Biosorption of uranyl ions from aqueous solutions by soluble renewable polysaccharides.

Polysaccharides derived from natural sources have been offered as environment friendly sorbents for the adsorption of heavy metals. We present a simple technique to remove uranyl ions from aqueous solutions by using representative polysaccharides. The adsorption efficiency of UO22+ decreased in the following order: xanthan gum > kappa > iota/guar gum, for instance, the efficiencies after sorption of 30 min with 500 mg per L uranyl acetate and 0.03 g of the corresponding polysaccharide were: 89.7%, 85.2%, 79.1% and 77.1%. Lowering the acidity in the system decreased the sorption efficiency with all the polysaccharides, and reducing the ratio between the amount of uranyl ions and the amount of polysaccharide increased the sorption efficiencies, e.g., using 500 mg per L uranyl acetate and 0.05 g of the corresponding polysaccharide (xanthan gum, kappa, iota, guar gum) yielded after 30 min sorption efficiencies of 94.3%, 91.5%, 89.0% and 87.7%, respectively. FTIR, SEM-EDS and TGA analyses verified the presence of uranium in the polysaccharides and showed that the uranyl ions were interacting with the different functional groups. Moreover, the addition of uranyl ions to the polysaccharides caused a sharp decrease in viscometry measurements. In addition, the measurements showed that the addition of uranyl lowered both modules, G' and G'', and made the solution more liquid.

Selective Sorption of Heavy Metals by Renewable Polysaccharides.

Renewable and biodegradable polysaccharides have attracted interest for their wide applicability, among them their use as sorbents for heavy metal ions. Their high sorption capacity is due mainly to the acidic groups that populate the polysaccharide backbone, for example, carboxylic groups in alginate and sulfate ester groups in the iota and lambda carrageenans. In this study, these three polysaccharides were employed, alone or in different mixtures, to recover different heavy metal ions from aqueous solutions. All three polysaccharides were capable of adsorbing Eu3+, Sm3+, Er3+, or UO22+ and their mixtures, findings that were also confirmed using XPS, TGA, and FTIR analyses. In addition, the highest sorption yields of all the metal ions were obtained using alginate, alone or in mixtures. While the alginate with carboxylic and hydroxyl groups adsorbed different ions with the same selectivity, carrageenans with sulfate ester and hydroxyl groups exhibited higher adsorption selectivity for lanthanides than for uranyl, indicating that the activity of the sulfate ester groups toward trivalent and smaller ions was higher.

Diplopia in the Younger Adult (≤65 Years Old) Compared With Older Adult (>65 Years Old) Population-Presentation, Progression, and Outcome.

BACKGROUND: Despite the impact of new-onset diplopia on the quality of life, there are few studies concerning new-onset diplopia in seniors. This study aimed to describe the epidemiology, etiology, prognosis, and outcome of different treatments in the older adults compared with younger adult patients presenting with new-onset binocular diplopia. METHODS: A retrospective chart review of patients ≥18 YO with new-onset binocular diplopia presenting between 2010 and 2021. Data collected included age at presentation, gender, duration of time since diplopia onset, imaging results, known trigger, etiology, treatment, and follow-up. RESULTS: Two hundred ten patients were included. Of them, 75 patients were ≤65 YO (35.7%, the "younger adult group") and 135 > 65 YO (64.3%, the "older adults group"). The common etiology in both groups was neurogenic (54.7% ≤ 65 vs 62.2% >65, P = 0.29). Cranial nerve palsies were more commonly microvascular in the older adults (96.0% vs 74.1%, P = 0.005), whereas tumor-related cranial nerve palsies were more frequent in younger adults (14.81% vs 2.04%, P = 0.03). A restrictive etiology was observed in 20% of younger adult compared with 11.1% of older adults group (P = 0.08). Sagging eye syndrome (SES) was the second most common etiology in the older adults group at 11.9%, compared with 1.3% in the younger adult group (P = 0.01). Decompensated phoria/tropia appeared in 16% of younger adult group compared with 11.9% of older adults (P = 0.4), with an obvious trigger (mostly cataract surgery) in the latter (80% older adults vs 20% younger adults, P = 0.019). Positive imaging findings were found in 46.7% of patients ≤65 compared with 25.3% of >65 (P = 0.01) and complete spontaneous resolution of diplopia was noted in 32.1% of the older adults compared with 11.8% of younger adults (P = 0.003). CONCLUSIONS: Neurogenic diplopia was the most common etiology for both groups, but is more prominent in the older adults. Noticeable findings in the older adults were SES diagnosis, identification of triggers for impaired fusion/diplopia, and a paucity of positive findings in imaging results. It is important to know these differences not only for managing seniors better, but also to minimize symptoms of binocular diplopia after lens-related procedures.

[CASE SERIES OF EARLY NEUROIMAGING IN PATIENTS WITH VASCULAR RISK FACTORS AND ISOLATED SIX CRANIAL NERVE PALSY, DEMONSTRATING THE DILEMMA OF EARLY IMAGING].

INTRODUCTION: There are various etiologies for isolated third, fourth and sixth cranial nerve palsies. The most common etiology in adults aged 50 years and older with vascular risk factors such as diabetes, hyperlipidemia, and hyperlipidemia, is microvascular ischemia. The role of early neuroimaging in older patients with vascular risk factors presenting with acute isolated ocular motor nerve palsy is controversial. AIMS: We present six cases of patients aged 50 years and older, with vascular risk factors, who suffered from acute isolated paralysis of the sixth nerve. All cases were diagnosed with a non-microvascular ischemia etiology. RESULTS: The identified etiologies included petroclival meningioma with involvement of the cavernous sinus, metastatic hepatoma, plasmacytoma, venous thrombosis, arterial-venous malformation and aneurysm. CONCLUSIONS: Despite the high cost and presumed low yield, early neuroimaging can change the clinical management in certain cases. DISCUSSION: Previous studies have found the yield of early neuroimaging in older vasculopathic patients with acute 4th or 6th cranial nerve palsies to be 1-15%. In spite of these reports, our cases demonstrate the need for early onset imaging in these cases.

Insights on hydrogen spillover on carbonaceous supports.

Hydrogen spillover is important in solid-phase catalytic hydrogenation reactions, as well as in hydrogen storage and scavenging. The present study explores the nature of this phenomenon by examining the effects of hydrogen pressure and addition of carbonaceous additives, such as carbon nanotubes (CNT) and C60 fullerene, on hydrogenation reaction kinetics and its products distribution. For these purposes, a solid-phase hydrogenation reaction was studied, where 1,4-bis-(phenyl-ethynyl)benzene (PEB) was used as a hydrogen acceptor. To the best of our knowledge, this is the first study in which both the reaction kinetics and products distribution of the solid-phase organic hydrogen acceptor were analyzed. A demonstration of hydrogen spillover phenomenon was provided on the basis of the combined interpretation of kinetics and hydrogenated organic products distribution, under different reaction conditions. The results were explained in terms of hydrogen active species availability, distribution and relative migration distance of these species through the carbonaceous media. The insights into the hydrogen spillover chemistry obtained in this research allow for a better understanding of this phenomenon and its implementation in the future hydrogen storage and transportation, and hydrogen-generating devices, including safety aspects of all these applications.

Sniffing Bacteria with a Carbon-Dot Artificial Nose.

HIGHLIGHTS: Novel artificial nose based upon electrode-deposited carbon dots (C-dots). Significant selectivity and sensitivity determined by "polarity matching" between the C-dots and gas molecules. The C-dot artificial nose facilitates, for the first time, real-time, continuous monitoring of bacterial proliferation and discrimination among bacterial species, both between Gram-positive and Gram-negative bacteria and between specific strains. Machine learning algorithm furnishes excellent predictability both in the case of individual gases and for complex gas mixtures. Continuous, real-time monitoring and identification of bacteria through detection of microbially emitted volatile molecules are highly sought albeit elusive goals. We introduce an artificial nose for sensing and distinguishing vapor molecules, based upon recording the capacitance of interdigitated electrodes (IDEs) coated with carbon dots (C-dots) exhibiting different polarities. Exposure of the C-dot-IDEs to volatile molecules induced rapid capacitance changes that were intimately dependent upon the polarities of both gas molecules and the electrode-deposited C-dots. We deciphered the mechanism of capacitance transformations, specifically substitution of electrode-adsorbed water by gas molecules, with concomitant changes in capacitance related to both the polarity and dielectric constants of the vapor molecules tested. The C-dot-IDE gas sensor exhibited excellent selectivity, aided by application of machine learning algorithms. The capacitive C-dot-IDE sensor was employed to continuously monitor microbial proliferation, discriminating among bacteria through detection of distinctive "volatile compound fingerprint" for each bacterial species. The C-dot-IDE platform is robust, reusable, readily assembled from inexpensive building blocks and constitutes a versatile and powerful vehicle for gas sensing in general, bacterial monitoring in particular.

Pharmacomechanical catheter thrombolysis for pregnancy-related proximal deep venous thrombosis: prevention of post-thrombotic syndrome.

OBJECTIVE: The efficacy of pharmacomechanical catheter-directed thrombolysis (PCDT) in preventing post thrombotic syndrome (PTS) for pregnancy related deep vein thrombosis (DVT) is unknown. STUDY DESIGN: An observational cross section study of women with pregnancy related proximal (femoral/iliofemoral) DVT who underwent PCDT followed by anticoagulation (study group), and women who were treated with anticoagulation alone (control group). Women were evaluated for PTS using the Villalta scale (primary outcome) and VEINES-QOL/Sym questionnaires. RESULTS: Eleven women with iliofemoral DVT underwent PCDT, two during their first trimester and nine postpartum; 18 women were treated with anticoagulation only. There were no significant differences in age, number of previous pregnancies, and duration of anticoagulation or thrombophilia between the groups. The time between DVT diagnosis and study inclusion was longer in the study group [median 50.5 (range 16-120) months] compared to the control group [median 27 (range 11-64) months], p = .4. None of the women in the PCDT group developed PTS, compared to six (33.3%, p = .03) in the control group, four of whom developed severe PTS. One patient in each group developed recurrent DVT, and one patient in the study group developed a calf hematoma. A reduced frequency of lower extremity symptoms was observed in the PCDT group (VEINES-Sym questionnaire), but no differences in quality of life (VEINES-QOL questionnaire) were reported. CONCLUSION: This study suggests that PCDT may reduce the incidence of PTS in women with pregnancy related proximal DVT.Bullet pointsDVT involving the iliofemoral veins and development of post thrombotic syndrome is frequent among pregnant or postpartum womenStudies of pharmacomechanical catheter-directed thrombolysis (PCDT) for deep vein thrombosis did not include pregnant or postpartum womenIn our observational cross section study women who underwent PCDT (mainly in the postpartum period) had reduced frequency of post-thrombotic syndrome compared to women who received anticoagulation onlyLarger studies are required to confirm the use of PCDT for prevention of PTS in this population.

Bilateral Transient Myopia with Sulfasalazine Treatment.

PURPOSE: Several case reports of transient drug-induced myopia have been reported, mainly due to sulfa drugs. We present a case of a sudden and significant increase in myopia associated with initiation of Sulfasalazine for long-standing ulcerative colitis in an adult Caucasian female. CASE REPORT: Our patient presented to the emergency room with acute bilateral visual loss. Ocular examination was normal, except for myopia of -4 Diopters (D) in both eyes (BE). The patient was advised to stop the medication, and her vision improved within 4 days to best corrected visual acuity (BCVA) of 6/7.5 with a refractive correction of -0.75 D in her right eye (RE) and BCVA of 6/6 with a refractive correction of -0.50 D in her left eye (LE). CONCLUSION: To the best of our knowledge, this is the second reported case of transient Sulfasalazine-induced myopia.

Thenoyltrifluoroacetone (TTA)-Carbon Dot/Aerogel Fluorescent Sensor for Lanthanide and Actinide Ions.

Contamination of groundwater with radioactive substances comprising actinides and lanthanides is a significant environmental hazard and thus the development of selective, sensitive, and easy-to-apply sensors for water-soluble actinide and lanthanide ions is highly sought. We constructed a new selective fluorescent sensor for UO2 2+, Sm3+, and Eu3+ based on a carbon dot (C-dot)-aerogel hybrid prepared through in situ carbonization of 2-thenoyltrifluoroacetone (TTA), a high-affinity heavy metal chelator. The TTA-C-dot-aerogel enabled the detection of UO2 2+ ions, which induced a significant red fluorescence shift, whereas Eu3+ and particularly Sm3+ ions gave rise to pronounced fluorescence quenching. Importantly, the lanthanide/actinide ion-selective TTA-C-dots could be synthesized only in situ inside the aerogel pores, indicating the crucial role of the aerogel host matrix both in enabling the formation of the C-dots and in promoting the adsorption and interactions of the lanthanide and actinide metal ions with the embedded C-dots.

Effect of changes in food groups intake on magnesium, zinc, copper, and selenium serum levels during 2 years of dietary intervention.

BACKGROUND: Essential elements in serum are related to specific changes in food groups intake. OBJECTIVE: To address the effect of 2-year food intake changes in an intervention study on serum concentrations of magnesium, zinc, copper, and selenium. METHOD: Two hundred thirty-one participants, a subgroup of the Dietary Intervention Randomized Control Trial (DIRECT) study (age = 52 years; body mass index = 32.8 kg/m(2); 85% males) randomized to low-fat, Mediterranean, or low-carbohydrate diets in a 2-year dietary intervention trial were followed for serum concentrations determined using inductively coupled plasma-mass spectrometry. Changes in the intake of 11 food groups were evaluated by food frequency questionnaires. RESULTS: Using multivariate regression models, adjusted for age, sex, baseline body weight (kg), and changes in intakes of 11 food groups (g/d), at 12 months, serum element elevations were observed mainly in the low-carbohydrate group: selenium, by increasing consumption of fats and oils (ß = 0.415, p = 0.009) and legumes (ß = 0.183, p = 0.010) and decreasing fruit intake (ß = -0.438, p = 0.030); copper, by increasing consumption of legumes (ß = 0.453, p = 0.018) and dairy products (ß = 0.320, p = 0.039); magnesium by increasing fish consumption (ß = 0.374, p = 0.042) in the low-carbohydrate group and in the entire study population (ß = 0.237, p = 0.016); and zinc exclusively in the low-fat group by decreasing consumption of fats and oils (ß = -0.575, p = 0.022). At 24 months, serum elements were elevated mainly in the low-fat diet group, mostly by decreasing intake of snacks, sweets, and cakes: zinc (ß = -0.570, p = 0.027), copper (ß = -0.649, p = 0.012), and selenium (ß = -0.943, p < 0.001). Also in this group, magnesium levels were elevated by increasing vegetable intake (ß = 0.395, p = 0.041), copper by increasing fruit intake (ß = 0.375, p = 0.025), and selenium by increasing consumption of bread, pasta, and cereals (ß = 0.751, p = 0.011). The entire group, further adjusted to assigned diet type, increased selenium (ß = 0.294, p = 0.004) and copper (ß = 0.220, p = 0.038) by increasing consumption of bread, pasta, and cereals; selenium level was also predicted by decreasing consumption of snacks, sweets, and cakes (ß = -0.256, p = 0.014). Introducing energy expenditure, expressed in metabolic equivalents (MET = 1 kcal·kg(-1)·h(-1)), as an additional variable emphasized the negative effect of sweets and cakes on increasing serum concentrations of zinc, copper, and selenium after 24 months (ß = -0.549, p = 0.021; ß = -0.669, p = 0.012; ß = -0.982, p < 0.001, respectively), especially in the low-fat diet group. No significant associations between changes in food groups intake and the 4 elements were found in the Mediterranean diet group. CONCLUSIONS: During this 2-year intervention, serum concentrations of 4 essential elements were associated with a diversity of food group intake patterns. Comprehensive predictors for elevating zinc, copper, and selenium in serum included decreasing consumption of sweets and cakes while increasing consumption of bread, cereals, and pasta.

Elements in maternal blood and amniotic fluid determined by ICP-MS.

OBJECTIVE: Knowledge about levels of toxic and non-toxic elements in amniotic fluid is limited. The aims of this study were: (1) to measure levels of trace elements Cu, Fe, Zn, B, Sr and Co in amniotic fluid and maternal serum during second trimester of pregnancy; and (2) to determine what correlations exists between elements levels in amniotic fluid and maternal serum. METHODS: The levels of, iron, copper, zinc, cobalt, strontium and boron were measured in blood and amniotic fluid during genetic amniocentesis using inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: Concentrations of the elements: Fe, Cu, Zn, Co, Sr and B in amniotic fluid were significantly lower than in maternal blood. For iron, zinc, cobalt, strontium and boron there was a linear correlation between levels in amniotic fluid and maternal serum. CONCLUSIONS: The concentration of trace elements in amniotic fluid was found to be lower than maternal serum and linearly correlated to its level.

Trace elements' concentrations in maternal and umbilical cord plasma at term gestation: a comparison between active labor and elective cesarean delivery.

OBJECTIVE: Trace elements are minerals required in minute quantities to maintain proper physical functioning. The role of trace elements in the process of parturition is poorly understood. This study was aimed to determine levels of trace elements' concentration in maternal plasma and umbilical venous and arterial plasma at term during active labor vs elective cesarean delivery (CD). STUDY DESIGN: A prospective case-control study was conducted. Forty healthy parturients in active labor at term with their newborns were compared to 40 healthy parturients matched for maternal age, parity, and gestational age, who delivered by elective CD (before commencement of labor). Samples of maternal venous blood and umbilical cord arterial and venous blood were drawn immediately following delivery. Trace elements' concentrations were measured using the inductively coupled plasma mass spectrometer (ICP-MS). RESULTS: Significant higher levels of manganese (Mn) and selenium were found in maternal venous plasma during active labor vs elective CD. Magnesium (Mg) levels were significantly higher in maternal venous blood during elective CD compared to active labor. Umbilical cord artery levels of Mg, Mn, and zinc (Zn) were significantly higher in active term labor vs elective CD. Also, significant higher levels of copper and Zn were found in umbilical cord vein between active labor and elective CD. CONCLUSION: Trace elements' concentrations differ significantly in fetal blood during active labor vs elective CD. Hence, trace elements may play a crucial role in the process of human parturition.

Severe pre-eclampsia is associated with abnormal trace elements concentrations in maternal and fetal blood.

OBJECTIVE: The study was aimed to compare trace elements concentrations in women with and without severe pre-eclampsia (PE). METHODS: A prospective case-control study was conducted comparing 43 parturients with severe PE (who received magnesium sulfate [MgSO4]) and 80 healthy parturients and their newborns, matched for gestational age and mode of delivery. Inductively coupled plasma mass spectrometry (ICPMS) was used for the determination of zinc (Zn), copper (Cu), selenium (Se) and magnesium (Mg) levels in maternal as well as arterial and venous umbilical cord serum. RESULTS: Zn levels (µg/L) were significantly higher in fetal arterial and venous blood of the PE group (947.3 ± 42.5 vs. 543.1 ± 226, 911.1 ± 220.2 vs. 422.4 ± 145, p < 0.001; respectively). Se levels (µg/L) were significantly lower in maternal and fetal arterial and venous cord blood of the PE group (98.6 ± 24.2, 110.7 ± 19.4, 82 ± 17.8 vs. 111.6 ± 17.6, 82.1 ± 17.4 vs. 107.1 ± 25.7, p < 0.001; respectively). Cu levels (µg/L) were significantly lower in fetal arterial and venous cord blood (581.6 ± 367.4 vs. 949 ± 788.8, p = 0.022, 608.3 ± 418.1 vs. 866.9 ± 812.6, p = 0.001 respectively) but higher in maternal blood (2264.6 ± 751.7 vs. 1048 ± 851.1, p < 0.001). These differences remained significant while controlling for the mode of delivery. Mg levels were significantly higher in the PE group as compared with the control group. CONCLUSIONS: Severe PE is associated with abnormal concentrations of Zn, Cu and Se. Therefore, trace elements may have a crucial role in the pathogenesis of severe PE.

Trace element concentrations in follicular fluid of small follicles differ from those in blood serum, and may represent long-term exposure.

OBJECTIVE: To determine the levels of elements in follicular fluid (FF) of patients undergoing IVF and evaluate the relationship between the concentration of elements in FF, follicular volume, and blood. DESIGN: Prospective blinded study. SETTING: University-based IVF center. PATIENT(S): Follicular fluid/blood samples from 6/3 patients, respectively, undergoing IVF. INTERVENTION(S): Single follicular aspirations of 33 follicles were performed. Blood samples ( approximately 5 mL) were drawn at the time of oocyte retrieval from 3/6 patients only. The concentrations 26 elements were measured by inductively coupled plasma mass spectroscopy. MAIN OUTCOME MEASURE(S): Trace elements concentrations in follicular fluid and blood. RESULT(S): [1] Calcium and magnesium were the most abundant, followed by Cu, Zn, Fe, Cr, Rb. The elements V, Sr, Se, B, As, Pb, Al, Mo, Mn, and Cs were found in trace amounts. The elements Li, Be, Ag, Cd, Ba, Ti, Bi, U were not detected. [2] Element concentrations in small follicles frequently differed from those of large follicles. [3] Element concentrations in large follicles more closely resembled those in blood. CONCLUSION(S): Concentrations of elements in FF of small follicles can differ from those of large follicles in the same woman and from those of blood serum. When follicles grow they become filled with fluid of an elemental composition similar to blood. Concentrations of elements in small follicles may represent longer term element exposure, whereas those of growing follicles represents the coincident blood concentrations.

Normalisation of spot urine samples to 24-h collection for assessment of exposure to uranium.

For dose assessment of workers at Nuclear Research Center Negev exposed to natural uranium, spot urine samples are analysed and the results are normalised to 24-h urine excretion based on 'standard' man urine volume of 1.6 l d(-1). In the present work, the urine volume, uranium level and creatinine concentration were determined in two or three 24-h urine collections from 133 male workers (319 samples) and 33 female workers (88 samples). Three volunteers provided urine spot samples from each voiding during a 24-h period and a good correlation was found between the relative level of creatinine and uranium in spot samples collected from the same individual. The results show that normalisation of uranium concentration to creatinine in a spot sample represents the 24-h content of uranium better than normalisation to the standard volume and may be used to reduce the uncertainty of dose assessment based on spot samples.

Lead concentrates in ovarian follicle compromises pregnancy.

Following absorption, lead can concentrate in bodily compartments where it disrupts cellular processes and can result in detrimental health consequences. The concentration and impact of lead within follicular fluid has not been characterized and we used inductively coupled plasma mass spectroscopy (ICP-MS) to determine lead levels in blood and follicular fluid from nine patients undergoing in vitro fertilization (IVF) treatment. Lead levels within follicular fluid were found to be significantly higher in non-pregnant patients compared to pregnant patients suggesting that elevated concentrations of the environmental toxicant lead adversely affect female reproduction.

Determination of 234U/238U ratio: comparison of multi-collector ICPMS and ICP-QMS for water, hair and nails samples, and comparison with alpha-spectrometry for water samples.

The (234)U/(238)U ratio in water, hair and nails samples was determined by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) and by alpha-spectrometry for the water samples only. A correlation of 0.99 was found between the two ICPMS methods and of 0.98 with alpha-spectrometry. The range of activity ratios was between 0.9 and 2.6 according to the MC-ICPMS measurements. The reproducibility of both ICPMS techniques was better than 4% for water samples containing 1 mug l(-1) of uranium and a (234)U/(238)U atom ratio of 54.9 x 10(-6). Sample preparation for the ICPMS consisted of dilution of water samples containing >10 microg l(-1) of uranium and measurement time was approximately 1 min, while alpha-spectrometry involved pre-concentration and separation of the uranium and counting times of 1,000 min.

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.

Urine, hair, and nails as indicators for ingestion of uranium in drinking water.

The concentration of uranium in urine, hair, and nails due to continuous exposure through ingestion of drinking water was studied. The study population consisted of 205 individuals living in 134 different households in southern Finland where drinking water is supplied from private drilled wells. The population was selected to include a broad range of uranium daily intake from drinking water (0.03-2,775 microg d). The uranium content in drinking water, urine (overnight collection), hair and nails was determined by ICPMS. Uranium in urine was corrected for the matrix effects by use of thallium as an internal standard and adjusted by creatinine normalization. Hair and toenail samples were rinsed to remove external contamination prior to acid digestion and analysis. The uranium content in all excretion pathways was correlated with the uranium intake, particularly at elevated levels (> or =10 microg d) where drinking water was the major source of exposure to uranium. The median of the individual uranium absorption factors for urine, hair, and toenails were fu=0.003, fh=0.003, and fn=4 x 10, respectively. The association between the different bioassays was examined. The absorption factor, f1, was calculated for the population with an intake above 10 microg d and was below 0.01 for 72% of the study persons (range 0.0002 to 0.070). No statistically significant difference in f1 values was found between women and men. However, the absorption factor was higher among younger (< 60 y) than older (> or =60 y) subjects and among people with a lower exposure (below 100 microg d) than among those that ingest over 100 microg d.