bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Optimal Toxicant Loading for Biological Closure of a Hazardous Waste Site
Authors: Bianchini MA , Portier RJ , Fujisaki K , Henry CB , Templet PH , Matthews JE
Published: February 2009

Information will be presented on Phase I and Phase II of a multitask effort to achieve biological closure of an abandoned hazardous waste site on the Mississippi River. Waste materials, consisting primarily of aliphatic and polycyclic aromatic hydrocarbons in the form of buried sludges and lagoon wastes, were examined. Optimal loading levels were evaluated on the basis of biodegradative potential tests and acute toxicity of leachate. Microbial adenosine 5a triphosphate (ATP) and microbial diversity were used in conjunction with Microtox™ tests to establish an acceptable land treatment experimental design. Methodology is presented on ascertaining optimal waste loading rates, based on percent oil and grease, for both laboratory mesocosm and field plots. Microbial ATP data indicated that both waste types stressed the indigenous microbial populations through Day 10. However, the microbial population showed recovery by Day 17. Lagoon wastes, applied at 4 and 8%, showed minimal stress and high microbial ATP levels by Day 17. Buried wastes showed comparable results for 2 to 4% waste loadings at Day 17. Microbial diversity indices confirmed ATP estimates, which suggested a maximum loading rate of 8% for lagoon wastes and 2 to 4% for buried wastes. EC50 levels of leachates predicted 3.0 to 9.0% waste weight (wet basis) for lagoon waste and 3.0 to 6% waste weight (wet basis) for the buried waste. A loading rate of 4% for lagoon waste and 2.5% for buried waste was selected as the acceptable mean loading rate. Gas chromatography/mass spectroscopy (GC/MS) data in subsequent Phase II studies (mesocosms) documented significant biotransformation and biodegradation of the wastes at these optimized loading rates.
Enhanced Biotransformation and Biodegradation of Polychlorinated Biphenyls in the Presence of Aminopolysaccharides
Authors: Portier KJ , Fujisaki K
Published: February 2009

Fate analysis predictions of agricultural or industrial source toxicants in aquatic or marine environments can be affected by the presence or absence of adapted (preexposed) microbial populations and amenable substrates for cometabolic or cooxidative biotransformation. Polychlorinated biphenyls (PCBs) were evaluated in controlled laboratory microcosm systems in the presence of the aminopolysaccharide polymer chitin. Toxicants evaluated included the commercial Aroclors 1232, 1248, and 1254. Crosscouplings of each PCB mixture and polymer were noted, resulting in an optimization of epiphytic microbial metabolic activity. Significant primary degradation was noted for the lesser chlorinated biphenyls, that is, Aroclor 1232. Gas chromatography analysis of Aroclor 1248 and 1254 showed several tetra and penta isomers remaining. However, when polymer epiphytic populations were predominantly adapted microbial strains, that is, a Pseudomonas species and an Acinetobacter species, additional refractile isomers were metabolized. A comparison of kinetic rate constants based on biotransformation of each commercial mixture showed significant changes in halflife as correlated to isomer mixture, available polymer, and microbial inoculation.
An Evaluation of Appropriate Expressions of Toxicity in Aquatic Plant Bioassays as Demonstrated by the Effects of Atrazine on Algae and Duckweed
Authors: Hughes JS , Alexander MM , Balu K
Published: February 2009

This investigation was undertaken to determine the toxicity of the herbicide atrazine to a variety of aquatic plant species as expressed by different endpoints, including the five-day EC50, the five-day no-observed effect concentration (NOEC), and the phytostatic and phytocidal concentrations. The validity of each of these endpoints and the related issues of test duration and biological response are discussed.

Tests were conducted with two freshwater algae (Anabaena flos-aquae and Navicula pelliculosa), a marine alga (Dunaliella tertiolecta), and a freshwater vascular plant, Lemna gibba (duckweed). The test procedure consists of a five-day exposure phase followed by a nine-day recovery phase, with standing crop as the measure of effect on growth.

Of the four endpoints, the NOEC is the most conservative and is also the most sensitive to the experimental design and statistical procedures used. A 50% reduction in population growth (EC50) is also conservative and is an acceptable parameter for a screening test. However, determination of the EC50 alone does not indicate the lethality of the test material or the recovery potential of the test species. Due to environmental significance and statistical considerations, the phytostatic and phytocidal concentrations are recommended as the primary responses.
A Short-Term Chronic Toxicity Test Using Daphnia Magna
Authors: Lewis PA , Horning WB
Published: February 2009

A seven-day short-term chronic toxicity test using ten-day-old Daphnia magna is described as a possible alternative to the Ceriodaphnia short-term test. The test was begun on Friday so that weekend work was limited to feeding. The test was conducted at 25°C, and the animals were fed daily.

Five tests using sodium pentachlorophenate conducted during the development of the method gave test results similar to those previously reported for Daphnia magna chronic tests and comparable to Ceriodaphnia short-term tests conducted at the U.S. Environmental Monitoring and Support Laboratory (EMSL), Cincinnati. This test can be completed with about half the labor required for the Ceriodaphnia test, and the neonates can be easily counted without the aid of a microscope.
Integrated Resource Management: The Challenge of the Next Ten Years
Authors: Cairns J
Published: February 2009

The past ten years have been notable because of the development of the process of hazard evaluation in which chemical fate was coupled in a systematic and orderly way with biological effects. This development was amplified in the five-book Pellston series that began with Estimating the Hazard of Chemical Substances to Aquatic Life, ASTM STP 657 and in the ASTM Aquatic Toxicology and Hazard Assessment series, of which this is the 10th volume. The future, however, is intriguing, so my comments will focus on that.

The next ten years will bring a concerted effort to use the results of hazard evaluation and aquatic toxicology, as well as other types of environmental and ecological information, in the process of integrated resource management. The purpose of the hazard assessment activities of Committee E-47 is to help prevent ecosystem damage. The purpose of integrated resource management, on the other hand, is to optimize performance of the ecosystem, which requires different information and a different management strategy than hazard assessment. Although much is written about the management of large natural systems such as drainage basins, little effective action has been taken. Institutional arrangements fragment the responsibility so that federal and state regulatory agencies and other organizations are often at odds and sometimes in direct conflict in their attempts to optimize that portion of resource management assigned to them.

Integrated resource management will require that some of the enormous resources now being spent on litigation be redirected into problem solving. Some of the prescriptive regulations, which now pit the regulators against the regulated in such ways that obvious solutions to simple problems cannot be implemented, must be changed. Since there is very little scientific and institutional information about integrated resource management, both of which will be essential for systems level quality control, and since funding to generate this information is not likely to come from traditional sources, some acknowledgement of the value of generating this information must be incorporated in the planning.

It is essential that committees of standards-setting organizations engaged in environmental assessment and related activities become much more active in developing integrated resource management approaches. Unless this is done soon and skillfully, even the finest standard methods will not be used effectively. Without integrated resource management, information will be fragmented, often inappropriate for the decision being made, or in apparent conflict with other equally valid information. In short, those engaged in environmental surveillance, monitoring, and hazard prediction must pay more attention to the structure of the management systems into which their methods will flow.
Quality Assurance Guidelines for Ground-Water Investigations: The Requirements
Authors: Jeffrey van Ee J , McMillion LG
Published: February 2009

The U.S. Environmental Protection Agency (EPA) is required to assess the quality of data that are collected in its research and monitoring programs, and this requirement is meant to apply to established areas such as air and water pollution monitoring as well as to the emerging use of geophysics in ground-water investigations. The Agency's quality assurance requirements are outlined, and the ability to meet the requirements in ground-water investigations is discussed. Suggestions are offered on how standards and standard methods can be developed, based upon the experiences obtained in the implementation of monitoring programs in air pollution in the 1970's. The concept of reference and equivalent methods is compared in the monitoring of the air quality with the assessment of ground-water quality for the EPA. The applicability of quality assurance to the many and varied steps in a ground-water investigation is discussed with emphasis given to geophysics. The lack of standard procedures and quality assurance guidelines for geophysical investigations of hazardous waste sites poses serious questions to the acceptance of emerging disciplines for ground-water quality studies.
Combining Surface Geoelectrics and Geostatistics for Estimating the Degree and Extent of Ground-Water Pollution
Authors: Kelly WE , Bogardi I , Nicklin M , Bardossy A
Published: February 2009

Geostatistical techniques are presented for estimating the areal distribution of specific conductance as an indicator of the degree and extent of ground-water pollution. Combinations of measurement types including surface geoelectrics and monitoring wells are evaluated in terms of the prediction error. A realistic example using several combinations of surface resistivity and borehole measurements of specific conductance is presented. Results of the example are analyzed and show the increase in prediction accuracy possible by combining the two measurement types.
An Application of Impedance-Computed Tomography to Subsurface Imaging of Pollution Plumes
Authors: Tamburi A , Roeper U , Wexler A
Published: February 2009

An impedance-computed tomography (ICT) algorithm and system, known as the Electroscan system, for impedance imaging with surface measurements is described. The algorithm determines the current flow paths iteratively and employs sparse-matrix techniques. The measurement system uses a grid of electrodes over the ground surface and introduces controlled currents into a subset of electrodes in a prescribed sequence. Voltage measurements (using high-impedance equipment) are taken at passive electrodes only. Tests are reported for controlled saline plumes injected into a porous media flow field in a laboratory plume, and an uncontrolled leachate plume coming from a sanitary landfill located in floodplain alluvium.
Ground-Water Monitoring Field Practice—An Overview
Authors: Riggs CO , Hatheway AW
Published: February 2009

The greatest difficulties in providing ground-water monitoring installations have not generally resulted from a need to develop new technologies but from the need to define and implement the administrative and communicative procedures that are required for legal and fiscal control. Many of the required field procedures that must be understood by permit writers and their inspectors have never been researched and documented but exist as evolved in day-to-day geotechnical practice and water well contracting. The field solution usually requires the selection of the appropriate available installation procedure. Selection of the well casing, intake screen, and sampling device according to material constituents is currently the most “unsettled” aspect of ground-water monitoring practice. It is emphasized that the field installation of a monitoring well system must relate to the site geology and hydrology, and that each ground-water monitoring device must be installed using the most appropriate drilling tools and techniques, and well materials, according to the suspected contaminants and the required accuracy of analysis.
The Chemical Composition of Leachate from a Two-Week Dwell-Time Study of PVC Well Casing and a Three-Week Dwell-Time Study of Fiberglass Reinforced Epoxy Well Casing
Authors: UM Cowgill
Published: February 2009

The primary objective of this study was to determine whether or not trace organic compounds of the U.S. Environmental Protection Agency (EPA) priority pollutant list could be extracted from treated polyvinyl chloride (PVC) well casing that had been constructed with the use of PVC solvent cement and a composite epoxy-fiber reinforced casing.

Sections of PVC well casing were glued together with PVC solvent cement. In an effort to create a barrier that would reduce the leaching of various compounds from the PVC and the adhering cement, three treatments of PVC well casing were executed. PVC well casing was sulfonated with dry nitrogen gas-enriched with sulfur trioxide (SO3) for 5 min, followed by a 3% calcium chloride (CaCl2) wash. The remaining two treatments applied to PVC pipe were a 3% CaCl2 wash and no treatment. A dwell-time study employing double-distilled water was carried out for a fortnight. Subsequently, the three leachates, the PVC solvent cement, the double-distilled water, and the 3% CaCl2 wash were analyzed for their components by gas chromatograph/mass spectrometer-specific ion monitoring (GC/MS-SIM). The results indicated that both sulfonation and the CaCl2 wash may act to minimize substances leaching out of the cement, but that this reduction fails to be sufficient enough to adequately protect water contained in such PVC well casing from contamination by substances leached from the cement. It has been ascertained that all detected contaminants originate from the PVC solvent cement. A field procedure is proposed for remedial action to remove PVC solvent cement contaminants from wells that have been thus contaminated.

An alternative to PVC well casing is fiberglass reinforced epoxy casing. Both powder (60 mesh, 200 mesh) and well casing were subjected to leachate tests. Of all the substances sought in these leachates, only cyclohexene oxide, bisphenol A, phenol, and di-n-butyl phthalate were detected, and these were encountered in the 200 mesh sample. It is hypothesized that grinding to 200 mesh exposes surfaces that would ordinarily not be exposed. A classical dwell-time study failed to confirm the presence of these compounds. As a result, a number of state agencies and EPA have approved the use of fiberglass reinforced epoxy casing for drinking water wells and monitoring wells for Superfund sites.
Design Considerations and Installation Techniques for Monitoring Wells Cased with Teflon PTFE
Authors: Dablow JF , Persico D , Walker GR
Published: February 2009

A representative sample of ground water is essential for investigations where analytical testing results at the parts per billion level are needed to properly assess the constituents, concentration, and extent of contaminant plumes which impact ground-water resources. Monitoring wells constructed with casings of Teflon PTFE (polytetrafluoroethylene) can significantly improve the confidence level in a representative sample because of the inertness of the casing material to sorption or desorption of possible contaminating chemicals, particularly volatile organic compounds. Three strength-related properties—pullout resistance of the threaded couplings, compressive strength of the screen sections and flexibility of the casing string—must be considered during the design of monitoring wells cased with Teflon PTFE. Experimental data indicate that Teflon casing can be suspended to depths of 107 m with little risk of flush-threaded joint failure. Compressive strength testing shows that Teflon behaves predominantly elastically and is subject to only small screen opening deformation. This deformation can be overcome by specifying the manufactured screen opening to be larger than the opening required by the well design. Special installation techniques are essential when working with Teflon to assure a properly constructed monitoring well, including two techniques to eliminate “snaking” of the well casing: borehole centralizers, and the insertion method.
Design Considerations and the Quality of Data from Multiple-Level Ground-Water Monitoring Wells
Authors: Patton FD , Rodney Smith H
Published: February 2009

The role of design in obtaining ground-water monitoring data is introduced. Several basic aspects of design are considered. These include the spatial distribution and length of monitoring zones and the percentage of the drill hole containing seals. Emphasis is placed upon multiple-level monitoring wells because, for most sites, they appear to be necessary to satisfy the requirements for establishing the three-dimensional distribution of natural piezometric and chemical data, as well as the influence of superimposed local variations. To facilitate the discussion of multiple-level monitoring wells, a proposed classification is presented.

Attention is given to mixing of fluids in the well bore annulus. Errors introduced by such mixing are shown to be related to the length of the monitoring zone with respect to the geometry and uniformity of the ground-water plumes. Analyses of samples affected by fluids mixing prior to and during sampling are shown to lead to significant errors in determining in-situ water quality.

The paper concludes that water samples and fluid pressures from short monitoring zones will generally be of a higher quality (that is, more representative of in-situ conditions) than data from longer monitoring zones.
Chemical Stability Prior to Ground-Water Sampling: A Review of Current Well Purging Methods
Authors: Panko AW , Barth P
Published: February 2009

Sample preservation and analysis of ground waters follow rigid protocols governed by well-established quality assurance/quality control procedures. Well purging requirements are less rigorously defined, making chemical sampling critical in obtaining representative data.

Purging a well for chemical sampling causes local changes in water chemistry in terms of temperature, pH, solubility of gases, and redox potential. Subtle changes over a more widespread area may also occur. Before sampling a new or existing well, hydraulic and chemical stability should be established between the aquifer water and the water within the well. This becomes more important as the concentration of contaminants being evaluated becomes lower or nears the detection limit of the test. The actual physical process of retrieving representative water samples, therefore, is complicated by the chemical implications of short-term aquifer dewatering.

In developing new wells, stability must be verified so that all traces of drilling fluid (where it has been used) and drilling debris are removed from the well and only aquifer water is sampled. This is typically performed by making volume-by-volume analysis of pH, specific conductance, and temperature until successive samples show consistent values. Properly developed existing wells usually reach chemical stability relatively rapidly.

Each monitoring well or set of wells has its own unique hydraulic and chemical characteristics. All wells, after first being drilled, must be purged to determine when equilibrium is reached. It cannot be assumed that removal of a fixed number of casing volumes of water will guarantee stability. Once this stability has been achieved, further tests are still required. These tests will determine the volume of water which must be removed to obtain a representative formation water sample, for each individual well or group of wells, in the same aquifer or overburden situation. It is essential that the evaluation of the hydraulic character of a well be made in conjunction with water chemistry. This evaluation should be made in light of the level of analytical accuracy required, and prior to establishing a standard number of volumes to be removed for purging prior to sampling for any well.
Investigations of Techniques for Purging Ground-Water Monitoring Wells and Sampling Ground Water for Volatile Organic Compounds
Authors: Unwin J , Maltby V
Published: February 2009

An experiment designed to detect and quantify contamination of simulated ground-water samples with stagnant water in a monitoring well found that an average of about 2 to 4% of the water pumped from locations above the screen and an average of about 1% of the water pumped from within the screen of the monitoring well came from the stagnant water above the pump inlet even when effects of drawdown were precluded. All runs showed peaks of contamination up to 8% or higher. The amount of contamination is highly variable over a short time frame. An experiment to identify the effects of the sampling device and the tendency of a compound to evaporate from water solution on the loss of the compound during the ground-water sampling process revealed that the potential for losses rises as the tendency to evaporate from solution increases, and that up to 30% loss can occur under certain circumstances. Less than 10% loss is more typical with the techniques normally used for such sampling. Little indication of differences between commonly used sampling devices was found.
Field Evaluation of Seven Sampling Devices for Purgeable Organic Compounds in Ground Water
Authors: Imbrigiotta TE , Gibs J , Fusillo TV , Kish GR , Hochreiter JJ
Published: February 2009

Seven different sampling devices—(1) a bladder pump, (2) a helical-rotor submersible pump, (3) a gear submersible pump, (4) an open bailer, (5) a point-source bailer, (6) a syringe sampler, and (7) a peristaltic pump—were evaluated to determine their ability to recover purgeable organic compounds (POCs) from ground water under field conditions. Significant differences among the mean concentrations obtained with each sampler were found for selected POCs at each of three sites. The overall order of the sampling devices from highest to lowest recovery using data from all three sites yielded the following: (1) gear submersible pump, (2) point-source bailer, (3) open bailer, (4) helical-rotor submersible pump, (5) bladder pump, (6) syringe sampler, and (7) peristaltic pump. The overall standardized mean concentrations of Samplers 1 through 5 were closely grouped, indicating these devices were very similar in their ability to recover POCs. A similar overall order of the coefficients of variation indicated no clear difference between the sampling devices in the precision with which they recovered POCs. However, the three samplers with the lowest coefficients of variation (highest precision) were all positive-displacement pumping devices whereas the three samplers with the highest coefficients of variation (lowest precision) were all grab-sampling devices.
A Hermetically Isolated Sampling Method for Ground-Water Investigations
Authors: Torstensson B-A , Petsonk AM
Published: February 2009

Ground-water studies are often associated with the use of actions or materials which can lead to introduction of errors or contamination. For instance, transfer of liquids from a bailer to a laboratory vial can permit volatile chemicals sampled from water in an open well to escape, or can give rise to external contamination or human contact with the fluids.

A set of devices, the BAT® Groundwater Monitoring System, has been developed which specifically eliminates these and other difficulties. All individual elements of the system are hermetically sealed, permitting in situ conditions (for example pressures and dissolved gases) to be maintained. Hydraulic interconnections and fluid transfers are achieved through use of hypodermic needles, flexible septa, and internally generated pressure gradients. The system permits pressurized sampling of both liquids and gases from virtually any depth in groundwaters, open or sectioned-off wells, and piping systems, as well as directly from surface waters. Groundwater may be extracted in situ from either the saturated or vadose zones of soil or rock formations.

Samples are taken in the field with the same presterilized and pre-evacuated vials that will be sent to the laboratory; no further transfers, pumps, or piping mechanisms are required. Since the samples are sealed and pressurized, the total gas content will remain the same as that at the sampling site, and the samples can truly be said to be representative of the in situ conditions.

The in situ system also contains additional above-ground components for use in ground-water investigations. These measure ground-water pressures or soil suctions, perform tests of hydraulic conductivity, and allow tracer tests to be run. All of these devices use needles and septa to access the only below-ground piece of equipment. This—a permanently installed and sealed filter tip—contains no electronics, and only a single moving part: a flexible septum.
Sampling Interaquifer Connector Wells for Polonium-210: Implications for Gross-Alpha Analysis
Authors: Oural CR , Upchurch SB , Ralph Brooker H
Published: February 2009

Ground water in peninsular Florida commonly has gross-alpha radioactivity in excess of 15 pCi/L. This activity, which is unsupported by radium, results from 210Po. Comparison of polonium with gross-alpha activity in samples collected and preserved by present methods indicates that gross-alpha analyses are inconsistent and frequently underestimate total alpha activity.

In interaquifer recharge wells, polonium decreases with depth owing to sorption and mixing with host water. Therefore, sampling depth affects polonium and gross-alpha activity determination. 210Po analysis is sensitive to sample collection, preservation, and preparation techniques. With few exceptions, sampler selection has little impact on polonium recovery. Bailers and air-lift samplers give unreliable polonium recovery. Sample preparation methods are critical to polonium recovery. Filtration and sample fixation must be in the field.
Suction Lysimeter Operation at Hazardous Waste Sites
Authors: Everett LG , McMillion LG , Eccles LA
Published: February 2009

Four questions relative to suction lysimeter performance have been raised by operators of land treatment systems. These questions deal with plugging of the porous segments, soil suction operational ranges, loss of volatile organics under negative pressure, and adsorption and screening of the various lysimeter parts. This paper describes the physical operation of a lysimeter, the characteristics of the lysimeters tested [high- and low-flow lysimeters with porous ceramic cups and lysimeters with porous polytetrafluoroethylene (PTFE) cups], and procedures followed in preparing the lysimeters for testing. It then presents the results of experiments dealing with the first three questions—plugging, operational ranges, and volatile organics loss. It was found that suction lysimeters placed in the vadose zone of most types of soils will initially drop off rapidly in intake rate, but will stabilize after about 15 L of moisture has been drawn through the porous cups. Packing a crystalline silica flour slurry around the cups of PTFE lysimeters negates most of the plugging associated with finer particles in soils. The effective operating range of ceramic lysimeters is between 0 and 60 centibars of suction, independent of the use of silica flour. The operating range of PTFE lysimeters without silica flour is extremely narrow, but with the use of silica flour is extended to about 7 centibars of suction. Volatile organics are lost from suction lysimeters, but the amount of the loss is difficult to estimate. The testing program indicates that before field installation all lysimeters should be checked for leaks using pressure techniques, and that lysimeters have “dead” spaces, that is, reservoirs of moisture, ranging from 34 to 80 mL, that cannot be extracted from the cups, and that must be taken into account when determining moisture collection rates. Information gathered during the test program is planned for inclusion in an Environmental Protection Agency (EPA) guideline document entitled “Unsaturated Zone Monitoring at Hazardous Waste Land Treatment Units.”
Measuring Effects of Permeant Composition on Pore-Fluid Movement in Soil
Authors: Olsen HW , Rice TL , Nichols RW
Published: February 2009

A laboratory experimental system is described for measuring the effects of permeant composition on pore-fluid movement in a soil specimen mounted in a conventional triaxial cell. These effects include the variation of permeability that arises when the pore-fluid composition changes within a soil, and also the tendency for a permeant composition gradient to cause pore-fluid movement. The system is based on the previously reported capabilities and advantages of the flow-pump method for permeability measurements. The system also utilizes a permeant-control subsystem that facilitates bringing deaired solutions of arbitrary chemical composition from storage reservoirs to the ends of a test specimen.
Methods for Virus Sampling and Analysis of Ground Water
Authors: Gerba CP
Published: February 2009

The consumption of contaminated ground water is responsible for almost half of the reported waterborne disease outbreaks each year in the United States. Enteric viruses continue to be a significant cause of such waterborne disease. Methods for virus detection in ground water are needed to assess the safety of ground-water supplies. Viruses in ground water may originate from septic tanks, leaking sewer lines, domestic and sludge landfills, land disposal of sewage effluent, leaking sewage ponds, etc. Because of the potential health significance of low numbers of viruses in water, it is necessary to sample large volumes of water (40 to 1000 L). The method most commonly used is the microporous filter adsorption/elution technique. This involves passing water through a filter to which the viruses adsorb and subsequently eluting (deadsorbing) the viruses off the filter using a 1 to 2-L suspension of 3% beef extract. This eluate is further reconcentrated to a volume of 20 to 30 mL before assay. Currently, this concentrate is then assayed by animal cell culture. Newer techniques for virus detection should dramatically reduce the time and cost of virus detection in ground water.
Determination of Aqueous Sulfide in Contaminated and Natural Water Using the Methylene Blue Method
Authors: Lindsay SS , Baedecker MJ
Published: February 2009

The methylene blue method for the colorimetric determination of aqueous sulfide was modified and evaluated for field use in the concentration range of 0.3 to 1500 µM sulfide. Aqueous sulfide (H2S, HS−, and S=) reacts with N,N-dimethyl-ρ-phenylenediamine sulfate and ferric chloride in an acidic solution, forming a methylene blue complex which is measured spectrophotometrically at 670 nm. Modifications to the method permit rapid and repetitive sampling, produce reproducible standard curves, and define the limitations on stability of reagents and of the color-complex. Field measurements are made easily after the reagents have been standardized in the laboratory. The method has a relative standard deviation of ±3.8% at 80 µM S= and ±0.84% at 420 µM S=.

The method was laboratory tested for possible interferences from phenols, polynuclear aromatic hydrocarbons and salts. Sulfide concentrations up to 70 µM were measured in ground water contaminated with creosote waste products including phenols and aromatic hydrocarbons. No interferences were found from these constituents.
Field Experimental Methods in Stratified Aquifers
Authors: Melville JG , Molz FJ , Güven O
Published: February 2009

Tracer injection and observation experiments are the best field methods available to characterize advection and dispersion in aquifers. Near Mobile, Alabama, single and two-well tracer experiments have been conducted in a confined sandy aquifer. Multilevel observation wells were designed, constructed, and operated in eleven different experiments.

Data have been selected from all the results which demonstrate observation well behavior. Isolation of sampling zones is shown to be necessary. Drilling mud remnants in or near the observation well are shown to invalidate measurements. In an experiment where an inflatable packer system suddenly failed, the loss of vertical integrity is shown in the electrical conductivity signals. Finally, mixing within sampling zones, sampling zone lengths, well installation, vertical integrity, and vertical integrity testing are discussed with an emphasis on desirable design characteristics.
Field Investigation of a Small-Diameter, Cylindrical, Contaminated Ground-Water Plume Emanating from a Pyritic Uranium-Tailings Impoundment
Authors: Morin KA , Cherry JA
Published: February 2009

As part of a larger study on the geochemical behavior and computer simulation of subsurface seepage from pyritic tailings impoundments, a detailed field study of such seepage has been conducted. At the field site, the tailings lie over a glaciofluvial sand aquifer. Near the southeastern corner of the tailings, acidic contaminated water (pH 4) seeps through the base of the tailings into the sand aquifer and flows laterally to the south as a distinct, roughly cylindrical plume. This plume contains up to 6000 ppm iron, up to 14 000 ppm sulfate (SO4), and elevated levels of other contaminants. The acidic seepage eventually encounters carbonate minerals in the aquifer, pH is then neutralized, and contaminants are attenuated through chemical precipitation, co-precipitation, and adsorption over a distance of several metres.

At the edge of the impoundment, the ground-water plume has a cross-sectional area of about 3 m2. Although the cross-sectional area suggests the plume is rather unimportant, the ground-water velocity is about 440 m/year, resulting in a lateral flux of more than 106 L of contaminant-laden water each year. The multilevel bundle piezometers installed to define this small-diameter plume are described and the installation techniques used to minimize disturbance of the plume are also addressed. Each bundle contains up to twelve individual piezometers with a vertical screen spacing of as small as 0.5 m. Horizontal distance between bundles is as small as 2.5 m.

The high total dissolved solids (TDS) water in the plume presents many problems for field and laboratory geochemical measurements. High partial pressures of carbon dioxide (CO2) in the water result in rapid degassing and subsequent pH fluctuation upon sampling. Because of the high degree of temperature-sensitive aqueous complexing in the water, temperature variations can affect pH measurements. Mixing of air with the water initiates iron oxidation. To acidify and stabilize a water sample, 30 mL of concentrated hydrochloric acid (HCl) must be added to each litre of sample, lowering the pH to about 1.5. Laboratory analysis of these samples often requires significant dilution, and the addition of neutral-pH and alkaline reagents to the sample causes ferric hydroxide precipitation and subsequent instrument clogging. Techniques are described to circumvent many of these problems and to collect reliable physical and chemical hydrogeologic data on this site.
Ground-Water Monitoring Techniques for Non-Point-Source Pollution Studies
Authors: Kimball CG
Published: February 2009

The results of a ground-water monitoring project are based on samples collected from monitoring wells. The wells must be properly installed, constructed, and placed in accordance with project objectives and goals. Ground-water sampling must be conducted such that a representative sample is consistently obtained. Ground-water monitoring system design considerations include project goals and objectives, geology, hydrologic characteristics, chemical parameters to be monitored, and analysis and evaluation plans. To achieve a high-quality monitoring project with the capability of meeting project goals and objectives, the integration of a number of disciplines is necessary. Hydrogeologists, geologists, chemists, statisticians, engineers, and trained and experienced technical field personnel all provide valuable input.

A Comprehensive Monitoring and Evaluation project designed to detect changes in nitrogen and pesticide concentrations from agricultural activities is underway in eastern South Dakota. The geology and sampling situations encountered vary considerably throughout the project area. Experience gained through this project and techniques and methodologies applicable to ground-water monitoring are presented.
Ground-Water Contamination and Land Management in the Karst Area of Northeastern Iowa
Authors: Stan Mitchem P , Hallberg GR , Hoyer BE , Libra RD
Published: February 2009

A statistical analysis of existing northeast Iowa water-quality data showed that systematic nonpoint contamination of ground-water quality was occurring in regional carbonate aquifers. Well-water quality generally improved with increased well depth and with natural geologic protection related to thickness of overlying bedrock or Quaternary aquitards. Nitrate levels were highest in areas where sinkholes were present; areas without sinkholes but with relatively thin protective cover had similar but somewhat lower levels of nitrate.

A detailed analysis of a single karst ground-water basin found the same systematic nitrate contamination along with low but persistent levels of herbicides. Agricultural practices were judged to be the sourceof the contaminants and infiltration was the principal mechanism. Ninety-five percent of the nitrate and 55 to 85% of the atrazine were delivered by infiltration and percolation.

Various state and Federal agencies, university researchers, local groups, and private organizations are cooperating in a seven-year project in the Big Spring basin to demonstrate and evaluate the effectiveness of best management practices on ground-water quality and on crop production. The project will provide research results to serve as a foundation for future policies and programs that agriculture must address relative to environmental problems.
Advanced Triaxial Testing of Soil and Rock
Authors: Donaghe RT , Chaney RC , Silver ML
Published: February 2009

Description

First publication of its kind in 25 years, this 900-page volume serves as an engineer’s guide for triaxial testing. Subjects include: equipment, test methods, and test interpretation and errors, and new test varieties.
Compositional Analysis by Thermogravimetry
Authors: Earnest CM
Published: February 2009

Description

The Special Technical Publication is the result of an international symposium, which was held 16 and 17 March 1987 at Philadelphia, PA. This symposium was organized and sponsored by the ASTM Committee E37 on Thermal Measurements. The symposium as well as the special technical publication cover a broad spectrum of applications of thermogravimetry to the compositional analysis of materials. We are very pleased with the wide range of material types (polymers, rubber, cements, coal, oil shales, clays, and so forth) as well as the fact that authors from seven different countries participated in this symposium and subsequent publication.
Oral testosterone replacement in symptomatic late-onset hypogonadism: effects on rating scales and general safety in a randomized, placebo-controlled study
Authors: Legros Jean-Jacques , Meuleman Eric J H , Elbers Jolanda M H , Geurts T B Paul , Kaspers Marion J G H , Bouloux Pierre M G , _ _
Published: February 2009

Objective

To investigate the effects of oral testosterone undecanoate (TU) on symptoms associated with late-onset hypogonadism (LOH).

Design

Multicenter, randomized, double-blind, placebo-controlled.

Methods

The study was performed in 14 study centers in seven European countries. Men ≥50 years (n=322) with symptoms of hypogonadism and testosterone deficiency (calculated free testosterone <0.26 nmol/l) were randomized and treated for 12 months with placebo or oral TU 80, 160 or 240 mg/day. Primary outcome was the total score on the Aging Males' Symptoms (AMS) rating scale after six months of treatment.

Results

Treatment of mild-to-moderate LOH symptoms in subjects with borderline hypogonadism with oral TU resulted in an improved total AMS score at month 6, but differences between groups were not statistically significant. There was greater improvement in subjects <60 years when compared with subjects ≥60 years (P=0.001), but baseline testosterone level had no influence on treatment response. The AMS sexual symptoms domain improved with oral TU 160 mg/day at months 6 (P=0.008) and 12 (P=0.012) compared with placebo, but not with 80 and 240 mg/day. Treatment was well-tolerated and there were no between-group differences in adverse events or drop-out rates.

Conclusions

In one of the largest placebo-controlled studies of testosterone therapy in LOH, oral TU did not improve total AMS score in subjects with mild-to-moderate symptoms compared with placebo, except the sexual symptom sub-domain where a modest improvement was reported with oral TU 160 mg/day.
Genetic variation in exon 17 of INSR is associated with insulin resistance and hyperandrogenemia among lean Indian women with polycystic ovary syndrome
Authors: Mukherjee Srabani , Shaikh Nuzhat , Khavale Sushma , Shinde Gayatri , Meherji Pervin , Shah Nalini , Maitra Anurupa
Published: February 2009

Objective

Polycystic ovary syndrome (PCOS) is a multigenic disorder, and insulin resistance is one of its hallmark features. Polymorphisms in exon 17 of insulin receptor (INSR) gene are reported to be associated with PCOS. We investigated this association in Indian women and its putative relationship with PCOS associated traits, which has not been explored so far.

Methods

In this case control study, the polymorphisms were investigated by direct sequencing in 180 women with PCOS and 144 age matched controls. Clinical, anthropometric, biochemical, and hormonal parameters were also estimated.

Results

The silent C/T polymorphism at His1058 in exon 17 of INSR was found to be present in our study population. The polymorphic genotype (CT+TT) was significantly associated with PCOS in lean women (χ2=8.493, df=1, P=0.004). It showed association with higher fasting insulin levels (P=0.02), homeostasis model assessment of insulin resistance (P=0.005), free androgen index (P=0.03), and lower quantitative insulin sensitivity check index (P=0.004) in lean PCOS women. No other novel or known polymorphism was identified in exon 17 in this cohort.

Conclusions

The study shows significant association of C/T polymorphism at His1058 of INSR with PCOS in the lean rather than obese Indian women. Its association with indices of insulin resistance and hyperandrogenemia is also seen in the same group. The findings strengthen the concept that pathogenesis of PCOS is different in lean and obese women.
Recent Achievement in the GaN Epitaxy on Silicon and Engineering Substrates
Authors: Arnaud Wilk , Lijadi Melania , Langer Robert , Bove Philippe , Thorpe James , Blanck Hervé , Hoel Virginie , Defrance Nicolas , DeJaeger Jean-Claude
Published: February 2009

Since the middle of the 90's, GaN epitaxy techniques have been developed, using either MOCVD or MBE growth methods. A low cost approach is presented aiming at satisfying thermal issues encountered on conventional substrates such as SiC, Sapphire and more recently Silicon. Domain of application are being covered with their associated challenges: RF and High Power applications. Stress engineering is one of the key parameters.
Investigation of Amorphous InGaZnO Based TFT Interface Properties with Synchrotron Radiation Analysis
Authors: Joo Minho , Choi Jongkwon , Noh Seokhwan , Park Kyuho , Ihm Kyuwook , Kim Kijeong , Kang Taihee
Published: February 2009

We investigated the amorphous indium gallium zinc oxide (IGZO) based TFT interface properties using synchrotron radiation analysis. Near edge x-ray absorption fine structure shows the presence of N2 molecules between gate dielectric layer and active channel layer. The physical damage enhanced by the sputtering process was the origin of the device degradation evolving molecular state N2.
Influence of In-Situ Arsenic Doped Emitter Poly Process Conditions on RF-BiCMOS Device Parametrics
Authors: Egloff Richard , Paik Namwoong , Beckett Susan , Codi Daniel , Mase Jerry , Tomassi Wayne
Published: February 2009

This paper discusses the influence of deposition conditions on in-situ As doped amorphous silicon emitter films used in NPN RF bipolar transistors. In-situ As doped amorphous and/or polysilicon layers improve electrical performance in BiCMOS devices by reducing the number of process steps and eliminating issues associated with implanted polysilicon on high aspect ratio topographies (plug effect). This study was made using a vertical furnace configuration capable of 150 wafer loads. Because adsorbed AsH3 decomposition species tightly bind to the active surface sites and inhibit the deposition rate, the process recipe is complex. Predictable bipolar parametrics require control of the As diffusion profile within the base region after activation, so a thorough understanding of emitter film growth and dopant incorporation is necessary.

We describe the relationship between process conditions and recipe variants on transistor gain (Hfe), base current (Ib), and emitter resistance (Re). SIMS and in-line sheet resistivity measurements were used to monitor dopant incorporation into the emitter. This data was found to be predictive not only of the Hfe for a population, but also as an indicator of potential “renegade” Hfe behavior.
Luminescence Properties in Er,O-codoped GaAs Light-Emitting Devices with Double Excitation Mechanism
Authors: Fujiwara Yasufumi , Fujii Kei , Fujita Ayafumi , Ota Yuji , Ito Yoshiaki , Kawasaki Takashi , Noguchi Kota , Tsuji Takahiro , Nishikawa Atsushi , Terai Yoshikazu
Published: February 2009

We fabricated a laser diode (LD) exhibiting a lasing from strained GaInAs quantum wells (QWs) embedded in Er,O-codoped GaAs (GaAs:Er,O) by organometallic vapor phase epitaxy (OMVPE). The lasing wavelength was designed to tune to the energy separation between the second excited states 4I11/2 and the ground state 4I15/2 of Er3+ ions. The threshold current for the lasing at room temperature was six times larger than that of a GaInAs QW-LD without Er doping, reflecting ultrafast carrier capture by an Er-related trap in GaAs:Er,O. The Er intensity revealed initially steep increase with injected current density in the region for spontaneous emission from the GaInAs QWs. In the stimulated QW emission region, the intensity continued to increase with the current density.
UV and Visible Luminescence of Pr3+ Doped Oxides: New Materials
Authors: Piccinelli Fabio , Speghini Adolfo , Ivanovskikh Konstantin , Meijerink Andries , Ronda Cees , Bettinelli Marco
Published: February 2009

The garnet Ca3Sc2Si3O12 (CSSO) and the silico-carnotite Ca3Y2Si3O12 (CYSO) and Ca3Lu2Si3O12 (CLSO) materials, both undoped and doped with Pr3+, have been synthesized by solid state reaction at high temperature. The luminescence spectroscopy and the excited state dynamics of the materials have been studied upon VUV and X-ray excitation using synchrotron radiation. All doped samples have shown efficient 5d-4f emission upon direct VUV excitation of 5d levels, but only CSSO:Pr3+ shows luminescence upon interband VUV or X-ray excitation. The VUV excited emission spectra of CYSO:Pr3+ and CLSO:Pr3+ show features attributed to emission from two distinct sites accommodating the Pr3+ dopant. The decay kinetics of the Pr3+ 5d-4f emission in CSSO:Pr3+ upon VUV excitation across the conduction band are characterized by decay times in the range 25-28 ns with no significant rise after the excitation pulse. They appear to be faster upon X-ray irradiation than for VUV excitation. Weak afterglow components are attributed to defect luminescence.