bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Aquatic Toxicity and Fate of Brass Dust
Authors: Haley MV , Johnson DW , Muse WT , Landis WG 
Published: February 2009

A series of environmental bioassays and fate studies have been performed on brass dust. The standardized aquatic microcosm (SAM) was used as the long term, ecosystem assay.
Short-term bioassays using Daphna magna and green algae were conducted. The 48-h EC50 of the brass dust to D. magna ranged from 0.016 to 0.026 mg/L. Microscopic investigations indicated that the daphnia filter and ingest the material. Green algae were not as affected by the brass dust as the daphnids. The 96-h IC50 for Ankistrodesmus falcatus is 0.316 mg/L and for Selenastrum capricornutum, 0.056 mg/L. At very low concentrations of the brass, algal growth was stimulated.
Fate studies indicate that brass disassociation in water varies with pH. At low pHs the material rapidly disassociates into Cu++ and Zn++ ions. At pHs above neutrality the disassociation is markedly slower.
The short-term bioassays and fate studies were used to set the concentrations of brass for the SAM (the SAM is standardized protocol containing algae, invertebrates, bacteria, and a protozoan inoculated in 3 L of medium). A study using CuSO4 served as a positive control for the brass microcosm. In both microcosms the concentration of available copper slowly decreased until an equilibrium was reached. In addition, both microcosms demonstrated a dose response relationship with an increase in algal biomass correlated with an increase in toxicant dose. The cause is likely to be the elimination of the primary grazers, daphnia, because of the test chemical's toxicity. Recovery as measured by positive population growth of the daphids also demonstrated a dose-response relationship.
How Clean Is Clean? A Use of Hazard Assessment in Groundwater for Evaluation of an Appropriate Formaldehyde Spill Remedial Action Endpoint
Authors: Staples CA 
Published: February 2009

A spill of formaldehyde from a pipe was discovered in October 1983 at a manufacturing site. Groundwater investigation revealed that much of the formaldehyde was trapped within a clay till layer 8 ft below the surface at a concentration of up to 9% by weight. The formaldehyde was leaching out of the unsaturated zone and moving into the saturated zone. A remedial action plan was begun that involved the oxidation of formaldehyde with injection of hydrogen peroxide coupled with pumping withdrawal and reuse of surrounding contaminated groundwater.
In the development of any hazardous waste site/groundwater remedial program, one issue that must be addressed is “When is the remediation finished?” or “How clean is clean?” In the case of the above formaldehyde spill, the specific question was how much formaldehyde can remain in the clay till such that leaching of the formaldehyde to groundwater with subsequent degradation, dispersion, and transport to a down gradient surface water with dilution would result in toxicologically safe concentrations for both humans and aquatic life? A remedial action endpoint of 100 ppm formaldehyde was predicted to achieve these human and environmental health goals using classical hazard assessment methodologies. These hazard assessment procedures are discussed in terms of their relative contribution and usefulness in the overall remedial action process.
Two-dimensional solute transport groundwater modeling was used to predict concentrations that may discharge into a down gradient river. Hydrogeologic features, including water level gradients, dispersivities, hydraulic conductivities, porosity, and aquifer material density, were measured with a calculated leaching rate and formaldehyde biodegradation rates for estimating down gradient solute transport times and concentrations. Formaldehyde entering surface waters would be diluted by appropriate stream flows to yield instream formaldehyde exposure concentrations. Resultant formaldehyde brook concentrations were combined with the conservative no impact concentration of 40 ppb to yield a margin of safety (MS). The instream formaldehyde concentration yielding an MS &lt; 1.0 was used to back calculate the formaldehyde level that could be left in groundwater for dispersion and biodegradation by natural processes (here, 100 ppm). These modeling calculations were used to guide the appropriate choice of the target remedial action endpoint by using conservative assumptions and parameter values. Model results were considered sufficiently valid by local regulatory personnel to be of use as guidance for setting the remedial action target endpoint while the model predictions are still being fully verified. Final verification by measuring formaldehyde instream concentrations is part of the longer term remediation plan (&lt;3 years).
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.
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 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.
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.
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.