PLUTONIUM, RADIOACTIVE: Nuclear Power Plant Emissions
Sediment/Soil
Concentrations :
SEDIMENT: Plutonium-239 and plutonium-240 cannot be distinguished by alpha
spectroscopy and are usually reported together(1). Plutonium concentrations in
soils/sediment at 91 waste sites at 18 US Department of Energy facilities ranged
from 0.00011 to 3.5X10+6 pCi/kg(2). Plutonium concentrations were measured in
various environmental matrices collected from Antarctica at the Ross Sea region
surrounding the Italian Terra Nova Base in 1989-96(3). Mean
plutonium-239+plutonium-240 concentrations ranged from 0.005-0.0969 and
<0.0003-0.0806 Bq/kg in lacustrine and marine sediment, respectively(3). Mean
plutonium-238 concentrations ranged from 0.0018-0.0199 and <0.0003-0.0125 Bq/kg
in lacustrine (wetland associated with a lake) and marine sediment,
respectively(3). The British Nuclear Fuels Ltd nuclear fuel reprocessing plants
at Sellafield in Cumbria, UK discharge low level radioactive waste into the
Irish Sea(4). Plutonium-239+plutonium-240 concentrations in sediment cores
samples collected in October 1994 from 9 sites around the intertidal area of the
Irish Sea, UK ranged from 2.98 to 265 Bq/kg(4). Plutonium-239+plutonium-240
concentrations in bottom sediments form the Fram Strait in the Arctic ranged
from not detected to 2.264 Bq/kg(5). There are 4 nuclear power plants and one
research institute with two small nuclear reactors along the river Elbe in
Germany(6). Plutonium-238 and plutonium-239+plutonium-240 concentrations in
sediments collected between 1986-88 from the river Elbe ranged from 22-39 and
159-181 mBq/kg, respectively(6). Plutonium-239+plutonium-240 concentrations in
sediment cores from Sagami Bay of the coast of Japan margin ranged from
0.94-2.89, 2.11-11.17, and 0.023-3.82 mBq/g dry weight in samples from Tokyo
Canyon, Sagami Nada, and Sagami Trough, respectively(7).
Environmental Water Concentrations :
SURFACE WATER: Plutonium-239 and plutonium-240 cannot be distinguished by alpha
spectroscopy and are usually reported together(1). Plutonium-239+plutonium-240
concentrations in filtered sea water from the Spanish Mediterranean coast
averaged 12 mBq/cu m(2). The mean plutonium-239+plutonium-240 concentration in
the particulate fraction was 1.5 mBq/cu m(2). The Savannah River Plant, the
principal plutonium production facility in for the US Department of Energy, is
located about 256 km upstream from the mouth of the Savannah River(3).
Plutonium-238 concentrations in the Savannah River Estuary ranged from 0.4 to
1.9 uBq/L and 26 to 100 mBq/kg in the dissolved phase and in suspended
particulate, respectively(3). Plutonium-239+plutonium-240 concentrations ranged
from 1.9 to 5.2 uBq/L and 235 to 665 mBq/kg in the dissolved phase and in
suspended particulate, respectively(3). There are 4 nuclear power plants and one
research institute with two small nuclear reactors along the river Elbe in
Germany(4). Plutonium-238 and plutonium-239+plutonium-240 concentrations water
collected between 1985-88 from the river Elbe ranged from 0.007-0.05 and
0.03-0.16 mBq/L, respectively(4).
Fish/Seafood Concentrations :
Plutonium-239 and plutonium-240 cannot be distinguished by alpha spectroscopy
and are usually reported together(1). Plutonium-239+plutonium-240 concentrations
in mussels collected in 1977 and 1978 from Bodega Head, CA and from Narragansett
Bay, RI ranged from 1.9 to 4.6 and 0.3 to 2.1 disintegrations per minute per kg
dry weight, respectively(2). There are 4 nuclear power plants and one research
institute with two small nuclear reactors along the river Elbe in Germany(3).
Plutonium-238 and plutonium-239+plutonium-240 was not detected (<0.1 mBq/kg)
in fish collected from the river Elbe(3).
Methods of Manufacturing :
In the past, most plutonium in DOE facilities was produced for nuclear weapons
and was composed of greater than 90 wt% plutonium-239 and about 6 to 8 wt%
plutonium-240. This material has been referred to as weapons grade or low
exposure plutonium. It is produced on a large scale by irradiating uranium-238
in moderated production reactors. Plutonium has also been produced as a
byproduct in the operation of research reactors, and commercial nuclear power
plants. It is recovered and purified by solvent extraction and ion exchange
processes. The resulting highly concentrated Pu(NO3)4 product solution is
converted to a nonhygroscopic PuF4 intermediate by one of several processes
before being reduced to metal with calcium. Plutonium is also produced from the
waste streams of the conversion processes and scrap recovery operations, which
include material from research and development efforts. Other processes for
reduction to metal include direct reduction of the oxide and electrolytic
reduction.
Sediment/Soil Concentrations :
SEDIMENT: Plutonium-239+plutonium240, plutonium-238, plutonium-241
concentrations were measured in intertidal sediment from the Irish Sea;
concentrations ranged from for 2.3-1,804, 0.32-34.7, and 218-37,884 Bq/kg dry
weight, respectively(1). Plutonium-238 and plutonium-239-plutonium-240
concentrations in surface sediments from the Mediterranean Sea near the
Vandellos Nuclear Power Plant collected in 1989 ranged from 0.22-0.80 and
8.2-12.6 Bq/kg, respectively(2).
Effluent Concentrations :
Among the major effluents from the use and processing of nuclear fuel are ...
plutonium. ... Of these, only tritium and plutonium can possibly enter water
supplies. The predominant form of plutonium release from nuclear power and
processing plants is as an aerosol that will have little or no impact on
drinking water. Although a single incident has occurred in which as much as
18,750 Ci of plutonium were released from liquid storage on a local basis, none
apparently reached off site water supplies. The usual rate of release from
liquid storage at a controlled sites is about 1 mCi/yr.
General Manufacturing Information :
.. ca. 400 tons of plutonium has been produced in nuclear power stations outside
centrally planned economies (i.e. excluding the former Eastern-bloc countries).
Major Uses :
Because of its high specific alpha activity and high decay heat, plutonium-238
has been used as an isotopic heat source for devices that generate
thermoelectric power, such as the Space Nuclear Auxiliary Power (SNAP) systems
used in lunar and deep space missions. /Plutonium-238/
Disposal Methods :
/SRP/ Wastes in the Waste Isolation Pilot Plant (WIPP) are from the nuclear
weapons industry (plutonium) - research and development. For a waste to be
accepted at WIPP it must be a transuranic "TRU" waste and: (1) </=
100 nanoCi/gram, (2) an alpha emitting transuranium isotope with atomic number
greater than uranium, and (3) have a half life greater than 20 years. The wastes
must be handled remotely if they produce >/= 200 millirems/hr; if less, they
can be contact handled.
Human Toxicity Excerpts :
/EPIDEMIOLOGY STUDIES/ A major study was performed on all 14,319 workers (11,635
men) employed at the Sellafield fuel reprocessing plant of British Nuclear Fuels
between 1947 and 1975 ... The mortality of these workers was studied up to the
end of 1992, and cancer incidence was examined from 1971 through 1986. The study
included 5,203 workers who were monitored for exposure to plutonium, of whom
4,609 were assessed for dose. The body burden of most workers was estimated to
be < 50 Bq, and only a few had > 1 kBq. ... (In this cohort, the average
cumulative doses from plutonium were 712 mSv to bone surfaces, 194 mSv to lung,
91 mSv to liver, and 58 mSv to red bone marrow ... ). The number of deaths /and
death rates/ from all cancers in plutonium workers is not excessive ... . The
numbers of deaths from cancers of the liver, lung, and bone were not in excess,
but there were significant excesses of deaths among plutonium workers when
compared with the rates in England and Wales from cancer of the pleura (SMR,
4.71; p < 0.001), breast cancer (SMR, 2.36; p < 0.05) and cancers of
ill-defined and secondary sites (SMR, 1.44; p < 0.05). /Plutonium, NOS/
Environmental Water Concentrations :
GROUNDWATER: Plutonium-239 and plutonium-240 cannot be distinguished by alpha
spectroscopy and are usually reported together(1). Plutonium-239+plutonium240
concentrations were measured in monitoring wells in a small aquifer in the
Mortandad Canyon, which receives liquid wastes from the Los Alamos National
Laboratory, NM in 1982 and 1983(2). Plutonium-239+plutonium-240 was detectable
in monitoring wells up to 3,390 meters downgradient from the discharge;
decreasing from 1,400 to 0.55 mBq/L between the first and last monitoring
well(2). Plutonium concentrations in groundwater at 91 waste sites at 18 US
Department of Energy facilities ranged from 0.0009 to 12.8 pCi/L(3).
Plutonium-239+plutonium-240 concentrations in porewater collected over a year
from an inter-tidal salt marsh in the Esk Estuary, West Cumbria, UK near the
British Nuclear Fuel Ltd Sellafield nuclear fuel reprocessing plant ranged from
0.84 mBq/L in August to 3.21 mBq/L in April(4).
Ecotoxicity Excerpts :
/FIELD STUDIES/ Activity concentrations of radionuclides (cesium-134,
cesium-137, plutonium-238, plutonium-239,- 240 and americium-241) were measured
in vegetation, invertebrates and wood mice, Apodemus sylvaticus, collected in
Lady Wood, a coniferous woodland in the vicinity of the British Nuclear Fuels
reprocessing plant at Sellafield, Cumbria, UK. Vegetation was of low diversity
and biomass with activity concentrations ranging from 1 to 5 Bq kg-1
(cesium-134), 0.3-0.5 Bq kg-1 (plutonium-238), 0.8-8 Bq kg-1 (plutonium-239 +
240), and 0.6-16 Bq kg-1 (americium-241), dry wt. Cesium-137 activity
concentrations were high compared to the reference site in Cheshire, varying
between 65 and 280 Bq kg-1. Marked inter-specific and temporal differences in
radionuclide activity concentrations were recorded for invertebrate populations.
Cesium-137, plutonium-238, plutonium-239,-240 and americium-241 activity
concentrations in detritivorous invertebrates were consistently higher than in
all other invertebrate groups reflecting contamination of the leaf litter. The
activity concentrations in detritivores increased during the autumn and winter,
reflecting changes in diet as food sources varied throughout the year. Activity
concentrations in invertebrates caught in Lady Wood were generally an order of
magnitude higher than for the reference site. Activity concentrations in wood
mice varied between 7 and 150 Bq kg-1 (cesium-137), 0.1-0.3 Bq kg-1
(plutonium-238), 0.1-0.6 Bq kg-1 (plutoniuim-239,-240) and 0.2-0.4 Bq kg-1
(americium-241). There were clear differences in the activity concentration of
cesium-137 (P < 0.01), plutonium-239 + 240 (P < 0.05) and americium-241 (P
< 0.05) in animals caught in Lady Wood compared to the reference site.
However, the activity concentrations for plutonium-238 were similar at both
sites, reflecting a low gastrointestinal transfer. Seasonal variation in
activity concentrations was observed for cesium-137, plutonium-238 and
americium-241. This variation is attributed to changes in the age structure of
the population and diet throughout the year. /Plutonium-238, Plutonium-239,-240/
Absorption, Distribution & Excretion :
Ingestion: The fractional absorption of plutonium-244 administered in citrate
solution with a midday meal to three volunteers was in the range 3x10-4 to
9x10-4. Measurements on two further volunteers increased the range to 1x10-4 to
1x10-3, with an average of 6x10-4. In volunteers who ate winkles collected on
the Cumbrian coast near to the nuclear-fuel reprocessing plant at Sellafield,
the average fractional absorption of plutonium was 1.7x10-4, with a range of
2x10-5 to 5x10-4. The fractional absorption from the gut of fall-out plutonium
in reindeer meat ... was estimated to be 8x10-4, but the estimate is uncertain.
/Plutonium-244 citrate/
Human Toxicity Excerpts :
/EPIDEMIOLOGY STUDIES/ A cohort of about 21,000 Russian nuclear workers who
worked at the Mayak plutonium production complex between 1948 and 1972 is under
study. The Mayak complex, which is located in the Chelyabinsk region of the
Russian Federation, includes three main plants; a reactor complex, a
radiochemical separation plant, and a plutonium production plant. Workers at all
three plants had potential for exposure to external radiation, and workers at
the radiochemical and plutonium production plants also had potential for
exposure to plutonium. Recently, data on workers at two auxiliary plants, who
had much less potential for exposure, have been added to the cohort under study
to expand the comparison group. As is the case for other nuclear worker cohorts,
estimates of annual external doses are available from individual film badge
monitoring data. Some workers were also monitored for plutonium exposure;
however, since routine testing based on large urine samples did not begin until
about 1970, only about 40% of workers with potential for such exposure have been
monitored. External exposure and exposure to plutonium for Mayak workers far
exceed those of other nuclear worker cohorts discussed previously... . For
example, for the nearly 11,000 monitored workers hired before 1959, the mean
cumulative external dose was 1.2 Gy, more than an order of magnitude higher than
any of the cohorts described /previously/... . Analyses focused on leukemia
(excluding chronic lymphocytic leukemia); cancers of the lung, liver, and bone
(analyzed as a group); and solid cancers excluding lung, liver, and bone cancers
(also analyzed as a group). The lung, liver and bone are the organs that receive
the largest doses from plutonium, and excess cancers in all three organs have
been clearly linked to plutonium exposure among Mayak workers. Analyses were
adjusted for internal exposure from plutonium by using the estimated body burden
for workers who had plutonium-monitoring data and by using a plutonium surrogate
variable for workers who were not monitored for plutonium. The plutonium
surrogate variable was recently developed from detailed work histories. For
leukemia, the estimated /excess risk ratio/ (ERR)/Gy was 6.9 (90% CI 2.9, 15)
for the period 3-5 years after exposure and 0.5 (90% CI 0.1, 1.1) for the period
5 or more years after exposure. The estimate based on the entire period was 1.0
(90% CI 0.5, 2.0). There were no statistically significant departures from
linearity and no evidence of modification by sex or age at hire. Estimates for
the solid cancer endpoints are /as follows:/ lung, liver or bone (linear model)
ERR/Sv 0.30 (90% CI 0.18, 0.46); other solid cancers (linear model) ERR/Sv 0.08
(90% CI 0.03, 0.14); all solid cancers (linear model) ERR/Sv 0.15 (90% CI 0.09,
0.20); lung, liver, or bone (linear-quadratic model) ERR/Sv 0.54 (90% CI 0.27,
0.89); other solid cancers (linear-quadratic model) ERR/Sv 0.21 (90% CI 0.06,
0.37); all solid cancers (linear-quadratic model) ERR/Sv 0.30 (90% CI 0.18,
0.43). /from table/ /Plutonium, NOS/
Major Uses :
Of the 15 plutonium isotopes, the two that have proven most useful are masses
239 and 238. Plutonium-239 is fissile, i.e., atoms of plutonium split upon
exposure to thermal or fast neutrons. Chemical reactions can release a few
electron volts of energy per atom; however, when a plutonium nucleus splits, it
releases about 200 MeV of energy and two or three neutrons. This release of
energy makes plutonium-239 useful for nuclear weapons and reactor fuel. In fact,
in light water reactors (LWRs) much of the power originates from the fission of
plutonium-239, which is produced by neutron capture in uranium-238. /Plutonium
isotopes/
Major Uses :
Uses of Plutonium Isotopes: Plutonium-236, plutonium-237. Popular environmental
and biological chemical tracers. Both available in microcurie quantities.
Plutonium-238. Small thermal and electric-power generators. Available in various
isotopic enrichments, ranging from 78% to 99+%. Plutonium-239. Nuclear weapons
and as a fast reactor fuel. Also, frequently used in chemical research where
production-grade material of mixed isotopic content is suitable. Available
enrichments range from 97% to 99.99+%. Plutonium-240. Principally in flux
monitors for fast reactors. Available enrichments range from 93% to 99+%.
Plutonium-241. The parent from which high-assay americium-241 can be isolated
for industrial purposes. Samples available in enrichments of 93%. Plutonium-242.
For study of the physical properties of plutonium; also as a mass spectroscopy
tracer and standard. Samples available in enrichments ranging from 95% to
99.9+%; enrichments of production-grade material range from 85% to 95%.
Plutonium-244. Currently, the only isotope available as a National Institute of
Standards and Technology (NIST) Standard Reference Material (SRM). /From table/
/Plutonium isotopes/
Artificial Pollution Sources :
Plutonium may be released to the environment by nuclear weapons testing,
accidents involving weapons transport, nuclear reactors, radioisotope
generators, fuel processing and reprocessing, and fuel transport(1). Atmospheric
nuclear weapons testing is the main source of plutonium in the environment, and
is the largest source of plutonium-239 and plutonium-240 in the environment(1).
An estimated 1.3X10+16 Bq of plutonium-239+plutonium-240 have been released to
the environment from atmospheric detonation of nuclear weapons(2). An estimated
7.9X10+14 Bq of plutonium-238 has been released, mostly from the burn-up of the
nuclear powered satellite SNAP-9(2). An estimated 3.7X10+13 Bq of
plutonium-239+plutonium-240 was released from the Chernobyl accident(2). Between
1954 and 1974 approximately 1.4X10+11 and 1.1X10+10 Bq of plutonium have been
released into the atmosphere and surface waters, respectively, from fuel
reprocessing operations at the Savannah River Plant, the principal plutonium
production facility for the US Department of Energy(3). Plutonium was first
discovered in 1940(2). Plutonium isotopes with mass numbers 232-246 have been
identified and all are radioactive(2). Plutonium-239 is the most important
isotope, as well as plutonium-238, plutonium-242, and plutonium-244(2).
Plutonium forms compounds with many metallic elements and all of the nonmetallic
elements, except those of the noble gas group(2).
Methods of Manufacturing :
Plutonium is produced in nuclear reactors from uranium-238 that absorbs neutrons
emitted by the fission of uranium-235, which is a naturally occurring uranium
isotope found with uranium-238. Uranium-239 is formed and emits a beta particle
to form neptunium-239 that decays by beta emission to form plutonium-239. Once
started, the process is spontaneous until the uranium fuel rods become a
specific uranium-plutonium mixture. The rods are dissolved in acid, and
plutonium is separated primarily by solvent extraction, finally producing a
concentrated plutonium solution. Pure plutonium metal can be prepared by
precipitating plutonium peroxide or oxalate, igniting the precipitate to PuO2,
converting the oxide to PuF3, and reducing Pu+3 to the metal in an ignited
mixture containing metallic calcium. /Plutonium/
Preventive Measures :
In a nuclear weapon accident involving fire or conventional explosion, most of
the radiation dose received by people in the immediate vicinity would result
from inhalation of plutonium-239. This is accompanied by the nuclide
americium-241, which is much easier to determine by external counting because of
the 60 keV gamma ray emission. In the event of an accident, a priority would be
to identify any people who have had intakes of plutonium-239 which were so large
that decorporation therapy should be considered. Direct measurement of lung
content provides the most rapid and convenient method for assessing intakes by
inhalation. A transportable system has been considered as this could be deployed
close to the site of the accident and would allow rapid measurements to be made.
The feasibility of a transportable americium-241-in-nose-blow and nasal swab
measurement system has also been considered. This would be used to help select
people for americium-241-in-lung measurements.
Methods of Manufacturing :
High-exposure plutonium, i.e., plutonium containing significant fractions of
plutonium-240, plutonium-241, and plutonium-242, is produced in power reactor
fuels. ... Reactor-produced plutonium goes through several different chemical
processes before it becomes a solid metal. Irradiated nuclear fuel elements are
dissolved in strong acid and the plutonium is chemically extracted from the
solution. ... The solution is put through another processing stage that converts
it from a liquid to a powder. ... The powder is then placed in a crucible mold
and heated without melting until it becomes a solid metal.
Mechanism of Action :
Lung cancer from radon or plutonium-239 exposure has been linked to
alpha-particles that damage DNA through large deletions and point mutations.
/The authors/ investigated the involvement of an epigenetic mechanism, gene
inactivation by promoter hypermethylation in adenocarcinomas from
plutonium-exposed workers at MAYAK, the first Russian nuclear enterprise
established to manufacture weapons plutonium. Adenocarcinomas were collected
retrospectively from 71 workers and 69 non-worker controls. Lung adenocarcinomas
were examined from workers and non-worker controls for methylation of the CDKN2A
(p16), O(6)-methylguanine-DNA methyltransferase (MGMT), death associated protein
kinase (DAP-K), and Ras effector homolog 1 genes (RASSF1A). The prevalence for
methylation of the MGMT or DAP-K genes did not differ between workers and
controls, while a higher prevalence for methylation of the RASSF1A gene was seen
in tumors from controls. In marked contrast, the prevalence for methylation of
p16, a key regulator of the cell cycle, was increased significantly (P = 0.03)
in tumors from workers compared with non-worker controls. Stratification of
plutonium exposure into tertiles also revealed a striking dose response for
methylation of the p16 gene (P = 0.008). Workers in the plutonium plant where
exposure to internal radiation was highest had a 3.5 times (C.I. 1.5, 8.5; P =
0.001) greater risk for p16 methylation in their tumors than controls. This
increased probability for methylation approximated the 4-fold increase in
relative risk for adenocarcinoma in this group of workers exposed to plutonium.
In addition, a trend (P = 0.08) was seen for an increase in the number of genes
methylated (> or =2 genes) with plutonium dose. Here /the authors/
demonstrate that exposure to plutonium may elevate the risk for adenocarcinoma
through specifically targeting the p16 gene for inactivation by promoter
methylation. /Plutonium-239/
Other Chemical/Physical Properties :
DECAY PATHWAY: Plutonium-236, half-life 2.851 years, decays via alpha emission,
5867 keV (69.3% 5767.7 keV; 30.6% 5721.0 keV) to uranium-232, half-life 68.9
years; decays via alpha emission, 5414 keV (68.2% 5320.1 keV; 31.6% 5263.4 keV)
to thorium-228, half-life 1.9116 years; decays via alpha emission, 5520 keV
(72.2% 5423.2 keV; 27.2% 5340.4 keV) to radium-224, half-life 3.66 days; decays
via alpha emission, 5789 keV (94.9% 5685.4 keV; 5.06% 5448.6 keV) to radon-220,
half-life 55.6 seconds; decays via alpha emission, 99.9% 6405 keV, to
polonium-216, half-life 0.145 seconds; decays via alpha emission, 99.998% 6778.3
keV, to lead-212, half-life 10.64 hours; decays via beta(-) emission (82.5% 335
keV maximum, 94.8 average energy; 12.3% 173.1 keV average energy)and gamma
emission (abs intensity: 100% 238.6 keV) to bismuth-212, half-life 60.55
minutes; 64.06% of bismuth-212 decays via beta (-) emission (86.6%, 832.5
average energy; 6.81%, 531.5 keV average energy) to polonium-212, half-life 45.1
seconds; 35.94% of bismuth-212 decays via alpha emission, 6207 keV (69.9% 6050.8
keV; 27.1% 6089.9 keV) to thallium-208, half-life 3.053 minutes; polonium-212
decays via alpha emission, 8954 keV (96.9% 11650 keV) to lead-208, half life
stable; thallium-208 decays via beta (-) emission (48.7%, 1796.3 keV maximum,
647.4 average energy; 24.5%, 1285.6 keV maximum, 439.6 keV; 21.8%, 1518.9 keV
maximum, 533.3 keV average energy) and gamma emission (abs intensities: 85.2%
583.2 keV; 22.8% 510.8 keV; 12.5% 860.6 keV) to lead-208, half-life stable.
Radiation Limits & Potential :
DECAY PATHWAY: Plutonium-236, half-life 2.851 years, decays via alpha emission,
5867 keV (69.3% 5767.7 keV; 30.6% 5721.0 keV) to uranium-232, half-life 68.9
years; decays via alpha emission, 5414 keV (68.2% 5320.1 keV; 31.6% 5263.4 keV)
to thorium-228, half-life 1.9116 years; decays via alpha emission, 5520 keV
(72.2% 5423.2 keV; 27.2% 5340.4 keV) to radium-224, half-life 3.66 days; decays
via alpha emission, 5789 keV (94.9% 5685.4 keV; 5.06% 5448.6 keV) to radon-220,
half-life 55.6 seconds; decays via alpha emission, 99.9% 6405 keV, to
polonium-216, half-life 0.145 seconds; decays via alpha emission, 99.998% 6778.3
keV, to lead-212, half-life 10.64 hours; decays via beta(-) emission (82.5% 335
keV maximum, 94.8 average energy; 12.3% 173.1 keV average energy)and gamma
emission (abs intensity: 100% 238.6 keV) to bismuth-212, half-life 60.55
minutes; 64.06% of bismuth-212 decays via beta (-) emission (86.6%, 832.5
average energy; 6.81%, 531.5 keV average energy) to polonium-212, half-life 45.1
seconds; 35.94% of bismuth-212 decays via alpha emission, 6207 keV (69.9% 6050.8
keV; 27.1% 6089.9 keV) to thallium-208, half-life 3.053 minutes; polonium-212
decays via alpha emission, 8954 keV (96.9% 11650 keV) to lead-208, half life
stable; thallium-208 decays via beta (-) emission (48.7%, 1796.3 keV maximum,
647.4 average energy; 24.5%, 1285.6 keV maximum, 439.6 keV; 21.8%, 1518.9 keV
maximum, 533.3 keV average energy) and gamma emission (abs intensities: 85.2%
583.2 keV; 22.8% 510.8 keV; 12.5% 860.6 keV) to lead-208, half-life stable.
Major Uses :
The half-life of plutonium-238 is short enough (88 years) to create a high heat
output and long enough to provide long-term power without replenishment. These
characteristics make it an ideal heat source for thermoelectric generators.
These generators have been used to power ocean buoys and space satellites where
long-term, reliable power is essential. /Plutonium-238/
Other Chemical/Physical Properties :
All plutonium isotopes are radioactive. Isotopes with even mass numbers (except
mass number 246) are primarily alpha emitters. Isotopes of mass numbers 232,
233, 234, 235, and 237 also decay by electron capture; isotopes of mass numbers
241, 243, 245, and 246 decay by beta emission. Many of the alpha-emitting
isotopes, such as plutonium-238 and plutonium-240, also fission spontaneously
and emit neutrons. All of the particle emissions are accompanied by X-ray and
gamma-ray emissions over a wide range of energies. /Plutonium isotopes/
Radiation Limits & Potential :
All plutonium isotopes are radioactive. Isotopes with even mass numbers (except
mass number 246) are primarily alpha emitters. Isotopes of mass numbers 232,
233, 234, 235, and 237 also decay by electron capture; isotopes of mass numbers
241, 243, 245, and 246 decay by beta emission. Many of the alpha-emitting
isotopes, such as plutonium-238 and plutonium-240, also fission spontaneously
and emit neutrons. All of the particle emissions are accompanied by X-ray and
gamma-ray emissions over a wide range of energies.
Major Uses :
Small amounts of plutonium-238 with low plutonium-236 content were used as a
power source for medical prosthetic devices such as cardiac pacemakers and a
prototype artificial heart, but lithium batteries have replaced these plutonium
power sources. /Plutonium-236 & plutonium-238/
Plant Concentrations :
Most of the plutonium found in field grown native plants and agricultural crops
is due to surface contamination rather than soil plant transfer. Plutonium concn
depends on plant species, on the type and age and status of vegetation; on the
pH; cation exchange capacity; mineral and organic composition of the soil; and
on the physical and chemical form of contamination; as well as its duration. The
highest uptake of plutonium in cheat grass occurs, for example, when plutonium
is present in the soil as the stable citrate complex or as a complex with
macromolecules, like humic acid or fulvic acid.
Environmental Fate/Exposure Summary :
Plutonium may be released to the environment by nuclear weapons testing,
accidents involving weapons transport, nuclear reactors, radioisotope
generators, fuel processing and reprocessing, and fuel transport. Atmospheric
nuclear weapons testing is the main source of plutonium in the environment, and
is the largest source of plutonium-239 and plutonium-240 in the environment.
Plutonium was first discovered in 1940. Plutonium isotopes with mass numbers
232-246 have been identified and all are radioactive. Plutonium-239 is the most
important isotope, as well as plutonium-238, plutonium-242, and plutonium-244.
Plutonium forms compounds with many metallic elements and all of the nonmetallic
elements, except those of the noble gas group. Plutonium occurs in naturally
occurring ores in very small amounts; the atom to atom ratio of plutonium to
uranium in uranium ores is <1 to 10+11 (e.g., less than one atom of plutonium
per 10+11 atoms of uranium). If released to air, plutonium compounds would exist
solely in the particulate phase in the ambient atmosphere since they are ionic
and would not be volatile. Particulate-phase plutonium compounds will be removed
from the atmosphere by wet and dry deposition. Plutonium is generally immobile
in soil. Physical processes, such as cultivation of soil, may redistribute
plutonium compounds between soil layers. Erosion by wind and water will also
transport plutonium compounds found in surface soils through the environment.
Plutonium compounds are ionic and will not volatilize from dry or moist soil
surfaces. In solution, the Pu(III-VI) oxidation states can exist simultaneously.
Plutonium oxidizes rapidly, forming insoluble PuO2, which is the most common
form of plutonium in the environment. Plutonium ions can form complex ions with
simple hard Lewis bases, such as ligands with oxygen donor groups. Partition
coefficients (Kd) ranging from 8X10+4 to 1.5X10+5 were determined for
(plutonium-239+plutonium-240) in arctic surface sediments from the Kara Sea. In
most natural aquatic systems, plutonium is associated with either sediments or
suspended particles; in areas where the amount of solid phase is limited,
plutonium remains in the dissolved phase. Kd values ranging from 1X10+5 to
7X10+5 L/kg have been reported for plutonium with suspended particulate in
environmental waters. It has been shown that plutonium associated with colloidal
materials can be mobile in groundwater systems over large distances and can bind
and transport radionuclides. Plutonium compounds are ionic and would not
volatilize from water surfaces. Bioconcentration factors of 1.6X10+4 and 2X10+3
in brown macroalgae and <500 and 40 in fish muscle were reported for
(plutonium-239+plutonium-240). Bioconcentration factors of 1,000 for mollusks
and algae, 100 in crustacea, and 10 for fish have been reported for plutonium.
Individuals working at facilities using or processing plutonium or uranium may
be exposed to plutonium compounds. As plutonium is dispersed throughout the
environment due to past atmospheric nuclear weapons testing, the general
population will have some exposure to plutonium compounds. An estimated 50-year
dose from plutonium due to atmospheric nuclear weapons testing conducted before
1973 is 0.2 millirad for individuals living in the north temperate zone of the
earth. Individual living near facilities that use or process plutonium may have
higher exposures to plutonium compounds than the general population. (SRC)
Other Chemical/Physical Properties :
DECAY PATHWAY: Plutonium-241, half-life 14.35 years, decays via beta (-)
emission (100%, 20.8 keV maximum, 5.23 keV average energy) to americium-241,
half-life 432.2 years; decays via alpha emission, 5683 keV (84.5% 5486 keV;
13.0% 5443keV) to neptunium-237, half-life 2,144,000 years
Radiation Limits & Potential :
DECAY PATHWAY: Plutonium-241, half-life 14.35 years, decays via beta (-)
emission (100%, 20.8 keV maximum, 5.23 keV average energy) to americium-241,
half-life 432.2 years; decays via alpha emission, 5683 keV (84.5% 5486 keV;
13.0% 5443keV) to neptunium-237, half-life 2,144,000 years
Cleanup Methods :
A pamphlet published by the Energy Research and Development Administration in
May 1976 entitled Radioactive Waste Management at Hanford describes one type of
traditional reprocessing plant ... /that is/ designed for recovery of neptunium
as well as plutonium and uranium. The Purex Extraction portion of the Hanford
Reprocessing Plant has processing equipment for sequentially dissolving depleted
fuel rods, treating such solutions with extractants for the recovery of
components such as plutonium and uranium and for the isolation of fission
products. ... The depleted fuel rods are dissolved to provide an aqueous
solution which is subjected to solvent extraction to recover the plutonium. ...
The ... plutonium stream is purified by a series of processing steps. The
fission products are separated and processed in an appropriate manner.
Methods of Manufacturing :
Commercial electric-power generating reactors generally produce plutonium by
irradiating uranium fuels to a total neutron exposure of more than 5000 megawatt
days per ton. The recoverable plutonium contains a larger fraction of heavier
isotopes. The rate of production and the isotopic composition depends on the
reactor type and method of operation, which depend on economics. In boiling
water reactors (BWR) and pressurized-water reactors (PWR), the rates of
production are 270 and 360 g plutonium per electrical megawatt yr of operation,
respectively.
General Manufacturing Information :
Upon fission, one gram of plutonium releases energy equivalent to that produced
by combustion of three metric tons of coal. In plutonium-fueled breeder power
reactors, more plutonium is produced than is consumed.
Human Toxicity Excerpts :
/CASE REPORTS/ /ACUTE RADIATION SYNDROME/ The accident ... occurred as a result
of reactor criticality ... . A large reactivity change as made manually during
testing control rods in the ZPR assembly causing a power excursion. Three
workers (A, B, and C) were on a platform surrounding the reactor tank while
another worker (D) leaned over the the tank and unclamped and withdrew a control
rod. A dull "thud" was heard and a blue light emanated from the top of
the reactor. The control rod was dropped back in and the workers left the room.
The patients were seen within 10 minutes by a physician. They were asymptomatic
and transported to a hospital. The doses were about 1.59, 1.26, 0.61, and 0.11
Gy. Only patient A was symptomatic. No fatalities resulted from this accident.
/Fissionable plutonium/
Spectral Properties :
Characteristic Emission Lines: L(beta1)L2M4= 0.67772; L(lambda)L3M1= 1.0226;
L(alpha1)L3M5= 0.86830; L(beta2)L3N5= 0.71851.
Other Chemical/Physical Properties :
DECAY PATHWAY: Plutonium-238, half-life 87.7 years, decays via alpha emission,
5593 keV (70.9% 5499 keV; 28.9% 5456 keV) to uranium-234, half-life 245,500
years
Other Chemical/Physical Properties :
DECAY PATHWAY: Plutonium-239, half-life 24,110 years, decays via alpha emission,
5245 keV (73.3% 5156 keV; 15.1% 5144 keV) to uranium-235, half-life 7.028X10+8
years
Other Chemical/Physical Properties :
DECAY PATHWAY: Plutonium-240, half-life 6564 years, decays via alpha emission,
5256 keV (72.8% 5168 keV; 27.1% 5144 keV) to uranium-235, half-life 2.342X10+7
years
Other Chemical/Physical Properties :
DECAY PATHWAY: Plutonium-242, half-life 373,300 years, decays via alpha
emission, 4984 keV (77.5% 4901 keV; 22.4% 4856 keV) to uranium-238, half-life
4.468X10+9 years
Radiation Limits & Potential :
DECAY PATHWAY: Plutonium-238, half-life 87.7 years, decays via alpha emission,
5593 keV (70.9% 5499 keV; 28.9% 5456 keV) to uranium-234, half-life 245,500
years
Radiation Limits & Potential :
DECAY PATHWAY: Plutonium-239, half-life 24,110 years, decays via alpha emission,
5245 keV (73.3% 5156 keV; 15.1% 5144 keV) to uranium-235, half-life 7.028X10+8
years
Radiation Limits & Potential :
DECAY PATHWAY: Plutonium-240, half-life 6564 years, decays via alpha emission,
5256 keV (72.8% 5168 keV; 27.1% 5144 keV) to uranium-235, half-life 2.342X10+7
years
Radiation Limits & Potential :
DECAY PATHWAY: Plutonium-242, half-life 373,300 years, decays via alpha
emission, 4984 keV (77.5% 4901 keV; 22.4% 4856 keV) to uranium-238, half-life
4.468X10+9 years
Radiation Limits & Potential :
The plutonium isotopes emit relatively few high-energy gamma rays, so even
kilogram quantities can be processed without serious gamma-exposure problems.
Because of the high density of plutonium, many gamma rays are self-absorbed. In
some instances, the decay products may become significant in radiation
protection and metallurgy. For instance, the isotope plutonium-236 often
constitutes less than 1% of plutonium and is often ignored in dose calculations.
However, if the plutonium is shielded by greater than 1 cm of lead or steel, the
decay products of plutonium-236 may be the largest contributors to exposure. The
decay product thallium-208 emits a highly penetrating gamma ray with an energy
of 2.615 MeV. In plutonium that contains a few weight percent plutonium-241, the
americium-241 decay product is important because it emits a large number of
60-keV photons, which can be a significant source of exposure to the hands and
forearms when handling plutonium in gloveboxes. Also, americium-241 can
contribute to neutron dose. Americium-241 contributes to increased alpha
emission which affects the neutron dose as well as radiolysis and helium
retention and release. Because of its importance to radiation exposure, the
fractional amount of americium-241 produced by beta decay from plutonium-241 is
given as a function of time since chemical separation.
Antidote and Emergency Treatment :
A nuclear accident dosimetry program/at the facility/ should provide absorbed
dose information/to the medical team/ within 24 hours after the incident. ... A
common initial screening method is to provide all workers in areas requiring
nuclear accident dosimetry with an indium foil in their personnel dosimeter or
security badge. During a criticality excursion the foil will become activated by
neutrons per the indium-115(n, gamma) indium-116m reaction and can be measured
with a portable beta-gamma survey instrument or ion chamber. The indium-116m has
a 54-min half-life and releases a 1-MeV beta (maximum energy) and a 1.3-MeV
gamma (80% of the time). An alternate screening is to measure body activity due
to neutron activation of the sodium in the blood via the sodium-23 (n, gamma)
sodium-24 reaction. Sodium-24 has 15-hour half-life and releases a 1.4-MeV beta
(maximum energy) and two gammas (1.37 MeV and 2.75 MeV). A beta-gamma survey
meter is used to measure the sodium-24 activity in the blood by placing the
detector probe against the individual's abdomen and having the individual bend
forward to enclose the detector. Alternatively, the probe can be positioned
under the armpit with the open window facing the chest area. ...Tthis method is
less sensitive than the use of indium foils and even a small reading can
indicate a significant exposure.
Atmospheric Concentrations :
On the basis of the measured and inferred plutonium concentration in the air of
New York and a constant inhalation rate of 20 cu m/day, inhalation intake
reflects the amt of radioactivity released by nuclear weapons tests. In 1960 ...
the amt diminished & rose again in 1963 to a max of 450 mbecquerel following
1961-1962 /nuclear weapons tests/. ... declined regularly after the Test Ban
Treaty of 1963 to a value of about 7 mbecquerel/yr during the period from
1972-1974.
Probable Routes of Human Exposure :
Individuals working at facilities using or processing plutonium or uranium may
be exposed to plutonium compounds(1). As plutonium is dispersed throughout the
environment due to past atmospheric nuclear weapons testing, the general
population will have some exposure to plutonium compounds(SRC). An estimated
50-year dose from plutonium due to atmospheric nuclear weapons testing conducted
before 1973 is 0.2 millirad for individuals living in the north temperate zone
of the earth(1). Individual living near facilities that use or process plutonium
may have higher exposures to plutonium compounds than the general population(SRC).
Human Toxicity Excerpts :
/CASE REPORTS/ /WOUND CONTAMINATION/ Glovebox Accident Involving
Plutonium-Americium Contamination and Hand Amputation. An employee ... in
plutonium fuel fabrication reached for an item in his glovebox and his glove was
caught by a milling machine that tore off his right hand. /An hour later/ ...
patient /arrived at the treatment center. ... The patient was surveyed for
external contamination while in the ambulance. No widespread removable
contamination was found, so the patient was brought in and placed on a
decontamination table /at which time the attending physician/ learned that the
patient had lost his right hand at the wrist. /A half-hr later/ the plant health
physics supervisor arrived with the contaminated hand wrapped in plastic in an
ice bucket. The hand was immediately counted ... and the patient's stump was
counted ... with a ... NaI crystal. An initial estimate ... indicated ... an
amount, if entering bone, /that/ could result in bone dose commitments in the
tens of millions of rem ... Additional measurements /after ....debridements/
indicated that ... remaining contamination on the hand and stump was still more
than 100 times the Maximum Permissible Body Burden (MPBB). .... The difficult
decision was made by the patient and his family, as well as the involved
physicians and health physicists, to reattach the hand despite its excessive
residual radioactivity. Considerations included the youth of the worker, his
right-handedness, location of the radioactivity, the availability of DTPA
chelation therapy, and the likelihood of the patient's availability of multiyear
observation. ... Unfortunately, circulation in the fingers of the reattached
hand did not improve quickly enough for tissue survival, so the hand was
reamputated, ... infused with formaldehyde and recounted ... showing about 4 uCi
(about 100 MPBB) still on the surface. ... Since reamputation of the hand was
done approximately an inch higher than the original accidental amputation, the
reamputated hand turned out to contain practically all of the remaining
contamination. ... The medical management of an injured and contaminated patient
in this case required at least about two person-days of professional dedication
of a medical-health physics team already experienced with accidents involving
external and internal contamination with americium-plutonium mixtures; this
input was in addition to collaboration with a number of other physicians and
medical and health physics technicians. The average medical institution likely
to receive contaminated victims of a terrorist attack will not have such
personnel or equipment resources. Any expectation of a medical capacity for
triage and management of such patients requires prior training and equipping of
personnel in each medical institution for the simplest counting and
spectrometric measurements, and ready-made methods of data interpretation.
Human Toxicity Excerpts :
/EPIDEMIOLOGY STUDIES/ The authors conducted a nested case-control study of the
association between lung cancer mortality and cumulative internal lung doses
among a cohort of workers employed at the Rocky Flats /Plutonium/ Plant in
Colorado from 1951 to 1989. Cases (n = 180) were individually matched with
controls (n = 720) on age, sex, and birth year. Annual doses to the lung from
plutonium, americium, and uranium isotopes were calculated for each worker with
an internal dosimetry model. Lung cancer risk was elevated among workers with
cumulative internal lung doses of more than 400 mSv in several different
analytical models. The dose-response relation was not consistent at high doses.
Restricting analysis to those employed for 15-25 years produced a statistically
significant linear trend with dose (chi-square = 67.2, p < 0.001), suggesting
a strong healthy worker survivor effect. The association between age at first
internal lung dose and lung cancer mortality was statistically significant (odds
ratio = 1.05, 95% confidence interval: 1.01, 1.10). No associations were found
between lung cancer mortality and cumulative external penetrating radiation dose
or cumulative exposures to asbestos, beryllium, hexavalent chromium, or nickel.
/Plutonium, NOS/
Human Toxicity Excerpts :
/EPIDEMIOLOGY STUDIES/ Cases of lung cancer among Mayak workers who were exposed
to plutonium were described ... . The incidence in workers who received
cumulative doses of external gamma-radiation higher than those permissible at
the time (most received doses > 100 roentgen (about 1 Gy) and > 0.02 uCi
[740 Bq] plutonium to the lung) 20 years after the beginning of exposure was
significantly higher than that in workers exposed to the same types of radiation
within permissible dose limits or in those who had never worked at Mayak. Since
that time, three epidemiological studies have been conducted ... a cohort study
by the epidemiology department, a cohort study by the internal dosimetry
laboratory, and a case-control study by the clinical department. These studies
are based on partially overlapping material. ... In the study by the
epidemiology department, mortality ... from lung cancer was analyzed only for
workers who were hired during the first decade of operations at Mayak (1948-58)
... . The number of lung cancer deaths observed in the cohort was 105, and the
expected numbers calculated from national statistics and for the internal
control group were 42.18 and 40.67, respectively. The risk for lung cancer
increased with the total dose of alpha-particles to the lung ... /and/ no
association was detected between death from lung cancer and the whole-body dose
of gamma-radiation. A significantly elevated rate of mortality from lung cancer
over the national average was ... /also/ reported ... among 666 women hired at
the radiochemical and plutonium production plant in 1948-58. ... The number of
observed cases (15) was significantly higher than that expected (2.57), and the
risk for cancer mortality was associated with the total dose of alpha-radiation
to the lung. Most of the deaths occurred among workers with the highest
equivalent dose of alpha particles to the lung (> 100 Sv). ... Another cohort
study was conducted at the ... internal dosimetry laboratory ... /and/ 80 lung
cancer deaths /were reported/, while 48.17 were expected (31.83 excess deaths).
All the excess deaths were concentrated in the dose category > 4.0 Sv ... .
The results of the case-control study of lung cancer in Mayak workers conducted
at the ... clinical department ... /which identified/ 11 potential risk factors
/with/ six significant ones. One was plutonium deposition in body. ...
/Examination of the distribution of lung cancers by lobe in 131 male workers at
Mayak and in 178 men who had never worked at Mayak ... /found/ ... the lung
cancers in the study subjects were located in the lower lobe more frequently
(45%) than in ... the control groups (25%), although the lung content of
plutonium is higher in the upper lobe of the lung. Mayak workers (168 cases: 154
men, 14 women) /were compared with/ ... unexposed population controls (157
control cases: 144 men, 13 women) ... the percentage of adenocarcinomas was
higher in the workers (46%) than in the unexposed population (33%), and the
highest percentage of adenocarcinomas (74%) was found among workers with
plutonium body burdens of > 11.0 kBq. /Plutonium, NOS/
Absorption, Distribution & Excretion :
This paper presents the analysis of urine bioassay data, spanning four decades,
from five workers who had wounds contaminated with plutonium at the Department
of Energy Rocky Flats Plant during the period 1961to 1967. The cases were
selected from participants in the Department of Energy-sponsored Former
Radiation Worker Medical Surveillance Program at Rocky Flats, which provided
medical monitoring, modern bioassay measurements, and internal dose
re-evaluations for former Rocky Flats workers. The cases include a variety of
wound types, excision treatment regimes, and monitoring information. These wound
cases illustrate the use of two multi-compartment wound models and three
plutonium urine excretion models for retrospective calculation of internal
plutonium depositions resulting from wounds for which no chelation therapy was
administered. Wound model compartment fractions and half times are determined
for each case and urine excretion model as are composite parameter values. The
urine analysis and wound count measurements obtained under the program provide
data with state-of-the art measurement sensitivity, as well as the opportunity
to include long-term excretion and wound site data that exceed 10,000 d
post-exposure for retrospective intake and dose evaluations. These data are
provided to the radiation dosimetry community for use in developing and testing
improved models for plutonium deposition in wounds.
Environmental Fate :
TERRESTRIAL FATE: Plutonium is generally immobile in soil(1,2). This is due to
the insolubility of PuO2, the predominant form of plutonium found in fallout
particles, and the interaction of Pu(IV) hydrolysis products with soil,
minerals, and organic, surfaces(2). PuO2 remains within the top few centimeters
of soil(1). Only a small fraction (<0.1%) of plutonium in soils is soluble
and may be mobile in soils and taken up by plants(2). The mobility of plutonium
in soils may be due to the presence of complexing agents or valence states other
than Pu(IV), that are less likely to undergo hydrolysis, forming insoluble
plutonium compounds(2). Physical processes, such as cultivation of soil, may
redistribute plutonium compounds between soil layers(2). Erosion by wind and
water will also transport plutonium compounds found in surface soils through the
environment(2). Plutonium compounds are ionic and will not volatilize from dry
or moist soil surfaces(SRC).
Soil Adsorption/Mobility :
Plutonium is generally immobile in soil(1,2). This is due to the insolubility of
PuO2, the predominant form of plutonium found in fallout particles, and the
interaction of Pu(IV) hydrolysis products with soil, minerals, and organic,
surfaces(2). PuO2 remains within the top few centimeters of soil(1). Only a
small fraction (<0.1%) of plutonium in soils is soluble and may be mobile in
soils and taken up by plants(2). The mobility of plutonium in soils may be due
to the presence of complexing agents or valence states other than Pu(IV), that
are less likely to undergo hydrolysis, forming insoluble plutonium compounds(2).
Partition coefficients (Kd) ranging from 8X10+4 to 1.5X10+5 were determined for
(239+240)Pu in arctic surface sediments from the Kara Sea(3). The behavior of
plutonium in soil is pH dependent(4). In the pH range of 2 to 8.5 soluble
plutonium is essentially completely sorbed, while in the range of pH 8.5-12
sorption decreased, with a minimum sorption (approx. 85%) observed at pH 12(4).
Above pH 12.5, essentially complete sorption was observed(4). Distribution
coefficients for soluble plutonium in Savannah River soil was found to be a
function of pH and oxidation state(4). Plutonium sorption was >95% complete (Kd>100)
starting at pH 2.5 for Pu(III) and Pu(IV) and at pH 7 for Pu(V)(4). At pH 6-7
sorption reached a maximum (Kd approx. 10,000) for Pu(III) and Pu(IV) and at pH
8 for Pu(VI) (Kd approx. 1,000)(4). At pH 12 the Kd values were >100 for all
three oxidation states(4). In a study using 13 soils plutonium sorption was
found to be high, with 62% of the measurements showing sorption of 99% or higher
and the lowest sorption measured was 87%(4). A Kd of 1.4X10+5 L/kg was estimated
for plutonium for suspended solids in the surface Mediterranean coastal
waters(5). Kd values ranging from 1X10+5 to 7X10+5 L/kg were reported for
plutonium for suspended particulate in the Savannah River Estuary, GA(6).
Body Burden :
Plutonium-239 and plutonium-240 cannot be distinguished by alpha spectroscopy
and are usually reported together(1). Plutonium-239 concentrations in tissues
from 12 autopsy cases in New York City (1973-76) were 0.00024, 0.0007, 0.00017,
and 0.0004 pCi/g in lung, liver, vertebrae, and gonads, respectively(2). Median
plutonium-239+plutonium-240 concentrations of 0.00016, 0.00012, 0.000095, 0.0007
and 0.000049 pCi/g in ribs, vertebrae, femur, liver and lungs, respectively,
were reported in tissues samples from autopsy cases of non-occupationally
exposed individuals from Great Britain(2). Plutonium-239+plutonium-240
concentrations of 0.00022, 0.00019, 0.00015, 0.00014, and 0.00018 pCi/g in ribs,
vertebrae, femur, liver and lungs, respectively, were reported in tissues
samples from autopsy cases of individuals living near a plutonium processing
plant in Great Britain(2).
Analytic Laboratory Methods :
SOLVENT EXTRACTION. A wide variety of organic extractants have been developed to
separate plutonium from other radionuclides and metals by selectively extracting
them from aqueous media. The extractants, among others, include organophosphorus
compounds such as phosphates (organoesters of phosphoric acid), amines and their
quaternary salts, alcohols, ketones, ethers, and amides. Chelating agents such
as thenoyltrifluoroacetone (TTA) and cupferron have also been used. Numerous
studies have been performed on the behavior of these systems. It has been found
that the performance of an extracting system is primarily related to the organic
solvent in which the extractant is dissolved and the concentration of the
extractant in the solvent, the nature of the aqueous medium (the acid present
and its concentration [pH] and the presence of salting agents), the temperature
of the system, and the presence and nature of oxidizing agents. One common
system, used extensively in the laboratory and in industrial process to extract
plutonium from fission products, illustrates the use of solvent extraction to
separate plutonium from uranium and other metals. The PUREX process (plutonium
uranium reduction extraction) is used in most fuel reprocessing plants to
separate the radionuclides. It employs TBP, tri-n-butyl phosphate ((C4H9O)3PO),
in a hydrocarbon solvent, as the extractant. The uranium fuel is dissolved in
nitric acid as Pu+3, and plutonium is oxidized to Pu+4 and uranium to U(VI) by
oxidizing agents. Plutonium and uranium are extracted into a 30 percent TBP
solution, and the organic phase is scrubbed with nitric acid solution to remove
impurities. The plutonium is removed by backextracting it as Pu+3 with a nitric
acid solution containing a reducing agent. Solvent extraction chromatography,
which uses an inert polymeric material as the
Clinical Laboratory Methods :
Method: spectrometry; Sample Preparation: dissolve starch; filter; wet ash;
extract, electrodeposit on platinum disk; Analyte: plutonium; Matrix: plant;
Detection Limit: 0.0027 pCi (0.1x10-4 Bq). /From table; Plutonium-238.
Plutonium-239; Plutonium-240/
Prior History of Accidents :
Mayak Production Association, 10 December 1968. An unfavorable geometry vessel
was being used in an improvised and unapproved operation as a temporary vessel
for storing plutonium organic solution. Two independent handling operations with
the same vessel and same contents less than one hour apart led to two prompt
critical excursions, each one resulting in the severe exposure of a worker... .
/Both were sent to the decontamination and medical facility at the plant in
Mayak and then/ were flown to Moscow for treatment. Samples of their blood
showed very high sodium-24 activities. Adjusted to the instant of the exposure,
they were 5,000 decays/min/mL (83 Bq/cm3) for the operator and 15,800
decays/min/mL (263 Bq/cm3) for the shift supervisor. The operator received an
estimated absorbed dose of about 700 rem and the shift supervisor about 2,450
rem. The operator developed acute, severe radiation sickness; both his legs and
one hand were amputated. He was still living 31 years after the accident. The
shift supervisor died about one month after the accident.
Methods of Manufacturing :
Plutonium-239 is produced in a nuclear reactor by neutron bombardment of the
nonfissionable isotope uranium-238. /Plutonium-239/
Methods of Manufacturing :
Bulk quantities of plutonium are produced through neutron capture by uranium-238
in nuclear reactors. /Plutonium-239/
Formulations/Preparations :
Plutonium-238: Produced from transmutation of neptunium-237 by neutron capture.
Available in milligram quantities as oxide powder at radiopurity of 80-97%.
Plutonium-239: Produced by neutron irradiation of uranium-238 and
electromagnetic separation. Available in milligram units as oxide powder at
radiopurity of 99-99.99%. Plutonium-240: Produced by transmutation of neptunium
or processing of curium-244. Available in milligram quantities as oxide powder
at a radiopurity of 75-95%. Plutonium-241: Prepared by sequential neutron
captures in uranium-238/plutonium by electromagnetic separation of plutonium.
Available in milligram quantities as oxide powder at a radiopurity of 80-93%.
All are classed as nuclear naterial requiring documentation of transfer.
/Plutonium isotopes/
Major Uses :
Weapons grade plutonium has the highest content of plutonium-239 and is mainly
used in nuclear warheads.
Fire Fighting Procedures :
Fire extinguishing must contain the plutonium and should not create a nuclear
criticality potential. The preferred method of extinguishing a plutonium fire is
by excluding oxygen, either by inerting the glove-box atmosphere or by
smothering the plutonium with a powder, eg, graphite, magnesia, or sodium
carbonate. Controlled burning of plutonium also is recommended. /Fissile
plutonium/
Cleanup Methods :
Decontamination is most successful when the material can be recycled for use in
a nuclear facility since the need to prove releasability (cleanliness) is
eliminated. Nevertheless, cleaning material for unrestricted release is also
possible in some cases. It may also be possible to decontaminate an item enough
to change its classification from TRU/transuranic/ waste to LLW /low-level
waste/, thereby allowing immediate disposal of the item, while a relatively
small quantity of decontamination waste is stored as TRU waste. Electropolishing
to remove the thinnest metal surface has been very effective and produces a
relatively small waste volume, especially when one of the wetted sponge units is
used rather than an emersion tank. Surface scabbling has been used in
decontamination of concrete, and various abrasive blasting methods have also
been effective. Strippable and self-stripping coatings may be used to
decontaminate surfaces, even though the primary application of strippable
coatings has been in preventing contamination of surfaces. /Plutonium compounds/
Antidote and Emergency Treatment :
As an immediate follow-up action for workers identified as being exposed during
a quicksort procedure, /the health physicist evaluating the incident should
make/ a more accurate dose estimate ... using personal nuclear accident
dosimeters, fixed location accident dosimeters, or biological activity analyses
(sodium-24 in the blood or phosphorous-32 in the hair). Part of these more
accurate analyses should include: 1) better definition of source
characteristics, 2) location of moderating materials, and 3) location and
orientation of the person(s) at the time of exposure and action of the person
following the irradiation. The health physics staff can provide valuable
information to support this analysis, particularly regarding the location and
orientation of workers to the excursion if they are involved in the rescue and
initial monitoring procedures.
Human Toxicity Excerpts :
/EPIDEMIOLOGY STUDIES/ Deaths among 5,413 workers employed at the Rocky Flats,
Colorado, nuclear weapons facility were investigated in order to estimate the
risks from exposure to plutonium and external radiation. The cohort consisted of
all white men who had been employed at this facility for at least two years
between the beginning of operations in 1952 and 1979. In comparison with death
rates for the USA, significantly fewer deaths from all causes, all cancers, lung
cancer, circulatory system diseases and accidents, poisonings and violence were
observed. .... No bone tumors occurred in this cohort. A significant excess of
benign and unspecified neoplasms was found; all seven cases were intracranial
tumors. In a case-control study of the brain tumors at Rocky Flats, no
statistically significant association was found with exposure to either external
radiation or plutonium ... . /Plutonium, NOS/
Human Toxicity Excerpts :
/EPIDEMIOLOGY STUDIES/ Prompted by a case of lung fibrosis in a retired
plutonium worker, /the authors/ tested the hypothesis that plutonium inhalation
increases the risk for developing chest radiograph abnormalities consistent with
pulmonary fibrosis. /The authors/ conducted a retrospective study of nuclear
weapons workers that included estimating absorbed doses to the lung with an
internal dosimetry model. /The/ study population consisted of 326
plutonium-exposed workers with absorbed lung doses from 0 to 28 Sv and 194
unexposed workers. ...The severity of chest radiograph interstitial
abnormalities /were compared/ between the two groups using the International
Labour Organization profusion scoring system. There was a significantly higher
proportion of abnormal profusion scores among plutonium-exposed workers (17.5%)
than among unexposed workers (7.2%), P < 0.01. Lung doses of 10 Sv or greater
conferred a 5.3-fold risk (95% CI 1.2-23.4) of having an abnormal chest X ray
consistent with pulmonary fibrosis when compared with unexposed individuals
after controlling for the effects of age, smoking and asbestos exposure. This
study shows that plutonium may cause lung fibrosis in humans at absorbed lung
doses above 10 Sv. /Plutonium, NOS/
Human Toxicity Excerpts :
/BIOMONITORING/ Chromosomal aberrations in human peripheral blood lymphocytes
are a recognized indicator of exposure to ionizing radiation in vivo. An
increase in the frequency of chromosomal aberrations above the background level
reflects direct exposure of circulating lymphocytes and also exposure of
hematopoietic precursor cells in the bone marrow ... . A banding technique that
allows recognition of many symmetrical aberrations which would be missed with
conventional staining was used to analyze peripheral blood lymphocytes from 54
plutonium workers from the British Nuclear Fuels facility at Sellafield, United
Kingdom. These workers had body burdens in excess of 296 Bq ... all had been
exposed at least 10 years before the analysis. These workers had also been
exposed to significant levels of external gamma-radiation. The controls were 39
newly hired workers with no known exposure to radiation or known clastogenic
chemical ... /The/ ... plutonium workers showed increased frequencies of both
symmetrical and asymmetrical chromosomal aberrations over those in controls. ...
Twenty-four of the workers in the above study were still employed at Sellafield
and therefore available for resampling 10 years later. Analysis of chromosomes
in G-banded peripheral blood lymphocytes was performed on two groups of workers
who had 20-50% and >50% of the maximum permissible body burden of plutonium.
A significant increase was found in the frequencies of symmetrical aberrations
in both groups when compared with workers with similar histories of exposure to
mainly external gamma-radiation but with little or no intake of plutonium and
with controls with negligible exposure, estimated to be < 50 mSv. /Plutonium,
NOS/
Human Toxicity Excerpts :
/BIOMONITORING/ /GENOTOXICITY/ /The authors/ recently demonstrated that a
significant proportion of apparently stable insertions induced after exposure to
a mean of one alpha particle/cell, detected using three-color FISH, were part of
larger unstable complexes when visualized by 24-color FISH. Interestingly,
regardless of the long-term persistence capability of the cell, the complexity
of each alpha-particle-induced complex appeared to be specific to the nuclear
traversal of a single alpha particle. To assess whether aberrations of a similar
complexity are observed in vivo and also to examine the usefulness of detecting
such aberrations as a biomarker of chronic exposure to alpha particles, /they/
have carried out a limited pilot study of Russian workers with large body
burdens of alpha-particle-emitting plutonium. ... Uunstable cells containing
non-transmissible complex aberrations /were found/ in all of the
plutonium-exposed subjects analyzed by mFISH. In addition, all of the complexes
seen were consistent with those previously observed in vitro. Non-transmissible
complex aberrations were more common than transmissible-type complexes,
consistent with ongoing/chronic exposure, and insertions were dominant features
of both types of complex. Accordingly, this preliminary study supports the
proposal that aberration complexity and non-transmissibility are the major
cytogenetic features of alpha-particle exposure that could potentially be
exploited as a specific indicator of chronic exposures to high-LET alpha
particles. /Plutonium, NOS/
Ecotoxicity Excerpts :
/FIELD STUDIES/Since 1946, personnel from the School of Fisheries, University of
Washington (Applied Fisheries Laboratory, 1943-1958; Laboratory of Radiation
Biology, 1958-1967; and Laboratory of Radiation Ecology, since 1967), have
studied the effects of nuclear detonations and the ensuing radioactivity on the
marine and terrestrial environments throughout the Central Pacific. A collection
of reports and publications about these activities plus a collection of several
thousand samples from these periods are kept at the School of Fisheries. General
findings from the surveys show that (1) fission products were prevalent in
organisms of the terrestrial environment whereas activation products were
prevalent in marine organisms; (2) the best biological indicators of fallout
radionuclides by environments were (a) terrestrial-coconuts, land crabs; (b)
reef-algae, invertebrates; and (c) marine-plankton, fish. Studies of plutonium
and americium in Bikini Atoll showed that during 1971-1977 the highest
concentrations of americium-241, 2.85 Bq/g (77 pCi/g) and plutonium-239,-240,
4.44 Bq/g (120 pCi/g), in surface sediments were found in the northwest part of
the lagoon. The concentrations in the bomb craters were substantially lower than
these values. Concentrations of soluble and particulate plutonium and americium
in surface and deep water samples showed distributions similar to the sediment
samples. That is, the highest concentration of these radionuclides in the water
column were at locations with highest sediment concentration. Continuous
circulation of water in the lagoon and exchange of water with open ocean
resulted in removal of 111G Bq/y (3 Ci/y) americium-241 and 222 G Bq/y (6 Ci/y)
plutonium-239,240 into the North Equatorial Current. A summary of the surveys,
findings, and the historical role of the Laboratory in radioecological studies
of the Marshall Islands are presented. /Plutonium-239, -240/
Absorption, Distribution & Excretion :
Inhalation: Measurements in human autopsy material of plutonium-239 resulting
from the atmospheric testing of nuclear weapons show that a relatively high
proportion of plutonium-239 is retained in lung tissue and tracheobronchial
lymph nodes, consistent with low solubility. /Plutonium-239/
Absorption, Distribution & Excretion :
... Plutonium deposition in a small number of former nuclear industry workers
was greatest, exclusive of the respiratory tract, in the skeleton followed by
the liver, striated muscle, and other organs and tissues. These authors
suggested that muscle and other soft tissue may act as a long-term storage depot
for plutonium.
Mechanism of Action :
Bystander effects from ionizing radiation have been detailed for a number of
cell systems and a number of end points. /The authors used/ a cell culture/ex
vivo rat model of respiratory tissue to determine whether a bystander effect
detected in culture could also be shown in a tissue. Examination by
immunofluorescence techniques of tracheal cell cultures after exposure to very
low doses of alpha particles /from plutonium-238/ revealed a large proportion of
cells with proliferating cell nuclear antigen (PCNA) bound in their nuclei. PCNA
was selected as an end point because it is involved in both DNA repair and the
changes in cell cycle that are typical of many reported bystander effects.
Maximum response can be detected in up to 28% of the cells in sub-confluent
cultures with a dose of only 2 mGy. At this dose less than 2% of the cell nuclei
have experienced a particle traversal and less than 6% of the cells have
experienced an alpha-particle traversal through either their nucleus or some
part of their cytoplasm. The hypothesis that this bystander response in
nontargeted cells is mediated through secreted factor(s) is presented, and
supporting evidence was found using partial irradiation and co-culture
experiments. Examination of the effect with excised pieces of trachea
demonstrated a response similar to that seen in culture. /Plutonium-238/
Sediment/Soil Concentrations :
SOIL: Plutonium-238 concentrations in soil at an industrial area where
nuclear-powered submarines are repaired and in an adjacent area were 0.5 and
1.4-2.0 Bq/kg dry weight, respectively(1).
Threshold Limit Values :
The Physical Agents TLV Committee accepts the occupational exposure guidance of
the International Commission on Radiological Protection (ICRP). Ionizing
radiation includes particulate radiation (e.g., alpha particles and beta
particles emitted from radioactive materials, and neutrons from nuclear reactors
and accelerators) and electromagnetic radiation (e.g., gamma rays emitted from
radioactive materials and X-rays from electron accelerators and X-ray machines)
with energy greater than 12.4 electron-volts (eV) ... The guiding principle of
radiation protection is to avoid all unnecessary exposures. ICRP has established
principles of radiological protection. There are (1) the justification of a work
practice: No work practice involving exposure to ionizing radiation should be
adopted unless it produces sufficient benefit to the exposed individuals or the
society to offset the detriment it causes. (2) The optimization of a
workpractice: All radiation exposures must be kept as low as reasonably
achievable (ALARA), economic and social factors being taken into account. (3)
The individual dose limits: The radiation dose from all relevant sources should
not exceed the /ICRP/ prescribed dose limits.
Analytic Laboratory Methods :
Personnel monitoring 1. External dosimetry: The most common device used to
monitor worker dose is the thermoluninescent dosimeter (TLD). Dosimeters can be
configured to monitor beta, gamma, X-ray, and neutron radiation. Supplemental
dosimeters (TLDs in finger rings or wrist bands) may also be worn for monitoring
extremity dose. There are dosimeters and gamma pencils equipped with alarms that
can be used, but they must be specially made for low-energy gamma rays. Nuclear
accident dosimeters (NADs) are required for facilities with sufficient
quantities of plutonium to form a critical mass. They are issued to personnel
and are also stationed throughout the facility. They contain different types of
materials that become radioactive through neutron activation. The neutron dose
is determined by evaluating the amount of activation of the NAD material.
Special Reports :
U.S. Nuclear Regulatory Commission; Regulatory Guide 8.34 - Monitoring Criteria
and Methods to Calculate Occupational Radiation Doses. 1992/ Available at http://www.nrc.gov/reading-rm/doc-collections/reg-guides/occupational-health/active/8-34/index.html
as of September 25, 2006
MORE ABOUT HEALTH EFFECTS
PLUTONIUM, RADIOACTIVE