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September 28, 2004
CRESP Amchitka Expedition Update:
Overview of Specimen Testing,
Data Management and Quality Assurance for Samples and Data Collected
BY Charles
W. Powers, CRESP II PI
Report Coordinated and Edited by Henry Mayer
This Amchitka
Expedition Update will discuss the samples and other data collected by
the CRESP expedition teams, and provide an overview of specimen testing,
data management and quality assurance programs currently being undertaken
by the joint CRESP team at Rutgers University, Vanderbilt University,
University of Medicine & Dentistry of New Jersey and the University
of Pittsburgh, and through the use of INEEL as an independent testing
laboratory.
Introduction
The
Amchitka Independent Assessment Science Plan (June 24, 2003) was developed
by CRESP to assess, for Native Communities, the U.S. Fish & Wildlife
Service, the Alaskan Department of Environmental Conservation, U.S. Department
of Energy and other stakeholders, whether there are currently increased
radiation health risks related to underground nuclear test shots to organisms
residing around Amchitka Island and to consumers of these organisms. It
will also provide a baseline for future monitoring as part of long-term
stewardship, prior to termination of the Department of Energy's Environmental
Management responsibility for Amchitka Island.
The
Amchitka Expedition Summary (June 10, 2004) described the basic hypotheses
that CRESP would be testing and the implementation plans it would be pursuing
in furtherance to the Science Plan, beginning with the collection of extensive
physical and biological samples on Amchitka and Kiska (reference site)
and in the waters that surround them between June 12 and August 8. Much
of this work was carried out with a research team of 25 and a six-man
crew aboard the Ocean Explorer. Additional marine samples were collected
with the assistance of a NOAA trawling expedition during the same time
frame.
Purpose
and Scope
There is public and agency concern that residual radionuclides from nuclear
tests may enter the marine food chain causing ecological and human health
effects. The specific objectives of the Science Plan are:
- To determine whether
or not current or future radionuclide releases from the shot cavities
to the marine environment pose significant risks to human health and
the ecosystem.
- To reduce uncertainty
about the extent of the hazard and nature of the risks to human health
and the ecosystem associated with any potential current or future radionuclide
release to the marine environment, and the factors that may affect such
risks.
- To devise and communicate
an appropriate basis for a monitoring plan that would detect potential
significant future risks to human health and the marine ecosystem as
early as practical.
Central to this effort
is sampling of marine biota, with particular reference to the food web
and potential exposure to humans and other important ecological species,
particularly those at high trophic levels. The CRESP field expedition,
conducted in collaboration with people of the Aleutian/Pribilof area and
coordinated with ongoing field studies under the auspices of A/PIA and
the State of Alaska, sought to address four major questions:
1. Are the foods safe
to eat with respect to radionuclides?
2. Within the context of available data from eco-receptors, is there any
indication that biota are at risk from radionuclides?
3. Can the data from the study be used to determine which species are
the best bioindicators to be used to design future monitoring, and
4. If the full range of physical and biological data obtained from the
expedition that indicates radionuclides above background, can we attribute
increased levels of radionuclides to a particular source?
Our results represent
only one point in time. Within a context of multiple species, multiple
locations within Amchitka transects and the reference site, and multiple
radionuclides, some of the possible outcomes from this single expedition
are given below:
1. Results are indistinguishable
for all radionuclides in comparison to other Amchitka sampling locations,
off-site reference site(s) or relevant literature values.
2. Some radionuclides exhibit elevated levels near Amchitka but are below
thresholds of concern to human health and the ecosystem and the source
of elevated levels is unknown.
3. Some radionuclides exhibit lower levels near Amchitka but are below
thresholds of concern to human health and the ecosystem, and the reasons
for the decreased levels are unknown.
4. Some radionuclides exhibit elevated levels near Amchitka and are above
thresholds of concern for ecosystem impacts but below thresholds of concern
for human health, and the source of elevated levels is unknown.
5. Some radionuclides exhibit elevated levels near Amchitka and are above
thresholds of concern for ecosystem and human health, but the source of
elevated levels is unknown.
6. Some radionuclides exhibit levels above thresholds of concern for ecosystem
impacts and human health, but results are indistinguishable amongst the
Amchitka sites and the reference site(s).
7. Any of cases 1-5 above, but the isotopic signature suggest Amchitka
as the source.
8. Any of cases 1-6 above, but the isotopic signatures suggest a source
other than Amchitka test shots.
9. Any of cases 1-6 above, but the isotopic signatures suggest both Amchitka
test shots and other sources of radionuclides are contributing to the
levels found.
The project's biological sampling and laboratory programs were designed
to provide results that would be scientifically defensible and relevant
under any combination of potential outcomes envisaged above.
Biological Samples
The expedition's field sampling plan was designed to do three things:
1) assess the current risk to the organisms in the marine ecosystem (from
Kelp to eagles, seabirds, mammals, and top-predatory fish), 2) assess
current risks to humans, and 3) design a long-term stewardship program
focusing on informative bioindicator species which can be sustained in
a reasonable and cost-effective biomonitoring plan. The sampling plan
was comprehensive, and recognized that top-trophic level species are indicators
of bioaccumulative contaminants (e.g. strontium, cesium). Further, it
is largely the top-trophic level organisms that the people eat. Each of
the species groups within these top-trophic levels is important, and tells
us something different about the food web, potential radionuclide distribution
in the marine ecosystem, and potential human exposure.
As more fully discussed
in the Science Plan, the potential exists for radionuclides from the test
shots to be carried into the marine environment by freshwater through
seeps along faults and fractures, or by diffuse flow. The exact location
of where these seeps or discharges may meet the marine environment, and
thus the exposure pathway through the food chain to top-trophic level
organisms, is extremely important to evaluate. Moreover, because this
is an area of extensive techtonic movement and seismic activity, pathways
to the surface and ocean may change in the future. To address these issues,
CRESP researchers from the Institute of Marine Sciences at University
of Alaska, Fairbanks and University of Alberta, Canada used: a) side-scan
sonar to depict and characterize the sub-surface Amchitka rock mass; b)
a CTD to detect salinity differences between the sea and any fresh water
seeps emanating from Amchitka ground water sources especially along the
transects from the nuclear test sites; and, c) magnetotulleric and audio-magnetotulleric
testing of the subsurface of the island, again along the cross island
transects contiguous to the nuclear test sites, to characterize the Amchitka
rock mass and to identify the depth and location of the most likely groundwater
pathways from the island into the sea. Very preliminary results from these
initiatives helped other researchers identify areas in the sea where multi-trophic
biological sampling would best detect the presence or accumulations of
radionuclides in that marine environment related to the test shots.
The initial design
in the Amchitka Science Plan was to have a three-pronged sampling approach
that was representative of Aleut subsistence foods, reflected key species
within the commercial fishery, and was indicative of the Amchitka marine
ecosystem. The marine ecologist team included both estuarine and marine
ecologists, as well as divers. Where possible, the initial selection included
species that could represent two or more of these groups, and that represented
different trophic levels. Within this sampling framework, the team expected
to collect organisms that represented different degrees of mobility. The
initial sampling plan was also based on best available knowledge about
the organisms that would be present. This information was obtained from
the literature, from advice of people who had worked on Amchitka or elsewhere
in the Aleutians, and from the team's own experience in the Aleutians
in 2003. Optimally, they hoped to have four specimen composites per species
per study location, and the number of study locations depended upon the
mobility of individual species. Sedentary species were expected at least
at two of the three test sites (Long Shot, Milrow, Cannikin) and at the
reference site (Kiska/Buldir), while highly mobile species were expected
around Amchitka and at Kiska/Buldir. The initial list served primarily
as a basis for identifying the most relevant species, and it was understood
that it might become necessary to collect ecological equivalents if dictated
by actual conditions at proposed sampling areas.
The actual sampling
in the summer of 2004 followed the initial design, including the employment
of Aleut hunters/fishers, marine ecologists (including divers), and a
fisheries biologist on a NOAA trawler. Sufficient samples of organisms
were obtained at all trophic levels to represent the marine system, to
sample commercial fisheries, and to provide a range of organisms that
subsistence Aleuts eat. It was extremely important to have Aleut hunters/fishers
as part of the sampling regime because they were able to hunt and fish
using current methods, as well as traditional methods of searching the
intertidal areas for subsistence foods (kelp, Gumboots, Chinese Hats,
and mussels). The Aleuts also hunted birds and fished with contemporary
methods now used in their villages. As an added bonus, the marine ecologist
team also collected some of the same species, allowing for a comparison
of different sampling methods. All three teams (Aleuts, marine ecologists,
fisheries biologist) collected some species, such as Pacific Cod.
The samples collected
represented a wide range of organisms and will allow an examination of
radionuclides among study sites, and between Amchitka and the reference
site. There were two aspects of sampling that were key: 1) Having sufficient
samples of some species in different study sites to allow for a statistical
comparison, and 2) Having a few samples from a range of key species that
would add to the team's understanding of the marine ecosystem around Amchitka
that serves as the base for key food chains (ultimately leading to humans).
Representative species that fall into category 1 include kelp, Green Sea
Urchin, Rock Jingle, Rock Greenling, Black Rockfish, Pacific Cod, sculpins,
Gulls, Eiders and Puffins. Sufficient numbers of specimens were collected
in some species in category 1 for excellent coverage of the marine environment;
for example, several hundred individual Sea Urchins (at several different
water depths), over a hundred individuals of Black Rockfish, Pacific Cod,
sculpins, and Rock Greenling, and 40-50 individual each of Gulls, Puffins
and Pigeon Guillemots were collected.
Species in category
2 include Atka Mackerel, Halibut, Eagle, and Octopus. Although fewer specimens
were collected, they are all top level predators, and each individual
is important in its own right. For example, a range of different sized
Halibut were collected, including one weighing a hundred pounds. In addition,
a number of subsistence foods in the intertidal beaches near the test
shots and at the reference site were collected, including Chinese Hats
(Limpets) Gumboots (Chitons) and mussels.
A final key feature
of the expedition's collection was the diversity of ages represented.
Both young (representing very local exposure) and adult Glaucous-winged
Gulls were collected (adults can reach more than 30 years in age). Whereas
Kelp, Sea Urchins, and Jingles do not reach great ages, some of the fish
collected can reach between 50 and 100 years of age in the Northern Pacific/Bering
Sea ecosystem.
In summary, the specimens
collected:
· Represented three groups (Aleuts, fisheries, marine ecosystem)
· Represented intertidal to benthic, and sea surface organisms
· Represented several trophic levels from primary producers, to
consumers, to top-level predators (including halibut, seabirds, Pacific
cod)
· Represented a range of mobilities, from sedentary kelp to highly
migratory fish
· Aleut hunters/fishers collected subsistence Aleut foods
· Collected samples from all three test sites and a reference site
(Kiska)
· Collected sufficient samples for statistical analysis for key
trophic levels, while having adequate samples from a wide range of species
to represent the marine ecosystem
· Collected organisms that ranged in lifespan from months to many
years
Receipt and Control
of Specimens in New Jersey
A total of 38 coolers containing the samples and specimens collected by
the J. Burger and S. Jewett teams on the Ocean Explorer were air shipped,
via Alaska Air, from Adak, Alaska to Newark, New Jersey on July 22th.
To minimize the possibility of losing significant samples, the team did
not pack all the same species from the same location in one cooler. A
total of 7 additional coolers, with marine samples from J. Weston's team
on the NOAA Gladiator trawler were shipped on August 8th. Together, the
45 coolers weighed a total of nearly 3,000 pounds. Each was appropriately
sealed, numbered and a chain of custody form attached for control purposes,
prior to their shipment. All were picked up and transported by refrigerated
truck to a refrigerated warehouse located in the NJ-NY Port Authority
area of Newark.
During August and
September the 38 coolers from the Ocean Explorer were delivered to the
Rutgers laboratory for purposes of completing a full inventory of the
specimens collected, resorting them into groupings of fish, birds and
others, and entering this data with new Chain of Custody information into
a centralized database managed by V. Vyas. All of the fish specimens were
transferred to freezers in the laboratory in anticipation of preparing
the first shipment of samples to the INEEL and Vanderbilt labs for testing.
Samples of each species were also retained for purposes of developing
laboratory methods and procedures, and the remaining newly numbered coolers
were returned to the refrigerated warehouse for storage.
Two Analytic Streams
The Rutgers team under J. Burger will be responsible for receiving, preparing,
and sending specimens to the analytical laboratories, and for maintaining
appropriate Chain of Custody and tracking records. D. Kosson and M. Stabin
at Vanderbilt will have overall responsibility for managing the specimen
testing and analysis program that will be conducted at INEEL and Vanderbilt
laboratories. The analysis at INEEL will focus on testing soft tissue,
bone and kelp for the large number of isotopes expected to be present.
A subset of these will also be analyzed at Vanderbilt for these analytes
for interlaboratory comparison. A separate Vanderbilt analytic stream
will focus on Cs-137 and other relevant gamma emitters.
Isotopes of interest
for analysis in this study are 137Cs, 152Eu, 60Co (gamma emitters), 238,
239, 240, 241Pu, 234, 235, 236, 238U, 241Am (alpha emitters), and 90Sr,
3H, 99Tc, 129I (beta emitters). Of these, 137Cs is most likely to accumulate
in muscle (soft tissue) and cause human health risks through consumption.
The other isotopes that are expected to result from the test shots accumulate
preferentially in either skeletal material (bones or exoskeletans) or
specific organs, with a lesser distribution in muscle. Detection limits
for analyses will be below levels necessary to detect human health risks
based on conservative estimates of lifetime consumption and risk thresholds.
More limited analysis will be used to ascertain the distribution of specific
isotopes amongst the sample types for a given biota. Ratios of isotopes
of Pu (indicative of nuclear detonations) and U (indicative of nuclear
reactor releases and enrichment processes), both of which accumulate in
skeletal materials, will be used to the extent possible to identify whether
Amchitka test shots are the likely source of measured radionuclides in
samples. Thus, the analysis of soft tissue will provide the primary insight
into human health risks from consumption, food chain transfers in the
marine ecosystem, and provide a baseline for comparison with future studies.
The analysis of skeletal material will provide indicators of sources of
contamination, information about foodchain accumulation, and also provide
an important baseline for comparison with potential future studies.
Initial Screening
Analysis
The CRESP team will use an initial screening analysis as a basis for understanding
the occurrence and indication of origin of radionuclides in a wide range
of organisms at different trophic levels in the marine ecosystem, for
foods that are consumed by the Aleuts, and for organisms that are harvested
commercially. This initial screen will consist of the analysis of muscle
tissue for 137Cs and 90Sr and analysis of corresponding skeletal material
for the full range of isotopes.
The rationale for the choice of organisms for screening was based on the
Science Plan's initial three-pronged approach (Aleut foods, commercial
fisheries, marine food web) and the availability of organisms within the
marine ecosystem around Amchitka and the Kiska reference site. Within
these constraints, organisms were selected based on their mobility (Table
1) and life history traits (Table 2).
The rationale for the number of organisms to be screened was a function
of mobility (Table 3). When organisms were sedentary, one composite was
screened from each from the three Amchitka test shots, and from Kiska.
When organisms were mobile, one composite from the west side and one from
the east side of Amchitak (in the region of the test shots) were chosen.
When organisms were highly mobile one composite from Amchitka region and
one from Kiska were chosen (Table 2).
Organisms that are
very important to the human food chain (i.e. Halibut, King Crab, Octopus)
but were collected in much smaller numbers will be examined during the
next phase of radionuclide analysis, as will organism that are key to
marine food web (i.e. Eagle, other kelp or invertebrates).
Spiked samples and
blanks (control samples) using commercially obtained samples of fish and
other species will also be included in material sent to analytical laboratories
as part of the analytical quality control. Spiking of samples will be
done by the RESL laboratory, also located at INEEL but a distinct organization
and facility from the INEEL group carrying out analysis. RESL is a DOE
laboratory responsible for quality assurance and quality control programs
associated with radionuclide analysis throughout the country, both in
the public and private sectors. Rutgers will include RESL control samples
maintained as blind samples along with Amchitka samples subsequently sent
to INEEL and Vanderbilt for analysis.
More Extensive Analysis
More extensive laboratory testing and analyses will be performed on selected
species within designated trophic levels based on the results obtained
in the initial screening analysis and any other data made available to
this study. One species representative of each of the selected trophic
levels will be identified for a more extensive analysis that will consist
of
· Up to 10 analysis for each sample location for 137Cs (soft tissue)
· Up to 4 analysis for each sample location for 90Sr (soft tissue)
· Up to 4 analysis for each sample location for remaining isotopes
of interest (e.g., U and Pu series, and other isotopes of interest) in
skeletal material
Selection of the species for more extensive analysis will be based on
human health risk and information about isotope sources based on U and
Pu isotope series results reported in the initial screening phase of laboratory
analysis. The following algorithm will be used for assigning priority
within a given trophic level:
Priority number =
log(10 x human health risk)/(10E-6) + (Pu information + U information)
Under this approach, the larger the priority number, the higher the priority
for the more extensive analysis of the species within the designated trophic
level. The human health value would equal 1 for a 10E-6 risk level. The
Pu information would equal 0.5 if characteristic Pu isotope ratio is measurable.
The U information would equal 0.5 if the characteristic U isotope ratio
is measurable. Thus, the value of the source information would be equal
to 0, 0.5 or 1. Tie values would favor human health if the risk value
was greater than 10E-6 and would favor source information if the risk
value was less than 10E-6.
Water and Sediment
Analysis
Water and sediment sampling in all shot site areas surrounding Amchitka
Island was performed to fulfill the Radiological Health and Safety provisions
of the overall Amchitka Expedition, Health and Safety Plan and to supplement
the physical and biological data collected on the expedition. By design,
the dive collections occurred in marine areas of highest probability of
discharge of radionuclides from freshwater seeps through faults and/or
fractures. Water and sediment samples were taken in both offshore and
near shore areas where expedition members would be handling equipment,
such as the CTD probe and collecting biological specimens. These samples
were screened for radioactivity by D. Volz to insure that expedition personnel
were not exposed to radiation in excess of HASP exposure guidelines.
Radionuclides trapped
in marine sediments and desorbed from sediment to water could be a major
source of contaminants to benthic organisms and thus to higher level trophic
organisms feeding on them. Detection of some radionuclides in sediment
samples may be
indicative of radionuclide discharges and movement within environmental
pathways, even if they do not represent a direct input into human food
pathways. Bottom water and sediment samples were taken to help evaluate
and redesign research questions and address uncertainties outlined in
the Science Plan, resulting from this linkage
Table 1. Mobility Traits Influencing Selection of Screening Species
_______________________________________________________________
Mobility Importance Species
______________________________________________________________
Sedentary Provides an indication Fucus
of point exposure Alaria nana
Alaria fistuloa
Locally mobile Integrates
exposure Sea Urchin
over a small area Rock Jingle
Black Rockfish
Rock Greenling
Glaucous-winged Gull
Mobile Provides an indication Yellow-Irish Lord
local movement within Ocean Perch
a few km of designated Walleye Pollock
site Tufted Puffin
Pigeon Guillemot
Common Eider
Brown King Crab
Migratory Provides an indication Atka Mackerel
of regional exposure Pacific Cod
Table 2: Rationale for Species Selection for Screening Analysis
Primary Producers:
The following species are all primary producers in the marine ecosystem,
are sedentary (and thus represent local exposure), and are the base of
food chains. There is good representation of the sedentary species from
the four study sites (Milrow, Long Shot,
Cannikin, Kiska), and for the mobile species from Amchitka and Kiska.
Alaria fistulosus - This kelp occurs at several depths, representing the
subtidal environment.
Alaria nana - This kelp occurs mainly in the intertidal.
Fucus - This brown algae occurs in the intertidal, and there is reference
data from other places.
Invertebrates:
Invertebrates are often the primary consumers in marine ecosystems, are
eaten by organisms higher on the food chain, and are fairly sedentary
representing local exposure. They are also eaten by the Aleut people.
Green Urchin - Urchins were abundant in most of the diving transects at
15, 30 and 60 feet and thus represent good coverage of the marine floor
environment. They are a primary food of Sea Otters, a species of concern.
They are also eaten by Eiders and Gulls (based on the literature and on
stomach contents we examined). And they are considered a delicacy by Aleuts.
Rock Jingle - They are less abundant, but are sedentary.
Vertibrates:
Vertebrates are often secondary or tertiary consumers, and have different
degrees of mobility. The species selected, at some stage in their life
cycle, are all eaten by Aleuts and some are part of commercial fisheries.
FISH:
Rock Greenling - This is a sedentary species, each male maintaining a
small territory, hence representing local exposure, that lives in the
kelp zone. It is eaten by Aleuts (as are its eggs), and is eaten by fish
higher on the trophic chain, such as Cod and Gulls.
Black Rockfish - This is a relatively sedentary species (representing
local exposure) that lives in the kelp zone and just outside the kelp
zone. It is eaten by Aleuts and is a little higher on the food chain than
the Rock Greenling.
Sculpin (Yellow Irish Lord) - This is a less sedentary (but not migratory)
species that is larger than Black Rockfish, eats invertebrates, and is
an Aleut food.
Atka Mackerel - This is a deep water, bottom fish that is relatively low
on the food chain, but is of commercial value and is migratory.
Pacific Cod - This fish can reach 50-60 pounds, and eats smaller fish,
such as Rock Greenling and Atka Mackerel, as well as Octopus, squid, fish
eggs, and crabs (all found in our specimen's stomachs). It is both a preferred
fish for the Aleut people and a major commercial species. It is mobile
to migratory.
Ocean Perch - Top-level predator of commercial interest that is mobile.
Walleye Pollock - This predatory fish is a major commercial species that
is mobile.
Halibut - This fish is a top-level predator, can reach large sizes (up
to 500 pounds) and advanced ages, and is highly prized both by Aleuts
and commercial fisheries, and is migratory.
BIRDS (all are residents):
Eiders - Common Eiders are hunted extensively by Aleuts and their eggs
are also eaten. It represents a low trophic level for birds, eating mussels,
snails, and urchins.
Gulls - Glaucous-winged Gull eggs are considered a delicacy by Aleuts,
and gulls represent an omnivorous species. We found urchins, starfish,
and fish (including Dolly Varden and Greenlings) in their stomachs. Since
there are nesting colonies at each of the test sites, and they normally
feed within 5 miles of their colony, they represent local exposure. They
do not migrate and so represent longer term exposure in the vicinity of
Amchitka. They also can live to be 30 + years old.
Young Gull - There were nesting colonies adjacent to each of the 3 test
shot areas, and on Kiska. Since parents feed their young entirely from
local foods (usually within 5 miles of nesting colonies), they represent
local exposure.
Tufted Puffin - They eat entirely fish of small to intermediate sizes.
They are less localized to test shots, and represent local exposure within
a local area. Birds were moving back and forth from the Long Shot to the
Cannikin shoreline.
Pigeon Guillemot - They eat mainly small fish, and are localized to the
sides of islands during the breeding season. Birds were moving back and
forth from the Long Shot to the Cannikin shoreline.
Table 3. Rationale for Selection of Screening Numbers
· Where possible, one sample from each of the four study sites
(Milrow, Long Shot, Cannikin, Kiska) for species that are sedentary or
are locally mobile will be selected for screening (N = 4 for screening
purposes).
Fucus Sea Urchin
Alaria nana Rock Jingle
Alaria fistulosa Black Rockfish
Glaucous-winged Gull Rock Greenling
(adults, chicks) Yellow-irish Lord
· Species that
are mobile within a few km of a designated site will be examined from
both sides of Amchitka (Bering Sea/Pacific Ocean), and from Kiska (N =
3).
Common Eider (eggs)
Pigeon Guillemot
Tufted Pigeon
· Species that are highly mobile or migratory will be examined
from Amchitka and from Kiska (N = 2).
Ocean Perch
Atka Mackerel
Walleye Pollock
· Where specimens
were available for both the inshore sampling and the NOAA trawl, species
will be screened from both sampling methods. This was true only for Pacific
Cod, and will include both sides of Amchitka from the near-shore sampling,
and from Amchitka and Kiska for the NOAA trawl (N = 5).
Table 4: Specimens for the INEEL Screen of Soft Tissue **
Kelp: Total = 12
Alaria fistulosa - 4
Alaria nana - 4
Fucus - 4
Fish: Total = 23
Black Rockfish - 4
Ocean Perch - 2
Atka Mackerel - 2
Rock Greenling - 4
Walleye Pollock - 2
Pacific Cod - 5
Sculpin - 4
Invertebrates: Total
= 8
Sea Urchin - 4
Rock Jingle - 4 Birds Total = 17
Common Eider eggs - 3
Tufted Puffin - 3
Glaucous Gull
adult - 4
young - 4
Pigeon Guillemot - 3
** When the sample
size is 4, one composite will be selected from near Milrow, Long Shot,
Cannikin, and Kiska. When the sample size is 3, one composite will be
selected from the Bering side of Amchitka, the Pacific side of Amchitka
(near the test shot region), and from Kiska. When the sample size is 2,
one composite each will be selected from around Amchitka and from Kiska.
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