United States
Environmental Protection
Agency
Office of Radiation Programs
Eastern Environmental
Radiation Facility
1890 Federal Drive
Montgomery, AL 36109
EPA 520/5-88-018
June 1989
Radiation
SEFft
Radiological Survey of the
Mare Island Naval Shipyard,
Alameda Naval Air Station,
and Hunters Point Shipyard
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DISCLAIMER
This report was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor any agency Thereof, nor any of their employees,
makes any warranty, express or implied, or assumes any legal
liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial product,
process, or service by trade name, trademark, manufacturer, or
otherwise does not necessarily constitute or imply its endorsement,
recommendation, or favoring by the United States Government or any
agency thereof. The views and opinions of authors expressed herein
do not necessarily state or reflect those of the United States
Government or any agency thereof.
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EPA--520/5-88-018
DE89 014543
EPA 520/5-88-018
Radiological Survey
of the
Mare Island Naval Shipyard, Alameda Naval Air Station,
and Hunters Point Shipyard
Mark 0. Semler
and
Richard L. Blanchard
Eastern Environmental Radiation Facility
1890 Federal Drive
Montgomery, Alabama 36109
March 1989
U.S. Environmental Protection Agency
Office of Radiation Programs
401 M Street SW
Washington. DC 204&Q
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Table of_Cgitjents
List of Figures ......................... v
List of Tables ........... ..... . ........ ¥
Preface
Introduction .......................... 1
Characteristics of the Harbor and Sanpling Arets ........ 3
Survey and Analytical Methods ...,...........i*. S
Results «nd Discussion ...................... 12
Conclusions ........................... li
References
Appendix;
1, Oescrfptioti of Saiples Collected ............ 17
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List of Figures
Figure
1 General location of sites surveyed in the San Francisco
and San Pablo Bays 2
2 Sampling locations at the Mare Island Naval Shipyard .... 6
3 Sampling locations at the Alameda Naval Air Station .... 7
4 Sampling locations at the Hunters Point Shipyard 8
List of Tables
Table
1 A summary of samples collected from the three Naval
facilities 11
2 A summary of radionuclide concentrations in harbor
sediment samples 13
3 A summary of the gamma-ray exposure rate measurements ... 14
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jPreface_
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 surveys conducted by EERF personnel
to assess levels of environmental radioactivity resulting from maintenance
and operation of nuclear-powered warships at Naval facilities located
within San Francisco and San Pablo Bays on the California coast. The
purpose of the survey was to determine if activities related to
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.
Charles R. Porter, Director
Eastern Environmental Radiation Facility
vii
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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. The surveys emphasize sampling
those areas and pathways that could expose the public.
In 1984, NAVSEA requested that EPA survey all active facilities
serving nuclear-powered warships over the next three years. This report
contains the results of surveys conducted at Naval facilities located at
Mare Island, Alameda, and Hunters Point in the San Francisco region. The
locations of these facilities are shown in Figure 1.
A previous survey was conducted in the area by EERF personnel (at
that time U.S. Public Health Service) in April 1967 (Ca67). The early
survey was conducted only at the Mare Island Naval Shipyard in San Pablo
Bay. Radioactivity attributable to nuclear-powered warship activities,
primarily H-3 and Co-60, was not detected at that time in any samples
collected from Mare Island Strait. Only natural radioactivity and
radioactivity attributed to fallout from nuclear weapons testing was
observed. The present study, conducted from September 8, 1986 to
September 17, 1986, was expanded to include the Naval facilities at
Alameda and Hunters Point in San Francisco Bay.
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VALLEJO
Figure 1, General location of sites surveyed in the San Francisco and San Pablo Bays.
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Characteri sties of the r|la^
Mare Island Strait and
Mare Island Strait is located in the northern part of San Pablo Bay
25 miles northeast of San Francisco. The strait is formed by the City of
Vallejo on the east side of the $apa River and Mare Island on the west
side. Mare Island Strait is approximately three miles long and is bounded
by the Sears Point Causeway on the north and San Pablo Bay on the south.
The width of the strait varies from approximately one thousand to two
thousand feet. The mean tidal range is 4.5 feet and the maximum current
velocity is 4.1 feet per second in the strait. The bottom of the strait
is characterized by soft mud and silt. Heavy silting action in the strait
necessitates the removal of approximately two million cubic yards of
bottom sediment annually in constant dredging operations. Over a
significant portion of its length, the strait is confined between the
piers and docks of Mare Island and a sea wall on the opposite shore ,
precluding bathing and agriculture in the vicinity of the Naval Shipyard.
The city of Vallejo has a population of approximately 80,000.
Vallejo is in a fertile agricultural section which produces grain, beets,
orchard fruits, grapes and livestock. Vallejo's principal industry is the
Mare Island Naval Shipyard. Since 1958 the shipyard has been involved in
the construction, maintenance and overhaul of nuclear-powered warships.
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Vallejo's water supply comes from Cache Slough approximately 25 miles
northeast of the city with the main pumping station at Maine Prairie
Slough. There is no commercial fishing in the strait but some sport
fishing is done.
Hunters Point Shipyard
The U.S. Navy Reservation at Hunters Point is located on
San Francisco Bay in the southeastern sector of the city of San Francisco.
Mare Island Naval Shipyard personnel occasionally perform maintenance of
nuclear-powered warships at Hunters Point. The Shipyard lies approximately
three miles from the Golden Gate at the southern periphery of over 80
piers and wharves along an improved waterfront used primarily for
commercial shipping enterprises. In addition to the commercial shipping
enterprises carried out along the waterfront, San Francisco Bay is also
used extensively for pleasure boating and limited commercial fishing
activities.
Alameda Naval Air Station
The Alameda Naval Air Station is located in what is called the East
Bay Area. It is on the northern end of the island occupied by the city of
Alameda. It is located about two miles south of the San Francisco -
Oakland Bay Bridge adjacent to the towns of Oakland and Alameda and
bordered by Inner Harbor and San Francisco Bay. The Alameda Naval Air
Station serves as a homeport for nuclear-powered warships.
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Survey and Analytical Methods
Navy personnel helped the EERF survey team identify the most probable
sampling locations, those where radioactivity associated with Naval
nuclear propulsion plants, if it were present, would most likely be
detected. Extensive sampling was done near the dry docks and pier areas
where nuclear warships are or have been serviced. Sampling sites at the
Mare Island Naval Shipyard, Alameda Naval Air Station, and Hunters Point
Shipyard are shown in Figures 2, 3, and 4, respectively. Samples of
bottom sediment, water, algae, sea lettuce, and mussels were collected.
According to past surveys, cobalt-60 is the predominant radioisotope
one would find in environmental media if radioactivity is present as a
result of Naval nuclear propulsion plant operations (Ca77, Se88);
therefore, environmental sampling focused on detecting this radioisotope.
Cobalt-60 content in all samples was determined by gamma-ray spectroscopy.
All water samples were also analyzed for tritium since this nuclide is
known to be produced in the coolant of light-water nuclear reactors.
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. All probe
measurements were made for 10 minutes. The underwater probe has been
useful in past surveys of other facilities to select areas for dredge
sampling of bottom sediment and to delineate areas of radioactivity.
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Figure 2. Sampling locations at the Mare Island Naval Shipyard,
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AIMIEWIIWW.WB STATION
«D
O.
•5"
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Ft. Avisadero
Figure 4. Sampling locations at the Hunters Point Naval Shipyard.
8
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However, due to the relatively low sensitivity (as compared to laboratory
measurements) of the probe} sediment samples were collected at the
locations of probe measurements for laboratory analysis. Duplicate
samples were collected for quality assurance purposes at approximately
5 percent of the sites.
A standard Peterson dredge was used to sample approximately the top
10 centimeters of sediment. These sediment samples were collected at all
locations identified in Figures 2, 3, and 4. In addition, a sediment
sample was collected in a background location a few hundred yards north of
the Napa Highway 37 bridge (No. 1) and at the support for the Highway 37
Bridge (No. 2). See Figure 1 for the locations of these two sampling
sites. At the laboratory these samples were dried, ground to a fine
3
powder, placed in a 400 cm sample counting container and counted on a
Ge(Li) or intrinsic germanium detector for 1000 minutes. The minimum
detectable activity for cobalt-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
materials were present from past operations which were subsequently
covered with sediment, it might be observed in the core samples. Core
samples were taken with a 3.8 centimeter diameter by 61 centimeter long
plastic tube. A mechanical driver was used to push the tube into the
sediment automatically capping the ends during retrieval. Core samples
were collected at locations 9, 10, and 15 at the Mare Island Naval
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Shipyard and at location No. 12 at the Hunters Point Shipyard. No cores
were collected from the sediments at the Alameda Naval Air Station because
it had no history of past nuclear ship activities. At the laboratory the
four cores were frozen and cut into 2.5 cm sections. The individual
sections were freeze-dried and counted on a Ge(Li) or intrinsic germanium
detector to determine gamma emitting radioisotopes. The minimum detectable
activity for cobalt-60 in this geometry is approximately 0.1 pCi/g.
Surface water samples were collected at the background location
(No. 1, Figure 1) at two locations at the Mare Island Naval Shipyard
(Nos. 9 and 31), at two locations at the Alameda Naval Air Station (Nos. 1
and 4), and at two locations at the Hunters Point Shipyard (Nos. 1 and
12). Public drinking water supplies were sampled at the Mare Island Naval
Hospital Clinic (No. 42, Figure 1), in Vallejo at the Royal Bay Best
Western Motel (No. 43, Figure 1), and at the San Francisco International
Airport (No. 44, Figure 1). These samples were analyzed for gamma
emitters (especially Co-60) and tritium. The minimum detectable activity
for tritium and cobalt-60 in water is 200 pCi/L and 5 pCi/L, respectively,
with the analysis procedures used.
Algae was collected from location 15 at the Mare Island Naval
Shipyard and location 2 at the Alameda Naval Air Station. Vegetation (sea
lettuce) and mussel samples were collected from the harbors at the Alameda
Naval Air Station and Hunters Point Shipyard. The algae and mussels were
3
dried in an oven, then packed into 200 cm containers and counted dry on
a Ge(Li) detector for 1,000 minutes to determine the concentrations of
10
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gamma emitting radioisotopes. The sea lettuce samples were treated in an
identical manner, except, as a result of larger sample quantities, they
3
were counted in 400 cm containers.
Gamma radiation surveys were made using pressurized ionization
chambers (PIC) or portable scintillation survey instruments that were
periodically calibrated with a pressurized ionization chamber. All
measurements were made 1 meter above the ground or water surface. Surveys
were conducted within the security exclusion area of the Mare Island Naval
Shipyard and in the dock and pier areas of each facility where sediment
(dredge) samples were collected. A summary of all samples collected from
the harbors of the three facilities is presented in Table 1.
Table 1. A summary of samples collected
from the three Naval facilities^8'
Facility
San Pablo Bay
Mare Island Naval
Shipyard
San Francisco Bay
Hunters Point Shipyard
Alameda Naval Air Station
Sampling
Sites
41
21
13
Water
3
2
2
Number of Samples
Sediment Cores
41 3
21 1
13 0
Aquatic
Life(b)
A
L, M
A, L, M
(^Samples were collected on September 8 to 11, 1986. See Appendix 1
a listing of all samples collecte
A-algae; L-sea lettuce; M-mussels.
, .
ma listing of all samples collected at each sampling location.
A-
11
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Results and Discussion
Previous experience with harbor bottom sediment sampling has shown
that if any significant amount of radioactivity has been released it
usually would be detectable in the sediment (Ca77, Se88). Radionuclides
tend to accumulate in the sediment over time which enables detection of
events that may have occurred in the past. Samples were collected at 75
locations at the three Naval facilities. No cobalt-60 or other gamma
emitting radionuclides from nuclear-powered warship operations were found
in any of the samples. The failure of the underwater gamma scintillation
probe to detect any areas on the harbor floor having radioactivity above
background further confirms the absence of any significant radioactive
contamination. The failure of the underwater gamma scintillation probe to
detect any areas on the harbor floor having radioactivity above background
further confirms the absence of any significant radioactive contamination.
Only naturally occurring nuclides and trace quantities of cesium-137,
typically fallout from previous worldwide nuclear weapons testing, were
found in the samples. A summary of the radionuclide concentrations
measured in these sediment samples is given in Table 2.
Core samples collected from 3 locations at Mare Island Naval Shipyard
(Nos. 9, 10, 15) and from one location at Hunters Point Shipyard (No. 12)
were analyzed for gamma emitting radionuclides. None of the eight
one-inch sections from any of the four cores contained radionuclides other
than those naturally occurring and trace amounts of cesium-137, about 0.15
pCi/g dry, that was relatively constant with depth reflecting a long-term
uniform deposition rate.
12
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Table 2. A summary of radionuclide concentrations in harbor sediment samples
Radionucli
Sampl es
K-40
Co-60
Cs-137
Pb-214
Bi-214
Ra-226
Th-232
de Mare Island
39
12 (8-14)
< 0.01
0.17 (0.07-0.32)
0.48 (0.30-0.56)
0.46 (0.29-0.52)
1.1 (0.8-1.4)
0.46 (0.32-0.55)
Hunters Point
12
<
0.19
0.42
0.40
0.99
0.38
21
(10-15)
: 0.
(0.
(0.
(0.
(0.
(0.
01
14-0.
36-0.
35-0.
80-1.
29-0.
23)
52)
51)
11)
42)
Alameda
12
<
0.19
0.42
0.40
1.4
0.37
Background
13
(9-14)
: 0.
(0.
(0.
(0.
(0.
(0.
01
08-0.
32-0.
31-0.
71-1.
26-0.
25)
49)
48)
15)
43)
< 0.
0.
0.
0.
1.
0.
2
11
01
05
60
56
4
73
Notes:
1) Concentrations are pCi/g dry weight.
2) Mean concentrations are given with the range shown in parentheses.
3) Approximate 2o counting errors are:
K-40 (3 percent); Cs-137 (10 percent); Pb-214 (7 percent); Bi-214
(7 percent); Ra-226 (20 percent); Th-232 (11 percent).
Surface water samples collected in the harbors at Mare Island,
Hunters Point, and Alameda had tritium levels below the minimum detectable
level of 200 pCi/L. Potassium-40s a naturally occurring radionuclide and
present at an average concentration of 230 ± 60 pCi/L, was the only gamma
emitting nuclide detected. Also, no detectable radioactivity was found in
the three drinking water samples from the water supplies of Mare Island,
Vallejo, and San Francisco.
Only very small quantities of naturally occurring radionuclides,
principally K-40 (about 30 pCi/g dry), and Cs-137 (< 0.1 pCi/g dry)
typical of fallout from previous nuclear weapons testing, were measured
in samples of algae collected in the harbors at Alameda and Mare Island.
Smaller quantities of these radionuclides were observed in the two sea
13
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lettuce samples from the harbors at Alameda and Hunters Point, Both mussel
samples contained only K-40 (10 pCi/g dry) and a trace of Cs-137 (0.02 pCi/g
dry). Thus, no radioactivity indicative of nuclear-powered ships was detected
in any of the biological samples that were collected from the harbors.
A summary of the gamma-ray exposure rates measured at each sampling
location in the harbors of the three Naval facilities (see Figures 2, 3,
and 4) is given in Table 3. The exposures were relatively constant over
the surface of the harbors, varying only within a small range. The average
exposure rate at all three facilities was 4.4 * 0.4 pR/hr, which is consistent
with that measured in nearby background areas, 4.1 * 0.2 pR/hr. The gamma-ray
exposure rate was also measured in the security exclusion zone of the
Mare Island Naval Shipyard on September 8S 1986. The gamma-ray survey began
at the causeway and proceeded south at 2-3 knots remaining about 100 yards
off the piers. The gamma-ray exposure rates varied from 3.5 to 5.0 jiR/hr
with an average of 4.0 pR/hr. These exposure rates again reflect natural
background levels.
Table 3. A summary of the gamma-ray exposure rate measurements
.(a)
NU. VI
Location of Survey Measurements
Mare Island Naval Shipyard 41
Alameda Naval Air Station 21
Hunters Point Shipyard 13
Average* Range
4.4 * 0.5 3.4-5.8
4.4 * 0.3 3.9-5.0
4.4 * 0.4 3.6-5.0
Background exposure rate was 4.1 * 0.2.
values are the standard deviation of the means.
14
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Conclusions
The radiological survey of the Mare Island Naval Shipyard, Alameda
Naval Air Station, and Hunters Point Shipyard provided the basis for the
following conclusions:
1. Only radionuclides of natural origin and trace amounts of Cs-137
from previous nuclear weapons testing were detected in the harbor
sediment samples. No radioactivity associated with the operation
and maintenance of nuclear-powered warships was detected in any
of either the dredge or core sediment samples.
2. No tritium or gamma-ray emitters, other than trace amounts of
those occurring naturally, were detected in surface water from
the harbors or in nearby drinking water supplies.
3. No gamma-ray emitters, other than trace amounts of those occurring
naturally, were detected in harbor algae, musselss or sea lettuce.
4. Gamma-ray surveys of the harbors failed to detect any exposure
rates elevated significantly above background.
5. Based on this survey, operations related to nuclear-powered
warship activities have contributed no detectable radioactivity
to the harbors at Mare Island, Alameda, and Hunters Point. Thus,
under present conditions Naval operations within these harbors
pose no radiological health problem to the public.
15
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References
Ca67 Cahill, D.F., McCurry, D.C., and Breakfield, W.D., 1967,
"Radiological Survey of Major California Nuclear Ports-April
1967"s U.S. Public Health Service, Southeastern Environmental
Radiological Health Laboratory Report, PB-178-728.
Ca77 Callis, R.S., Windhara, S.T., and Phillips* C.R.S 1977,
"Radiological Survey of Puget Sound Naval Shipyard, Bremerton,
Washington and Environs", U.S. Environmental Protection Agency
Report, EPA 520/5-77-001.
Se88 Sensintaffar, E.I, and Blanchard, R.L., 1988, "Radiological
Survey of the Norfolk Naval Station, the Norfolk Naval Shipyard,
and Newport News Shipbuilding", U.S. Environmental Protection
Agency Report, EPA 520/5-88-017.
16
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1
Description of SamplesCollected
Sampling
Site No.
Samples Collected
Sampling
Site No.
Samples Collected
Mare Isi and Naval Shipyard
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
1
2
3
4
5
6
7
Sediments surface water
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment, core,
surface water
Sediment, core
Sediment
Sediment
Sediment
Sediment
Sediment, core, algae
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Alameda Naval Air
Sediment, surface water
Sediment, algae
Sediment
Sediment, surface water
Sediment
Sediment
Sediment
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
Station
8
9
10
11
12
13
(a)
(b)
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment, surface water
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Drinking water
Drinking water
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sea Lettuce
Mussels
17
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APPENDIX 1 - Continued
Description of Sampjes Collected
Sampling
Site No.
Samples Collected
Sampling
Site No.
Sarnies Collected
Hunters Point Naval Shipyard
1
2
3
4
5
6
7
8
9
10
11
12
Sediment, surface water
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment, core, surface water
13
14
15
16
17
18
19
20
21
44
(a)
(b)
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Sediment
Drinking water
Sea lettuce
Mussel s
(a) Samples of sea lettuce were floating.
(b) Collected from multiple sites across the harbor.
18
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