Chapter VIII.
Testing and
Analysis Procedures for
Uranium and Depleted Uranium
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Summary:
Simple laboratory procedures are not sufficient for identifying and quantifying depleted uranium in samples taken from the environment, from body tissues, or from body fluids. First, there is the problem of concentration. Typically, samples being tested for DU have such low concentrations of DU that any successful procedure must have a very high level of sensitivity. Second, there is the problem of natural uranium (NU), which permeates our natural environment, requiring special procedures to differentiate between NU and DU.
Despite these difficulties, several methods have been developed to accomplish this task. Since NU and DU, by definition, differ in the ratio of uranium isotopes contained within their respective samples, methods utilizing various types of mass spectroscopy (MS) have been the most frequently used. With MS, a spectrum is produced containing a peak for each different mass ion detected, with each peak’s height being proportional to the abundance of that ion. The spectrum of a pure NU sample would show a peak at 238 mass units that was 142 times as large as the peak at 235 mass units due to the natural abundances of U-238 and of U-235 being 99.3% and 0.7%. For a DU sample with 99.8% U-238 and 0.2% U-235, the spectrum would show a peak at 238 mass units that was close to 500 times as large as the peak at 235 mass units. In most real samples, NU and DU are mixed, so the peak ratios lie between these two extremes and the actual concentrations of each must be calculated from the observed ratio.
Other methods rely on alpha or gamma radiation spectra analysis of the radiation emitted by uranium samples. Spectra of gamma emissions can be analyzed to reveal isotope abundances, since different isotopes release packets of gamma rays having a spectrum of certain specific energies. Since several different isotopes are usually present in a given sample, their individual spectra are overlapped, requiring the researcher to recognize each overlapping signature. Computer analysis plays an important role in these analyses.
Neutron activation analysis may also be employed, since one of the isotopes of concern, U-235, is fissionable. Bombarding the sample with neutrons will cause U-235 to undergo fission and produce radioactive fission products which have more intense gamma ray emissions that are easier to detect and quantify. This technique may lower the detection limits for U-235 and allow more accurate analysis of samples containing very low concentrations of uranium.
Finally, finding appropriate biomarkers for uranium make it possible to pinpoint environmental contamination with greater accuracy. Knowing which plants readily incorporate uranium from water or soil and the degree to which they are prone to do this gives the researcher a handle for assessing uranium contamination.
Details:
Larsen’s paper of 2000, (8), and Fortuna’s paper of 200, (20), both present some general notes relating to determining of isotope ratios and items to consider when drawing conclusions from these ratios. Fortuna also addresses the problem of environmental remediation.
Coleman (1) published depth-dose curves in Mylar for DU in 1983 to measure workers’ exposure levels. Cassorla (2) compared gamma ray spectrometry and neutron activation analysis for the determination of uranium isotope ratios. In 1989, Camins (3) reviewed DU detection methods for aerosol and soil samples, while Miyajima (4) and Flynn (5) reported methods for detecting and measuring low concentrations of DU.
In 1999, Baglan (7) published protocols for inductively-coupled plasma mass spectroscopy (ICP-MS) monitoring of uranium workers’ urine specimens and found ICP-MS to provide better sensitivity to low U-235 concentrations than alpha spectrometry. In February of 2000, Ejnik, (11), of the Armed Forces Radiobiology Research Institute (AFRRI) in Bethesda, MD used ICP-MS to identify DU in veterans’ urine samples while Kalinich (12), (21) in the same labs, developed a rapid colorimetric method for identifying uranium in shrapnel. Desideri , (22), reported comparison of ICP-MS and alpha spectroscopy for the analysis of various actinides, including plutonium, amerecium and U-236, obtained from sample penetrator shells used by NATO. The presence of these isotopes in DU penetrators clearly show that the DU being used to manufacture DU munitions underwent neutron bombardment (activation) in a nuclear reactor. Montaser (16) compared the sensitivities of two different types of ICP-MS instrumentation for analysis of DU in biological matrices.
Goldstein (6)
reported that preparing samples for uranium isotope analysis by first using
extraction chromatography and ion exchange before performing the alpha
spectroscopy resulted in greater sensitivity.
Abu-Qare (19) first derivitized uranium in rats urine with dibenzoylmethane and used UV spectroscopy to identify and quantify uranium, finding 2 ng/ml to be the limit for detection of uranium and 10 to 100 ng/ml to be the effective range of quantification.
Barrata (13) and Forte (14) look into methodologies for analyzing food and water samples for uranium isotopes. Roth (23) assesses the difficulties of determining a time-zero body burden of depleted uranium from urine samples taken some time after exposure.
Magnoni (15) analyzed mollusk samples from the Adriatic sea for DU, and Edmands (17) analyzed uranium levels and isotope ratios in black oak trees near the Concord, MA DU penetrator fabrication facility and found that, once incorporated into tree sap, uranium ions are highly mobile through cellular tissue. He also determined that uranium concentrations in black oak sapwood reflect concentrations in shallow ground water feeding the tree.
(Return to: TOP; Table of Contents; Author Index)
1. Depth-dose curves for strontium-90 and natural and depleted uranium in Mylar, by RL Coleman, Health Physics Serv., Tennessee Valley Auth., Muscle Shoals, AL, Health Physics Vol. 44(4), 1983 (pp. 395-402).
[Coleman1983xxHPv44n4p395].
2. Comparative studies for determination of the uranium-235/uranium-238 ratio in solutions of natural and depleted uranium using gamma spectrometry and neutron activation analysis, by F Cassorla, et al., Nucleotecnica Vol. 8(14), 1988 (pp. 7-15).
[Cassorla1988xxNv8n14p7].
3. Analysis of Beryllium and depleted uranium: An overview of detection methods in aerosols and soils, by I. Camins, Lawrence Livermore Natl. Lab, Livermore, CA, Report, Energy Res. Abstr. Vol. 14(14), 1989 (Abstract 28146).
[Camins1989xxERAv14n14p28146].
4. RIS and detection of isotopes of low abundance, by M Miyajima, et al., Natl. Lab. High Energy Physics, KEK (Japan), 1989.
[Miyajima1989Report].
5. Use of the USRADS system for real time radiation survey measurements for depleted uranium environmental contamination, by CR Flynn, et al., Chemrad Tennessee Corp., Oak Ridge, TN. Waste Management Vol. 2, 1989 (pp. 603-607).
[Flynn1989xxWMv2nxp603].
6. Measurement and application of uranium isotopes for human and environmental monitoring, by SJ Goldstein SJ, et al., Inorganic Trace Analysis Group, Chemical Science and Technology Division, Los Alamos National Laboratory, NM 87545, USA. Health Phys. Vol. 72(1), Jan. 1997 (pp. 10-18).
An
improved method is described utilizing extraction chromatography, anion
exchange, and alpha spectroscopy for measurement of uranium isotopes in human
and environmental surveillance studies. These methods provide a sensitivity of
approximately 0.7 mBq per isotope per sample and are generally accurate within
the precision of the measurements. The extraction chromatography methods
greatly simplify separation of uranium from iron in silicate matrices and
provide increased sample throughput and data quality for water, soil, and air
filter samples. For bioassay samples, the coprecipitation/anion exchange/alpha
spectrometric methods provide rapid throughput and sufficient sensitivity to
meet new analytical performance standards in human monitoring studies. In
addition, the 234U:238U data can be used as a fingerprint of natural vs.
anthropogenic sources of uranium. For 1995 data from our laboratory, a large
percentage (79-94% by matrix) of samples appear to be of natural 234U:238U
isotopic composition. For all matrices, samples with higher uranium
concentration generally have more depleted isotopic composition (smaller
234U:238U). A small percentage of soil (11%), air filter (3%), urine (3%), and
water (3%) samples have depleted isotopic signatures at the 95% confidence
interval, indicating anthropogenic contributions of uranium to these samples.
[Goldstein199701HPv72n1p10].
(PMID: 8972822 [PubMed - indexed for MEDLINE])
7. Implementation of
ICP-MS protocols for uranium urinary measurements in worker monitoring,
by N Baglan, et al., Institut de Protection et de Surete Nucleaire, Departement
de Protection de la sante de l'Homme et de Dosimetrie, IPSN,
Fontenay-aux-Roses, France. nicolas.baglan@ipsn.fr Health Phys. Vol. 77(4), Oct. 1999
(pp. 455-461).
The
uranium concentration in human urine spiked with natural uranium and rat urine
containing metabolized depleted uranium was determined by ICP-MS. The use of
ICP-MS was investigated without any chemical treatment or after the different
stages of a purification protocol currently carried out for routine monitoring.
In the case of spiked urine, the measured uranium concentrations were
consistent with those certified by an intercomparison network in
radiotoxicological analysis (PROCORAD) and with those obtained by alpha
spectrometry in the case of the urine containing metabolized uranium. The
quantitative information which could be obtained in the different protocols
investigated shows the extent to which ICP-MS provides greater flexibility for
setting up appropriate monitoring approaches in radiation protection routines
and accidental situations. This is due to the combination of high sensitivity
and the accuracy with which traces of uranium in urine can be determined in a
shorter time period. Moreover, it has been shown that ICP-MS measurement can be
used to quantify the 235U isotope, which is useful for characterizing the
nature of the uranium compound, but difficult to perform using alpha
spectrometry.
[Baglan199910HPv77n4p455]. (PMID: 10492353
[PubMed - indexed for MEDLINE])
8. Some notes and comments regarding natural and processed uranium isotopes, by IL Larsen, Teledyne-Brown Engineering, Knoxville, TN. Radioactivity and Radiochemistry Vol. 11(2), 2000 (pp. 6-10).
Discusses
using isotope ratios to ascertain DU concentration in samples and
considerations to take into account when deriving conclusions from these
measurements.
[Larsen2000xxRRv11n2p6].
9. Comparison of scintillation detection efficiencies of depleted uranium in wounds, by SZ Chandler, et al., Hill AF Base, Utah. Journal of Radioanalytical and Nuclear Chemistry Vol. 243(2), 2000 (pp. 451-457).
Determined
that bismuth germinate (BGO) detectors had higher efficiency and lowest minimum
detectable activity (MDA=5.8 kBq) relative to NaI crystal detectors for both
shallow, medium and deep depth wounds containing embedded DU fragments.
[Chandler2000xxJRNCv243n2p451].
10. Bullet Scintigraphy: Can gamma camera be used for depleted uranium accident measurements? by R Spaic, et al., Inst. of Nuclear Med., Med. Military Acad., Belgrade, Yugoslavia. Bilten Instituta za Nuklearne Nauke Vinca Vol. 5(1-4), 2000 (pp. 15-17).
For
detection of DU, X-rays with an energy of 100 keV and 20% window width are used
(about 40% of DU gamma emissions are within this limit).
[Spaic2000xxBINNVv5n1to4p15].
11. Determination of the isotopic composition of uranium in urine by inductively coupled plasma mass spectrometry, by JW Ejnik, et al., Armed Forces Radiobiology Research Institute, Bethesda, MD 20889-5603, USA. ejnik@mx.afrri.usuhs.mil Health Phys. Vol. 78(2), Feb. 2000 (pp. 143-146).
A
simple method based on inductively coupled plasma mass spectrometry (ICP-MS)
was developed to identify exposure to depleted uranium by measuring the
isotopic composition of uranium in urine. Exposure to depleted uranium results
in a decreased percentage of 235U in urine samples causing measurements to vary
between natural uranium's 0.72% and depleted uranium's 0.2%. Urine samples from
a non-depleted uranium exposed group and a suspected depleted uranium exposed
group were processed and analyzed by ICP-MS to determine whether depleted
uranium was present in the urine. Sample preparation involved dry-ashing the
urine at 450 degrees C followed by wet-ashing with a series of additions of
concentrated nitric acid and 30% hydrogen peroxide. The ash from the urine was
dissolved in 1 M nitric acid, and the intensity of 235U and 238U ions were
measured by ICP-MS. After the samples were ashed, the ICP-MS measurements
required less than 5 min. The 235U percentage in individuals from the depleted
uranium exposed group with urine uranium concentrations greater than 150 ng
L(-1) was between 0.20%-0.33%, correctly identifying depleted uranium exposure.
Samples from the non-depleted uranium exposed individuals had urine uranium
concentration less than 50 ng L(-1) and 235U percentages consistent with
natural uranium (0.7%-1.0%). A minimum concentration of 14 ng L(-1) uranium was
required to obtain sufficient 235U to allow calculating a valid isotopic ratio.
Therefore, the percent 235U in urine samples measured by this method can be
used to identify low-level exposure to depleted uranium.
[Ejnik200002HPv78n2p143]. (PMID: 10647980
[PubMed - indexed for MEDLINE]).
12. A procedure for the rapid detection of depleted uranium in metal shrapnel fragments, by JF Kalinich, et al., Armed Forces Radiobiology Res. Inst., Bethesda, MD. Military Medicine Vol. 165(8), Aug. 2000 (pp. 626-629).
Treating
a shrapnel fragment for 5 minutes in nitric acid in an ultrasonic cleaner,
sufficient metal is solubilized to allow for colorimetric detection using a
pyridylazo dye. Using masking agents as sodium citrate and EDTA, the reaction
can be made specific for depleted uranium.
[Kalinich200008MMv165n8p626].
13. Determination of isotopic uranium in food and water, by EJ Baratta, et al., USFDA, Winchester, MA. Journal of Radioanalytical and Nuclear Chemistry Vol. 248(2), 2001 (pp. 473-475).
Discusses
the methodology used for the determination of isotopic uranium in the analysis
of food and water samples and results from sample surveys.
[Baratta2001xxJRNCv248n2p473].
14. Determination of
uranium isotopes in food and environmental samples by different techniques: a
comparison, by M Forte, et al., ARPA Lombardia, Division of Radiological
Protection Milan, Italy. Radiat Prot
Dosimetry. Vol. 97(4), 2001 (pp. 325-328).
The
uranium concentration in 59 samples of bottled and tap water, mainly from
northern Italy, was measured by different techniques. Results obtained by
inductively coupled plasma mass spectrometry (ICP-MS), semiconductor alpha
spectrometry and low level liquid scintillation counting with alpha/beta
discrimination (LSC) have been compared. High resolution gamma spectrometry and
semiconductor alpha spectrometry have been used to analyse uranium in a variety
of organic and inorganic samples. Isotopic secular equilibrium in the 238U
series may be lacking or hidden by auto-absorption phenomena, so caution should
be used in evaluating gamma spectrometry data. Alpha spectrometry has also been
used to ascertain the possible pollution from depleted uranium in the
environment.
[Forte2001xxRPDv97n4p325].
( PMID: 11878412 [PubMed - indexed for MEDLINE]).
15. Variations of
the isotopic ratios of uranium in environmental samples containing traces of
depleted uranium: theoretical and experimental aspects, by M
Magnoni, et al., ARPA
Piemonte-Dipartimento di Ivrea, Italy. m.magnoni@arpa.piemonte.it. Radiat Prot Dosimetry Vol. 97(4), 2001
(pp. 337-340).
The
possibility of using conventional analysis, such as gamma spectrometry and
alpha spectrometry, for the detection of traces of depleted uranium (DU) in
environmental samples has been investigated. The expected values have been
compared with the experimental results obtained by using mollusc samples
gathered in the Adriatic Sea. The analysis has shown that it is possible to
detect DU. if the percentage composition is about 20% depleted uranium and 80% natural
uranium, for a sample containing 10 Bq x kg(-1) of 238U. The possibility of
extending this approach to samples with any given uranium concentration is
investigated.
[Magnoni2001xxRPDv97n4p337]. (PMID: 11878415
[PubMed - indexed for MEDLINE]).
16. Ultratrace and isotopic analysis of long-lived radionuclides and depleted uranium by direct liquid introduction-inductively coupled plasma mass spectrometry, by A Montaser, et al., George Washington U, Washington, DC. ACS Abstracts 2001, 221st NUCL-176.
An
analysis of the performance of a double-focusing inductively coupled plasma
mass spectrometer (ICP-DFMS) and a quadrupole-based ICPMS (ISP-QMS) in the
analysis of long-lived radionuclides, including isotopes of uranium, using
direct injection high efficiency nebulizers. Samples included radioactive waste
samples and detection of depleted uranium in biological matrices.
[Montaser2001xxACSANUCL176].
17. Uptake and
mobility of uranium in black oaks: implications for biomonitoring depleted uranium-contaminated
groundwater, by JD Edmands, et al., Department of Earth Sciences, Boston
University, MA 02215, USA. Chemosphere
Vol. 44(4), Aug. 2001 (pp. 789-795).
In
a preliminary study, the uptake and the mobility of uranium (U) by black oak
trees (Quercus velutina) were assessed by measuring the isotopic composition of
tree rings in two mature oak trees in a heavy metal contaminated bog in
Concord, MA. The bog is adjacent to a nuclear industrial facility that has been
processing depleted uranium (DU) since 1959. Over the past 40 years, DU has
been leaking from an onsite holding basin and cooling pond down gradient to the
bog where the oaks are located. Because DU has no source outside the nuclear
industry, contamination from the industrial facility is readily discernable
from uptake of natural U by measuring isotopic compositions. Isotope ratio
analysis confirms the occurrence of DU in bark, sapwood and heartwood tree
rings dating back to 1937, pre-dating the introduction of DU at the site by at least
20 years. Isotope dilution analysis indicates high concentrations of U (>3
ppb) in sapwood that drop rapidly to relatively constant concentrations
(0.3-0.4 ppb) in heartwood. These data indicate that once incorporated into
tree cells, U is mobile, possibly by diffusion through the tree wood.
Concentrations of U in sapwood are approximately equal to average U
concentrations in groundwater onsite over the past 10 years, suggesting that
oak trees can be used as present-day bioindicators of U-contaminated groundwater.
We suggest that regional sampling of oak bark and sapwood is a reasonable,
inexpensive alternative to drilling wells to monitor shallow groundwater U
contamination.
[Edmands200108Cv44n4p789].
(PMID: 11482670 [PubMed - indexed for MEDLINE]).
18. A convenient
method for discriminating between natural and depleted uranium by gamma-ray
spectrometry, by M Shoji, et al., Radioisotope Research Center, Toyama
Medical and Pharmaceutical University, Sugitani, Japan. shojim@ms.toyama-mpu.ac.jp . Appl
Radiat Isot. Vol. 55(2), Aug. 2001 (pp. 221-227).
A convenient method for discriminating between natural and depleted
uranium reagent was developed by measuring and analyzing the gamma-ray spectra
of some reagents with no standard source. The counting rates (R) of
photoelectric peaks of gamma-rays from nuclides with the same radioactivity
divided by their emission probability (B) are expressed as a function of
gamma-ray energy. The radioactivities of 234Th and 234mPa and 21.72 times that
of 235U are equal to the radioactivity of 235U in natural uranium. Therefore,
the plot of 21.72-fold R/B for 235U should be on a curve fitted to the points
for 234Th and 234mPa in natural uranium. Depleted uranium with a 235U isotopic
composition of less than 0.68% could be discriminated from natural uranium in
the case of a reagent containing 4.0 g of uranium.
[Shoji200108ARIv55n2p221]. (
PMID: 11393763 [PubMed - indexed for MEDLINE]).
19. Determination
of depleted uranium, pyridostigmine bromide and its metabolite in plasma and
urine following combined administration in rats, by AW Abu-Qare , et
al., Department of Pharmacology and Cancer Biology, Duke University Medical
Center, PO Box 3813, Durham, NC 27710, USA.
J Pharm Biomed Anal. Vol. 26(2), Sept. 2001 (pp. 281-289).
A
simple and reliable method was developed for the quantification of depleted
uranium, the anti nerve agent drug pyridostigmine bromide
(PB;3-dimethylaminocarbonyloxy-N-methyl pyridinium bromide) and its metabolite
N-methyl-3-hydroxypyridinium bromide in rat plasma and urine. The method
involved using solid phase extraction and spectrophotometric determination of
uranium, and high performance liquid chromatography (HPLC) with reversed phase
C(18) column, and UV detection at 280 nm for PB and its metabolite. Uranium was
derivatized using dibenzoylmethane (DBM) then the absorbance was measured at
405 nm. PB and its metabolite were separated using a gradient of 1--40% acetonitrile
in 0.1% triflouroacetic acid water solution (pH 3.2) at a flow rate of 0.8
ml/min in a period of 14 min. Limits of detection were 2 ng/ml for uranium and
50 ng/ml for PB and its metabolite. Limits of quantitation were between 10 and
100 ng/ml for uranium and the other two analytes, respectively. Average
percentage recovery of five spiked plasma samples were 83.7+/-8.6, 76.8+/-6.7,
79.1+/-7.1, and from urine 82.7+/-8.6, 79.3+/-9.5 and 78.0+/-6.2, for depleted
uranium, PB and N-methyl-3-hydroxypyridinium bromide, respectively. The
relationship between peak areas and concentration was linear for standards
between 100 and 1000 ng/ml for all three analytes. This method was applied to
analyze the above chemicals and metabolites following combined administration
in rats.
[AbuQare200109JPBAv26n2p281].
( PMID: 11470205 [PubMed - indexed for MEDLINE]).
20 Practical aspects of the detection of radioactive contamination caused by the use of ammunition with depleted uranium, in Serbian, by D Fortuna, et al. , Hemijska Industrija Vol. 55(7-8), 2001 (pp. 346-348).
In
addition to covering detection of DU in the environment, decontamination
methods are also analyzed.
[Fortuna2001xxHIv55n7to8p346].
21. Staining of
intracellular deposits of uranium in cultured murine macrophages, by JF
Kalinich, et al., Applied Cellular Radiobiology Department, Armed Forces
Radiobiology Research Institute, Bethesda, MD 20889-5603, USA. kalinich@mx.afrri.usuhs.mil. Biotech Histochem. Vol. 76(5-6), Sept.
– Nov. 2001 (pp. 247-252).
In
our studies of the health effects of internalized depleted uranium, we
developed a simple and rapid light microscopic method to stain specifically
intracellular uranium deposits. Using J774 cells, a mouse macrophage line,
treated with uranyl nitrate and the pyridylazo dye
2-(5-bromo-2-pyridylazo)-5-diethylaminophenol, uranium uptake by the cells was
followed. Specificity of the stain for uranium was accomplished by using
masking agents to prevent the interaction of the stain with other metals.
Prestaining wash consisting of a mixture of sodium citrate and
ethylenediaminetetraacetic acid eliminated staining of metals other than
uranium. The staining solution consisted of the pyridylazo dye in borate buffer
along with a quaternary ammonium salt, ethylhexadecyldimethylammonium bromide,
and the aforementioned sodium citrate/ethylenediaminetetraacetic acid mixture.
The buffer was essential for maintaining the pH within the optimum range of 8
to 12, and the quaternary ammonium salt prevented precipitation of the dye.
Staining was conducted at room temperature and was complete in 30 min. Staining
intensity correlated with both uranyl nitrate concentration and incubation
time. Our method provides a simple procedure for detecting intracellular
uranium deposits in macrophages.
[Kalinich20009BHv76n5to6p247].
(PMID: 11871745 [PubMed - indexed for MEDLINE]).
21a. Determination of uranium in urine - measurement of
isotope ratios and quantification by use of inductively coupled plasma mass
spectrometry, by Krystek P, et al., Laboratory of Inorganic-Analytical Chemistry, National Institute of
Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The
Netherlands. petra.krystek@rivm.nl .
Anal Bioanal Chem. Vol. 374 (2), Sept. 2002 (pp. 226-229).
For
analysis of uranium in urine determination of the isotope ratio and
quantification were investigated by high-resolution inductively coupled plasma
mass spectrometry (HR ICP-MS). The instrument used (ThermoFinniganMAT ELEMENT2)
is a single-collector MS and, therefore, a stable sample-introduction system
was chosen. The methodical set-up was optimized to achieve the best precision
for both the isotope ratio and the total uranium concentration in the urine
matrix.Three spiked urine samples from an European interlaboratory comparison
were analyzed to determine the (235)U/(238)U isotope ratio. The ratio was found
to be in the range 0.002116 to 0.007222, the latter being the natural uranium
isotope ratio. The first ratio indicates the abundance of depleted uranium.The
effect of storage conditions and the stability for the matrix urine were
investigated by using "real-life" urine samples from unexposed
persons in the
22. Determination of (236)U and transuranium elements in depleted uranium ammunition by alpha-spectrometry and ICP-MS, by D Desideri, et al., General Chemistry Institute, Urbino University, Urbino, Italy. Anal Bioanal Chem. Vol. 374(6), Nov. 2002 (pp. 1091-1095). Epub 2002 Oct 16.
It
is well known that ammunition containing depleted uranium (DU) was used by NATO
during the Balkan conflict. To evaluate the origin of DU (the enrichment of
natural uranium or the reprocessing of spent nuclear fuel) it is necessary to
directly detect the presence of activation products ((236)U, (239)Pu, (240)Pu,
(241)Am, and (237)Np) in the ammunition. In this work the analysis of actinides
by alpha-spectrometry was compared with that by inductively coupled plasma mass
spectrometry (ICP-MS) after selective separation of ultratraces of transuranium
elements from the uranium matrix. (242)Pu and (243)Am were added to calculate
the chemical yield. Plutonium was separated from uranium by extraction
chromatography, using tri- n-octylamine (TNOA), with a decontamination factor
higher than 10(6); after elution plutonium was determined by ICP-MS ((239)Pu
and (240)Pu) and alpha-spectrometry ((239+240)Pu) after electroplating. The
concentration of Pu in two DU penetrator samples was 7 x 10(-12) g g(-1) and 2
x 10(-11) g g(-1). The (240)Pu/(239)Pu isotope ratio in one penetrator sample
(0.12+/-0.04) was significantly lower than the (240)Pu/(239)Pu ratios found in
two soil samples from Kosovo (0.35+/-0.10 and 0.27+/-0.07). (241)Am was
separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid
(HDEHP), with a decontamination factor as high as 10(7). The concentration of
(241)Am in the penetrator samples was 2.7 x 10(-14) g g(-1) and <9.4 x
10(-15) g g(-1). In addition (237)Np was detected at ultratrace levels. In
general, ICP-MS and alpha-spectrometry results were in good agreement.The presence
of anthropogenic radionuclides ((236)U, (239)Pu,(240)Pu, (241)Am, and (237)Np)
in the penetrators indicates that at least part of the uranium originated from
the reprocessing of nuclear fuel. Because the concentrations of radionuclides
are very low, their radiotoxicological effect is negligible.
[Desideri200211ABCv374n6p1091]. (PMID:
12458425 [PubMed]).
23. Assessment of exposure to depleted uranium, by P Roth, et al., GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstadter Landstr. 1, 85764 Neuherberg, Germany. Roth@gsf.de. Radiat Prot Dosimetry. Vol. 105(1-4), 2003 (pp. 157-161).
In
most circumstances, measurement of uranium excreted in urine at known times
after exposure is potentially the most sensitive method for determining the
amount of depleted uranium (DU) incorporated. The problems associated with this
approach are that natural uranium is always present in urine because of the
ingestion of natural uranium in food and drink, and that the uncertainties in
the intakes as assessed from excretion measurements can be quite large, because
many assumptions concerning the exposure characteristics (time pattern of
exposure, route of intake, chemical form, solubility, biokinetics within the
body) must be made. Applying currently available methods and instruments for
the measurement of uranium in urine samples, DU incorporations of levels
relevant with respect to potential health hazards can be detected reliably,
even a long time after exposure.
[Roth2003xxRPDv105n1to4p157]. (PMID: 14526948
[PubMed - in process]).
24. Simple method for depleted uranium determination, by I Bikit, et. al., Institute of Physics, Faculty of Sciences, University of Novi Sad, Serbia and Montenegro, Yugoslovia. Japanese Journal of Applied Physics, Part 1, Vol. 42(8), 2003 (pp.5269-5273).
When
the issue of depleted uranium (DU) presence in the environment emerged, methods
for anal. discrimination of DU against natural uranium should be developed. We
present here a simple gamma-spectrometric method, based on the 238U-226Ra
activity (non) equil. The detection limit of the method for DU is of the order
of magnitude 10 Bq/kg (for about 50 ks counting), thus the method is
appropriate for the detn. of small amts. (=100 Bq/kg) of DU in environmental
samples. The method is tested on about 90 soil samples.
[Bikit200308JJAPv42n8p5269]
25. Laser ablation inductively coupled plasma mass
spectrometry measurement of isotope ratios in depleted uranium contaminated
soils, by Seltzer MD., Naval
Air Warfare Center Weapons Division, China Lake, California 93555, USA. Michael.seltzer@navy.mil. Appl
Spectrosc. Vol. 57 (9), Sept. 2003 (pp. 1173-1177).
Laser
ablation of pressed soil pellets was examined as a means of direct sample
introduction to enable inductively coupled plasma mass spectrometry (ICP-MS)
screening of soils for residual depleted uranium (DU) contamination.
Differentiation between depleted uranium, an anthropogenic contaminant, and
naturally occurring uranium was accomplished on the basis of measured 235U/238U
isotope ratios. The amount of sample preparation required for laser ablation is
considerably less than that typically required for aqueous sample introduction.
The amount of hazardous laboratory waste generated is diminished accordingly.
During the present investigation, 235U/238U isotope ratios measured for field
samples were in good agreement with those derived from gamma spectrometry
measurements. However, substantial compensation was required to mitigate the
effects of impaired pulse counting attributed to sample inhomogeneity and
sporadic introduction of uranium analyte into the plasma.
[Seltzer200309ASv57n9p1173] (PMID: 14611049 [PubMed - indexed for MEDLINE]).
26. Validated measurements of the uranium isotopic signature
in human urine samples using magnetic sector-field inductively coupled plasma
mass spectrometry, by Tresl I, et al., European Commission Joint Research Centre, Institute for Reference
Materials and Measurements, Retieseweg, B-2440 Geel, Belgium. Environ Sci
Technol. Vol. 38 (2), Jan. 2004 (pp. 581-586).
Increased
interest in measuring uranium isotope ratios in environmental samples
(biological materials, soils, dust particles, water) has come from the
necessity to assess the health impact of the use of depleted uranium (DU) based
ammunitions during recent military conflicts (e.g., Gulf war, Kosovo) and from
the need to identify nondeclared nuclear activities (nuclear safeguards). In
this context, very important decisions can arise which have to be based on
measurement data of nondisputable uncertainty. The present study describes the
certification to 2.5% (k = 2) relative combined uncertainty of n(235U)/n(238U)
at ultralow uranium levels (approximately 5-20 pg g(-1)) in human urine
samples. After sample decomposition and matrix separation, the isotope ratios
were measured by means of a single-detector magnetic sector-field inductively
coupled plasma mass spectrometry instrument fitted with an ultrasonic
nebulizer. Correction for mass discrimination effects was obtained by means of
the certified isotopic reference material IRMM-184. The analytical procedure
developed was validated in three complementary ways. First, all major sources
of uncertainty were identified and propagated together following the ISO/GUM
guidelines. Second, this quality was controlled with a matrix matching
NUSIMEP-3 sample (approximately 0.06-0.7% difference from certified). Third,
the instrumental part of the procedure was proven to be reproducible from the
confirmation of the results obtained for three samples remeasured 7 months
later (approximately 1.5% difference). The results obtained for 33 individuals
indicated that none seemed to have been exposed to contamination by DU.
[Tresl200401ESTv38n2p581] (PMID: 14750735 [PubMed - indexed for MEDLINE]).
27. Determination of depleted uranium
in environmental samples by gamma-spectroscopic techniques, by
Karangelos DJ, et al., Nuclear
Engineering Section, Mechanical Engineering Department, National Technical
University of Athens, 15780 Athens, Greece. J Environ Radioact. Vol. 76 (3),
2004 (pp. 295-310).
The
military use of depleted uranium initiated the need for an efficient and
reliable method to detect and quantify DU contamination in environmental
samples. This paper presents such a method, based on the gamma spectroscopic
determination of 238U and 235U. The main advantage of this method is that it
allows for a direct determination of the U isotope ratio, while requiring
little sample preparation and being significantly less labor intensive than
methods requiring radiochemical treatment. Furthermore, the fact that the sample
preparation is not destructive greatly simplifies control of the quality of
measurements. Low energy photons are utilized, using Ge detectors efficient in
the low energy region and applying appropriate corrections for self-absorption.
Uranium-235 in particular is determined directly from its 185.72 keV photons,
after analyzing the 235U-226Ra multiplet. The method presented is applied to
soil samples originating from two different target sites, in
28. Neptunium-237 determination in
depleted uranium ammunition by alpha spectrometry, by Desideri D, et al., Istituto di Chimica Generale, Universita
di Urbino, Piazza Rinascimento 6, 61029 Urbino, Italy. d.desideri@uniurb.it . Ann Chim. Vol.
94 (4), April 2004 (pp. 347-352).
[Desideri200404Acv94n4p347]
(PMID: 15242100 [PubMed - indexed for MEDLINE]).
29. A simplified method to create
quantitative, "fixed" uranyl-contaminated metal coupons, by
McKeown CK, et al.,
A
method was developed and validated to quantitatively apply and "fix" uranyl
contamination onto a metal surface (steel). Simple approaches are needed to
create test surfaces in order to quantify contaminant removal or
"decon" methods. We used steel discs sized to allow direct and
accurate alpha counting in a Ludlum scanner from radioactive contaminants. A
typical 3.8-cm-diameter coupon had a depleted uranyl loading of about 0.1 mg U
cm with a count of 980 dpm. The resulting alpha radiation was measured with a
precision of >97% for the same coupon. The alpha concentration on replicate
coupons differed by as much as 9% (standard deviation). This method, based on
earlier methods, required a uranyl solution to be dried but lowers the baking
temperature to less than 100 degrees C to increase safety in a typical
radiological laboratory. A dike was used to provide a uniform coating of the
uranyl solution. [McKeown200405HPv86supp5pS113] (PMID: 15069301 [PubMed -
indexed for MEDLINE]).
30. Assessment of
drinking water radioactivity content by liquid scintillation counting: set up
of high sensitivity and emergency procedures, by Rusconi R,et al., ARPA Lombardia,
In
our institute, different procedures have been developed to measure the
radioactivity content of drinking water both in normal and in emergency
situations, such as those arising from accidental and terrorist events. A
single radiometric technique, namely low level liquid scintillation counting
(LSC), has been used. In emergency situations a gross activity screening is
carried out without any sample treatment by a single and quick liquid
scintillation counting. Alpha and beta activities can be measured in more than
one hundred samples per day with sensitivities of a few Bq/L. Higher
sensitivity gross alpha and beta, uranium and radium measurements can be
performed on water samples after specific sample treatments. The sequential
method proposed is designed in such a way that the same water sample can be used
in all the stages, with slight modifications. This sequential procedure was
applied in a survey of the Lombardia district. At first tap waters of the 13
largest towns were examined, then a more detailed monitoring was carried out in
the surroundings of Milano and
31. Characterisation of depleted uranium
(DU) from an unfired CHARM-3 penetrator, by Trueman ER, et al., Postgraduate Research Institute for
Sedimentology, School of Human and Environmental Science, Whiteknights,
University of Reading, Reading RG6, 6AB, UK. Sci Total Environ. Vol. 327 (1-3),
July 2004 (pp. 337-340).
[Trueman200407STEv327n1to3p337].
(PMID: 15172592 [PubMed - indexed for MEDLINE]).
32. Determination of depleted uranium
in urine via isotope ratio measurements using large-bore direct injection high
efficiency nebulizer-inductively coupled plasma mass spectrometry, by
Westphal CS, et al., Department of
Chemistry, The
Inductively
coupled plasma mass spectrometry (ICP-MS), coupled with a large-bore direct
injection high efficiency nebulizer (LB-DIHEN), was utilized to determine the
concentration and isotopic ratio of uranium in 11 samples of synthetic urine
spiked with varying concentrations and ratios of uranium isotopes. Total U
concentrations and (235)U/(238)U isotopic ratios ranged from 0.1 to 10 microg/L
and 0.0011 and 0.00725, respectively. The results are compared with data from
other laboratories that used either alpha-spectrometry or quadrupole-based
ICP-MS with a conventional nebulizer-spray chamber arrangement. Severe matrix
effects due to the high total dissolved solid content of the samples resulted
in a 60 to 80% loss of signal intensity, but were compensated for by using
(233)U as an internal standard. Accurate results were obtained with
LB-DIHEN-ICP-MS, allowing for the positive identification of depleted uranium
based on the (235)U/(238)U ratio. Precision for the (235)U/(238)U ratio is
typically better than 5% and 15% for ICP-MS and alpha-spectrometry,
respectively, determined over the concentrations and ratios investigated in
this study, with the LB-DIHEN-ICP-MS system providing the most accurate
results. Short-term precision (6 min) for the individual (235)U and (238)U
isotopes in synthetic urine is better than 2% (N = 7), compared to
approximately 5% for conventional nebulizer-spray chamber arrangements and
>10% for alpha-spectrometry. The significance of these measurements is discussed
for uranium exposure assessment of Persian Gulf War veterans affected by
depleted uranium ammunitions. [Westphal200409ASv58n9p1044] (PMID: 15479520
[PubMed - indexed for MEDLINE]).
33. Uranium analysis in urine by
inductively coupled plasma dynamic reaction cell mass spectrometry, by Ejnik JW, et al., Chemistry
Department,
Urine
uranium concentrations are the best biological indicator for identifying
exposure to depleted uranium (DU). Internal exposure to DU causes an increased
amount of urine uranium and a decreased ratio of (235)U/(238)U in urine
samples, resulting in measurements that vary between 0.00725 and 0.002 (i.e.,
natural and depleted uranium's (235)U/(238)U ratios, respectively). A method
based on inductively coupled plasma dynamic reaction cell mass spectrometry
(ICP-DRC-MS) was utilized to identify DU in urine by measuring the quantity of
total U and the (235)U/(238)U ratio. The quantitative analysis was achieved
using (233)U as an internal standard. The analysis was performed both with and
without the reaction gas oxygen. The reaction gas converted ionized (235)U(+)
and (238)U(+) into (235)UO(2) (+) (m/z=267) and (238)UO(2) (+) (m/z=270). This
conversion was determined to be over 90% efficient. A polyatomic interference
at m/z 234.8 was successfully removed from the (235)U signal under either DRC
operating conditions (with or without oxygen as a reaction gas). The method was
validated with 15 urine samples of known uranium compositions. The method
detection limit for quantification was determined to be 0.1 pg U mL(-1) urine
and an average coefficient of variation (CV) of 1-2% within the sample
measurements. The method detection limit for determining (235)U/(238)U ratio
was 3.0 pg U mL(-1) urine. An additional 21 patient samples were analyzed with
no information about medical history. The measured (235)U/(238)U ratio within
the urine samples correctly identified the presence or absence of internal DU
exposure in all 21 patients. [Ejnik200505ABCv382n1p73] (PMID: 15900454 [PubMed
- in process]).
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