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Articles 1 - 15 of 15
Full-Text Articles in Chemistry
The Roles Of Tidal Marshes In The Estuarine Biochemical Processes: A Numerical Modeling Study, Xun Cai
The Roles Of Tidal Marshes In The Estuarine Biochemical Processes: A Numerical Modeling Study, Xun Cai
VIMS Articles
Observations suggest that the existence of tidal marsh can alter the oxygen and nutrient dynamics in adjacent water bodies, but assessing the impacts of large tidal marshes on an estuary is challenging. In this study, we use a modeling approach to investigate the roles of tidal marshes on the estuarine biochemical processes. The marsh model, which simulates the ecological functions of marshes at seasonal and annual time-scales, is embedded inside an unstructured-grid three-dimensional hydrodynamic and eutrophication model (SCHISM-ICM). This modeling system simulates the growth and metabolism of the tidal marshes and links biological processes to nutrient dynamics in the water …
Honey As A Biomonitor For Air Pollutant Deposition In The Eastern United States Using Ion Chromatography And Scanning Electron Microscopy, Cole Cochran
Undergraduate Honors Theses
Anthropogenic activities generate metal, acid, and particulate air pollutants which negatively impact human and ecological health. In the United States, power plant, industrial, and vehicle emissions are leading causes of air pollution, however, the measurement of air pollution at high-resolution spatial regimes remains a challenge. Honey has emerged as a powerful biomonitoring tool to effectively quantify contaminants without the need for a large array of monitoring instruments. I hypothesized that honey could be used to effectively measure and map modern air pollutant spatiotemporal relationships over the Eastern U.S. Using ion chromatography with sulfate as an indicator for air pollution and …
Analytical Chemistry Of Plastic Debris: Sampling, Methods, And Instrumentation, Robert C. Hale, Meredith E. Seeley, Ashley E. King, Lehuan H. Yu
Analytical Chemistry Of Plastic Debris: Sampling, Methods, And Instrumentation, Robert C. Hale, Meredith E. Seeley, Ashley E. King, Lehuan H. Yu
VIMS Books and Book Chapters
Approaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include …
The Development And Application Of An Antibody-Based Biosensor For The Detection Of The Petroleum-Derived Compounds, Candace Rae Spier
The Development And Application Of An Antibody-Based Biosensor For The Detection Of The Petroleum-Derived Compounds, Candace Rae Spier
Dissertations, Theses, and Masters Projects
Petroleum is one of the most important natural resources, but can also be problematic to environmental and human health. Petroleum is comprised of thousands of compounds, including polycyclic aromatic hydrocarbons (PAHs) and heterocycles, some of which are toxic and/or carcinogenic. Traditional analytical methods for environmental monitoring of low-level PAHs are time-consuming labor-intensive, and often laboratory-bound. Efforts to achieve timely, sensitive, and accurate analysis of PAHs in the field have become a priority for environmental research and monitoring. Antibody-based biosensors are presently being developed for environmental analysis. Anti-PAH antibody molecules can be coupled with electronic transducers to provide new biosensor technology …
Bioavailability Of Biosolids- And Consumer Product-Associated Polybrominated Diphenyl Ether (Pbde) Flame Retardants To Terrestrial Invertebrates, Michael O. Gaylor
Bioavailability Of Biosolids- And Consumer Product-Associated Polybrominated Diphenyl Ether (Pbde) Flame Retardants To Terrestrial Invertebrates, Michael O. Gaylor
Dissertations, Theses, and Masters Projects
The primary objectives of this research were therefore to evaluate polybrominated diphenyl ether (PBDE) bioavailability to ecologically distinct soil invertebrates exposed to Penta-BDE-treated consumer polyurethane foam (PUF) products and biosolid products with incurred PBDEs. In laboratory bioassays, earthworms (Eisenia fetida) bioaccumulated SigmaPBDEs (47+99+100+183) up to 11,000 mug/kg lipid after 28 days from a mixture of artificial soil and anaerobically-digested sludge biosolid (ADB). Earthworms also bioaccumulated SigmaPBDEs (47+99+100+153+154+183) up to 13,500 and 838,000 mug/kg lipid after 28 d from a mixture of artificial soil and composted sludge biosolid (CB) and Penta-BDE-spiked artificial soil (SAS), respectively. No previous lab studies on bioaccumulation …
Interactions Between Macroalgae And The Sediment Microbial Community: Nutrient Cycling Within Shallow Coastal Bays, Amber Kay Hardison
Interactions Between Macroalgae And The Sediment Microbial Community: Nutrient Cycling Within Shallow Coastal Bays, Amber Kay Hardison
Dissertations, Theses, and Masters Projects
Ephemeral macroalgal blooms are considered a symptom of eutrophication in shallow coastal lagoons, but their influence on nutrient cycling dynamics in these systems is not fully understood. From 2006-2008, I conducted a series of experiments to determine the influence of living and senescent macroalgae on sediment carbon (C) and nitrogen (N) cycling in coastal lagoons along the Delmarva Peninsula, USA. In particular, I focused on how macroalgae affect the microbial community at the sediment-water interface of shallow subtidal sediments because this complex consortium of autotrophic (e.g. benthic microalgae, BMA) and heterotrophic (e.g. bacteria) organisms plays a critical role in nutrient …
Environmental Analysis Of Selected Estrogens And Androgens: Applying Ultra-Performance Liquid Chromatography And Combating Matrix Interference, Stacie L. Rice
Environmental Analysis Of Selected Estrogens And Androgens: Applying Ultra-Performance Liquid Chromatography And Combating Matrix Interference, Stacie L. Rice
Dissertations, Theses, and Masters Projects
Investigations of environmental hormone contamination commonly utilize solidphase extraction (SPE) followed by high-performance liquid chromatography / (electrospray ionization) tandem mass spectrometry (HPLC/(ESI)MS2) in the detection of estrogens. Matrix interference is widely reported. In this study, androgens were targeted alongside estrogens as environmentally co-introduced endocrine disrupting chemicals. Analytical methods were developed in parallel for detection of several hormones from each class, with comparison of protocols and instrumental parameters. Ultraperformance LC (UPLC®), an emerging technology advertised for reduced retention times, was used in place of HPLC for hormone separation. Applicability to diverse aqueous samples was tested. Matrix interference was combated with two …
Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin
Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin
Dissertations, Theses, and Masters Projects
The interactive effects of humic acids (HAs) and salinity on the bioavailability and toxicity of the pesticides chlorpyrifos and 4,4'-dichlorodiphenyltrichloroethane (DDT) were investigated. The effects of various HAs on the toxicity of chlorpyrifos were initially assessed with the chronic MicrotoxRTM test. Environmentally relevant concentrations of Aldrich, Peat, Leonardite and Suwannee River HAs had no significant effect on the toxicity of either chlorpyrifos or copper (Cu), the test's positive control. as reductions in contaminant toxicity had previously been reported for some contaminants by HAs, it appeared that salinity might be a mitigating factor. Thus salinity effects were further investigated with Aldrich …
Development Of A Quantitative Competetive Polymerase Chain Reaction Assay For The Detection And Quantitation Of Perkinsus Marinus In Oyster Tissues And Environmental Water Samples, Heather A. Yarnall
Development Of A Quantitative Competetive Polymerase Chain Reaction Assay For The Detection And Quantitation Of Perkinsus Marinus In Oyster Tissues And Environmental Water Samples, Heather A. Yarnall
Dissertations, Theses, and Masters Projects
No abstract provided.
Development Of Supercritical Fluid Extraction (Sfe) For The Determination Of Polychlorinated Biphenyls In Tissues Of Aquatic Biota, Michael O. Gaylor
Development Of Supercritical Fluid Extraction (Sfe) For The Determination Of Polychlorinated Biphenyls In Tissues Of Aquatic Biota, Michael O. Gaylor
Dissertations, Theses, and Masters Projects
No abstract provided.
Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen
Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen
Dissertations, Theses, and Masters Projects
Chloroguaiacols are common components of bleached kraft pulp mill effluent known to bioaccumulate in aquatic organisms, and sorb onto particulate material and sediments. Ionization properties of the chloroguaiacols must be known in order to explain their sorptive behavior in aquatic systems. to obtain this information, thermodynamic acid dissociation constants (p&K\sb{lcub}\rm a{rcub})& of guaiacol (o-methoxyphenol) and nine chloroguaiacols have been determined by spectrophotometric methods. These experimental p&K\sb{lcub}\rm a{rcub}& values have been compared with literature values, values predicted by the Hammett equation and predictions by quantum chemical calculations using MOPAC 6.0 with AM1 and MNDO Hamiltonian operators. Experimental and predicted acidities were …
Molecular Diffusion Coefficients For Polycyclic Aromatic Hydrocarbons In Air And Water, Kurt E. Gustafson
Molecular Diffusion Coefficients For Polycyclic Aromatic Hydrocarbons In Air And Water, Kurt E. Gustafson
Dissertations, Theses, and Masters Projects
No abstract provided.
Atmospheric Input Of Polycyclic Aromatic Hydrocarbons To The Sea Surface Microlayer, Lino J. Gallo
Atmospheric Input Of Polycyclic Aromatic Hydrocarbons To The Sea Surface Microlayer, Lino J. Gallo
Dissertations, Theses, and Masters Projects
Atmospheric input of polycyclic aromatic hydrocarbons (PAH) to water was studied and the effects of sea surface microlayer (SSM) determined. The York River system and the Perrin River areas were monitored with a drum skimmer and a high volume air sampler. Experiments were conducted in the laboratory under controlled conditions. The SSM extracted vapor phase PAH of low molecular weight from the air, and there, aromatic compounds went from dissolved into particulate phase very rapidly. Water covered with a natural SSM received much less atmospheric input of PAH than water without SSM in a given period of time. Henry's law …
Pcb Congener Analysis With Hall Electrolytic Conductivity Detection, Robert D. Edstrom
Pcb Congener Analysis With Hall Electrolytic Conductivity Detection, Robert D. Edstrom
Dissertations, Theses, and Masters Projects
This work reports the development of an analytical methodology for the analysis of PCB congeners based on integrating relative retention data provided by other researchers. The retention data were transposed into a multiple retention marker system which provided good precision in the calculation of relative retention indices for PCB congener analysis. Analytical run times for the developed methodology were approximately one hour using a commercially available GC capillary column. A Tracor Model 700A Hall Electrolytic Conductivity Detector (HECD) was employed in the GC detection of Aroclor standards and environmental samples. Responses by the HECD provided good sensitivity and were reasonably …
Distribution Of Ammonia Nitrogen In The Lower York River, Virginia : Spring, 1961, Bernard C. Patten, Virginia Fisheries Laboratory, Virginia Institute Of Marine Science
Distribution Of Ammonia Nitrogen In The Lower York River, Virginia : Spring, 1961, Bernard C. Patten, Virginia Fisheries Laboratory, Virginia Institute Of Marine Science
Reports
No abstract provided.