment
Sediment
Sediment, Surface Water
Sediment
Sediment, Core
Sediment
Sediment
Sediment, Surface Water
Sediment, Core, Biota3
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment, Core
Sediment, Biota3
35
-------
APPENDIX A — Continued
Description of Samples Collected
Facility/Site No.
Samples Collected
New London Submarine Base
67
68
69
70
71
72
73
74
76
88
State Pier
77
78
79
83
84
85
86
87
Sound Signature Facility
80
81
82
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment, Surface Water,
Biota8
Sediment
Sediment
Sediment
Drinking Water
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
'The nearest site to the biota collection area.
36
-------
APPENDIX B
Concentration of Cobalt-60 in Individual Sediment Samples
Site No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
35
36
37
38
Co-60, pCi/g Site No. Co-60, pCi/g
0.23±0.02a
0.07±0.02
0.09±0.01
0.09±0.01
0.07±0.01
0.30±0.03
0.13±0.03
0.2010.04
0.21±0.02
0.18±0.03
0.21±0.02
0.15±0.03
0.23±0.02
0.23±0.02
0.22±0.02
0.16±0.02
New London
0.02±0.01
0.07±0.02
NAC
0.02±0.01
Electric Boat
17
18
19
20
21
22
23
24
25
26
27
30
31
32
33
34
Harbor and Thames River
39
40
41 <
75
0.22±0.02
0.21±0.01
0.21±0.02
0.20±0.02
0.20±0.04
0.39±0.03
0.34±0.02
0.65±0.05
0.16±0.02
0.06±0.01
0.34±0.03
0.07±0.03
0.18±0.02
0.12±0.02
0.17±0.02
0.24±0.04
0.03±0.01b
0.01±0.01b
0.01b
0.11±0.02
New London Submarine Base
42
43
44
45
46
47
48
49
0.05±0.01
0.18±0.02
NA
0.01±0.01
0.15±0.02
0.18±0.02
0.18±0.02
0.18±0.02
59
60
61
62
63
64
65
66
0.21±0.02
0.09±0.02
0.20±0.04
0.05±0.01
0.07±0.01
0.15±0.02
0.19±0.03
0.13±0.02
37
-------
APPENDIX B — Continued
Concentration of Cobalt-60 in Individual Sediment Samples
Site No.
50
51
52
53
54
55
56
57
58
Co-60, pCi/g
0.19±0.02
0.12±0.03
NA
0.14±0.02
NA
0.18±0.02
0.23±0.04
0.16±0.02
0.21±0.03
Site No.
67
68
69
70
71
72
73
74
76
Co-60, pCi/g
0.17±0.02
0.15±0.02
0.16±0.02
0.06±0.01
0.15±0.02
0.07±0.01
0.16±0.02
0.15±0.02
0.16±0.02
State Pier
77
78
79
83
80
81
0.60±0.05
0.2110.02
0.23±0.03
0.26±0.02
Sound Signature
0.08±0.02
0.20±0.02
84
85
86
87
Facility
82
0.21±0.02
0.16±0.02
0.19±0.03
0.22±0.02
0.20±0.03
"Error term is given as 2—Sigma counting error,
Concentration measured in background sample.
"NA-Not Analyzed.
38
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APPENDIX C
Concentration of Radionuclides in Sediment Core Samples
Concentration, pCi/a dry weight
Depth, cm
2.5
5.1
7.6
10.2
12.7
15.2
17.8
20.3
22.9
25.4
27.9
2.5
5.1
7.6
10.2
12.7
15.2
2.5
5.1
7.6
10.2
12.7
2.5
5.1
7.6
K-40 Cs-137
Electric Boat,
18 0.3
18 0.2
25 0.1
22 0.1
20 0.1
17 0.4
18 0.1
17 0.04
21
24
16
Electric Boat,
18 0.2
18 0.2
19 0.1
19 0.1
22 0.1
20 0.2
Electric Boat,
18
14 0.1
17 0.1
20 0.1
20 0.1
Electric Boat,
25 0.2
20 0.2
20 0.2
Co-60 Ra-226
Site 8
0.18
1.7
0.12 1.8
0.16
0.15
0.15
0.10
0.11 1.6
0.07 2.3
Site 21
0.10
0.11 0.9
0.06
1.7
0.05 2.0
0.12
Site 26
0.07
1.9
0.07 2.0
2.6
Site 15
0.12
0.19 1.5
0.16 1.5
Th-232
0.6
0.7
1.6
0.7
0.8
0.9
0.9
1.1
0.8
2.3
1.0
0.9
1.0
1.6
1.0
0.8
0.7
0.8
1.0
0.8
2.2
1.0
0.9
39
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APPENDIX C — Continued
Concentration of Radionuclides in Sediment Core Samples
Concentration, pCi/q
Depth, cm
10.2
12.7
15.2
17.8
20.3
22.9
25.4
27.9
30.5
33.0
35.6
38.1
40.6
43.2
2.5
5.1
7.6
10.2
12.7
15.2
17.8
20.3
22.9
25.4
2.5
5.1
7.6
10.2
K-40 Cs-137
22
22
22
22
19
20
19
24
18
22
20
21
18
18
18
23
16
21
20
20
21
21
17
20
22
16
20
18
Electric Boat,
0.5
0.2
0.2
0.3
0.2
0.2
0.2
0.2
0.2
0.1
0.4
0.2
0.1
Submarine Base,
0.1
0.2
0.1
0.3
0.2
0.2
0.2
0.2
Submarine Base/
0.2
Co-60
Site 15
0.11
0.17
0.19
0.17
0.15
0.15
0.14
0.12
0.15
0.10
0.15
Site 48
0.16
0.24
0.14
0.16
0.26
0.28
0.37
0.26
0.17
Site 52
0.21
0.31
0.29
dry weight
Ra-226
1.6
1.7
1.9
2.0
1.2
2.4
2.4
2.1
Th-232
1.6
0.8
1.0
1.7
0.9
0.9
1.0
1.1
1.7
1.0
1.2
0.9
0.3
0.8
0.8
0.8
0.8
1.3
1.0
1.1
0.9
0.8
1.3
1.8
0.7
1.1
0.8
40
-------
APPENDIX C — Continued
Concentration of Radionuclides in Sediment Core Samples
Concentration, pCi/q dry weight
Depth, cm K-40 Cs-137 Co-60 Ra-226 Th-232
Submarine Base, Site 52
12.7 20 0.2 0.23 1.0
15.2 18 0.2 0.23 1.0
17.8 23 0.1 0.25 2.4
Submarine Base, Site 65
2.5 22 0.1 0.27 0.9
5.1 21 0.36 1.5
7.6 22 0.3 0.29 0.9
10.2 21 0.2 0.23 1.0
12.7 16 0.26 1.2
NOTE: The approximate uncertainties are: K-40 <10%); Cs—137
(60%); Ra-226 (80%); Th-232 (30%); Co-60 (75% for concentrations
less than 0.1 pCi/L) ; Co-60 (50% for concentrations between 0.1 and
0.2 pCi/L); Co-60 (35% for concentrations greater than 0.2 pCi/L).
41
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APPENDIX D
Local Gamma Exposure Rate Survey
Location
Average Exposure Rate
Groton & Eastern Side of Thames River
South of Electric Boat
1) Jupiter Point
2) Avery Point
3) Tyler Place on Eastern Point
Shoreline, NE of Hobbs Island
Shoreline, Point Juck
4)
5)
6)
North of Electric Boat
7) Shoreline, North of Electric
Boat off Thomas Street
8) Shoreline, Thomas Street at
Creaker Memorial
9) Shoreline, Thomas Street at
School Street
10) Shoreline, Thomas Street
between Board and Bridge Street
11) Shoreline, under 1-95 bridge
South of New London Submarine Base
12) Shoreline, South of USS Nautilus
Memorial
13) Shoreline, between USS Nautilus
and the Submarine Base
North of New London Submarine Base
14) North Gate of Submarine Base on
Military Highway
15) Military Highway at Mill Cave
16) Shoreline, Bluff Road at Brown's
Crossing
17) Shoreline, Riverside Place at
Hurlbut Road
10
9
10
6
5
Corner of Shore & Avery St. Mouth of River 8
10
7
3
8
7
11
7
12
7
12
7
42
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APPENDIX D — Continued
Local Gamma Exposure Rate Survey
Average Exposure Rate
Location //R/hr
New London & Western Side of Thames River
Uncasville Area
18) Shoreline, end of Powerhouse Road 6
19) Shoreline, off Lanthrop Road 10
20) Shoreline, end of Lower Bartlett Road 11
Quaker Hill Area
21) Shoreline, end of Cap Road 9
22) Shoreline, end of Richard's
Grove Road 10
23) Shoreline, end of Benham Avenue 8
New London, North of 1-95 Bridge
24) Shoreline, end of Saltonstall Street 10
25) Shoreline, end of Farnsworth Street 9
26) U.S. Coast Guard Academy, end of
pier for USS Eagle 3
27) Shoreline, end of Lewis Street 7
28) Shoreline, under 1-95 bridge 8
New London, South of 1—95 Bridge
29) Shoreline, off 16th Street, North
of State Pier 11
30) Shoreline, Bank Street, between
Pearl Street and Captain WK 10
New London, South of Fort Trumbull
31) Shoreline, Pequot Avenue, south
of Fort Turmbull 7
32) Shoreline, Pequot Avenue, between
Plant and Thames Streets 6
33) Shoreline, Pequot Avenue at
Chapel Street 7
34) Shoreline, Pequot Avenue, north
of New London Lighthouse 7
35) Shoreline, Pequot Avenue at Lower
Boulevard 7
43
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APPENDIX D — Continued
Local Gamma Exposure Rate Survey
Average Exposure Rate
Location //R/hr
Long Island Sound
36) Shoreline, Pequot Avenue at
Neptune Avenue 7
37) Shoreline, Ocean Beach Park 9
New London Submarine Base
Base Marina
38) Shoreline, near Bldg. 181 12
39) Shoreline, near Bldg. 387 10
Lower Base Survey
40) Shoreline, near Bldg. 176 6
41) Shoreline, near Bldg. 175 7
42) Shoreline, near Bldg. 174 9
43) Shoreline, near Bldg. 178 9
44) Near RADCON ship berthed between
piers 12 & 13 10
Base Golf Course
45) Course Green at first hole 19
46) Course green at second hole 15
47) Course Green at third hole 15
44
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