United States
Environmental Protection
Agency
Office of Radiation Programs
Eastern Environmental
Radiation Facility
1890 Federal Drive
Montgomery, AL 36109
EPA 520/5-87-009
June 1987
Radiation
Radiological Survey of
Charleston Naval Base and
Shipyard and the Charleston
Naval Weapons Station
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Radiological Survey
of the
Charleston Naval Base and Shipyard
and the Charleston Naval Weapons Station
J. Michael Smith
Eastern Environmental Radiation Facility
1890 Federal Drive
Montgomery, Alabama 36109
July 1987
U.S. Environmental Protection Agency
Office of Radiation Programs
401 M Street SW
Washington, DC 20460
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Table of Contents
List of Figures v
List of Tables v
Preface vii
Introduction 1
Characteristics of Charleston Naval Base
and Shipyard and Weapons Station 1
Survey and Analytical Methods 2
Results and Discussion 7
Conclusions 14
References 15
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List of Figures
Figure
1 General Site Sampling Locations, Charleston Harbor, SC . . . 3
2 Sampling Locations Along the Charleston Shipyard Piers ... 4
3 Sampling Locations, Charleston Naval Weapons Station .... 5
4 External Gamma Readings (uR/hr) Measured at the
Charleston Naval Station and Naval Shipyard, August 1985 . 9
5 External Gamma Readings (yR/hr) Measured at the Naval
Weapons Station, August 1985 10
List of Tables
Table
1 Results of Harbor Water Analysis 8
2 Results of Aquatic Life Sample Gamma Analysis 12
3 Exposure Measurements Observed at Sampling Sites with ... 13
Pressurized lonization Chamber
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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 Eastern Environmental Radiation Facility (EERF) is a fully
integrated participant with other components of the Office in these
efforts. The Facility provides comprehensive capability for evaluating
radiation sources through planning and conducting environmental studies,
nationwide surveillance, and laboratory analysis. The EERF 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 survey conducted by EERF
personnel to assess levels of environmental radioactivity resulting from
maintenance and operation of nuclear-powered warships at the Charleston
Naval Base and Shipyard and the Charleston Naval Weapons Station, near
Charleston, South Carolina. The purpose of the survey was to determine
if operations related to nuclear powered warship activities 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.
Charles R. Porter, Director
Eastern Environmental Radiation Facility
Vll
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Introduction
Since 1963, the Eastern Environmental Radiation Facility (EERF),
U.S. Environmental Protection Agency (USEPA), in cooperation with the
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 the operation of nuclear powered
warships, during construction, maintenance, overhaul, or refueling, have
created elevated levels of radioactivity and whether any elevated levels
that are found constitute a significant hazard to the public health and
safety or the environment. The surveys emphasize sampling those areas and
pathways that could expose the public.
In 1984, NAVSEA requested that all active facilities servicing
nuclear powered warships be resurveyed over the next three years.
Charleston Naval Base and Shipyard and the Naval Weapons Station,
Charleston, SC, which were surveyed by EERF personnel in August 1985, are
the second group of facilities to be completed under this agreement. The
Harbor was last surveyed by the EERF (then the U.S. Public Health Service)
in January, 1966 (1). The 1985 survey was similar to that in 1966 except
that more detailed sampling was performed around the piers and near the
dry docks than in 1966 and the newer equipment used is generally more
sensitive, which results in lower levels of detectability.
Characteristics of Charleston Naval Base and Shipyard and Weapons Station
Charleston Harbor is formed by the confluence of the Ashley, Cooper
and Wando Rivers and lies seven miles inland of the Atlantic Ocean. It
serves the city of Charleston, South Carolina, which is the closest
population center. The Charleston Naval Base and Shipyard and the Naval
Weapons Station are located on the Cooper River, immediately north of the
City of Charleston. The Shipyard contains the submarine base, berthing
areas and repair basins while the Weapons Station is the weapons loading
location for the submarines.
Of the three rivers forming the harbor, the Cooper has the most
influence. The Ashley and Wando are tidal throughout their lengths and
contribute no fresh water in-flow except for local run-off. The Cooper
is tidal to the Pinopolis Dam, a part of the Santee-Cooper Power Project
of the State of South Carolina. As a result of the hydroelectric power
plant, which operates on a demand basis, the mean discharge prior to 1985
was approximately 15,000 cfs (2, 3). In 1985, a rediversion canal forming
a new outlet for Lake Moultrie was completed which carries most of the
Santee River water diverted into Lake Moultrie back to the Santee River.
The purpose of the rediversion canal is to reduce the requirements for
maintenance dredging of Charleston Harbor. Since completion of the
rediversion canal in 1985, the mean discharge is approximately 3,000 cfs
V«J ) T1 ) .
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Survey and Analytical Methods
The basic purposes of the survey were to document the radioactivity
levels in the harbor and environs, ascertain whether there is any public
health significance of these levels and, if possible, determine their
origin. Specifically, the survey was designed to determine:
(a) The radionuclides and levels of radioactivity currently present
in and adjacent to the harbor,
(b) The location of radioactivity in the harbor area,
(c) The distribution of radioactivity between the various components
of the environment, i.e., harbor bottom sediment, water, fish,
and shellfish.
To achieve these goals, samples of harbor and drinking water, harbor bottom
sediment, shellfish, and fin fish were collected and returned to the EERF
for radioanalysis. In addition, a gamma scintillation probe designed to
measure activities in situ was utilized in an attempt to determine the
relative geographiclCistribution of activity on the harbor bottom.
Sampling sites were selected to represent the most probable locations
where radioactivity could be deposited and which are accessible to the
public. Extensive sampling was done in the vicinity of all dry docks,
berthing areas, and repair facilities where nuclear powered warships are
or have been serviced. Discussions were held with Navy personnel to aid
in selecting sampling locations. Sampling locations are shown in Figure 1
for the general area surrounding the Charleston Naval Base and Shipyard
and the Charleston Naval Weapons Station. Figures 2 and 3 show sampling
locations for the Naval Base and Shipyard and the Naval Weapons Station,
respectively.
Since cobalt-60 is the predominant radioisotope associated with Naval
nuclear propulsion plants, environmental sampling focused on detecting
this radioisotope. In the 1966 survey of Charleston, low levels of
cobalt-60 were found in harbor bottom sediment. Some manganese-54 was
also detected in the harbor sediment.
An underwater gamma scintillation probe with a 10 centimeter by 10
centimeter sodium iodide detector was used with a portable multichannel
pulse height analyzer to help locate areas of radioactivity. A background
was taken at Site 1 and stored in the memory for subtraction from each
measurement to yield net activity. All probe measurements were made for
10 minutes. The underwater probe has been useful in past surveys to
select areas for dredge sampling of bottom sediment and to delineate areas
of radioactivity. However, due to the relatively low sensitivity (as
compared to laboratory measurements) of the probe, sediment samples were
collected at all locations of probe measurement where sediment was
available. Probe measurements were duplicated for quality assurance
purposes at approximately 10% of the sites.
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Charleston Naval
Weapons Station
See Figure 3
Charleston Naval
Shipyard and Base j__ ^"^fj
See Figure 2
Atlantic Ocean
Figure 1: General Site Sampling Locations, Charleston Harbor, South Carolina
3
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Dry Dock #1
Dry Dock #2
Shipyard
M
PierN
Pier P
Figure 2: Sampling Locations Along the Charleston Shipyard Piers
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To NWS Main Gate
Figure 3: Sampling Locations, Charleston Naval Weapons (NWS) Station
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A standard Peterson dredge was used to sample approximately the top
10 centimeters of harbor bottom sediment. These sediment samples were
collected at 105 sampling locations. At approximately 5% of the sampling
sites, duplicate sediment samples were collected. At the laboratory the
samples were dried, ground to a fine powder, placed in 400 cnr containers,
and counted on a Ge(Li) or intrinsic germanium detector for 1,000 minutes.
Sediment core samples have been useful in determining the vertical
distribution of radioactivity in past surveys. Radioactive materials from
past operations which were subsequently covered with sediment might be
observed in the core samples. Core samples were taken with a 3.8
centimeter diameter by 61 centimeter long plastic tube. The tube was
pushed into the sediment as far as possible, capped on each end, and
carefully removed. At the laboratory the cores were frozen and cut into
2.5 cm sections. Sections were dried, weighed and counted on a Ge(Li) or
intrinsic germanium detector for 1,000 minutes to determine gamma emitting
radioisotopes. The activity is reported per gram dry weight.
Water samples were collected at 10 locations in the harbor and from 2
public drinking water supplies. These samples were placed in 1 liter
containers and counted on a Ge(Li) or intrinsic germanium detector for
1,000 minutes to detect gamma emitting radioisotopes, especially Co-60.
Seventeen aquatic life samples (shellfish and fish) were collected at
various locations in the harbor by the South Carolina Fish and Game
Division. These samples were shipped to EERF where they were prepared by
cutting and packing in 400 cm3 containers and counted wet on a Ge(Li) or
intrinsic germanium detector for 1,000 minutes to determine levels of
gamma emitting radioiostopes.
Direct gamma radiation exposure was monitored and recorded
continuously each day using a pressurized ionization chamber (PIC) mounted
on the survey boat. The average surface exposure rate at each sampling
location was identified on the continuous record.
An overland survey was also conducted, along the shoreline areas and
the perimeter fences that are accessible to the public, in both the
shipyard and the weapons station. A few other areas within these
facilities were also monitored. These measurements were made with a
scintillation survey meter that was periodically calibrated with a PIC.
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Results and Discussion
Harbor bottom sediment sampling was the most extensive, since past
surveys have shown that if radioactivity had been released, it would
usually be detectable in the sediment. Samples were collected at 105
locations. Only naturally occurring radionuclides and trace amounts of
Cs-137 (typically fallout from previous worldwide nuclear weapons testing)
were found in these sediment samples. The EERF minimum detectable
activity for cobalt-60 in sediment is approximately 0.01 pCi/gram and we
did not detect cobalt-60 in any of these sediment samples.
Core samples were collected at 7 locations and analyzed for gamma
emitting radionuclides. None of these cores contained other than
naturally occurring radionuclides and trace amounts of Cs-137.
Harbor water samples were collected at eight locations. The
radionuclide content of these samples determined by gamma analysis is
shown in Table 1. Only naturally occurring K-40 was found in these water
samples. Sample 91 was collected at the Weapons Station near Snow Point
and showed no detectable radioactivity. It is believed that a sample this
far upstream would be fresh water and that this is the reason that no K-40
was detected in the sample. All other harbor water samples collected in
this study were collected downstream from location 91.
Drinking water samples were collected at the shipyard diving locker
room and from the Charleston municipal drinking water supply. The samples
were gamma analyzed and no detectable radioactivity was found in these
samples.
During the overland survey of the Naval Base and Shipyard perimeters,
external gamma exposures were observed between 6 and 46 yR/hr (see Figure
4). All radiation levels above general background (which is 8-15 yR/hr in
the Charleston area) were due to natural radioactivity included in stone,
asphalt or concrete used in shoreline riprap, roadbeds, and other
construction, or due to natural radioactivity in sand used for
sandblasting operations. For the Naval Weapons Station, external
radiation levels were observed between 5 and 50 yR/hr (see Figure 5). All
radiation levels above background are associated with the asphalt road
beds on the site or with the asphalt and stone riprap used along parts of
the shoreline near Wharf Alpha and Piers B and C. For both the Naval Base
and Shipyard and the Weapons Station, the occasional slightly elevated
radiation levels detected in the overland survey are not associated with
any nuclear operations at the facilities but result from sandblasting
sand, asphalt, stone and concrete, which are slightly higher in natural
radioactivity content than the silt and soil along the shoreline.
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Table 1
Results of Harbor Water Analysis
Location
1
5
6
24
42
63
91
100A
100B
Radionuclide
K-40
K-40
K-40
K-40
K-40
K-40
K-40
K-40
Activity (pCi/1)
+_ 2 sigma error
200 * 24%
140 + 31%
220 + 23%
65 + 88%
190 + 27%
120 + 34%
ND
145 + 33%
100 + 45%
ND-No detectable radioactivity.
8
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McMillian Ave Gate
- • 9
Hospital Gate
Shipyard Gate
(Reynolds Ave.)
Naval Base
Main Gate
Govt. Property Boundary
Shipyard Industrial Area Boundary
Figure 4: External Gamma Readings (pR/hr) Measured at the Charleston
Naval Station and Naval Shipyard, August 1985.
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To NWS Main Gate
Floating Dry Dock
Figure 5: External Gamma Readings (uR/hr) Measured at the Naval Weapons Station, August 1985.
10
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Aquatic life samples (fish and shellfish) were collected by the
South Carolina Fish and Game Division and shipped to EERF for analysis.
The results are presented in Table 2. All radioactivity detected in these
samples is of natural origin with no contribution based on shipyard or
weapons station operations. The absence of detectable Co-60 activity in
seafood is important from the public health standpoint since many seafood
organisms tend to concentrate this isotope to levels greatly in excess of
its concentration in the surrounding water and bottom sediment.
Pressurized ionization chamber (PIC) readings were taken at most
sediment sampling locations and the external gamma radiation levels
measured are listed in Table 3. Measurements made over water were with
the PIC approximately fifteen feet above the water surface. Measurements
made over land were with the PIC approximately 3 feet above the land
surface. Background levels were measured at all locations where data were
recorded.
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Table 2
Results of Aquatic Life Sample Gamma Analysis*
Sample
Type
Flounder
Crabs
Shrimp
Trout
Spot
Shrimp
Trout
Shrimp
Shrimp
Shrimp
Crabs
Crabs
Crabs
Crabs
Crabs
Crabs
Shrimp
Location
Radionuclide Concentration
(pCi/gm wet) + 2 sigma error (%}
Charleston Harbor
Shipyard, Piers H & X
Rebellion Reach
Rebellion Reach Harbor
Rebellion Reach
Shipyard, Piers A-J
Shipyard, Piers J-A
Ft. Johnson
Ft. Johnson
Miscellaneous Locations
Shipyard
Shipyard
Shipyard
Weapons
Weapons
Weapons
Weapons
, Pier
, Pier
Station
Station
Station
Station
M
M
, Pier
, Pier
, Pier
A
B
C
Locations
K-40
2.7+ 7%
1.4+13%
2.8+17%
2.7+16%
2.6+8%
2.0+12%
3.1+16%
1.6+24%
2.5+11%
2.2+ 9%
1.9+13%
1.8+ 9%
1.8+11%
1.4+13%
2.0+13%
1.5+11%
2.1+ 8%
0
0
0
0
0
0
Pb-214
.083+51%
.028+52%
.10 +25%
.049+61%
.16 +19%
.11 +20%
0
0
0
0
0
0
Bi-214
.086+34%
.023+58%
.12 +20%
.055+40%
.17 +22%
.092+22%
0
0
0
0
Th-232
.048+47%
.074+41%
.076+37%
. 18 +29%
™"
* Note: Samples were collected by the South Carolina Fish and Game Division.
The EPA sample location numbering system did not include location numbers for
these samples. Blanks in the table indicate that no detectable levels of the
radionuclide appeared in that sample.
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Table 3
Exposure Measurements Observed at Sampling Sites
with Pressurized lonization Chamber
Site
1
2
3
4
5
6
7
8
9
10
11
T2
13
14
15
16
T7
18
19
24
28
29
30
34
35
36
37
39
40
41
42
43
44
Exposure (yR/hr) Site Exposure (yR/hr) Site Exposure (yR/hr)
4.0
4.0
5.0
4.0
4.3
4.0
4.0
4.2
4.2
3.9
4.1
4.0
4.1
4.2
4.5
4.5
3.7
4.0
4.3
4.7
5.0
4.8
3.8
4.0
4.5
4.2
4.5
6.5
5.1
4.4
4.5
4.0
4.8
45
46
47
48
49
53
54
55
56
57
58
59
60
61
62
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
4.0
4.6
4.5
4.5
4.5
4.4
4.2
4.2
4.0
4.5
4.1
4.2
5.2
4.5
4.5
5.0
5.0
4.7
4.5
4.0
5.2
4.7
5.2
4.3
4.0
4.5
4.2
4.2
5.2
5.1
5.6
5.4
4.3
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
4.0
4.6
3.5
4.0
4.0
4.8
4.6
4.1
4.0
4.8
4.0
3.8
4.7
5.0
4.4
4.0
4.5
4.2
6.0
4.0
4.0
4.4
13
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Conclusions
The radiological survey of the Charleston Naval Base and Shipyard and
the Naval Weapons Station provided the basis for the following conclusions:
1. All samples collected during this survey contained only low
levels of natural radioactivity and cesium-137 from fallout. There
was no detectable radioactivity in any of the samples due to nuclear
operations at the shipyard or weapons station.
2. The low levels of cobalt-60 in harbor sediment have decreased to
non-detectable levels since the 1966 survey.
3. Drinking water from the shipyard and from the Charleston
municipal water supply did not contain any detectable radioactivity.
4. In the overland survey of the base and shipyard and the weapons
station, no elevated readings from nuclear powered warship operations
at these facilities were detected.
5. Navy practices to restrict the release of radioactive material
to the minimum practical into the harbor have been effective.
14
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References
1. U.S. Department of Health, Education and Welfare, 1966, "Radiological
Survey of Charleston Harbor, Charleston, South Carolina", Public
Health Service, Division of Radiological Health, Southeastern
Radiological Health Laboratory, Montgomery, Alabama.
2. U.S. Army Corps of Engineers, 1957, "Investigation for Reduction of
Maintenance Dredging in Charleston Harbor, South Carolina; Summary
Report of Model Investigation", U.S. Army Engineers Waterway
Experiment Station, Vicksburg, MS, Report No. 2-444.
3. Patterson G.G., 1983, "Effect of the Proposed Cooper River
Rediversion on Sedimentation in Charleston Harbor, South Carolina",
U.S. Geological Survey, Columbia, SC, Water-Resources Investigations
Report 83-4198.
4. Patterson G.G. and Cooney T.W., 1986, "Sediment Transport and
Deposition in Lakes Marion and Moultrie, SC", Proceedings of the
Third International Symposium on River Sedimentation, rhe unlversity
of Mississippi, Jackson, MS, pp. 1336-1345.
15
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