Distribution of uranium and thorium in dolomitic gravel fill and shale saprolite.

The objectives of this study were to examine (1) the distribution of U and Th in dolomitic gravel fill and shale saprolite, and (2) the removal of uranium from acidic groundwater by dolomitic gravel through precipitation with amorphous basaluminite at the U.S. DOE Oak Ridge Integrated Field Research Challenge (ORIFRC) field site west of the Oak Ridge Y-12 National Security Complex in East Tennessee. Media reactivity and sustainability are a technical concern with the deployment of any subsurface reactive media. Because the gravel was placed in the subsurface and exposed to contaminated groundwater for over 20 years, it provided a unique opportunity to study the solid and water phase geochemical conditions within the media after this length of exposure. This study illustrates that dolomite gravel can remove U from acidic contaminated groundwater with high levels of Al(3+), Ca(2+), NO(3-), and SO4(2-) over the long term. As the groundwater flows through high pH carbonate gravel, U containing amorphous basaluminite precipitates as the pH increases. This is due to an increase in groundwater pH from 3.2 to ∼6.5 as it comes in contact with the gravel. Therefore, carbonate gravel could be considered as a possible treatment medium for removal and sequestration of U and other pH sensitive metals from acidic contaminated groundwater. Thorium concentrations are also high in the carbonate gravel. Thorium generally shows an inverse relationship with U from the surface down into the deeper saprolite. Barite precipitated in the shallow saprolite directly below the dolomitic gravel from barium present in the acidic contaminated groundwater.

Estimating kinetic mass transfer by resting-period measurements in flow-interruption tracer tests.

Flow-interruption tracer test is an effective approach to identify kinetic mass transfer processes for solute transport in subsurface media. By switching well pumping and resting, one may alter the dominant transport mechanism and generate special concentration patterns for identifying kinetic mass transfer processes. In the present research, we conducted three-phase (i.e., pumping, resting, and pumping) field-scale flow-interruption tracer tests using a conservative tracer bromide in a multiple-well system installed at the US Department of Energy Site, Oak Ridge, TN. A novel modeling approach based on the resting-period measurements was developed to estimate the mass transfer parameters. This approach completely relied on the measured breakthrough curves without requiring detailed aquifer characterization and solving transport equations in nonuniform, transient flow fields. Additional measurements, including hydraulic heads and tracer concentrations in large pumping wells, were taken to justify the assumption that mass transfer processes dominated concentration change during resting periods. The developed approach can be conveniently applied to any linear mass transfer model. Both first-order and multirate mass transfer models were applied to analyze the breakthrough curves at various monitoring wells. The multirate mass transfer model was capable of jointly fitting breakthrough curve behavior, showing the effectiveness and flexibility for incorporating aquifer heterogeneity and scale effects in upscaling effective mass transfer models.

A pilot study of personality pathology in patients with anorexia nervosa: modifiable factors related to outcome after hospitalization.

OBJECTIVE: To assess improvement in aspects of personality in patients hospitalized with anorexia nervosa (AN) and its relationship to improved depression, body mass index (BMI), and eating disorder outcome after treatment. METHOD: Twenty females hospitalized with AN completed intake and discharge assessments of BMI, depression and eating disorder severity, as well as personality pathology with the Minnesota Multiphasic Personality Inventory (MMPI-2) and the Revised NEO Personality Inventory (NEO PI-R). Clinical outcome for a subset of patients at 1-year post-hospitalization was determined. RESULTS: The only factor that predicted better versus worse outcome at 1-year post-hospitalization was change in Low Self-Esteem (LSE) from the MMPI-2. Improved LSE from admission to discharge predicted remission at 1-year post-hospitalization, while worsening LSE predicted relapse. Regardless of outcome, NEO PI-R Neuroticism remained pathologically elevated in AN patients during hospitalization. DISCUSSION: Pathological levels of neuroticism may represent a vulnerability factor for AN. In contrast, self-esteem appears to be a modifiable factor that predicts outcome following hospitalization, and may be an important target for treatment.

Deposition of uranium precipitates in dolomitic gravel fill.

Uranium-containing precipitates have been observed in a dolomitic gravel fill near the Department of Energy (DOE) S-3 Ponds former waste disposal site as a result of exposure to acidic (pH 3.4) groundwater contaminated with U (33 mg L(-1)), Al3+ (900 mg L(-1)), and NO3- (14 000 mg L(-1)). The U containing precipitates fluoresce a bright green under ultraviolet (UV) short-wave light which identify U-rich coatings on the gravel. Scanning electron microscopy (SEM) microprobe analysis show U concentration ranges from 1.6-19.8% (average of 7%) within the coatings with higher concentrations at the interface of the dolomite fragments. X-ray absorption near edge structure spectroscopy (XANES) indicate that the U is hexavalent and extended X-ray absorption fine structure spectroscopy (EXAFS) shows that the uranyl is coordinated by carbonate. The exact nature of the uranyl carbonates are difficult to determine, but some are best described by a split K(+)-like shell similar to grimselite [K4Na(UO2)(CO3)3 x H2O] and other regions are better described by a single Ca(2+)-like shell similar to liebigite [Ca2(UO2)(CO3)3 x 11(H2O)] or andersonite [Na2CaUO2(CO3)3 x 6H2O]. The U precipitates are found in the form of white to light yellow cracked-formations as coatings on the dolomite gravel and as detached individual precipitates, and are associated with amorphous basalumnite [Al4(SO4)(OH)10 x 4H2O].

Uranium removal from contaminated groundwater by synthetic resins.

Synthetic resins are shown to be effective in removing uranium from contaminated groundwater. Batch and field column tests showed that strong-base anion-exchange resins were more effective in removing uranium from both near-neutral-pH (6.5)- and high-pH (8)-low-nitrate-containing groundwaters, than metal-chelating resins, which removed more uranium from acidic-pH (5)-high-nitrate-containing groundwater from the Oak Ridge Reservation (ORR) Y-12 S-3 Ponds area in Tennessee, USA. Dowex 1-X8 and Purolite A-520E anion-exchange resins removed more uranium from high-pH (8)-low-nitrate-containing synthetic groundwater in batch tests than metal-chelating resins. The Dowex 21K anion-exchange resin achieved a cumulative loading capacity of 49.8 mg g(-1) before breakthrough in a field column test using near-neutral-pH (6.5)-low-nitrate-containing groundwater. However, in an acidic-pH (5)-high-nitrate-containing groundwater, metal-chelating resins Diphonix and Chelex-100 removed more uranium than anion-exchange resins. In 15 m L of acidic-pH (5)-high-nitrate-containing groundwater spiked with 20 mg L(-1) uranium, the uranium concentrations ranged from 0.95 mg L(-1) at 1-h equilibrium to 0.08 mg L(-1) at 24-h equilibrium for Diphonix and 0.17 mg L(-1) at 1-h equilibrium to 0.03 mg L(-1) at 24-h equilibrium for Chelex-100. Chelex-100 removed more uranium in the first 10 min in the 100mL of acidic-(pH 5)-high-nitrate-containing groundwater ( approximately 5 mg L(-1) uranium); however, after 10 min, Diphonix equaled or out-performed Chelex-100. This study presents an improved understanding of the selectivity and sorption kenetics of a range of ion-exchange resins that remove uranium from both low- and high-nitrate-containing groundwaters with varying pHs.

Distribution of uranium contamination in weathered fractured saprolite/shale and ground water.

The objective of this study was to determine how structure, stratigraphy, and weathering influence fate and transport of contaminants (particularly U) in the ground water and geologic material at the Department of Energy (DOE) Environmental Remediation Sciences Department (ERSD) Field Research Center (FRC). Several cores were collected near four former unlined adjoining waste disposal ponds. The cores were collected, described, analyzed for U, and compared with ground water geochemistry from surrounding multilevel wells. At some locations, acidic U-contaminated ground water was found to preferentially flow in small remnant fractures weathering the surrounding shale (nitric acid extractable U [U(NA)] usually < 50 mg kg(-1)) into thin (<25 cm) Fe oxide-rich clayey seams that retain U (U(NA) 239 to 375 mg kg(-1)). However, greatest contaminant transport occurs in a 2 to 3 m thick more permeable stratigraphic transition zone located between two less permeable, and generally less contaminated zones consisting of (i) overlying unconsolidated saprolite (U(NA) < 0.01 to 200 mg kg(-1)) and (ii) underlying less-weathered bedrock (U(NA) generally < 0.01 to 7 mg kg(-1)). In this transition zone, acidic (pH < 4) U-enriched ground water (U of 38 mg L(-1)) has weathered away calcite veins resulting in greater porosity, higher hydraulic conductivity, and higher U contamination (U(NA) 106 to 745 mg kg(-1)) of the weathered interbedded shale and sandstone. These characteristics of the transition zone produce an interval with a high flux of contaminants that could be targeted for remediation.

Phylogenetic and functional biomakers as indicators of bacterial community responses to mixed-waste contamination.

Few studies have demonstrated changes in community structure along a contaminant plume in terms of phylogenetic, functional, and geochemical changes, and such studies are essential to understand how a microbial ecosystem responds to perturbations. Clonal libraries of multiple genes (SSU rDNA, nirK, nirS, amoA, pmoA, and dsrAB) were analyzed from groundwater samples (n = 6) that varied in contaminant levels, and 107 geochemical parameters were measured. Principal components analyses (PCA) were used to compare the relationships among the sites with respect to the biomarker (n = 785 for all sequences) distributions and the geochemical variables. A major portion of the geochemical variance measured among the samples could be accounted for by tetrachloroethene, 99Tc, No3, SO4, Al, and Th. The PCA based on the distribution of unique biomarkers resulted in different groupings compared to the geochemical analysis, but when the SSU rRNA gene libraries were directly compared (deltaC(xy) values) the sites were clustered in a similar fashion compared to geochemical measures. The PCA based upon functional gene distributions each predicted different relationships among the sites, and comparisons of Euclidean distances based upon diversity indices for all functional genes (n = 432) grouped the sites by extreme or intermediate contaminant levels. The data suggested that the sites with low and high perturbations were functionally more similar than sites with intermediate conditions, and perhaps captured the overall community structure better than a single phylogenetic biomarker. Moreover, even though the background site was phylogenetically and geochemically distinct from the acidic sites, the extreme conditions of the acidic samples might be more analogous to the limiting nutrient conditions of the background site. An understanding of microbial community-level responses within an ecological framework would provide better insight for restoration strategies at contaminated field sites.

Measurement of dissolved H2, O2, and CO2 in groundwater using passive samplers for gas chromatographic analyses.

A simple in-situ passive dissolved gas groundwater sampler, comprised of a short length of silicone tubing attached to a gastight or other syringe, was adapted and tested for in-situ collection of equilibrium gas samples. Sampler retrieval after several days of immersion in groundwater allowed the direct injection of the sample onto a gas chromatograph (GC), simplifying field collection and sample handling over the commonly used "bubble stripping" method for H2 analyses. A GC was modified by sequencing a thermal conductivity (TC) detector followed by a reductive gas (RG) detector so that linear calibration of H2 over the range 0.2-200,000 ppmv was attained using a 0.5-mL gas sample; inclusion of the TC detector allowed the simultaneous quantification of other fixed gases (O2, CO2, He, and Ne) to which the RG detector was not responsive. Uptake kinetics for H2 and He indicated that the passive sampler reached equilibrium within 12 h of immersion in water. Field testing of these passive samplers revealed unusually large equilibrium gas-phase H2 concentrations in groundwater, ranging from 0.1 to 13.9%, by volume, in 11 monitoring wells surrounding four former radiological wastewater disposal ponds at the Y-12 plant in Oak Ridge, Tennessee.

Mineralogical characteristics and transformations during long-term operation of a zerovalent iron reactive barrier.

Design and operation of Fe0 permeable reactive barriers (PRBs) can be improved by understanding the long-term mineralogical transformations that occur within PRBs. Changes in mineral precipitates, cementation, and corrosion of Fe0 filings within an in situ pilot-scale PRB were examined after the first 30 months of operation and compared with results of a previous study of the PRB conducted 15 months earlier using X-ray diffraction and scanning electron microscopy employing energy dispersive X-ray and backscatter electron analyses. Iron (oxy)hydroxides, aragonite, and maghemite and/or magnetite occurred throughout the cores collected 30 mo after installation. Goethite, lepidocrocite, mackinawite, aragonite, calcite, and siderite were associated with oxidized and cemented areas, while green rusts were detected in more reduced zones. Basic differences from our last detailed investigation include (i) mackinawite crystallized from amorphous FeS, (ii) aragonite transformed into calcite, (iii) akaganeite transformed to goethite and lepidocrocite, (iv) iron (oxy)hydroxides and calcium and iron carbonate minerals increased, (v) cementation was greater in the more recent study, and (vi) oxidation, corrosion, and disintegration of Fe0 filings were greater, especially in cemented areas, in the more recent study. If the degree of corrosion and cementation that was observed from 15 to 30 mo after installation continues, certain portions of the PRB (i.e., up-gradient entrance of the ground water to the Fe0 section of the PRB) may last less than five more years, thus reducing the effectiveness of the PRB to mitigate contaminants.

Impact of sample preparation on mineralogical analysis of zero-valent iron reactive barrier materials.

Permeable reactive barriers (PRBs) of zero-valent iron (Fe(0)) are increasingly being used to remediate contaminated ground water. Corrosion of Fe(0) filings and the formation of precipitates can occur when the PRB material comes in contact with ground water and may reduce the lifespan and effectiveness of the barrier. At present, there are no routine procedures for preparing and analyzing the mineral precipitates from Fe(0) PRB material. These procedures are needed because mineralogical composition of corrosion products used to interpret the barrier processes can change with iron oxidation and sample preparation. The objectives of this study were (i) to investigate a method of preparing Fe(0) reactive barrier material for mineralogical analysis by X-ray diffraction (XRD), and (ii) to identify Fe mineral phases and rates of transformations induced by different mineralogical preparation techniques. Materials from an in situ Fe(0) PRB were collected by undisturbed coring and processed for XRD analysis after different times since sampling for three size fractions and by various drying treatments. We found that whole-sample preparation for analysis was necessary because mineral precipitates occurred within the PRB material in different size fractions of the samples. Green rusts quickly disappeared from acetone-dried samples and were not present in air-dried and oven-dried samples. Maghemite/magnetite content increased over time and in oven-dried samples, especially after heating to 105 degrees C. We conclude that care must be taken during sample preparation of Fe(0) PRB material, especially for detection of green rusts, to ensure accurate identification of minerals present within the barrier system.

Exercise rhabdomyolysis in military aircrew: two cases and a review of aeromedical disposition.

INTRODUCTION: Exercise rhabdomyolysis (ER) is a rare, sometimes catastrophic condition where muscle fibers breakdown in response to exertion and release their breakdown products into the circulation. While ER was brought to the medical community's attention largely through reports from military training establishments we are unaware of ER having resulted from the activities of military aircrew. This paper reports two cases of ER in military aircrew and discusses the condition and the approaches taken in determining their future aeromedical disposition. CASE REPORTS: Rhabdomyolysis occurred in two military pilots as a result of their aircrew duties. One, an experienced pilot, suffered rhabdomyolysis as a result of centrifuge based G-training, while the other, a cadet in training, suffered rhabdomyolysis precipitated by exertion during moderately warm weather. Further investigation revealed the second case to also have the Malignant Hyperthermia Trait. AEROMEDICAL DISPOSTION: After wide consultation and lengthy deliberations both of these aircrew were returned to their full previous flying status. No further complications or recurrences have occurred.

Effect of normobaric hypoxia on sound localization.

BACKGROUND: Three-dimensional (3D) audio displays have considerable potential for conveying spatial information in the aviation environment. How reliably these displays will function in that environment will depend in part on the extent to which sound localization is affected by hypoxia. Many aircraft systems operators are routinely exposed to mild hypoxia, and all are at risk of exposure to more severe hypoxia. METHODS: We have examined hypoxia's effect on localization by measuring the localization performance of four subjects exposed to simulated altitudes of 0, 1200, 2400 and 3700 m above sea level for about 30 min. Sounds to be localized were presented from a free-field source at locations covering 360 degrees of azimuth and extending from -47.6 to + 80 degrees elevation. RESULTS: Localization performance was statistically indistinguishable across the altitudes tested. Average localization errors ranged from 12.6 degrees +/- 0.7 SE at 2400 m to 14 degrees +/- 0.84 SE at 0 m. CONCLUSION: The finding that hypoxia induced by exposure to simulated altitudes as high as 3700 m has no effect of sound localization is encouraging with respect to the continued development of 3D audio displays for use in the aviation environment.

Effect of normobaric hypoxia on auditory sensitivity.

Previous psychophysical studies of hypoxia's effects on auditory sensitivity have provided mixed results but the weight of evidence supports the conclusion that sensitivity is unaffected by hypoxia. This conclusion is discrepant with that drawn from physiological studies in which hypoxia has been found to affect auditory-evoked response (AER) latency. One possible explanation of this discrepancy concerns the relatively low maximum frequency (8 kHz) for which hypoxia's effects were assessed in the psychophysical studies. We have extended the range of frequencies over which hypoxia's effects have been examined to include frequencies up to 16 kHz. Thresholds for 1-, 8-, 10-, 12-, 14- and 16-kHz tones were measured at levels of hypoxia equivalent to altitudes of 0, 1,200, 2,400 and 3,700 m. Our results indicate that sensitivity for frequencies up to 16 kHz is unaffected by hypoxia. We suggest that AER latency does not provide a valid measure of auditory sensitivity.

Peptide capillary zone electrophoresis mass spectrometry of recombinant human erythropoietin: an evaluation of the analytical method.

An evaluation of capillary zone electrophoresis-mass spectrometry (CZE-MS) as an analytical methodology for the separation and characterization of complex glycopeptides and nonglycopeptide structures has been performed. The evaluation employed endoproteinase V8 digested recombinant human erythropoietin (rHuEPO) that was further fractionated by reverse phase chromatography. The peptides were subjected to sequence analysis and evaluated by capillary electrophoresis, with or without mass detection, for peptide purity. The peptide mass determined from the sequence was then compared to the mass obtained from CZE-MS. Glycosylation sites and carbohydrate branch patterns were easily determined, site specific microheterogeneity (either O-acetylation of N-acetylneuraminic acids or lactosamine extensions of the carbohydrate chain length) was assessed directly, glycosylation site occupancy was evaluated qualitatively, and nonglycopeptides were resolved and analyzed on-line with ease. Incomplete peptide digestion products were detected and identified by CZE-MS. Protein sequence coverage by CZE-MS was 98.2 percent complete from a single map. Off-line evaluation of peptide purity by CZE greatly aided the interpretation of multiple sequence analysis and, in validating that, the CZE-MS was detecting all peptides present. All off-line CZE and on-line CZE-MS experiments employed a capillary that was dynamically coated with Polybrene in the presence of polyethylene glycol; separations were conducted in 0.67 M formic acid.

Accuracy of two pulse oximeters during maximal cycling exercise.

This study compared the measurement of oxygen saturation of haemoglobin (SaO2) by two pulse oximeters (Ohmeda Biox 3700e and Criticare 504 USP) with the measurement of SaO2 in arterial blood samples by CO-oximetry. Unlike many previous validation studies, arterial blood was sampled in ground glass rather than plastic syringes. Twenty men, 11 well-trained cyclists (mean +/- SE, age = 23.3 +/- 1.5 years, mass = 71.4 +/- 1.1 kg VO2max = 77 +/- 1 ml.kg1.min-1) and 9 relatively untrained subjects (age = 27.1 +/- 2.8 years, mass = 78.1 +/- 2.2 kg VO2max = 51 +/- 3 ml.kg 1.min-1) performed two maximal cycle ergometer tests each in an hypobaric chamber. The tests were at 745 mm Hg or 695 mm Hg with simultaneous measurement of SaO2 by the pulse oximeters and the CO-oximeter at rest, minute 7 of exercise and at VO2max. The best correlations, to the Co-oximeter measurement (SCO-OXO2) were found when all data from rest and exercise were combined (Criticare: r = 0.94; Ohmeda: r = 0.91). The bias measurements showed the Ohmeda underestimated SCO-OXO2 at all levels (mean = -2.5 +/- 1.9%) and the Criticare overestimated SCO-OXO2 at all levels, although to a lesser degree (mean = 0.9 +/- 1.5%). In conclusion, these results highlight the need for validation of individual pulse oximeters and that the effect of dyshaemoglobins must also be considered.

Reduced performance of male and female athletes at 580 m altitude.

This study examined the effect of mild hypobaria (MH) on the peak oxygen consumption (VO2peak) and performance of ten trained male athletes [x (SEM); VO2peak = 72.4 (2.2) ml x kg(-1) x min(-1)] and ten trained female athletes [VO2peak = 60.8 (2.1) ml x kg(-1) x min(-1)]. Subjects performed 5-min maximal work tests on a cycle ergometer within a hypobaric chamber at both normobaria (N, 99.33 kPa) and at MH (92.66 kPa), using a counter-balanced design. MH was equivalent to 580 m altitude. VO2peak at MH decreased significantly compared with N in both men [-5.9 (0.9)%] and women [-3.7 (1.0)%]. Performance (total kJ) at MH was also reduced significantly in men [-3.6 (0.8)%] and women [-3.8 (1.2)%]. Arterial oxyhaemoglobin saturation (SaO2) at VO2peak was significantly lower at MH compared with N in both men [90.1 (0.6)% versus 92.0 (0.6)%] and women [89.7 (3.1)% versus 92.1 (3.0)%]. While SaO2 at VO2peak was not different between men and women, it was concluded that relative, rather than absolute. VO2peak may be a more appropriate predictor of exercise-induced hypoxaemia. For men and women, it was calculated that 67-76% of the decrease in VO2peak could be accounted for by a decrease in O2 delivery, which indicates that reduced O2 tension at mild altitude (580 m) leads to impairment of exercise performance in a maximal work bout lasting approximately 5 min.

Increased arterial desaturation in trained cyclists during maximal exercise at 580 m altitude.

This study utilized a hypobaric chamber to compare the effects of mild hypobaria (MH; 50 mmHg, approximately 580 m altitude) on blood O2 status and maximal O2 consumption (VO2max) in 9 untrained and 11 trained (T) cyclists with VO2max values of 51 +/- 3 and 77 +/- 1 ml.kg-1.min-1, respectively. In both groups, arterial O2 saturation (SaO2) decreased significantly during maximal exercise, and this effect was enhanced with MH. Both these responses were significantly greater in the T cyclists in whom the final SaO2 during MH was 86.5 +/- 0.9%. When the group data were combined, approximately 65% of the variance in SaO2 could be attributed to a widened alveolar-arterial Po2 difference. The arterial PO2 during maximal exercise at sea level in the T group was on the steeper portion of the hemoglobin-O2-loading curve (T, 68.3 +/- 1.3 Torr; untrained, 89.0 +/- 2.9 Torr) such that a similar decrease in arterial PO2 in the two groups in response to MH resulted in a significantly greater fall in both SaO2 and calculated O2 content in the T group. As a consequence, the VO2max fell significantly only in the T group (mean change, -6.8 +/- 1.5%; range, + 1.2 to - 12.3%), with approximately 70% of this decrease being due to a fall in O2 content. This is the lowest altitude reported to decrease VO2max, suggesting that T athletes are more susceptible to a fall in inspired PO2.

In vitro growth of B lymphocytes infiltrating human melanoma tissue by transformation with EBV: evidence for secretion of anti-melanoma antibodies by some transformed cells.

Epstein Barr virus was used to transform the B lymphocytes infiltrating metastatic tumor tissue from seven patients with melanoma. In this way it was possible to establish continuously growing B lymphoblastoid cell lines (LCL) derived from the tumor-infiltrating B lymphocytes from each of the seven patients. Antibody production of up to 50 micrograms/ml could be achieved by such cultures, and the lymphoblastoid cells could be cloned readily by limit dilution on a feeder layer of irradiated fetal fibroblasts. Preliminary analysis of the antibodies produced by lymphoblastoid cell lines established from tumors from two of the patients indicated that most were of IgM type and bound to a panel of melanoma cell target cells, as well as to some nonmelanoma tumor cell lines. Cloned LCL were produced from the tumor-infiltrating B cells from one of the patients, and of 100 such clones tested, 9% secreted antibody that bound to autologous tumor cells, and one of these clones produced antibody that appeared to be melanoma specific.