Wind and soil: Reconstructing atmospheric dispersion of plutonium at Rocky Flats
Seth Masia for Ackland, Peterson, Ruttenber: Nuclear West, Dec. 12, 2005
The Rocky Flats nuclear weapon factory released plutonium into the environment
sporadically over a 37 year period. Before 1980, little or no effort was made to measure
or record these releases. Beginning in 1981, a number of studies attempted to gauge the
level of contamination in the regions around the plant, and especially to determine the
effects on human health.
Because plutonium emits alpha particles, once absorbed into the body it is a
serious carcinogen. Ingested plutonium is absorbed into liver and bone tissue and held
there for the life of the organism; health effects are very serious but rare in humans. This
is because plutonium in the soil is most likely to be taken up into plant roots, and it finds
its way into the food chain mainly through consumption of roots. (1) Coloradans are not
enthusiastic about consuming the roots of locally grown crops.
The real danger for people living and working in the vicinity of the Rocky Flats
plant lies in inhaling plutonium. Inhaled plutonium causes lung cancer. Particles under 30
microns in diameter are capable of being inhaled, and once lodged in the lung have a
biological half-life of about 500 days (that is, after 500 days, half the plutonium has been
cleared from the lung). Physicians suggest that smokers have trouble clearing plutonium
from their lungs, and are thus more susceptible to alpha particle cancer. Other studies
suggest that people exercising outdoors – young athletes, farm and ranch workers – are
the population most likely to inhale and retain plutonium. On the other hand, this group is
likely to be the healthiest of all downwind populations to begin with and may not, in fact,
be the group most susceptible to plutonium health hazards.
1
Particles of inhalable size are easily transportable in the wind. In order to estimate
the effect on human health in the communities near Rocky Flats, it’s important to
understand the way the wind flows around the plant site, and where the wind can take
plutonium particles. A number of studies have addressed these questions. Because few
data exist regarding wind, weather and plutonium quantities at the time of release, these
studies have involved a great deal of guesstimation and fudging. In recent years, very
detailed studies have been completed regarding wind patterns across the National Wind
Technology Center’s turbine testing site, which now occupies the north end of Rocky
Flats. Sophisticated models are of very little use in dose reconstruction, absent
contemporary weather data for input. What they tell us about the local microclimate,
however, leads to some conclusions about the fate of plutonium in the immediate
environment.
In siting the bomb factory in 1952, the Atomic Energy Commission was
apparently uninterested in the wind environment. The original site selection report, based
on prevailing winds at Stapleton Airport 20 miles to the east, misrepresented the situation
grossly. The site survey reported only that surface winds blow from the southeast (2).
Half a century later, the successor agency, DOE offered a more complex assessment for
the National Wind Technology Center. Its turbine site, the assessment said,
. . . offers two dominant and predictable wind regimes. These two different flows
give the wind energy program the ability to test in westerly winds which are
characteristic of the California wind farms, and in easterly winds characteristic of
the great plains (sic) where most future development is expected to occur. During
late fall and winter, high velocity winds sweep across the Continental Divide and
funnel down through the canyons of the Front Range. These westerly winds, often
reaching velocities greater than 100 miles per hour [444 m/second], allow the
testing of wind turbines in the most severe and turbulent of environments. During
late winter and spring, low pressure areas flow across the southern Great Plains,
spawning thunderstorms and driving plains air from the south and east up against
2
the front ranges and Continental Divide. Since these winds sweep unimpeded
across the southern Great Plains, they are stable and provide a smooth flow from
the easterly direction. These predictable wind flow regimes enable the site staff to
depend on high velocity turbulent west winds for performance, loads and fatigue
testing. The eastern flow generates controlled and repeatable conditions that are
ideal for conducting certification testing. Despite these predictable wind patterns,
winds are not persistent over long periods of time, and frequent periods of calm
enable technicians to climb towers and work on man lifts. . .(3)
Fig. 1: National Wind Technology Center turbine testing site at Rocky Flats,
looking northwest toward Eldorado Canyon. DOE photo.
Even this description is too simple. In real life, the wind descends the eastern
escarpment of the Rocky Mountain in tumultuous but predictable ways, and interacts
with the winds of the high plains in a complex system. Where the mountains meet the
prairie—for instance, at the 6200-foot elevation of the Rocky Flats site—the wind can do
extraordinary things. Here follows an abstract of the typical Rocky Flats wind modes:
On a windy day, such as we had on Monday, Dec. 5, 2005, winds roar down
canyons at a steady 50 to 60mph, with gusts over 100mph. The wind scours the soil
surface and carries dust off to the east. Just west of Rocky Flats, parallel flows from
Eldorado Canyon and Coal Creek Canyon form a jet that moves tumbleweed,
newspapers, plastic bags, dust, dirt, and radionuclides toward the east and then northeast.
On most days with good weather, the wind near the mountains forms a backwash
circulation. A moderate prevailing wind comes off the mountains from the west, and a
3
large gentle rotor sets up below it, so that fine weather at the Boulder Airport, for
instance, usually brings a light breeze from the east. Similarly, good weather at Rocky
Flats has a gentle easterly flow.
At ground level on a calm clear day, summer or winter, the sun is strong enough
to create thermals. A thermal is a vertical stream or bubble of warm air that forms over a
solar-heated hot patch on the ground – typically pavement, a plowed field, a dark rooftop
or a dark granite outcrop. As it rises, a thermal can create a dust devil – a miniature clearair tornado, with surface wind typically swirling at 30 to 60mph across a vortex 20 to 100
feet wide. (4) The vortex sucks dust off the prairie, including plutonium particles. The
dust can fall out of the vortex at any altitude, or it can be carried upward to the 12,000
foot level. On summer days, this is the cloud base – the bottoms of the cumulus clouds
that begin to form at around noon and build steadily toward late afternoon. Particles
pulled into clouds will eventually precipitate out in the form of rain or snow, wherever
the cloud happens to be when it grows heavy and cold enough. This could be over
Broomfield, or over Nebraska. (5) A plutonium particle embodied in a raindrop is most
likely to return to the soil and poses a low respiration risk. Dr. Harvey Nichols of the
Ecology and Evolutionary Biology Department at the University of Colorado noted this
in 1975, when he collected samples of radioactive snow from around the Rocky Flats site.
(6)
Convective circulation is constant in good daytime weather, especially in the
summer. It would be a transport mechanism for surface soil contaminants, as for instance
at Area 903. NREL has performed detailed measurements of daytime convective-driven
turbulence and stable nocturnal flow at the Rocky Flats wind turbine lab. (7)
4
Calm days turn into windy nights. At dusk, convective activity ceases. About an
hour after sundown, the nocturnal pattern begins. Katabatic winds begin to flow down the
canyons. A katabatic wind is a mass of cool air descending a slope, driven by gravity. It
flows like water down the valleys. West of Rocky Flats, Eldorado and Coal Creek
Canyons channel and focus the wind into a jet that rushes across the Rocky Flats
reservation, moving east and northeast. At ground level, this flow interacts with the
backwash below the main stream. (8) Detailed surface studies commissioned by the
Department of Energy beginning in 1991 documented this nocturnal flow pattern and
plotted the canyon jet phenomenon (see Figure 3). A second mode was observed, in
which flow from the canyon mouth oscillates, with alternating eastward and westward
breeze across the site through the night. (9)
Further from the mountains, nocturnal wind is usually governed by the low level
jet stream. This steady stream of cool air flows at 1000 to 6000 feet above the ground; in
the Great Plains the stream pulls moisture up from the Gulf of Mexico, feeding lateevening thunderstorms and helping to keep the land lush. The stream typically flows at
60 to 100 mph from the south, and it drags along a 6 to 10mph breeze at ground level.
This is the typical good-weather pattern at Stapleton Airport and Denver International.
Descending out of the low jet stream is what provokes the final bump as your late-night
flight enters the DIA traffic pattern. (10)
Above 14,000 feet, and extending up to over 35,000 feet, the prevailing west wind
forms a mountain wave. The wave begins to form whenever the steady wind speed at the
mountaintops exceeds 20 knots. In winter months the wind often pours through the
mountain passes at 30 to 60mph, and is faster at higher altitudes. Visualize the wave as
5
Figure 3: In this sketch, stolen from a basic meteorology text for pilots, Rocky Flats is
located roughly at Mile 5, the 6200-foot elevation. The site regularly experiences
katabatic winds, backflow breeze, convective lift, and violent mountain wave strikes.
Stapleton Airport is located at 25 miles, in a prairie wind regime.
river water flowing over rocks. Well above the rocks, the flow is smoothly laminar. If
there’s a little moisture up there, it condenses into lovely domed lenticular clouds,
describing the shape of the wave peaks. At the lower margin of the wave, where it drags
against calmer air below or gets sucked into the lee of the mountains, you can see the
turbulence in the form of tumbling rotor clouds. Usually these are friendly-looking
puffball clouds, but when the wave is strong and steady a rotor can look like a long,
rolling log – a sort of horizontal tornado called a roll cloud. A small plane flying through
a rotor experiences something like a spin cycle. Big jets bounce badly. This is why flights
6
arriving in Denver often feel like a rollercoaster ride. When the wave is very strong, it
can follow the lee slope of the mountains and actually scour the ground around Rocky
Flats, at speeds of 80 to 100 mph. Anything on the surface – or buried within inches of
the surface – can potentially be lofted by winds of this magnitude. This means that any
plutonium in the soil can cycle into the atmosphere.
Recall that respirable particles are smaller than 30 microns. A 1961 study
suggests that particles of this size settle through the atmosphere at the rate of about
.3cm/second; smaller particles fall out more slowly. Plutonium is a heavy metal, but at
this scale the cube-square rule means that a transuranic particle behaves aerodynamically
pretty much like any other airborne mote. (11) Over Colorado this fall-out rate is
overwhelmed by convective lift that often exceeds 3m/sec. In the case of a nocturnal
release, plutonium particles lofted to 500 meters above the Rocky Flats site might remain
airborne for at least 45 hours. In normal good weather, the cloud would be borne
eastward on the canyon jet at about 20 mph, until it met the light northward flow of the
prairie wind regime. Any part of the cloud entering the low level jet stream could be over
Wyoming within three hours. By mid-morning, in sunny weather, the cloud would be
entrained in convective circulation and lofted to the cloud base. Unless rained out, most
of the cloud would remain aloft for weeks. In effect, it would be lost amidst the roughly
4200 kilograms of plutonium lofted by atmospheric nuclear testing between 1945 and
1982.
This would also be the fate of any plutonium scoured from the ground by
convective dust devils or high wind events. What we can say is that plutonium left in
7
unprotected soil at Rocky Flats will eventually become airborne. Some of the larger
particles will descend on local communities. Smaller particles join the global problem.
The Rocky Flats Cleanup Agreement of June 2003 specified that the top three feet
of soil contain no more than 50 pCi/g of plutonium, which would seem to limit the
amount of potential blow-off. (12) But this assumes no further soil disturbance. Currently
the site is nearly devoid of prairie dog colonies, which is assumed to be the result of 35
years of earthmoving activity by Dow and Kaiser-Hill (it may be due to plutonium
poisoning of invading prairie dogs). If the new wildlife refuge comes to harbor prairie
dogs in the same concentration as is found in Boulder County Open Space, the site will
eventually contain about 30 burrows per acre. According to information published on the
National Park Service website, a typical burrow is about ten feet deep, 24 feet long and
ends in a nesting chamber. About 10 cubic feet of fill is brought to the surface with each
burrow, or about two million cubic feet for the entire site. If the deeper soil contains 1000
pCi/g—the cleanup target value for soil three to six feet deep—this quantity of prairie
dog till could contain about 17x10E13 pCi of plutonium. Sean Smallwood, a consulting
ecologist from Davis, California, has testified that prairie dogs and other burrowing
mammals, along with insects and earthworms, move enough soil that eventually 11% of
the Rocky Flats will be transported off-site by wind and water. (13)
Planning documents for the Rocky Flats National Wildlife Refuge emphasize
limitation of prairie dog populations to short-grass areas, (14) but ungulate grazers are
another issue. In its natural state the prairie supports rhizome grasses, which grow
interlocking root systems to hold soil solidly. When the prairie is disturbed, rhizome
grasses are easily displaced by invasive weeds such as knapweed, destroying the rhizome
8
net. Grazing animals have been shown to disturb unprotected soil sufficiently to promote
massive wind erosion. (15)
After the bomb factory closed, the Colorado Department of Public Health and
Environment (CDPHE) hired an outside firm, Radiological Assessments Corp. (later
changed to Risk Assessment Corp.) to do an independent reconstruction of major
radionuclide releases and spills. Part of the job involved running computerized
atmospheric dispersion models in an attempt to reconstruct the migration and deposition
of radionuclides released into the air during the fires of 1957 and 1969, and over a
number of years from the leaking barrels at Area 903.
The U.S. government has been the world leader in atmospheric modeling, largely
as part of the Cold War arms race with the Soviets. These airflow models can be of global
scale, in which case they’re usually called climate models; of continental scale, for local
weather forecasting; or of millimeter scale and smaller, for predicting aircraft and engine
performance. Dispersion models fall between weather-scale and wind-tunnel scale
programs. They model wind and weather in a region 10- to 100-km on a side, and
recently have included terrain features adopted from microclimate simulators. Between
1945 and 1999, the government funded development of about 100 separate atmospheric
dispersion models, of steadily evolving sophistication. (16) Today the state-of-the-art
model for tracking atmospheric dispersion is maintained by NARAC, the National
Atmospheric Release Advisory Center. The center provides tracking services to local
authorities in hazardous substance release emergencies. (17)
9
ASCOT experiment
In 1989 the Department of Energy launched the Atmospheric Studies in Complex Terrain
program, and in February, 1991 ASCOT researchers conducted field experiments in the
Rocky Flats district. An elaborate network of temporary measuring stations and
atmospheric sounding devices was established around the Rocky Flats, as far out as 25km
in all directions. These were set up not only to report wind speed and direction at multiple
altitudes, but also to track the course of an inert trace gas (sulfur hexafluoride) released
from a stack at Rocky Flats. The tracing results were used to fine-tune the Regional Air
Model/Lagrangian Particle Dispersion Model (RAMS/LPDM), a complex supercomputer
program developed for the Savannah River reactor. Twelve tests were conducted over
four nights and two days, and the RAMS model was validated. Over the next six years
the model was used in six more detailed studies of the Rocky Flats wind environment.
The result was a multi-level model duplicating the measured canyon jets. (18)
Figure 3: Wind jets exiting Eldorado and Coal Creek Canyons at 8pm on February 4,
1991, as graphed by RAMS during ASCOT field experiments. DOE screenshot.
10
1957 fire
Neither the NARAC nor RAMS models have been run against the 1957 or 1969 fire
emissions. There’s a reason. Sophisticated programs require finely detailed input data. At
the time of the most serious incident, the 1957 fire that released somewhere between 11
and 36 Ci of inhalable plutonium, no such data were available for Rocky Flats. In 1957
the facility recorded wind speed and direction only at one location, and had no downwind
sampling program. Radiological Assessments Corp., the independent contractor hired by
CDPHE to reconstruct the downwind risk of plutonium release, was able to find only a
second-hand account of wind data for 1957. Wind speeds were averaged every 15
minutes during the night of the 1957 fire, but no peak speeds were recorded. Wind
direction data were precise only to 45 degrees, and interviews with Rocky Flats
employees suggested that at times the wind direction reports were inaccurate by 180
degrees. RAC’s researchers supplemented these inadequate data with cloud cover
information from Stapleton Airport and Lowry Air Force Base, 25 miles away. (19)
National Weather Service records suggest that it was a pleasant autumn night, with peak
wind at Stapleton just 16 knots and no precipitation. (20) The RAC team also knew that
because the released material had passed through a burning filtration system, the particle
size was quite small—eminently breathable.
RAC ran five different computer models against the sketchy data, and then chose
to focus on the output of the RATCHET (Regional Atmospheric Transport Code for
Hanford Environment Tracking) program, developed in 1994 for the Centers for Disease
Control. Hanford, 45 miles downwind from the Cascade Range, is not sited in complex
terrain, and its wind regime is fairly simple. RATCHET doesn’t account for terrain shape,
11
and therefore wouldn’t model a canyon jet. Instead it predicts surface friction, which
affects turbulence in the boundary layer, by modeling “surface roughness length” (low
for grassy plains, high for cities and mountains). Moreover, RATCHET doesn’t account
for wind shear, which is the reality that the wind blows in different directions, and at
N
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5.0E-012
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Lafayette
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Concentration
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Receptor Locations
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Denver County
Denver
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Golden
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Air Force
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I-25
Federal and State Routes
Other Roads
Elevation Contour Interval
200 meters
0 km
10 km
20 km
30 km
40 km
Fig. 4: RATCHET reconstruction of 1957 fire dosage.
Compare to the ASCOT model in Figure 3. RAC map.
different speeds, at different altitudes. Where highly sophisticated modeling programs run
on parallel-processing supercomputers, RATCHET was simple enough to run on a
Pentium-90 PC – but it tolerated the thin dataset and drew a nice map. (21) RATCHET
12
showed a dispersion pattern for the 1957 fire cloud in which the plutonium emission
floated south, then arced eastward across Arvada to follow the South Platte River off to
the northeast. The heaviest dose apparently fell on Arvada, and RAC concluded that a
laborer working out of doors there while the cloud passed over would have increased his
lifetime cancer risk by about two parts per million.
It’s not an unreasonable estimate, and as RAC claims, it probably errs
conservatively—that is, it overestimates the dosage on the ground. An understanding of
the Rocky Flats wind regime suggests that few of the respirable particles descended to the
ground, but instead dispersed to the Nebraska winds.
1969 fire
During the mid-Sixties, Rocky Flats installed a dozen monitoring stations around the site,
consisting of filtration systems that could be sampled daily and weekly. These were to
prove of some use when, beginning in 1990, ChemRisk, a private contractor, undertook a
dispersion reconstruction study of the Mother’s Day fire of 1969. ChemRisk used a 1986
model called INPUFF2. INPUFF model is not listed in DOE’s software inventory, but
it’s apparently descended from a family of dispersion models developed for use by
DOE’s enrichment plants beginning in 1979. (22) As RAC would find later, the limiting
factor was the thin input dataset: wind data were coarse, and no offsite sampling had been
done. The simulation suggested that over the course of the six-hour fire, which lasted
through the late afternoon and early evening wind regimes, two plumes carried a small
amount of plutonium to the east and southwest.
13
Fig. 5: RATCHET model of plutonium deposition following the
Mother’s Day fire of 1969. RAC map.
When RAC took over the dose reconstruction job in 1992, they resorted to the
RATCHET model. RAC reported that only about .3 gram (20 mCi) of plutonium was
released during the fire, and that all of it remained on-site – on the roof of Building 776,
directly under its filtration exhaust, and on the ground nearby. According to National
Weather Service records for Stapleton Airport, May 11, 1969 was a warm, dry day with
light and variable breezes. The RATCHET model suggested that no distinguishable
14
plume developed, with most of the plutonium release settling in the immediate vicinity of
Rocky Flats.
903 Area leakage
In the process of machining plutonium into “skulls,” the cup-shaped hemispheres that
would be welded into spherical implosion bombs, machine oil was used to cool, clean
and lubricate the carbide steel cutting tools. This oil need to be cleaned off the finished
plutonium parts, and carbon tetrachloride was used for this job. The result was a toxic
mixture of carbon tet, machine oil and small quantities of plutonium dust. This slurry,
along with cleaning rags, was packaged in steel drums and stored outdoors on a flat
grassy area that came to be called 903 Area. Carbon tetracholoride degrades to
hydrochloric acid, corroding the steel drums from within while weathering corroded them
from without. By the late Fifties, the barrels began to leak into the soil. By 1962, when
the 903 Area housed 4729 barrels, the leakage had been noted by Rocky Flats employees.
Beginning in 1967, the plant worked to repackage and ship the waste liquid to the
Idaho National Engineering Laboratory for burial. By 1969 all drums had been removed
and the grassy site was graded to remove 260,000 square feet of topsoil soaked with oil
containing up to 200 grams of plutonium. This was a mistake, because the disturbed soil
generated a persistent wind-borne dust cloud. In the summer of 1969 the area was paved
over. (23)
15
In recent years, Boulder County has experienced an average of 13 high-wind
events each winter, defined as a day with peak gusts over 70mph. In reconstructing the
N
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Mountain
Arsenal
Federal
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International
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Cherry Hills
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iver Va
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6
lley
Denver
Platte R
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Ridge
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0.500
Lafayette
Lowry
Air Force
Base
Aurora
Receptor Locations
County Line
I-70
Interstate
6
I-25
Federal and State Routes
Other Roads
Elevation Contour Interval
200 meters
0 km
10 km
20 km
30 km
40 km
Fig. 6. RATCHET model of average annual plutonium exposure from 903 Area wind
erosion. RAC map.
downwind dosage, RAC identified a total of 24 high wind events for the entire decade of
the 1960s. Based on sampler data, the team focused on six days in the winter of 1968-69
16
as the occasion of the heaviest plutonium transport. On the most severe of these days,
gusts over 120 mph were recorded in Boulder.
For this computer reconstruction, RAC drew on some additional weather data.
NCAR had a data-gathering site, identified as Kent, on Davidson Mesa, 10 km north of
the Rocky Flats plant. A group of portable meteo stations were in place just to the north
of the site, and were being used to calibrate the Rocky Flats air samplers; these produced
paper tape records of hourly wind speed and direction. In addition to detailed weather
reports from Stapleton Airport, RAC now had access to similar records from Jefferson
County Airport, six kilometers to the east. In addition, an attempt was made to reconcile
RATCHET’s output with the more detailed ASCOT/RAMS winter test data. As a result,
the RATCHET map for 609 Area deposition more closely resembles the ASCOT winter
test pattern.
The final RAC report to the Colorado Department of Public Health and
Environment acknowledged that dust, and plutonium, transport occurs in moderate wind.
It’s also the case that wind transport of surface soil occurs even in the absence of
industrial-grade perturbation, such as earth grading. The report acknowledges this:
In addition, the samplers surrounding the 903 Area and the S-8 sampler, in particular,
had generally higher counts rates from 1964 to 1969 compared to other years. These
higher counts suggest suspension of plutonium-contaminated soil was occurring
somewhat regularly during this period. (24)
The dose reconstruction team therefore aimed at an annualized average “flow”
model – in effect, a model of continual light downwind deposition of the leaked material.
17
Comprehensive assessment
The final RAC report, dated September, 1999, attempted to roll all that was learned about
extraordinary and routine releases into a single document. A key point made was that
monitoring improved dramatically from 1970 onward. With the improved data it became
clear that the major mechanism of transport for inhalable plutonium is resuspension.
Resuspension is defined as the lifting into the atmosphere of soil-fixed plutonium through
wind erosion or perturbation of contaminated soil. (RAC also discussed resuspension of
plutonium in groundwater; that issue is beyond the scope of this paper.)
The other significant observation regarding inhalable plutonium is that
RATCHET consistently underestimated deposition within the plant boundary and
overestimated deposition at distances over 10km from the plant. (25) This is consistent
with the conjecture, based on more complex models for windflow, that most small
particles left the immediate area to join the background of airborne radionuclide products
of nuclear testing programs. This is probably good news for folks living immediately
downwind of Rocky Flats, and less good for the rest of the world’s life forms.
RAC’s summation leads to the conclusion that at Rocky Flats the issue of
airborne plutonium cannot be separated from that of contaminated soil. The wind and the
soil constitute a single interacting system. As long as the wind blows from the mountains
across the prairie, the soil will continue to give up small quantities of plutonium to the
atmosphere. Unless the Rocky Flats National Wildlife Refuge plans to ban gophers and
eradicate knapweed, its plutonium-bearing soil will be continually perturbed, lofted and
redeposited eastward. It will still be blowing in the wind ten half-lives and 250,000 years
hence, when the plutonium will finally be safely depleted.
18
Fig. 7: Prairie dogs bring up about 10 cubic
feet of soil for each burrow. FreeStock photo.
19
Notes
1. Agency for Toxic Substances, Disease Registry of U.S. Public Health Service,
with the U.S. Environmental Protective Agency, 1990: Toxicological Profile for
Plutonium.
2. Ackland, Len. Making a Real Killing: Rocky Flats and the Nuclear West, p. 91.
1999: Albuquerque. The University of New Mexico Press.
3. U.S. Department of Energy, 1994: Environmental assessment, National Wind
Technology Center of the National Renewable Energy Laboratory, Golden,
Colorado
4. Towner, M.C., Ringrose, T.J., Patel, M.R. et al. 2004: “Close Encounter with a
Terrestrial Dust Devil.” Lunar and Planetary Science XXXV.
5. Dr. Hans Friedli, Scientist, Atmospheric Chemistry Division, National Center for
Atmospheric Research, Boulder; interview, November 2005.
6. Leroy Moore, PhD, environmental consultant, Rocky Mountain Peace and Justice
Center, Boulder; interview, December 2005.
7. Kelley, N., Hand, M., Larwood, S. and McKenna, E., 2002: The NREL LargeScale Turbine Inflow and Response Experiment – Preliminary Results. Golden:
National Renewable Energy Lab Preprint, January 14-17 2002.
8. Poulos, G.S., Bossert, J.E., McKee, T.B. and Pielke, R.A., 2000: “The interaction
of katabatic flow and mountain waves. Part I: observations and idealized
simulations.” Journal of Atmospheric Sciences, Vol 57, pp 1919-1936.
9. Doran, J. C., 1996: “The influence of canyon winds on flow fields near Colorado's
Front Range.” Journal of Applied Meteorology, 35, 587-600 also
Doran, J. C., 1993: “An overview of the ASCOT program.” Preprints, ANS
Topical Meeting on Environmental Transport and Dosimetry, Charleston, South
Carolina, American Nuclear Society, pp. 31-35 also
Varvayanni, M., Bartzis, J.G., Catsaros, N., Delgiannis, P., Elderkin, C.E., 1997.
“Simulation of Nocturnal Drainage Flows Enhanced by Deep Canyons: The
Rocky Flats Case.”Journal of Atmospheric Sciences, Vol 36, pp 775-791.
10. Thurlow, Dave. The Weather Notebook. Available on World Wide Web:
http://www.weathernotebook.org/transcripts/1997/04/08.html
11. Lapple, C.E., 1961: “Characteristics of Particles and Particle Dispersoids,"
Stanford Research Institute Journal, Third Quarter 1961.
20
12. Moore, Leroy, 2005: Rocky Flats: A Local Hazard Forever. Boulder: Rocky
Mountain Peace and Justice Center.
13. Leroy Moore interview, Dec. 8, 2005. Also see Morrison, M.L., Smallwood, K.S.
and Beyea, J., 1997: “Monitoring the dispersal of contaminants by wildlife at
nuclear weapons production and waste storage facilities.” The Environmentalist
17, 289-295
14. U.S. Fish and Wildlife Service, 2003: Rocky Flats National Wildlife Refuge
Planning Update. Available on the World Wide Web:
(http://www.fws.gov/rockyflats/documents/Planning_Update_3.pdf)
15. Neff, J.C., Reynolds, R.C., Belnap, J., Lamothe, P., 2005: “Multidecadal impacts
of grazing on soil physical and biogeochemical properties in southeast Utah.”
Ecological Applications 15(1) pp. 87-88.
16. Mazzola, C.A., Addis, R.P., Emergency Management Lab, Oak Ridge, 1995:
Atmospheric Modelling Resources, 2nd edition. U.S. Department of Energy.
17. John Nasstrom, PhD, ARAC program manager, Lawrence Livermore National
Laboratory, interview November 2005.
18. Pacific Northwest Laboratories, Flows in Complex Terrain. Available on the
World Wide Web: http://www.pnl.gov/atmos_sciences/as_meso3.html
19. Rood., A.S. and Grogan, H.A., 1999: Estimated Exposure and Lifetime Cancer
Incidence Risk from Plutonium Released from the 1957 Fire at the Rocky Flats
Plant. RAC Report No. 2-CDPHE-RFP-1999-FINAL
20. National Weather Service website: http://nws.noaa.gov
21. Reed Hodgin, Alphatrac Inc.; former RAC developer, interview November 2005.
22. Mazzola, Addis, 1995. ADM.
23. Rood., A.S. and Grogan, H.A., 1999: Estimated Exposure and Lifetime Cancer
Incidence Risk from 903 Area Plutonium Releases at the Rocky Flats Plant, RAC
Report No. 2- CDPHE-RFP-1999-FINAL.
24. Rood and Grogan, 1999: 903 Area, p. 9.
25. Rood., A.S. and Grogan, H.A., 1999: Comprehensive Exposure and Lifetime
Cancer Incidence Risk from Plutonium Released from the Rocky Flats Plant,
RAC Report No. 2- CDPHE-RFP-1999-FINAL p. 88.
21
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23