Daily uranium excretion in German peacekeeping personnel serving on the Balkans compared to ICRP model prediction.

An investigation was performed to assess a possible health risk of depleted uranium (DU) for residents and German peacekeeping personnel serving on the Balkans. In order to evaluate a possible DU intake, the urinary uranium excretions of volunteers were collected and analysed using inductively coupled plasma mass spectrometry (ICP-MS). In total, more than 1300 urine samples from soldiers, civil servants and unexposed controls of different genders and ages were analysed to determine uranium excretion parameters. All participating volunteers, aged 3-92 y, were grouped according to their gender and age for evaluation. The results of the investigation revealed no significant difference between the unexposed controls and the peacekeeping personnel. In addition, the geometric means of the daily urinary excretion in peacekeeping personnel, ranging from 3 to 23 ng d(-1) for different age groups, fall toward the lower end of renal uranium excretion values published for unexposed populations in literature. The measured data were compared with the International Commission on Radiological Protection prediction for the intake of natural uranium by unexposed members of the public. The two data sets are in good agreement, indicating that no relevant intake of additional uranium, either natural or DU, has appeared for German peacekeeping personnel serving on the Balkans.

Mineral absorption in the black rhinoceros (Diceros bicornis) as compared with the domestic horse.

To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for black rhinoceroses (Diceros bicornis), we investigated the apparent absorption (aA) of macro- and microminerals in eight black rhinoceroses from three zoological institutions in a total of 32 feeding trials with total faecal collection, with additional data from three unpublished studies (18 feeding trials). Feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Mn, Cu, Zn and Co. The resulting aA coefficients, and the linear relationships of apparently absorbable dietary mineral content to total dietary mineral content [per 100 g dry matter (DM)], were compared with data for domestic horses. Rhinoceroses had significantly higher aA coefficients for Ca and Mg (because of a higher calculated 'true' absorption), and lower ones for Na and K (because of calculated higher endogenous faecal losses). High absorption efficiency for divalent cations is hypothesized to be an adaptation to a natural diet of particularly high Ca:P ratio (approximately 14:1); an effective removal of Ca from the ingesta guarantees sufficient P availability at the fermentation site in the hindgut. Higher faecal losses of Na and K are hypothesized to be linked to a higher faecal bulk per DM intake in black rhinoceroses as compared with horses because of a generally lower digestive efficiency. There were no relevant differences in the absorption patterns of microminerals. In particular, there were no discernable differences in Fe absorption within the rhinoceroses for diets with and without tannin supplementation. Several of the zoo diets assessed in this study were deficient in Cu, Mn or Zn, and most contained excessive levels of Fe when compared with horse requirements. The findings of this study indicate that differences in mineral absorption between occur even between species of similar digestive anatomy; that in particular, Ca absorption might vary between hindgut fermenters with Ca:P ratio in their natural diet; that Na might be a particularly limiting factor in the ecology of free-ranging rhinoceroses; that moderate doses of tannins do not seem to markedly influence mineral absorption; and that diets for captive animals should contain adequate, but not excessive mineral levels.

Measurements of daily urinary uranium excretion in German peacekeeping personnel and residents of the Kosovo region to assess potential intakes of depleted uranium (DU).

Following the end of the Kosovo conflict, in June 1999, a study was instigated to evaluate whether there was a cause for concern of health risk from depleted uranium (DU) to German peacekeeping personnel serving in the Balkans. In addition, the investigations were extended to residents of Kosovo and southern Serbia, who lived in areas where DU ammunitions were deployed. In order to assess a possible DU intake, both the urinary uranium excretion of volunteer residents and water samples were collected and analysed using inductively coupled plasma-mass spectrometry (ICP-MS). More than 1300 urine samples from peacekeeping personnel and unexposed controls of different genders and age were analysed to determine uranium excretion parameters. The urine measurements for 113 unexposed subjects revealed a daily uranium excretion rate with a geometric mean of 13.9 ng/d (geometric standard deviation (GSD)=2.17). The analysis of 1228 urine samples from the peacekeeping personnel resulted in a geometric mean of 12.8 ng/d (GSD=2.60). It follows that both unexposed controls and peacekeeping personnel excreted similar amounts of uranium. Inter-subject variation in uranium excretion was high and no significant age-specific differences were found. The second part of the study monitored 24 h urine samples provided by selected residents of Kosovo and adjacent regions of Serbia compared to controls from Munich, Germany. Total uranium and isotope ratios were measured in order to determine DU content. (235)U/(238)U ratios were within +/-0.3% of the natural value, and (236)U/(238)U was less than 2 x 10(-7), indicating no significant DU in any of the urine samples provided, despite total uranium excretion being relatively high in some cases. Measurements of ground and tap water samples from regions where DU munitions were deployed did not show any contamination with DU, except in one sample. It is concluded that both peacekeeping personnel and residents serving or living in the Balkans, respectively, were not exposed to significant amounts of DU.

Leaching of depleted uranium in soil as determined by column experiments.

The basic features of the leachability of depleted uranium (DU) projectiles in soil was investigated by using 12 projectiles (145-294 g DU) and 16 columns installed in an air-conditioned laboratory. Two soils widely distributed in Europe, a sandy-loamy cambisol and a silty-loamy luvisol, were filled into the columns (3.3 kg dry soil each). The effluents of all columns were collected weekly during the observation period of 1 year. In 648 samples, 235U and 238U were determined by inductively coupled plasma mass spectrometry. The leaching rates of 238U from natural uranium were in general about 0.01 microg week-1 or smaller, while those of 238U from the DU munitions varied considerably and reached values of up to 100 microg week-1, for the different columns. In total, about 0.3 microg natural uranium corresponding to 20 ppm of its inventory in the soil was leached during the observation period. From the projectiles, an average of about 50 microg DU were leached corresponding to 18 ppm of the corroded DU mass (about 1.6% of the mean initial DU mass of the projectiles). Assuming that corrosion and leaching continue as observed, the mobilisation of 238U from DU munitions will last, on an average, for thousands of years in the soils investigated, while the munitions themselves will have been corroded after a much shorter time. It is proposed to use, for the investigated soil types, the mean leaching rates of the six columns with projectiles for transport calculations of 238U to the groundwater and, thus, for a better risk assessment of the water-dependent uptake pathways of DU.

Thorium and uranium contents in human urine: influence of age and residential area.

Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of (232)Th and (238)U in urine of unexposed Jordanian subjects living in six cities. The range of (232)Th excretion in all subjects was found to be 1.4-640 microBq d(-1) with an average of 34.8 microBq d(-1) (geometric mean 15.8 microBq d(-1)). Results showed no statistically significant correlation with age and residential area. The average value obtained is in agreement with levels considered normal in some recent publications. The average value of (238)U in all samples was found to be 3955 microBq d(-1) (geometric mean 1107 microBq d(-1)), which is higher than reported figures from Germany and India, but in agreement with those figures given in ICRP publication, number 23. The mean values of the different groups were found to be proportional to age up to 60 years. A noticeable drop is observed for subjects greater than 60 years old.

Assessment of exposure to depleted uranium.

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.

Determination of 235U and 238U in urine samples using sector field inductively coupled plasma mass spectrometry.

The high sensitivity of SF-ICP-MS (sector field inductively coupled plasma mass spectrometry) using a torch with the "guard-electrode" (capacitive decoupled plasma) allows the determination of 238U (isotope abundance 99.2%) and 235U (0.8%) and their isotope ratio in human urine samples down to the physiological level of <10 ng/l total uranium. For sample preparation UV photolysis was used. Some quality criteria like for the detection limit, the reproducibility, recovery and the isotope ratio are given. The method can be applied in occupational as well as in environmental medicine because of its outstanding detection power.

Application of capillary zone electrophoresis-inductively coupled plasma mass spectrometry and capillary isoelectric focusing-inductively coupled plasma mass spectrometry for selenium speciation.

The high resolution potential of capillary electrophoresis (CE) makes CE techniques valuable for separations of selenium species, both, organic and inorganic. Such effective separations of charged species are possible using the CZE mode (Z = zone). Very powerful separations can be achieved by capillary isoelectric focusing, when analysing molecules showing different isoelectric points (pI) values, such as organic Se species. Inductively coupled plasma (ICP) MS is an element-specific multi-element detector, providing extremely low detection limits. The combination of CE with ICP-MS promises a powerful tool for metal speciation. Therefore, an online hyphenation of CE [using capillary zone electrophoresis (CZE) or capillary isoelectric focusing (cITP) model] with ICP-MS, which was developed earlier, was modified and applied to selenium speciation. Separation was differentiated from the detection step during hyphenation. This resulted in short separation times (10 min) and a subsequent detection step lasting 100 s. Firstly, a CZE method was applied, providing a separation of six Se species of interest in one run [Se(IV), Se(VI), selenium carrying glutathione (GSSeSG), selenomethionine (SeM), selenocystine (SeC), selenocystamine (SeCM)]. This CZE method used an alkaline background electrolyte (Na2CO3/NaOH). The Se species were separated sufficiently from each other. Detection limits were calculated as 10 or 20 micrograms Se l-1 for inorganic Se species and 30-50 micrograms Se l-1 for organic Se species. The method was applied to standard mixtures and body fluids like human milk and serum. Secondly, a cIEF separation (pH range 2-10) was employed for organic Se species only in parallel. Detection limits were around 10-30 micrograms Se l-1. The method was applied to standard mixtures and body fluids like human milk and serum.

Selenium speciation by interfacing capillary electrophoresis with inductively coupled plasma-mass spectrometry.

The high resolution potential of capillary electrophoresis (CE) makes CE techniques valuable for separations of selenium species. Further, inductively coupled plasma-mass spectrometry (ICP-MS) affords element-specific multi-element detection, providing extremely low detection limits. The combination of CE with ICP-MS promises to become a powerful tool for metal speciation. Therefore, an on-line hyphenation of CE with ICP-MS, which was developed earlier (Michalke, B., Schramel, P., Fresenius' J. Anal. Chem. 1997, 257, 594-599), was modified and applied to selenium speciation. For this reason, capillary zone electrophoresis (CZE) methods were developed, providing the possibility to analyze six Se species of interest in one run: Se (IV), Se (VI), selenium carrying glutathione (GSSeSG), selenomethionine (SeM), selenocystine (SeC), and selenocystamine (SeCM). The final CE method used an alkaline background electrolyte (Na2CO3/NaOH) with separation differentiated from the detection step during hyphenation. This resulted in short separation times (10 min) and a subsequent detection step of 100s. The Se species were sufficiently separated from each other and appeared at 7s (SeCM), 16s (Se [VI]), 22s [SeC], 27s (Se [IV]), 35s [SeM] and 56s (GSSeSG) during the detection step. Detection limits were calculated as 10 or 20 microg Se/L for inorganic Se species and 35-50 microg Se/L for organic Se species.

Hyphenation of capillary electrophoresis to inductively coupled plasma mass spectrometry as an element-specific detection method for metal speciation.

A stepwise development for the use of capillary electrophoresis and inductively coupled plasma mass spectrometry (ICP-MS) for speciation investigations is presented. The high resolution power of CE is used for the separation of metal species, whereas ICP-MS is taken for element-specific detection with low detection limits. This contribution starts with an off-line combination of both instruments. Separation and identification of species in model solutions and real samples are shown by scanning UV detection at the CE unit with subsequent metal quantification in peak related fractions, applying electrothermal vaporization ICP-MS. Finally, first separations are demonstrated, using the on-line hyphenation with a laboratory-made nebulizer. Here, standard solutions are separated and monitored by UV and ICP-MS. Stability of electrical current during nebulization was checked and a possibly interfering suction flow was estimated. After optimization sufficient electropherograms were obtained. Advantages and problems are discussed for both modes.

[The selenium content in the blood of newborn sheep and goats--equally contributing to the effect of supplemental oral selenium as a prophylaxis]. / Zum Selengehalt im Blutplasma neugeborener Schaf- und Ziegenlämmer--gleichzeitig ein Beitrag über die Wirkung oral zugeführten Selens im Rahmen der Prophylaxe.

The article is based on the analysis of selenium concentration in blood plasma of 9 goats and their kids (n = 17), from two different places, as well as of 12 sheep and their lambs (n = 19) from several flocks. The selenium concentration was measured using ASS. In addition, the activity of CK was determined enzymatically. There was a low plasma selenium level in lambs and goat kids immediately post-natal depending on the selenium state of the mothers. After application of vitamin E and selenium to a group of lambs their selenium levels increased remarkably over 24 hours. Ten days later the average selenium concentration in the plasma of those animals that had been treated was three times as high as that of the control group. It was shown that the absorption of vitamin E and selenium when given orally to newborn lambs is comparable with the absorption after parenteral application, and that a significant increase of the plasma selenium level is attainable by oral application.

Selenium in Kashin-Beck disease areas.

In this article, the duplication portion technique was used to determine the daily intakes of selenium and ten other elements in the 24-h total diets collected in the typical Kashin-Beck endemic areas, i.e., Shanxi Province and Inner Mongolia Autonomous of China. The contents of Ca, Mg, Cu, Fe, Zn, Mn, Al, Sr, Ba, and P in freeze-dried samples were determined by ICP-AES. Se was determined by differential pulse catalytic polarography. The average Se contents in total diets of Shanxi Kashin-Beck endemic and nonendemic areas were 0.009 and 0.021 micrograms/g (dry weight), respectively (P less than 0.001), corresponding to the daily intakes for Se of 4.6 and 10.5 micrograms. After the Se-supplemented fertilizer was applied (225 g of Na2SeO3/ha), the average Se content in total diets of Kashin-Beck disease area was increased to 0.0336 micrograms/g, which corresponded to the average daily intake for Se of 16.8 micrograms. In Inner Mongolia Kashin-Beck endemic and nonendemic areas, the average Se contents in total diets were 0.006 and 0.017 micrograms/g, respectively (p less than 0.001), corresponding to the average daily intakes for Se of 3 and 8.5 micrograms. The contents of other ten elements in total diets in endemic and nonendemic areas were reported and compared.

Serum trace element levels in HIV-infected subjects.

The absolute number of T4 cells and the serum concentrations of Ca, Cu, Fe, K, Mg, P, Se, and Zn were determined in 59 Walter-Reed staged, HIV-infected men, compared to healthy controls, serum levels of Ca, Cu, and Fe were significantly higher, those of P and Se significantly lower in the HIV-infected subjects. In the HIV-infected cases, but not in the controls, the concentrations of Se and Zn, of Ca with Cu and Fe, and of Fe with P, were directly correlated. In the controls, the correlation between the levels of K and Mg was direct, and inverse between those of Zn and P. Trace element levels did not significantly correlate with WR-stage. However, the absolute number of T4 cells was directly correlated with the serum Mg concentration.

The importance of selenium in the prenatal and postnatal development of calves and lambs.

Selenium deficiency is responsible for Zenker type muscle degeneration in calves, lambs, and foals in the prenatal and postnatal stages of development. Investigations have shown that the selenium GSH Px, and vitamin E content of the maternal and fetal parts of the placenta in cattle are different. Similarly, low concentrations of selenium are present in milk from cows and sheep. In addition to an inadequate supply of selenium and vitamin E as a contributory cause of fetal nutritive muscular dystrophy (FNMD), it is assumed that a placental transport block and/or impaired selenium metabolism in the placenta are also responsible. Postnatal nutritive muscular dystrophy, however, is attributed to either acute selenium and vitamin E deficiency in basic feed or impaired plant absorption of selenium as a result of antagonistic elements, such as sulphur.

[Trace element concentrations in HIV infected patients]. / Spurenelementkonzentrationen bei HIV-Infizierten.

The serum concentrations of Ca, Cu, Fe, K, Mg, P, Se and Zn and the absolute number of T4 cells were determined in 59 HIV-infected men. Serum levels of Ca, Cu and Fe were significantly higher, those of P and Se significantly lower in the infected, compared to healthy controls. In the HIV-infected cases the concentrations of Se and Zn, of Ca with Cu and Fe, and of Fe with P, were directly correlated. In the controls, the correlation between the levels of K and Mg was direct, and inverse between those of Zn and P. WR-stage and trace element levels did not correlate. The absolute number of T4-lymphocytes was directly correlated with the serum Mg concentration.

Metabolic and nutritional parameters in patients after colonic polypectomy.

Breath methane and hydrogen, plasma acetate, serum selenium, vitamin A and beta-carotene were measured in 47 patients from whom colonic polyps had been removed by endoscopic polypectomy between 3 months and 2 years previously. Patients were compared with 39 control subjects in whom no abnormality was detected during colonoscopy. The proportion of methane exhalers was significantly (p less than 0.0005) higher in patients after polypectomy (66.0%) than in controls (28.2%). Mean plasma acetate was lower (p less than 0.025) in post-polypectomy patients (70.5 microM) than in control subjects (97.1 microM) while breath hydrogen was similar in both groups. The serum concentrations of the antioxidants selenium and beta-carotene showed no differences between the groups whereas vitamin A was higher (p less than 0.01) in serum samples of patients after polypectomy than of controls. These findings indicate that the colonic environment in post-polypectomy patients exhibits certain characteristics which may be related to the formation of benign tumors and possibly colon cancer.

Selenium, cadmium, lead, and mercury concentrations in human breast milk, in placenta, maternal blood, and the blood of the newborn.

The concentrations of the trace elements Cd, Hg, Pb, and Se during the perinatal period in human placenta and in the blood of the mother and the newborn (cord blood) were determined. Breast milk (colostrum and mature milk) was also included to permit correlations between the different compartments. For Cd, a placental barrier exists, in accord with previous observations. For Pb, a strong correlation between the concentrations in the blood of the mother and of the newborn was found. The concentration of Hg was in most cases below the detection limit. Its concentration in colostrum was higher than in the mature milk. The results for Se reflect the knowledge about an essential trace element. Strong positive correlations were noted between maternal blood and cord blood and maternal milk. Anodic stripping voltammetry (DPASV) was used for the determination of Cd and Pb, cold vapor AAS (CVAAS) for the determination of Hg, and instrumental neutron activation analysis (INAA) for the determination of Se.

Concentrations of lead, cadmium, mercury and other elements in seeds of Lupinus mutabilis and of other legumes.

Several species of legumes and varieties of lupins were examined for their heavy metal content in the seeds. Atomic absorption spectrometry was the main analytical tool. Validity and reproducibility of the results was checked by analyzing the same materials at two different laboratories performing the same technique. Additionally, inductively coupled plasma emission spectroscopy was applied. In grains of Lupinus mutabilis which constitute a traditional food in Andean populations, the following contents of heavy metals were determined: 0.10-0.25 microgram/g Cd; 0.5-1.6 microgram/g Pb; 0.10-0.15 microgram/g Hg. Seeds of other legumes contained 0.05-0.35 microgram/g Cd; 0.1-0.2 microgram/g Pb; 0.01-0.04 microgram/g Hg. The high lead content of lupins is easily reduced to one tenth by traditional extraction with boiling water. The mercury content, too, is decreased by this technique. The high manganese content of 1 300-1,400 micrograms/g of Lupinus albus compared to other legumes (25-37 micrograms/g) seems to be characteristic for this species and may be of nutritional significance. The comparison of the heavy metal contents of legume seeds of different origin and variety indicates a complex pattern of environmental and genetic factors that contribute to the specific metal contents of individual harvests. On the level of varieties the environmental factors (climate, soil, geology, agricultural techniques) seem to exhibit more important influences on the specific accumulation of heavy metals than genetic factors. In contrast, on the level of species or genera, the accumulation of heavy metals seems to be dominated by genetic factors rather than by environmental influences.

[Determination of the selenium levels of the blood plasma in newborn calves--its significance from the clinical viewpoint]. / Bestimmungen von Selenkonzentrationen im Blutplasma neugeborener Kälber--ihre Bedeutung aus klinischer Sicht.

In a collection of newborn calves including DRB, DSB and DFV breeds (n = 27) the plasma Selenium concentration was measured directly after parturition up until six weeks after parturition by means of neutron-activating analysis. Minimal Selenium concentration occurred on the fourth day. The values of the subsequent Selenium concentrations exceeded those immediately after parturition only slightly. The tested group could be divided into two subgroups, one of which consisted of calves with extremely low initial Selenium concentrations, whereas the animals in the others showed high levels immediately after parturition (0.019 +/- 0.004 micrograms/ml versus 0.046 +/- 0.010 micrograms/ml of plasma). The diagrams appeared to be parallel on two different levels. Nine out of 10 calves with low Selenium levels showed after parturition retarded development and/or suffered from various diseases whereas the other calves (n = 17) showed no signs of clinical disease nor alterations in the race-specific development throughout the testing period.