Determination of the isotopic composition of uranium in urine by inductively coupled plasma mass spectrometry

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.     

Elevated urine uranium excretion by soldiers with retained uranium shrapnel.

The use of depleted uranium in munitions has given rise to a new exposure route for this chemically and radioactively hazardous metal. A cohort of U.S. soldiers wounded while on or in vehicles struck by depleted uranium penetrators during the Persian Gulf War was identified. Thirty-three members of this cohort were clinically evaluated, with particular attention to renal abnormalities, approximately 3 y after their injury. The presence of retained shrapnel was identified by x ray, and urine uranium concentrations were measured on two occasions. The absorption of uranium from embedded shrapnel was strongly suggested by measurements of urine uranium excretion at two time intervals: one in 1993/1994 and one in 1995. Mean urine uranium excretion was significantly higher in soldiers with retained shrapnel compared to those without shrapnel at both time points (4.47 vs. 0.03 microg g(-1) creatinine in 1993/1994 and 6.40 vs. 0.01 microg g(-1) creatinine in 1995, respectively). Urine uranium concentrations measured in 1995 were consistent with those measured in 1994/1993, with a correlation coefficient of 0.9. Spot urine measurements of uranium excretion were also well correlated with 24-h urine collections (r = 0.95), indicating that spot urine samples can be reliably used to monitor depleted uranium excretion in the surveillance program for this cohort of soldiers. The presence of uranium in the urine can be used to determine the rate at which embedded depleted uranium fragments are releasing biologically active uranium ions. No evidence of a relationship between urine uranium excretion and renal function could be demonstrated. Evaluation of this cohort continues.     

Urinary uranium concentrations in an enlarged Gulf War veteran cohort

Depleted uranium was first used on a large scale as a major component of munitions and armaments employed by the U.S. armed forces during the Gulf War in 1991. In response to concern that exposure to depleted uranium may have been a cause of health problems suffered by returning veterans of that war, an already existing surveillance program following depleted uranium "friendly fire" victims was enlarged to assess the wider veteran community's exposure to depleted uranium. Between August 1998 and December 1999, 169 Gulf War veterans submitted 24-h urine samples for determination of urinary uranium concentration and questionnaires describing their potential exposures to depleted uranium while in the Gulf War theatre. Depleted uranium exposure assessment was determined from 30 separate questionnaire items condensed into 19 distinct exposure scenarios. Results of urine uranium analysis were stratified into high and low uranium groups with 0.05 microg uranium/g creatinine being the cut point and approximate upper limit of the normal population distribution. Twelve individuals (7.1%) exhibited urine uranium values in the high range, while the remaining 157 had urine uranium values in the low range. A repeat test of urine for 6 of these 12 produced uranium results in the low range for 3 of these individuals. Exposure scenarios of the high and low uranium groups were similar with the presence of retained shrapnel being the only scenario predictive of a high urine uranium value. Results emphasize the unlikely occurrence of an elevated urine uranium result and consequently any uranium-related health effects in the absence of retained depleted uranium metal fragments in the veterans.     

Determination of natural and depleted uranium in urine at the ppt level: an interlaboratory analytical exercise

An analytical exercise was initiated in order to determine those procedures with the capability to measure total uranium and uranium (238U/235U) isotopic ratios in urine samples containing >0.02 microg U kg-1 urine. A host laboratory prepared six identical sets of twelve synthetic urine samples containing total uranium in the range of 25 to 770 ng U kg-1 urine and with 238U/235U isotopic ratios ranging from 138 (100% NU) to 215 (51% DU). Sets of samples were shipped to five testing laboratories (four based in Canada and one based in Europe). Each laboratory utilized one of the following analytical techniques: sector field inductively coupled plasma mass spectrometry (ICP-SF-MS), quadrupole inductively coupled plasma mass spectrometry (ICP-Q-MS), thermal ionization mass spectrometry (TIMS), and instrumental/delayed neutron activation analysis (I/DNAA), in their analyses.     

Biologic monitoring for urinary uranium in gulf war I veterans

Biologic monitoring for total uranium in urine of Gulf War I veterans concerned about past exposure to depleted uranium (DU) has been offered by the Departments of Veterans Affairs and Defense since the late 1990's. DU, a component of U.S. munitions and tank armor, was first used during that conflict. Two hundred and twenty-seven veterans submitted samples for analysis from January 2000 through December 2002, which included a 24-h urine sample for determination of total urinary uranium concentration and completed questionnaires describing their wartime exposure experiences. Thirty questionnaire items characterizing DU exposure opportunities were collapsed into 19 exposure categories. Urine uranium (U) results were stratified into low and high uranium groups with 0.05 microg U g creatinine as the cut point. Exposure scenarios in the high and low uranium groups were similar in frequency and type with only the presence of retained shrapnel being predictive of a high urine uranium value, as found in the first phase of this surveillance of 169 veterans performed prior to 2000. Twenty-two veterans exhibited U levels in the high range. Isotopic analysis, available for 21 of these 22, revealed that all but three of these samples contained natural and not depleted uranium. These three participants had retained DU shrapnel as a result of their past injuries. Thus, even with an enlarged cohort, elevated urine uranium values in the absence of retained DU fragments are unlikely. The utility of isotopic analysis to more fully characterize uranium biomonitoring results is also demonstrated.     

ICP-MS对我国9种典型土壤中铀含量及235U／238U比值的分析

目的研究采用不同的土壤预处理方法联合电感耦合等离子体质谱（ICP—MS）技术,同时分析土壤中铀含量及235U／238U比值的方法,并且分析我国9种典型土壤中的铀含量及235u／238U比值。方法 分别采用微波消解、灰化法和直接酸溶法对土壤样品进行预处理,通过ICP—MS同时测定土壤中的铀含量和235U／238U。采用建立的方法分析我国9种土壤中的铀含量及235u／238u。结果铀元素在0～400μg／kg线性良好（r=0．9999）,精密度较高（RSD为0．11％～2．37％）。土壤样品预处理方法中,以HNO3＋HF＋H2O2为消解试剂进行微波消解得到的结果与推荐值吻合较好（相对误差为5．2％）,土壤中铀回收率为100．6—109．O％,最低检测限为0．86ng／kg。我国9种土壤中的铀浓度为1．2～4．0mg／kg,各种土壤中的235U／238U均接近天然水平（0．00725）。结论本研究建立了微波消解与ICP—MS联合应用,同时分析土壤中的铀含量及235u／238u的方法,该方法线性范围宽、准确度高、检测限低,采用该方法检测的我国9种土壤中的铀含署和235TT／238U均在正常水平。     

An examination of uranium levels in Canadian forces personnel who served in the Gulf War and Kosovo

A uranium bioassay program was conducted involving 103 active and retired Canadian Forces personnel. The total uranium concentrations in each of two 24-h urine collections were analyzed separately at independent commercial laboratories by inductively coupled plasma mass spectrometry (ICP-MS) and by instrumental neutron activation analysis (INAA). The mean and median concentrations were determined to be 4.5 ng L(-1) and 2.8 ng L(-1), respectively, from ICP-MS and 17 ng L(-1) and 15 ng L(-1), respectively, from INAA. The total uranium concentrations were sufficiently low so that isotopic (238U:235U ratio) assays could not be performed directly from urine samples. Isotopic assays were performed on hair samples from 19 of the veterans participating in the testing. The isotopic hair assays were scattered around the natural 238U:235U ratio of 137.8, ranging from 122 +/- 21 to 145 +/- 16 (1sigma). Due to concern expressed in the media over possible depleted uranium exposure and long-term retention in bone, a single bone sample (vertebrate bone marrow) from a deceased member of the Canadian Forces was also analyzed for total uranium content and isotopic ratio by ICP-MS. The sample was shown to have 16.0 +/- 0.3 microg kg(-1) uranium by dry weight and a 238U:238U isotopic ratio of 138 +/- 4, consistent with natural uranium.     

Rapid determination of uranium isotopes in urine by inductively coupled plasma-mass spectrometry

Following a radiological or nuclear emergency involving uranium exposure, rapid analytical methods are needed to analyze the concentration of uranium isotopes in human urine samples for early dose assessment. The inductively coupled plasma mass spectrometry (ICP-MS) technique, with its high sample throughput and high sensitivity, has advantages over alpha spectrometry for uranium urinalysis after minimum sample preparation. In this work, a rapid sample preparation method using an anion exchange chromatographic column was developed to separate uranium from the urine matrix. A high-resolution sector field ICP-MS instrument, coupled with a high sensitivity desolvation sample introduction inlet, was used to determine uranium isotopes in the samples. The method can analyze up to 24 urine samples in two hours with the limits of detection of 0.0014, 0.10, and 2.0 pg mL(-1) for (234)U, (235)U, and (238)U, respectively, which meet the requirement for isotopic analysis of uranium in a radiation emergency.     

Surveillance of depleted uranium exposed Gulf War veterans: health effects observed in an enlarged "friendly fire" cohort.

To determine clinical health effects in a small group of US Gulf War veterans (n = 50) who were victims of depleted uranium (DU) "friendly fire," we performed periodic medical surveillance examinations. We obtained urine uranium determinations, clinical laboratory values, reproductive health measures, neurocognitive assessments, and genotoxicity measures. DU-exposed Gulf War veterans with retained metal shrapnel fragments were excreting elevated levels of urine uranium 8 years after their first exposure (range, 0.018 to 39.1 micrograms/g creatinine for DU-exposed Gulf War veterans with retained fragments vs 0.002 to 0.231 microgram/g creatinine in DU exposed but without fragments). The persistence of the elevated urine uranium suggests ongoing mobilization from the DU fragments and results in chronic systemic exposure. Clinical laboratory outcomes, including renal functioning, were essentially normal. Neurocognitive measures showing subtle differences between high and low uranium exposure groups, seen previously, have since diminished. Sister chromatid exchange frequency, a measure of mutation in peripheral lymphocytes, was related to urine uranium level (6.35 sister chromatid exchanges/cell in the high uranium exposure group vs 5.52 sister chromatid exchanges/cell in the low uranium exposure group; P = 0.03). Observed health effects were related to subtle but biologically plausible perturbations in central nervous system function and a general measure of mutagen exposure. The findings related to uranium's chemical rather than radiologic toxicity. Observations in this group of veterans prompt speculation about the health effects of DU in other exposure scenarios.     

Urinary isotopic analysis in the UK Armed Forces: no evidence of depleted uranium absorption in combat and other personnel in Iraq

Objectives

To assess the distribution and risk factors of depleted uranium uptake in military personnel who had taken part in the invasion of Iraq in 2003.

Methods

Sector field inductively coupled plasma-mass spectrometry (SF-ICP-MS) was used to determine the uranium concentration and ²³⁸U/²³⁵U isotopic ratio in spot urine samples. The authors collected urine samples from four groups identified a priori as having different potential for exposure to depleted uranium. These groups were: combat personnel (n = 199); non-combat personnel (n = 96); medical personnel (n = 22); and “clean-up” personnel (n = 24) who had been involved in the maintenance, repair or clearance of potentially contaminated vehicles in Iraq. A short questionnaire was used to ascertain individual experience of circumstances in which depleted uranium exposure might have occurred.

Results

There was no statistically significant difference in the ²³⁸U/²³⁵U ratio between groups. Mean ratios by group varied from 138.0 (95% CI 137.3 to 138.7) for clean-up personnel to 138.2 (95% CI 138.0 to 138.5) for combat personnel, and were close to the ratio of 137.9 for natural uranium. The two highest individual ratios (146.9 and 147.7) were retested using more accurate, multiple collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) and found to be within measurement of error of that for natural uranium. There were no significant differences in isotope ratio between participants according to self-reported circumstances of potential depleted uranium exposure.

Conclusions

Based on measurements using a SF-ICP-MS apparatus, this study provides reassurance following concern for potential widespread depleted uranium uptake in the UK military. The rare occurrence of elevated ratios may reflect the limits of accuracy of the SF-ICP-MS apparatus and not a real increase from the natural proportions of the isotopes. Any uptake of depleted uranium among participants in this study sample would be very unlikely to have any implications for health.Depleted uranium is a by-product from the manufacture of enriched uranium. Uranium as it occurs naturally in the earth''s crust comprises two main isotopes, ²³⁸U and ²³⁵U, in a ratio of approximately 137.9:1. Enriched uranium contains a higher proportion of the more radioactive ²³⁵U, and is used as a nuclear fuel. Conversely, the depleted uranium that remains after extraction of enriched uranium from natural uranium contains proportionately less ²³⁵U with a ²³⁸U/²³⁵U ratio in the order of 490:1.¹ It is a weakly radioactive alpha emitter (40% less radioactive than natural uranium), but has a high density (approximately 70% greater than lead), which has been exploited in specialist engineering applications. It has also been used for military purposes, in particular in armour-piercing rounds. The first major use of depleted uranium weapons was by US and UK forces in the 1991 Gulf War, and they were subsequently also used in the Balkans campaign and in the 2003 Iraq War.When a depleted uranium round strikes an armoured target, it undergoes spontaneous combustion, a substantial proportion being converted to a fine aerosol of largely (>65%) insoluble uranium oxides. Exposure to this material, either through inhalation or through ingestion of contaminated food or water, could pose a hazard from its radioactivity or chemical toxicity. Thus, while depleted uranium weapons are effective in battle, there is an urgent need to establish whether their use carries important long-term risks to health.As with any toxic material, risk will depend on the route and level of exposure. Estimates can be made of the radioactive dose associated with a given uptake of uranium oxides, and also of the maximum kidney concentration and resultant risk of renal damage from chemical toxicity (the kidney is the most sensitive target organ). Thus, knowledge of the uptakes of depleted uranium as a consequence of its military use would enable assessment of any resultant long-term risks to health.Uptake of depleted uranium can be estimated retrospectively by measurement of uranium isotopes in urine. At a rate depending on its chemical speciation, the depleted uranium that is taken up by the body will be dissolved in tissue fluids, redistributed, and excreted via the kidney. Within the urine, it will be mixed with natural uranium arising from normal dietary exposures, and this will manifest as an elevation of the ²³⁸U/²³⁵U ratio above the value of 137.9 for natural uranium. Based on empirical data, a biokinetic model has been developed which predicts the level of depleted uranium excretion in the urine at a given interval after exposure to a specified inhaled dose of uranium oxides similar in chemical composition to that produced when a depleted uranium round impacts on an armoured target.²Such exposure may occur in military units that use depleted uranium munitions, such as armoured brigades, or those tasked with “cleaning up tanks” that have been attacked with depleted uranium munitions. The Royal Society (2001) report on depleted uranium munitions distinguished three levels of exposure that might occur in battlefield scenarios.³ The highest exposures (through inhalation of depleted uranium aerosols and injury by shrapnel fragments) would be expected in combat personnel who were in a vehicle when it was struck by a depleted uranium round or entered it immediately afterwards (level 1). Level 2 exposures (by inhalation or ingestion following hand-to-mouth transfer) would occur in personnel working in or on contaminated vehicles after combat, and the lowest exposures (level 3) would occur in other circumstances (for example, through dispersal of depleted uranium oxides downwind of fires). In theory, medical personnel might sustain cross-contamination from injured personnel, vehicles or ground when providing aid to casualties of depleted uranium munitions.In this paper we report the urinary uranium excretion of members of the UK Armed Forces who took part in the 2003 Iraq War, in which depleted uranium munitions were used. Our study focussed on specific groups identified as being at particular risk of exposure, including a group with potential for level 2 exposures, together with a low-risk control group. All participants were selected from a large epidemiological study of the war in Iraq on the health of the UK Armed Forces.⁴The main aim of the present study was to assess the distribution and risk factors of any uranium exposures resulting from the use of depleted uranium weapons, using isotopic analysis of urine as the main index of exposure.     

An incident study about acute and chronic human exposure to uranium by high-resolution inductively coupled plasma mass spectrometry (HR-ICPMS)

From the year 2003 to 2005 around 1700 Dutch soldiers made a part of the international stabilisation force in Iraq. An incident happened as a group of four Dutch soldiers found a 30mm bullet identified as containing depleted uranium (DU). The main pathway of the acute exposure is via inhalation of small uranium containing particles, e.g. from a bullet during its explosion. To develop a method for acute exposure investigations were carried out about finding an efficient and suitable way to sample nasal mucus as medium of inhalation. Generally, in human exposure studies with regard to natural uranium (NU) or DU, urine is the matrix for analysis. Uranium concentrations in urine are based on daily ingestion depending on the composition of drinking water and food. A second possibility is the acute exposure to uranium after an incident, either through inhalation or impact. Nevertheless, the results deliver only interpretations in respect to chronic/long-term exposure. For the acute exposure procedures like sniffling out into cleansing tissues and rinsing the nose were tested with real-life samples from four soldiers involved in an incident with possibly acute exposure to uranium. For the quantification of uranium high-resolution inductively coupled plasma mass spectrometry (HR-ICPMS) was applied.     

The utility of spot collection for urinary uranium determinations in depleted uranium exposed Gulf War veterans.

The utility of spot urine collections for uranium bioassay determinations was examined in a small cohort of depleted uranium exposed Gulf War veterans. Some members of the group are excreting elevated concentrations of urinary uranium resulting from the metabolism of retained metal fragments, the residua of several friendly fire incidents. Uranium determinations were performed on both 24-h timed collections and spot urine samples using kinetic phosphorescence analyzer (KPA) methodology. Results ranged from non-detectable to 30.7 mcg g(-1) creatinine in a 24-h collection. A creatinine-standardized spot sample and a 24-h uncorrected sample both correlated highly (R2=0.99) with a creatinine corrected 24-h collection, presumed to be the best estimate of the urinary uranium measure. This relationship was upheld when the population was stratified by uranium concentration into a high uranium group (> or = 0.05 mcg U/g creatinine) but for the lower uranium group (< 0.05 mcg U/g creatinine) more variability and a lower correlation was seen. The uncorrected spot sample, unadjusted for volume, concentration or creatinine had the lowest correlation with the 24-h creatinine adjusted result, especially at lower urinary uranium concentrations. This raises questions regarding the representativeness of such a sample in bioassay programs.     

Measurement of the 234U/238U ratio by MC-ICPMS in drinking water, hair, nails, and urine as an indicator of uranium exposure source

The isotopic ratio (234)U/(238)U in drinking water and in hair, toenail, and urine samples from 45 individuals who consumed 0.2-2775 microg d(-1) of uranium in their drinking water was determined using a multi-collector inductively coupled plasma mass spectrometer (MC-ICPMS). The U/U atom ratio in the water samples varied from 51 x 10(-6) to 252 x 10(-6) whereas in secular equilibrium (i.e., unity activity ratio) the ratio is 54.9 x 10(-6). The correlation of the (234)U/(238)U ratio between hair and nail samples was 0.98, and between hair and nails and urine the ratio was 0.91 and 0.89, respectively. The correlation of the ratio between water and the hair or nails was 0.97 but only 0.72 for water and urine, possibly due to spectral interferences. These results conclusively demonstrated that the uranium found in the bioassays can be traced to the drinking water, thus providing a direct link to the source of exposure. Hair may serve as an excellent indicator of occupational or environmental exposure to uranium and provide information regarding its source. Bioassay of hair is attractive as it is an effective bio-concentrator, samples can be easily stored, the concentration reflects an integrated value, and, finally, the measurement of the (234)U/(238)U isotopic ratio in digested hair samples by MC-ICPMS is feasible and highly informative. Hair bioassay can also be used to assess exposure to depleted uranium long after the subjects have left the area suspected of contamination.     

Determination of 238u/235u, 236u/238u and uranium concentration in urine using sf-icp-ms and mc-icp-ms: an interlaboratory comparison

Accidental exposure to depleted or enriched uranium may occur in a variety of circumstances. There is a need to quantify such exposure, with the possibility that the testing may post-date exposure by months or years. Therefore, it is important to develop a very sensitive test to measure precisely the isotopic composition of uranium in urine at low levels of concentration. The results of an interlaboratory comparison using sector field (SF)-inductively coupled plasma-mass spectrometry (ICP-MS) and multiple collector (MC)-ICP-MS for the measurement of uranium concentration and U/U and U/U isotopic ratios of human urine samples are presented. Three urine samples were verified to contain uranium at 1-5 ng L and shown to have natural uranium isotopic composition. Portions of these urine batches were doped with depleted uranium (DU) containing small quantities of U, and the solutions were split into 100 mL and 400 mL aliquots that were subsequently measured blind by three laboratories. All methods investigated were able to measure accurately U/U with precisions of approximately 0.5% to approximately 4%, but only selected MC-ICP-MS methods were capable of consistently analyzing U/U to reasonable precision at the approximately 20 fg L level of U abundance. Isotope dilution using a U tracer demonstrates the ability to measure concentrations to better than +/-4% with the MC-ICP-MS method, though sample heterogeneity in urine samples was shown to be problematic in some cases. MC-ICP-MS outperformed SF-ICP-MS methods, as was expected. The MC-ICP-MS methodology described is capable of measuring to approximately 1% precision the U/U of any sample of human urine over the entire range of uranium abundance down to <1 ng L, and detecting very small amounts of DU contained therein.     

ICP-MS测定广州市饮用水中铀及其同位素比值

目的:建立饮用水中铀及其同位素比值的分析方法,了解广州市饮用水中铀的含量水平和同位素比值情况。方法:水样经酸化后直接用ICP-MS进行分析。结果:总铀的测定的精密度优于1.4%、检出限小于0.0005 ng/ml,加标回收率为97.6%～101%;235U/238U同位素比值测定的精密度优于0.7%;广州市饮用水中铀的平均浓度为0.185 ng/ml,235U/238U同位素比值为0.7012%～0.7159%。结论:可采用ICP-MS准确测定广州市饮用水中的铀及其同位素比值,方法简便、快速、准确。     

Validation of uranium determination in urine by ICP-MS

A rapid procedure--dilution of urine+ICP-MS measurement--for the determination of uranium in urine was validated. Large ranges of concentration and isotopic composition were studied on urine samples excreted by occupationally exposed workers. The results were consistent with those obtained by fluorimetry and by alpha spectrometry after a purification procedure, two currently used techniques. However, the proposed procedure is limited for determination of the minor isotope 234U. Thus for worker monitoring, the conversion of 234U mass concentration into activity concentration can lead to an erroneous value of the effective dose, in particular for a contamination at very low level with highly enriched uranium. A solution to avoid this hazard is to perform a chemical purification prior to ICP-MS measurement to lower uncertainty and detection limit for 234U.     

Health effects of depleted uranium on exposed Gulf War veterans

A small group of Gulf War veterans possess retained fragments of depleted uranium (DU) shrapnel, the long-term health consequences of which are undetermined. We evaluated the clinical health effects of DU exposure in Gulf War veterans compared with nonexposed Gulf War veterans. History and follow-up medical examination were performed on 29 exposed veterans and 38 nonexposed veterans. Outcome measures employed were urinary uranium determinations, clinical laboratory values, and psychiatric and neurocognitive assessment. DU-exposed Gulf War veterans with retained metal shrapnel fragments are excreting elevated levels of urinary uranium 7 years after first exposure (range 0.01-30.7 microg/g creatinine vs 0.01- 0.05 microg/g creatinine in the nonexposed). The persistence of the elevated urine uranium suggests on-going mobilization from a storage depot which results in a chronic systemic exposure. Adverse effects in the kidney, a presumed target organ, are not present at this time, though other effects are observed. Neurocognitive examinations demonstrated a statistical relationship between urine uranium levels and lowered performance on computerized tests assessing performance efficiency. Elevated urinary uranium was statistically related to a high prolactin level (>1.6 ng/ml; P=0.04). More than 7 years after first exposure, DU-exposed Gulf War veterans with retained metal fragments continue to excrete elevated concentrations of urinary uranium. Effects related to this are subtle perturbations in the reproductive and central nervous systems.     

Biological Monitoring for Depleted Uranium Exposure in U.S. Veterans

Background

As part of an ongoing medical surveillance program for U.S. veterans exposed to depleted uranium (DU), biological monitoring of urine uranium (U) concentrations is offered to any veteran of the Gulf War and those serving in more recent conflicts (post-Gulf War veterans).

Objectives

Since a previous report of surveillance findings in 2004, an improved methodology for determination of the isotopic ratio of U in urine (²³⁵U:²³⁸U) has been developed and allows for more definitive evaluation of DU exposure. This report updates previous findings.

Methods

Veterans provide a 24-hr urine specimen and complete a DU exposure questionnaire. Specimens are sent to the Baltimore Veterans Affairs Medical Center for processing. Uranium concentration and isotopic ratio are measured using ICP-MS at the Armed Forces Institute of Pathology.

Results

Between January 2003 and June 2008, we received 1,769 urine specimens for U analysis. The mean urine U measure was 0.009 μg U/g creatinine. Mean urine U concentrations for Gulf War and post-Gulf War veterans were 0.008 and 0.009 μg U/g creatinine, respectively. Only 3 of the 1,700 (0.01%) specimens for which we completed isotopic determination showed evidence of DU. Exposure histories confirmed that these three individuals had been involved in “friendly fire” incidents involving DU munitions or armored vehicles.

Conclusions

No urine U measure with a “depleted” isotopic signature has been detected in U.S. veterans without a history of retained DU embedded fragments from previous injury. These findings suggest that future DU-related health harm is unlikely in veterans without DU fragments.     

电感耦合等离子体质谱法测定食品中铀及其同位素比值

目的:建立食品中铀及其同位素比值的分析方法。方法:食品经湿法消化后直接用ICP-MS进行分析。结果:总铀的测定的精密度优于1.5%、检出限小于0.02μg/kg,加标回收为94.8%～101%;235 U/238 U同位素比值测定的精密度优于0.8%,标准物质的分析结果和证书值一致。结论:可采用ICP-MS准确测定食品中的铀及其同位素比值,方法简便、快速、准确。     

Implementation of ICP-MS protocols for uranium urinary measurements in worker monitoring.

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.