Urine Uranium Concentrations Research Articles

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.

A sensitive method for the determination of uranium in biological samples utilizing kinetic phosphorescence analysis (KPA)

Kinetic phosphorescence analysis is a technique that provides rapid, precise and accurate determination of uranium concentration in aqueous solutions. This technique utilizes a laser source to excite an aqueous solution of uranium, and measures the emission luminescence intensity over time to determine the luminescence decay profile. The lifetime of the luminescence decay profile and the linearity of the log luminescence intensity versus time profile are indications of the specificity of the technique for uranium determination. The luminescence intensity at the onset of decay (the initial luminescence intensity), which is the luminescence intensity at time zero after termination of the laser pulse used for excitation, is proportional to the uranium concentration in the sample. Calibration standards of known uranium concentrations are used to construct the calibration curve between the initial luminescence intensity and uranium concentration. This calibration curve is used to determine the uranium concentration of unknown samples from their initial luminescence intensity. We developed the sample preparation method that allows the determination of uranium concentrations in urine, plasma, kidney, liver, bone spleen and soft tissue samples. Tissue samples are subjected to dry-ashing in a muffle furnace at 600°C and wet-ashing with concentrated nitric acid and hydrogen peroxide twice to destroy the organic component in the sample that may interfere with uranium determination by KPA. Samples are then solubilized in 0.82 M nitric acid prior to analysis by KPA. The assay calibration curves are linear and cover the range of uranium concentrations between 0.05 μg 1 −1 and 1000 μg 1 −1 (0.05–1000 ppb). The developed sample preparation procedures coupled with the KPA technique provide a specific, sensitive, precise and accurate method for the determination of uranium concentration in tissue samples. This method was used to quantify uranium in different tissue samples obtained over a period of 90 days following a single intraperitoneal uranium dose of 0.1 mg kg −1 in rats.

Flow injection method for determination of uranium in urine and serum by inductively coupled plasma mass spectrometry

The uranium concentration in urine of a population that is not occupationally exposed to uranium compounds is in the range 1–40 ng l −1 with a median around 10 ng l −1. This is analytically challenging for routine analysis because at such low levels it is difficult to prevent contamination during sample preparation. The method presented here is based on sample introduction via a flow injection analysis system and inductively coupled plasma mass spectrometric detection, and requires virtually no sample preparation, except for acidification of the urine sample with a few drops of HNO 3 The analysis is fully automated and fast with an analysis time of 60 s per sample. The lower limit of detection is 1.5ng l −1. Memory and matrix effects may be decreased by adding 1 g l −1 of a surfactant (Triton-X 100) to the carrier stream. The validity of the results is demonstrated through measurement of standard reference materials, standard dilution experiments and, at higher concentrations, by comparison with results obtained by an independent method based on laser induced fluorescence.

The Relationships Between Urinary Elimination, Airborne Concentration, and Radioactive Hand Contamination for Workers Exposed to Uranium

The purposes of this study were to estimate the proportional contribution of uranium dust exposure to urinary excretion of the metal, and to examine the influence of hand contamination on the elimination of uranium from the urine of workers who performed different jobs. The study was based on records taken from a gaseous diffusion plant in 1956. Regression techniques were used to investigate the relationship between uranium concentration in urine and exposure variables, including the concentration of uranium dust and the incidence of hand contamination. The proportional contribution of airborne to urinary uranium was estimated by the slope of this relationship. It is concluded that the workers eliminated uranium at relatively constant rates per unit air concentration (0.67 to 1.27 micrograms/L per micrograms/m3). In addition to airborne uranium, hand contamination significantly contributed to the elimination among maintenance crew, but not among production workers. Furthermore, the production index was shown to be a useful surrogate for airborne and urinary uranium.

The Relationships Between Urinary Elimination, Airborne Concentration, and Radioactive Hand Contamination for Workers Exposed to Uranium

The purposes of this study were to estimate the proportional contribution of uranium dust exposure to urinary excretion of the metal, and to examine the influence of hand contamination on the elimination of uranium from the urine of workers who performed different jobs. The study was based on records taken from a gaseous diffusion plant in 1956. Regression techniques were used to investigate the relationship between uranium concentration in urine and exposure variables, including the concentration of uranium dust and the incidence of hand contamination. The proportional contribution of airborne to urinary uranium was estimated by the slope of this relationship. It is concluded that the workers eliminated uranium at relatively constant rates per unit air concentration (0.67 to 1.27 µg/L per µg/m3). In addition to airborne uranium, hand contamination significantly contributed to the elimination among maintenance crew, but not among production workers. Furthermore, the production index was shown to be a useful surrogate for airborne and urinary uranium.

Determining the normal concentration of uranium in urine and application of the data to its biokinetics.

A method was developed to determine the concentration of uranium (238U) in urine. This method involved preconcentration of uranium from urine with calcium phosphate neutron activation followed by simple radiochemical separation. Using this method, it was possible to detect 0.2 ng of 238U. The average and geometric mean concentration of uranium found in urine of subjects from a normal background environment was 12.8 and 9.4 ng L-1, respectively. The concentration of uranium in the urine and the daily intake of uranium by the same population was used to arrive at the gastrointestinal absorption factor (f1) for uranium incorporated in the diet. The f1 factor was estimated to be 1.6%.

Content of uranium trace in urine determined from fission track etch technique

The sensitive and simple technique of fission track etch has been applied to determine trace concentration of uranium in normal human (smokers and non-smokers, males of age group 25–30 y) urine samples. Results indicate heterogeneous distribution in both the types with levels spread uniform ranging from (0.9–6.5) × 10 −3 μg/l and in the non-uniform part (0.14–1.0) × 10 −3 μg/l forming 10–52% of the overall contents of the order (1.2–7.1) × 10 −3 μg/l. From this limited-samples study, uranium concentration in urine does not appear to have any conclusive dependence on the smoking or non-smoking habits of the individuals.

Simultaneous determination of uranium, its isotopes, and alpha activity in urine by mass spectrometry.

Abstract The concentration, isotopic composition, and alpha activity of uranium in urine are determined in one analysis by isotopic dilution and surface ionization mass spectrometry. The isotope 233U is added as an internal standard, and the uraniumi is extracted with tri-n-octylphosphine oxide for the mass spectral analysis. The complete analysis is obtained on as little as 0.1 μg of uranium. The relative standard deviations are ±1% to ±8% at 10 μg of uranium per liter of urine.

NaF粉末ペレット法による尿中ウラン分析

A simplified method of urinary uranium analysis using sodium fluoride pellet has been developed. In this method a predetermined volume of urine not previously subjected to any chemical treatment is dropped on a pellet of sodium fluoride (NaF) powder, and after drying, it is sintered in an electric furnace for about 10 min at a temperature of 950°C. When the sintered pellet is exposed to ultra violet light, it emits fluorescence of a certain wavelength characteristic of uranium, and of intensity fairly well proportionate in a wide range with the concentration of uranium in the sample urine. An important merit of this method lies in its simplicity, and it can be effectively used in practice for quantitative analysis of urinary uranium in radiation protection measures.