Development of a Pre-Impact Environmental Site Characterization for the Bryan Mound, Texas Strategic Petroleum Reserve

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This thesis presents a model for developing site-specific contingency plans to be used during spill response, remediation, and post-spill monitoring using the Strategic Petroleum Reserve's Bryan Mound site as a case study. Bird and vegetation observations provide baseline data for biological conditions, and sediment sampling for total petroleum hydrocarbons serves as a chemical component of the model. Results demonstrate previously unknown conditions that would hinder remediation and affect the persistence of petroleum contaminants. Results also established previously unmapped dominant bird and vegetation types likely to be impacted by a spill at the site. This model points to a reconsideration of individual facilities' responsibilities when planning for large-scale disasters and protecting the sensitive ecosystems surrounding their sites.
Date: December 2001
Creator: Hernandez, Sylvia A.
System: The UNT Digital Library

Development, Validation, and Evaluation of a Continuous, Real-time, Bivalve Biomonitoring System

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A biological monitoring tool to assess water quality using bivalve gape behavior was developed and demonstrated. The purpose of this work was to develop methodologies for screening water quality appropriate to the goals of the watershed paradigm. A model of bivalve gape behavior based on prediction of behavior using autoregressive techniques was the foundation of the bivalve biomonitoring system. Current technology was used in developing the system to provide bivalve gape state data in a continuous real-time manner. A laboratory version of the system, including data collection and analysis hardware and software, was developed for use as a toxicological assay for determination of effective concentrations of toxicant(s) or other types of stress on bivalve gape behavior. Corbicula fluminea was monitored and challenged with copper, zinc, and chlorpyrifos using the system. Effective concentrations of 176±23µg/L copper, 768±412µg/L zinc, and 68µg/L chlorpyrifos were observed using a natural water with high dissolved organic carbon concentrations. A rugged field version of the bivalve biomonitoring system was developed and deployed in two locations. The field systems were fitted with a photovoltaic array, a single board computer, and a CDPD telemetry modem for robust remote operation. Data were telemetered at a time relevant rate of once …
Date: December 2002
Creator: Allen, H. Joel
System: The UNT Digital Library

Integrating life cycle analysis and the ecological footprint calculator to foster sustainable behaviors

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Many tools have been developed to assess global, national or regional sustainable development policies. However, as governments develop sustainable policies, individuals must also feel empowered to affect their personal impact on the planet. This thesis integrates three sustainability concepts that lend themselves to individual sustainability: The natural step, life cycle assessment, and the ecological footprint. TNS serves to provide the meaning and substance toward sustainable development. LCA helps provide the framework for assessing sustainability. The EF calculator determines the driving components and measures the qualitative decisions made through TNS and LCA. From the analysis of the household footprint calculator a simplified footprint calculator was developed to assist individuals and communities in setting benchmarks and goals as they move away from over-consumption and towards a sustainable lifestyle.
Date: December 2002
Creator: Anderle, Kathryn
System: The UNT Digital Library

Removal of selected water disinfection byproducts, and MTBE in batch and continuous flow systems using alternative sorbents.

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A study was conducted to evaluate the sorption characteristics of six disinfection byproducts (DBPs) on four sorbents. To investigate sorption of volatile organic compounds (VOCs), specially designed experimental batch and continuous flow modules were developed. The investigated compounds included: chloroform, 1,2-dichloroethane (DCE), trichloroethylene (TCE), bromodichloromethane (BDCM), methyl tertiary butyl ether (MTBE), bromate and bromide ions. Sorbents used included light weight aggregate (LWA), an inorganic porous material with unique surface characteristics, Amberlite® XAD-16, a weakly basic anion exchange resin, Amberjet®, a strongly basic anion exchange resin, and granular activated carbon (GAC). Batch experiments were conducted on spiked Milli-Q® and lake water matrices. Results indicate considerable sorption of TCE (68.9%), slight sorption of bromate ions (19%) and no appreciable sorption for the other test compounds on LWA. The sorption of TCE increased to 75.3% in experiments utilizing smaller LWA particle size. LWA could be a viable medium for removal of TCE from contaminated surface or groundwater sites. Amberlite® was found unsuitable for use due to its physical characteristics, and its inability to efficiently remove any of the test compounds. Amberjet® showed an excellent ability to remove the inorganic anions (>99%), and BDCM (96.9%) from aqueous solutions but with considerable elevation of pH. …
Date: December 2002
Creator: Kadry, Ahmed Y.
System: The UNT Digital Library

The Potential of Coelomocyte Chemotaxis as an Immune Biomarker in the Earthworm, Lumbricus terrestris

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Coelomocyte migration responses, both random and chemotatic, were examined in the earthworm Lumbricus terrestris. Coelomocyte random migration patterns towards non-stimulatory, non-chemotatic solutions were described. Migration responses to immunostimulatory agents lipopolysaccharides (LPS), N-formly-methionyl-leucyl-phenylalanine (FMLP), sheep erythrocytes, Saccharomyces cerevisiae, Aeromonas hydrophila, Eisenia fetida and Rhabditis pellio were characterized. Chemotaxis was reported to LPS, FMLP, sheep erythrocytes, S. cerivesae and E. fetida. Bio-indicator potential of chemotaxis is discussed relative to variability in migration responses.
Date: December 1999
Creator: Mota, Jennifer A.
System: The UNT Digital Library

Ecological Enhancement of Timber Growth: Applying Compost to Loblolly Pine Plantations

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This study explored the application of compost onto a small loblolly pine tree forest in northeast Texas. Its purpose was to determine if the application of various amounts of compost would provide for accelerated rates of growth for the trees. Soil parameters were also monitored. A total of 270 trees were planted and studied in a northeast Texas forest ecosystem. Compost rates of 5, 25, and 50 tons per acre with either soil or compost backfill were utilized and compared to a control without compost. Nonparametric and parametric ANOVA and Chi-Square tests were utilized. The results indicated that greater application rates retained greater moisture and higher pH levels in the soil. Compost applications also yielded a greater survival rate as well as larger tree height and diameter when compared to the control. The 25 ton/acre application backfilled in native soil achieved the greatest average in height and diameter when compared to the averages for the control plot. Greater growth differences for the 25S application can be attributed to additional nutrients coupled with a stable pH consistent with native soil acidity.
Date: December 1999
Creator: Stuckey, Harold Troy
System: The UNT Digital Library

Solid phase microextraction of amino-dinitrotoluenes in tissue.

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TNT (2,4,6-trinitrotoluene) readily and predominantly transforms to 2ADNT (2-amino-4,6-dinitrotoluene) and 4ADNT (4-amino-2,6-dinitrotoluene) in environmental matrixes and tissues. Solid phase microextraction (SPME) was used to extract ADNTs (amino-dinitrotoluenes) from tissue as a potential method to investigate the recalcitrance of metabolically-generated ADNTs versus absorbed ADNTs. Tubifex tubifex was allowed to metabolize TNT into ADNTs in 24-hr static non-renewal exposure test followed by 24-hr depuration in clean reconstituted hard water. Polyacrylate-coated (PA) SPME fibers were then deployed and agitated in tissue homogenates containing metabolically-generated ADNTs for 48 hr to provide a measure of available ADNTs. Extractability of ADNTs from T. tubifex tissue containing metabolically-generated ADNTs was significantly less than extractability of ADNTs from T. tubifex tissue containing absorbed ADNTs: 50-60% and 81-90% of expected extractability based on fiber-water partition ratio. The lower SPME extractability of metabolically-generated ADNTs may stem from the unavailability of metabolically-generated ADNTs sequestered in tissue or bound to tissue macromolecules during metabolism of TNT to ADNT. Tissue extractions using SPMEs may be able to estimate such bound organic residues in tissue and serve as potential indicators of toxicological bioavailability and biomagnification potential of tissue-associated organic compounds.
Date: December 2004
Creator: Tsui-Bowen, Alethea
System: The UNT Digital Library

Influence of Sediment Exposure and Water Depth on Torpedograss Invasion of Lake Okeechobee, Florida

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Torpedograss (Panicum repens) was first observed in Lake Okeechobee in the 1970s and appears to have displaced an estimated 6,400 ha of native plants, such as spikerush (Eleocharis cellulosa), where inundation depths are often less than 50 cm. Two series of studies evaluated substrate exposure and water depth influences on torpedograss establishment and competitiveness. Results revealed that fragments remain buoyant for extended periods and so facilitate dispersal. Once anchored to exposed substrate fragments can readily root and establish. Subsequently, torpedograss thrives when subjected to inundations to 75 cm and survives prolonged exposure to depths greater than 1 m. These findings suggest that fluctuating water levels contribute to torpedograss dispersal and colonization patterns and that low water levels increase marsh area susceptible to invasion. The competition study found that spikerush grown in monoculture produces significantly more biomass when continually inundated to shallow depths (10 to 20 cm) than when subjected to drier conditions (-25 cm) or greater inundations (80 cm). In contrast, torpedograss establishes more readily on exposed substrate (-25 to 0 cm) compared to inundate substrates. During the first growing season biomass production increases as substrate exposure interval increases. However, during the second year, established torpedograss produces more biomass when …
Date: December 2006
Creator: Smith, Dian H.
System: The UNT Digital Library

Modeling of Land Use Change Effects on Storm Water Quantity and Quality in the City of Carrollton and the North Texas Area

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Development and population are rapidly increasing in urbanizing areas of North Texas and so is the need to understand changes in storm water runoff flow and its contamination by nutrients, sediment, pesticides and other toxicants. This study contributes to this understanding and has two primary components: first, development of a graphical user interface for a geographic information system and storm water management database, and second, performing a two-scale hydrological modeling approach (the US Corp of Engineers HEC-HMS model and the US Environmental Protection Agency SWMM model). Both primary components are used together as a toolkit to support the storm water management program of the City of Carrollton, located in North Texas. By focusing limited city resources, the toolkit helps storm water managers in the process of compliance with federal regulations, especially the National Pollution Discharge Elimination System permit, and provides guidance for reporting, planning and investigation. A planning example was conducted by modeling potential changes in storm water quality due to projections of land use based on the City of Carrollton's Comprehensive Plan. An additional component of this study is the evaluation of future changes in surface water quantity and quality in the North Central Texas area, specifically in a …
Date: December 2003
Creator: Duncan, Phillip Brent
System: The UNT Digital Library

Comparative Bioavailability of Dietary and Dissolved Cadmium to Freshwater Aquatic Snails

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Heavy metal bioaccumulation in aquatic organisms may occur through direct or indirect uptake routes. Research indicates that the significance of uptake route varies with contaminant and organism exposed. The relative importance of different metal sources in aquatic systems was investigated by exposing freshwater snails to dietary or dissolved sources of cadmium. Snails were exposed to control, contaminated food only, contaminated water only, and contaminated food and water treatments. During the 15-day exposure, samples were taken to determine Cd concentration in snail soft tissue, snail shell, algal food, and overlying water. Analyses of snail soft tissue and shells indicate that exposure route significantly affects Cd concentrations in the tissues. In both cases, dissolved Cd is the primary contributor to metal body burden.
Date: December 2003
Creator: White, Jessica C.
System: The UNT Digital Library