High Chloride Levels Research Articles

Groundwater Plume Mapping in a Submerged Sinkhole in Lake Huron

A multidisciplinary exploratory project team from the Institute for Exploration, the Great Lakes Environmental Research Laboratory, Grand Valley State University, and the University of Michigan located and explored a submerged sinkhole in Lake Huron during September 2003. A CTD system and an ultra-short baseline (USBL) acoustic navigational tracking system integrated with an open frame remotely operated vehicle (ROV) provided high-resolution depth, temperature, and conductivity maps of the sinkhole and plume. Samples were also peristaltically pumped to the surface from a depth of 92 meters within and outside of the sinkhole plume. A 1-2 m thick cloudy layer with a strong hydrogen sulfide odor characterized the water mass close to the plume. Relative to ambient lake water, water samples collected within this layer were characterized by slightly higher (4-7.5 °C) temperatures, very high levels of chloride and conductivity (10-fold) as well as extremely high concentrations of organic matter (up to 400 mg C/L), sulfate, and phosphorus. Our observations demonstrated the occurrence of unique biogeochemical conditions at this submerged sinkhole environment.

Sensitive quantification of iodide by ion-exchange chromatography with electrochemical detection at a modified platinum electrode

A rapid and very sensitive method for the accurate determination of free iodide in real samples is described. The method is based on anion-exchange chromatographic separation coupled with amperometric detection at a modified platinum electrode under constant applied potential (+0.85 V vs. Ag AgCl). An experimental setup with an in-line and very effective method of electrode modification is proposed using an amperometric thin-layer cross-flow detector and a flowing solution 300 mg/L of iodide; the working electrode is polarised to the limiting current for oxidation of iodide to iodine in acidic solutions with the consequent formation of an iodine-based film. The results indicated that the modified electrode exhibits high analytical response for iodide electrooxidation with good stability and long-life. The signal intensity of daily experimental sessions (8 h), during which standards and real samples were repeatedly injected, exhibits a moderate lowering (i.e. < 6%). Using a mixture of 25 mM HNO3 and 50 mM NaNO3 as an eluent phase in ion-exchange chromatography, the detection limit of iodide was estimated to be 0.5 microg/L (S/N = 3) with an injection volume of 50 microL. This method was applied successfully to quantify the iodide content of milk samples and in wastewaters as well as trace amounts in common vegetables and solutions containing high chloride levels.

Efeito do nível energético e da suplementação com cloretos de potássio e de amônia na dieta sobre as respostas fisiológicas e o desempenho de frangos de corte no verão

Realizou-se este estudo com o objetivo de verificar o efeito do nível energético da ração e da suplementação com cloretos de potássio e de amônia na dieta de frangos de corte no verão. Foram utilizados 240 frangos machos, Hubbard, com peso médio inicial de 1204 g, distribuídos num delineamento inteiramente casualizado, em esquema fatorial 2 x 3 x 2, 2 níveis de KCl (0,0% e 1,2%) x 3 níveis de NH4Cl (0,0%, 0,2% e 0,4%) x 2 níveis de energia (3000 e 3200 Kcal EM/kg de ração), com 4 repetições de 5 aves por repetição. O índice de temperatura do globo negro e umidade (ITGU), observado às 9 horas e 15 horas foi de 76 e 83, respectivamente. Houve interação (P&lt;0,01) do KCl com NH4Cl para a temperatura superficial. O nível energético da ração afetou (P&lt;0,01) a temperatura superficial no turno da tarde. Para a temperatura retal, freqüência respiratória, pH do sangue e o desempenho não se verificou efeito (P&gt;0,05) dos fatores estudados. A ingestão de água aumentou (P&lt;0,05) com a adição de KCl. Para a conversão alimentar houve melhora (P&lt;0,05) com a elevação do nível energético e piora (P&lt;0,05) com o nível mais elevado de cloreto de amônia. Houve interação (P&lt;0,05) entre o KCl e o nível energético da ração para o consumo de ração. Concluiu-se que, nas condições deste experimento, os fatores estudados não afetam a temperatura retal, freqüência respiratória, pH sanguíneo nem o desempenho de frangos de corte. Porém, a conversão alimentar melhora com a elevação do nível energético da ração e piora com a adição de cloreto de amônia à dieta em nível alto.

Latex-Coated Polymeric Monolithic Ion-Exchange Stationary Phases. 1. Anion-Exchange Capillary Electrochromatography and In-Line Sample Preconcentration in Capillary Electrophoresis

A sulfonated methacrylate monolithic polymer has been synthesized inside fused-silica capillaries of diameters 50-533-microm i.d. and coated with 65-nm-diameter fully functionalized quaternary ammonium latex particles (AS18, Dionex Corp.) to form an anion-exchange stationary phase. This stationary phase was used for ion-exchange capillary electrochromatography of inorganic anions in a 75-microm-i.d. capillary with Tris/perchlorate electrolyte and direct UV detection at 195 nm. Seven inorganic anions (bromide, nitrate, iodide, iodate, bromate, thiocyanate, chromate) could be separated over a period of 90 s, and the elution order indicated that both ion exchange and electrophoresis contributed to the separation mechanism. Separation efficiencies of up to 1.66 x 10(5) plates m(-1) were achieved, and the monoliths were stable under pressures of up to 62 MPa. Another latex-coated monolith in a 250-microm-i.d. capillary was used for in-line preconcentration by coupling it to a separation capillary in which the EOF had been reversed using a coating of either a cationic polymer or cationic latex particles. Several capillary volumes of sample were loaded onto the preconcentration monolith, and the analytes (inorganic anions) were then eluted from the monolith with a transient isotachophoretic gradient before being separated by electrophoresis in the separation capillary. Linear calibration curves were obtained for aqueous mixtures of bromide, nitrite, nitrate, and iodide. Recoveries of all analytes except iodide were reduced significantly when the sample matrix contained high levels of chloride. The preconcentration method was applied to the determination of iodide in open ocean water and provided a limit of detection of 75 pM (9.5 ng/L) calculated at a signal-to-noise ratio of 3. The relative standard deviation for migration time and peak area for iodide were 1.1 and 2.7%, respectively (n = 6). Iodide was eluted as an efficient peak, yielding a separation efficiency of 5.13 x 10(7) plates m(-1). This focusing was reproducible for repeated analyses of seawater.

Influence of the Environment on the Atmospheric Corrosion of Bronze

This paper presents a comparative study of the atmospheric corrosion of bronze samples exposed for 12 months, at two sites: an urban atmosphere with intense traffic, in the city of Lisbon, and a rural marine atmosphere, Cabo da Roca, with a high degree of humidity, strong winds and high levels of chlorides all the year round. Exposures were started in the summer. Levels of SO2, NO2 and chlorides, in both atmospheres, were measured during the period of exposure. Climatic data for both sites was also collected and analysed. Weight losses and weight gains of samples with 4, 6, 8 and 12 months of exposure were measured and the average corrosion rates calculated. Chemical composition and morphology of the patinas formed during the exposure period, at both sites, were compared as well as the morphology of the corroded surfaces. Significant differences, related to the level of pollutants and meteorological variables, were found.

Removal of Chloride in the Kraft Chemical Recovery Cycle of Pulp Mills Using the Ion-Exchange Process

High levels of chloride in the kraft recovery cycle of pulp mills can cause serious problems, particularly in recovery boiler operation. The treatment of ash collected from the electrostatic precipitator (ESP) for chloride removal was investigated experimentally using the ion-exchange process based on an amphoteric resin (BIORAD AG 11 A8). Saturation and regeneration experiments in a fixed bed were carried out for different flow rates. Experimental adsorption results obtained in the saturation step were well predicted with a mathematical model that takes into account dispersed plug flow for the bulk liquid, external mass-transfer resistance, intraparticle mass transfer by pore diffusion, and instantaneous equilibrium of adsorption at the pore/wall interface. The equilibrium was modeled using an extended Langmuir−Freundlich isotherm for three components (Cl-, SO42-, and CO32-) based on single-component equilibrium data. The resin performance was tested during cyclic operation, in which a chloride removal e...

Determination of nitrate and nitrite in rat brain perfusates by capillary electrophoresis.

A fast and simple method for the direct, simultaneous detection of nitrite (NO(2) (-)) and nitrate (NO(3) (-)) in rat striatum has been developed using a capillary electrophoresis separation of low-flow push-pull perfusion samples. The method was optimized primarily for nitrite because nitrite is more important physiologically and is found at lower levels than nitrate. We obtained a complete separation of NO(2) (-) and NO(3) (-) in rat striatum within 1.5 min. Optimal CE separations were achieved with 20 mM phosphate, 2 mM cetyltrimethylammonium chloride (CTAC) buffer at pH 3.5. The samples were injected electrokinetically for 2 s into a 40 cm x 75 microm ID fused-silica capillary. The separation voltage was 10 kV (negative polarity), and the injection voltage was 16 kV (negative polarity). UV detection was performed at 214 nm. The limits of detection obtained at a signal-to-noise ratio (S/N) of 3 for nitrite and nitrate were 0.96 and 2.86 microM. This is one of the fastest separations of nitrite and nitrate of a biological sample ever reported. Interference produced by the high physiological level of chloride is successfully minimized by use of CTAC in the run buffer.

The laboratory investigation of concrete affected by TSA in the UK

Abstract Procedures that have been successfully employed by Geomaterials Research Services Ltd. in the determination of the distribution of the thaumasite form of sulfate attack (TSA) in concrete samples taken from bridge and other motorway structures throughout the UK are described. Electron microprobe analysis has been used to provide confirmation of the presence of thaumasite and to investigate the distribution of sulfate compounds including gypsum and ettringite in cement paste at the surfaces of concrete affected by sulfate attack. Electron microprobe analysis has the advantage that it is capable of detecting very small quantities of thaumasite. Electron microprobe analysis used in conjunction with petrographic analysis is regarded as the most effective tool for the diagnosis of TSA and other forms of sulfate attack. The analysis of numerous cores taken from bridge foundations throughout the UK shows that the development of TSA is often accompanied by the formation of calcium carbonate in cement paste. High levels of chloride in the cement paste of TSA damaged concrete suggest the importance of run-off moisture as a contributory factor in the development of TSA.

Photo‐induced Hg(II) reduction in snow from the remote and temperate Experimental Lakes Area (Ontario, Canada)

This paper reports a net snow‐to‐air Hg transfer from the remote and temperate Experimental Lakes area (Ontario, Canada). More than 40% loss of total Hg concentration was observed in surface snow within 24 hours of its deposition on the ground. Stratigraphic profiles of total Hg in various snowpacks demonstrated a systematic decrease in total Hg concentration with snow depth pointing to snow‐to‐air Hg transfer and not snow‐to‐ground transfer. These results confirm observations made in a suburban area (Sainte‐Foy, Quebec, Canada) receiving higher atmospheric deposition of Hg perhaps differently associated chemically. The occurrence of this phenomenon is therefore extended geographically to include snow from pristine regions. It is hypothesized that the loss of Hg is caused by a sunlight‐initiated Hg(II) reduction in snow and subsequent gas transfer of Hg0 to the atmosphere. Polychromatic action spectra demonstrated that Hg(II) reduction in snow was mostly mediated by UV‐B irradiation and not visible, or UV‐A wavelengths. In addition to Hg(II) reduction in snow, we observed Hg0 oxidation in snow samples spiked with Cl−. Hg0 oxidation could limit the potential for Hg loss from snowpacks from coastal polar or subpolar regions (where snow often contains high chloride levels) by competing with Hg(II) reduction and slowing the snow‐to‐air Hg transfer. However, in regions under minimal marine influences, watershed budgets of Hg should consider the possibility of Hg loss from snow with time of deposition on the ground. Also, snow core studies should consider historic sunlight irradiation if extrapolation from snow cores is desired to estimate past ambient Hg levels.

Improved Electrochemical Determinations of Chloride-Induced Steel Corrosion in Concrete

A significant amount of infrastructure is located in a marine environment or in environments where high levels of chloride are present. Current specification methods are generally lacking in regard to predicting service life of reinforced concrete (RC) structures in aggressive environments and qualitative judgments are typically used to make predictions concerning service life. Much research has focused on prediction of chloride diffusion coefficients where more quantitative links to service life can be established. The problem with such techniques is that assumptions of the chloride threshold level for steel depassivation must be made, and this introduces generally unacceptable levels of uncertainty for asset owners. One approach appears to lie in improving the understanding of the electrochemical behavior of steel in concrete such that more accurate predictions of service life can be derived in the future. Work presented in this paper relates to the analysis of a significant amount of data on electrochemical corrosion rates of steel in concrete.

Corrosion inhibitor systems for remedial treatment of reinforced concrete. Part 1: calcium nitrite

Laboratory investigations were performed to assess the efficacy of calcium nitrite as an inhibitor when used in surface treatments applied to reinforced concrete specimens that were chloride contaminated to varying extents in the presence or absence of carbonation. The corrosion responses of embedded steel bars at various depths of cover were monitored electrochemically during a controlled programme of cyclic wetting and drying undertaken for several months prior to the inhibitor treatment and for approximately 18 months thereafter. On completion of the exposure tests, measurements of corrosion weight losses and their distribution on the steel surfaces were also made. In non-carbonated specimens with high levels of internal chloride and carbonated specimens with even low levels of internal chloride, the surface-applied inhibitor treatment appeared to be ineffective under the conditions of the experiments and enhancement of local corrosion rates was observed in some specimens.

Acute exposure of Siberian sturgeon ( Acipenser baeri, Brandt) yearlings to nitrite: median-lethal concentration (LC 50) determination, haematological changes and nitrite accumulation in selected tissues

Exposure of Siberian sturgeon ( Acipenser baeri) yearlings (172.0±18 g; mean±S.D.) to several NO 2 −–N concentrations (0, 25, 130, 180 and 275 mg/l) was studied for 72 h in static tests. At 72 h, the median-lethal concentration of NO 2 −–N was 130 mg/l in water with high chloride content (130.5 mg/l). Nitrite exposure produced high levels of methaemoglobin (MetHb) but did not seem to cause mortality, as surviving fish showed higher levels (82.7±5.6%) than torpid specimens (60.8±4.5%). Levels of MetHb were unrelated to environmental and plasmatic nitrite concentrations, as both torpid and surviving fish exposed to the highest nitrite levels (275 mg/l of NO 2 −–N) presented similar concentrations of MetHb to those exposed to 25 mg/l of NO 2 −–N, thus indicating the ability of Siberian sturgeon yearlings to regulate plasmatic nitrite levels and maintain them lower than the environmental concentration of the toxicant. Nitrite exposure caused changes in the plasmatic electrolyte balance, which is characterised by extracellular hyperkalemia, high plasmatic chloride levels and low plasmatic sodium concentration. Differences between the nitrite concentration in the liver of torpid (46.3±9.0 mg/l) and surviving specimens (19.1±13.1 mg/l) exposed to several concentrations of NO 2 −–N suggest a significant contribution of the liver in nitrite detoxification pathways, and would thus explain a possible nitrite tolerance of Siberian sturgeon yearlings.

Effect of inorganic N on the population, in vitro colonization and morphology of Acetobacter diazotrophicus (syn. Gluconacetobacter diazotrophicus )

We investigated whether Acetobacter diazotrophicus (syn.Gluconacetobacter diazotrophicus) could be recovered only from sugarcane plants either with low or no application of fertiliser N. We report here the enrichment and enumeration of A. diazotrophicus from high N-fertilised samples where high heterotrophic populations reduce the numbers of A. diazotrophicus ultimately diminshing its isolation frequency as reported earlier. The growth medium of micropropagated sugarcane seedlings of the varieties Co 8021, Co 86249, Co 86010, Co 86032, and Co 87025 was amended with potassium nitrate, ammonium nitrate, ammonium chloride and urea. The colonisation and AR activity of A. diazotrophicus were affected in the presence of high levels (25 mM) of ammonium chloride and ammonium nitrate but remained unaffected in low levels of N (i.e 1/10th of MS liquid medium) and with high levels of potassium nitrate (25 mM) and urea (500 ppm). A. diazotrophicus was detected in the inoculated plants both at low and high levels of N based on the amplification of a specific 16S rRNA gene fragment using PCR based method targeting a stretch of 445 bp with primers AC and DI. High levels of N in the growth medium induced morphological changes on A. diazotrophicus cells resulting in long pleomorphic cells. The percentage of pleomorphic cells was in the decending order from NH4NO3, NH4Cl, KNO3, and urea. These changes were more prominent in ammonium chloride and ammonium nitrate than potassium nitrate, urea and N free medium. The morphological changes and the increased heterotrophic populations may play a role on the survival ofA. diazotrophicus in high N-fertilised samples/environments.

Disease severity associated with cystic fibrosis mutations delta F508 and S549R [T-G

We compared the clinical severity associated with the two cystic fibrosis [CF] mutations S549R [T [R] G] and deltaF508. Clinical and biochemical variables of CF were compared in two age- and sex-matched groups of CF children in the United Arab Emirates [UAE]. The clinical severity of mutations S549R [T [R] G] and delta F508 showed comparable patterns, with very low Shwachman scores and high sweat chloride levels. We conclude that patients homozygous for the CF mutations deltaF508 and S549R [T [R] G] have a severe clinical presentation and illness and are indistinguishable on clinical grounds.

Retention of inorganic oxyanions by organo-kaolinite

A natural kaolinite (KGa-1b) was treated with the surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) to a level twice that of the cation exchange capacity (CEC). Sorption of nitrate, arsenate, and chromate by the resultant organo-kaolinite was then quantified. Sorption of each oxyanion was well-described by the Langmuir isotherm. Sorption of nitrate was the greatest, with a Langmuir sorption maximum of 24 mmol/kg, although chromate showed the highest sorption affinity of 20 L/kg. Sorption of nitrate, arsenate, and chromate on organo-kaolinite was at least two orders of magnitude greater than their sorption on unmodified kaolinite. Desorption of the bromide counterion indicated that each of the oxyanions was retained by ion exchange on an HDTMA bilayer formed on the organo-kaolinite. Chromate sorption on the organo-kaolinite was unaffected by solution pH in the range 5–9, but decreased at pH 11 due to competition of OH − for anion exchange sites. Similarly, chromate exchange by organo-kaolinite was reduced in the presence of high background levels of chloride. Chromate was effectively retained when flowing through a packed bed of organo-kaolinite: after an input of more than 40 pore volumes, the effluent concentration of chromate was less than 10% of the input concentration, and 90% of the original HDTMA remained on the organo-kaolinite. The results demonstrate that properly prepared organoclays can remove oxyanions, as well as nonpolar organics, from contaminated waters.

Reductive Dehalogenation of Chlorinated Ethenes with Elemental Iron: The Role of Microorganisms

Trichloroethne (TCE) transformation and the product distribution in an aqueous medium containing zero-valent iron (Fe(0)) was investigated in the presence of an anaerobic mixed culture to assess the potential role of microorganisms in permeable iron barriers. The presence of the culture increased the rate of TCE disappearance and changed the product distribution. Rapid formation and degradation of cis-dichloroethene ( cis-DCE) was observed in reactors containing cells plus Fe(0) or H 2 as a bulk reducing agent. High levels of vinyl chloride (VC) were formed and very similar profiles were obtained in the Fe(0) plus cell and H 2 plus cell reactors, but not in Fe(0)-only reactors. The similar trends observed in Fe(0)–cell and H 2–cell reactors suggest that most cis-DCE and VC in the Fe(0)–cell reactors were produced and transformed biologically rather than abiotically. Accumulation of methane in the Fe(0)–cell system indicates that hydrogen gas generated during anaerobic iron corrosion could support a methanogenic culture. Digital confocal images showed that the microorganisms were able to colonize the iron surface. The results suggest that potential development of dechlorinating populations in Fe(0) barriers may alter the TCE reduction pathway and produce VC, which would have significant impact on the performance of Fe(0) barriers.

Agénésie déférentielle bilatérale et hernie inguinale chez un enfant. Une présentation précoce rare de la mucoviscidose

Epididymal and ductal anomalies can be discovered incidentally during inguinal herniorraphy in children. The congenital bilateral absence of vas deferens is frequently associated with cystic fibrosis. Case report. – This agenesia of vas deferens was detected in a 5-month-old boy who underwent an inguinal herniorraphy. Although the child did not present any symptoms, he actually presented cystic fibrosis: the sudoral test showed high levels of chloride (95 mmol/L) and an isolated homozygous delta F 508 deletion on the gene CFTR was evidenced on genetic investigations. Conclusion. – The congenital bilateral absence of vas deferens is the most frequent anomaly of the male genital tract discovered in adults investigated for azoospermia. Relations with cystic fibrosis are well established but congenital bilateral absence of vas deferens discovered during infancy is an exceptional situation that requires genetic investigations to show evidence of a likely underlying cystic fibrosis.

Oil production, agriculture, and groundwater quality in the southeastern Gulf Coast Aquifer, Texas.

Associations between groundwater quality and land use were evaluated in the southeastern Gulf Coast Aquifer, Texas. Data from 19234 oil/gas wells and 256 water wells were mapped with a geographic information system (GIS) and statistically analyzed. Water wells near oil/gas wells had significantly higher levels of chloride, bromide, and total dissolved solids (TDS). Bromide-chloride ratios were also higher at water wells near oil/gas wells. Shallower water wells had significantly higher chloride, bromide, TDS, and nitrate concentrations. Nitrate concentrations were higher beneath cropland compared to other land uses. Results of this study suggest that oil/gas production and agriculture have impacted water quality in the Gulf Coast Aquifer.

Contrasted dynamics of nitrate and chloride in groundwater submitted to the influence of a hedge

The groundwater close to a bottomland hedge presented strong vertical and lateral gradients of nitrate and chloride concentrations. The strong transpiration by trees in summer and the dissymmetry of the root development induced persistent high chloride level in depth upslope from the hedge. Nitrate concentration, on the other hand, decreased sharply in the same area, taken up by the vegetation or denitrified by the microorganisms, whose activity was enhanced at the bottom of the hedge. Au voisinage d'une haie de ceinture de fond de vallée, la nappe présente de forts gradients latéraux et verticaux des concentrations en chlorure et en nitrate. La forte transpiration des arbres de la haie en été et la dissymétrie du développement racinaire conduisent à un enrichissement persistant en chlorure en amont de la haie, en profondeur. Le nitrate, en revanche, disparaı̂t durablement dans cette même zone, absorbé par les arbres et/ou dénitrifiés par les micro-organismes, dont l'activité est favorisée au pied de haie.

Clinical, urodynamic and endoscopic characteristics of the stanford pouch ileal neobladder constructed with absorbable staples.

The clinical, urodynamic and endoscopic aspects of the Stanford pouch ileal neobladder formed with absorbable staples were investigated. A Stanford pouch ileal neobladder was formed using absorbable staples after radical cystoprostatectomy in 30 male patients with the diagnosis of muscle invasive carcinoma of the bladder between 1995 and 1998. The mean age of the patients was 62 (range 41-70) years. Patients were followed with arterial blood gas, serum biochemistry, pouch cystography, urodynamic tests and endoscopy. Five (16.7%) patients had early postoperative complications and three were related to the neobladder. One year postoperatively, low grade (I, II) vesicoureteral reflux was present in five (16.7%) cases. The mean preoperative and 6 months postoperative serum creatinine levels were 1.07+/-0.3 mg/dL and 1.2+/-0.4 mg/dL, respectively, but the difference was not statistically significant (P=0.1). Six months postoperatively the mean serum chloride level was 109+/-4.5 (range 100-113) mmol/L and the mean arterial blood pH was 7.37+/-0.2 (range 7.3-7.4). Two (6.7%) patients required oral alkaline supplementation because of high chloride levels. All the patients except one were continent throughout the day after 1 year. However, nocturnal enuresis was present in 25 (83.3%) cases. The pouch capacity was increased gradually up to 12 months postoperatively and the mean pouch capacity 12 months postoperatively was 460+/-95.8mL. Micturition occurred spontaneously in most patients while some needed abdominal straining. None of the patients had a residual urine of more than 60 mL. The mean maximum flow rate 6 months postoperatively was 9.8 (range 5.4-15.0) mL/s. After 6 months the stapled edge was noticed as a nodular line. One year postoperatively only a white scar could be observed at the suture line. The Stanford pouch ileal neobladder constructed using absorbable staples was able to provide a good capacity low pressure reservoir with a low rate of complications.