Department of Environmental Science

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The Texas TGV Proposal: Nexus or Nightmare?
(1994) Stoodley, Scott Howard; Alexander, Sara E.; Baylor University.
This thesis objectively analyzes the current Texas TGV High Speed Rail (HSR) proposal. The purpose is to determine whether or not this proposal is in the best economic and environmental interests of the State of Texas and in the larger picture, the United States. The primary objectives are to analyze current HSR systems throughout the world and to critically evaluate the specifications of the Texas proposal. It will also assess the relative success of the HSR systems that are in operation in reference to current U.S. expenditures on different modes of transportation. The major arguments for and against this proposal will also be evaluated. After a comprehensive review, it is the determination of this thesis that the proposed Texas TGV system is in the best interest of the state and in the larger picture, the United States.
Community needs assessment among the Gujjars in Northern India.
(2002) Dorrell, Janet C.; Alexander, Sara E.; Baylor University.
The perceived needs of the Gujjars of northern India were investigated in the Gurdaspur District of Punjab, India. The purpose of this study was to provide baseline data on the Gujjars who migrate to and from the states of Punjab to Himachal Pradesh by assessing their basic human needs within Johan Holmberg's sustainable development framework. These baseline data were gathered using a Needs Assessment Survey that represents approximately seventy-five Gujjar families who suffer problems of under-representation and social, economic and geographic marginalization. The analysis encompassed in the approach, defined as advocacy anthropology, suggested that the Gujjars do perceive a need for development and advocacy, specifically in the areas of education, land distribution, medical access, freedom from exploitation, political empowerment, and relief from poverty.
Multigenerational responses of Daphnia magna to Ethynylestradiol and Faslodex.
(2006-05-11T16:06:37Z) Clubbs, Rebekah L.; Brooks, Bryan W.; Environmental Studies.; Baylor University. Dept. of Environmental Studies.
Select environmental contaminants can disrupt normal functions of aquatic invertebrate endocrine systems. While ecological risk assessments often rely on standardized laboratory toxicity tests to assess ecological impacts, these techniques may not be appropriate for endocrine active compounds, including select pharmaceuticals in the environment. Subsequently, multigenerational designs are recommended to assess organismal responses to low-level exposures to these compounds. The objective of this study was to investigate effects of a mammalian estrogen receptor agonist and antagonist on endocrine biomarkers and transgenerational life-history parameters of a model invertebrate, Daphnia magna. Results from this study suggest that the pharmaceuticals, Ethynylestradiol and Faslodex, model therapeutics designed to interact with vertebrate estrogen receptors, did not act through the ecdysone receptor in D. magna. Thus, toxicity Ethynylestradiol and Faslodex exerted on D. magna likely resulted from non-endocrine-mediated responses, which may reduce uncertainty in future assessments of invertebrate responses to endocrine active pharmaceuticals in the environment.
Resident perceptions of management issues in the Red River Gorge: a qualitative assesment.
(2006-07-30T19:32:29Z) Hutson, Kathleen Adams.; Alexander, Sara E.; Environmental Studies.; Baylor University. Dept. of Environmental Studies.
Management of protected areas is oftentimes a difficult process, particularly when stakeholder groups with different agendas are impacted by decisions regarding use of the resource. The Red River Gorge area in eastern Kentucky has struggled over the past few decades as residents, visitors and managers of the region work to define how the area should most effectively be managed under the guidance of the Multiple Use Sustained Yield Act. Specific objectives of the study include the following: • to explore the nature of relationships between hosts and guests in the Red River Gorge • to identify any impacts of the National Wild and Scenic River designation • to determine resident preferences for future development of Red River Gorge • to determine residents feelings about current management of Red River Gorge, and • to offer a set of recommendations for managing agencies addressing the current needs of residents.
A baseline assessment of local mercury deposition from coal-fired power plants in Central Texas.
(2006-10-02T15:11:58Z) Furl, Chad Van.; Lehr, Larry L.; Van Walsum, G. Peter (Gerard Peter), 1963-; White, Joseph Daniel.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Coal-fired power plants represent the largest source of anthropogenic mercury in the world. The Central Texas region as represented by the Heart of Texas Council of Governments contains two coal-fired power plants located in Freestone and Limestone Counties. A third plant, Sandy Creek, is currently being proposed for McLennan County. The primary objective of the study is to estimate the amount of mercury being deposited via wet deposition in 2003 from two existing power plants in Central Texas, Big Brown and Limestone, and predict deposition from a proposed plant, Sandy Creek. The Industrial Source Code Short-Term model was used to estimate wet deposition, and empirical data was collected to determine the mercury levels in environs near the plants. According to the research and statistical analyses, the Central Texas power plants studied appear to be having no impact on the water quality of area surface waters.
The fate of phosphate in the MixAlco process and its applicability to a Central Texas watershed.
(2007-01-19T16:21:19Z) Doyle, Erin E.; Van Walsum, G. Peter (Gerard Peter), 1963-; Environmental Studies.; Baylor University. Dept. of Environmental Studies.
The MixAlco process is proposed as a means to reduce phosphorus concentrations in dairy cow manure in order to help improve water quality in the Lake Waco watershed. Numerous dairy farms and intensive agricultural practices are located in this Central Texas watershed, and dairy manure is a major source of nutrients, particularly phosphorus. Nutrients, such as nitrogen and phosphorus, are the main causes of eutrophication. The MixAlco process, which can use dairy manure as a source of biomass to produce a mixed alcohol fuel, may reduce phosphorous levels in manure wastes. The dairy manure filtrate was analyzed for soluble reactive phosphorous (SRP) before and after the first two steps of the MixAlco process. An average reduction of 86 percent was observed from beginning to end. A reduction in SRP may ease the impact dairy manure has on eutrophication in the Lake Waco watershed to help improve water quality.
Support host selection of Lonicera japonica and its interaction with different environmental and biotic factors in Cameron Park, Waco, Texas.
(2008-06-05T14:41:08Z) Gao, Song, 1981-; Bratton, Susan.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Japanese honeysuckle (Lonicera japonica), an exotic woody vine, has naturalized in riparian forests in central Texas. The objective of this study was to quantify its existence pattern associated with different environmental and biotic factors in Cameron Park, Waco, Texas. Eighty-eight 8 × 4 meter plots were established along twelve trails in the area and treatment experiments were taken during May to August 2007. Through cumulative ordinal regression analysis, I found that cover of L. japonica was only significantly related to native vine cover and only the treatment of clearing both native and exotic vines showed a significant effect. As for the support host, its height class is strongly correlated with the climbing behavior of L. japonica. These results suggested that biotic factors play a more important role in its invasion and support hosts with low to medium height contribute to its spread from understory to canopy layer of the forest, whereas high tree hosts carry more stems to a longer distance in the canopy.
Accumulation of trifluralin and trinitrotoluene (TNT) in two aquatic invertebrates: formation and persistence of unextractable biotransformation products.
(2008-06-09T13:12:51Z) Dudley, Melissa B.; Chambliss, C. Kevin.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Exposure to nitroaromatic compounds has been reported to result in unextractable residues, or residues not readily extracted by traditional techniques. However, limited information is available about the formation rate and biological half-life of unextractable residues in aquatic organisms. In this study, two aquatic invertebrates, Lumbriculus variegatus and Hyalella azteca, were exposed inaqueous media to ¹⁴C-labeled trinitrotoluene and trifluralin. Unextractable residues were formed in both organisms by both compounds. TNT formed a greater percentage of unextractable residues than trifluralin. L. variegatus accumulated more TNT-related unextractable residues compared to H. azteca, while the reverse was true for trifluralin. H. azteca eliminated unextractable residues moreefficiently than L. variegatus. Additionally, the biological half-life of unextractable residues was longer than that of the extractable residues. The presence and biological persistence of unextractable residues indicates that these compounds, and especially TNT, could cause subtle and chronic biological effectsand serve as indicators of exposure.
Prymnesium parvum effects on green algae, cladocerans and fish in field and laboratory studies.
(2008-08-12T21:45:34Z) Ureña-Boeck, Fabiola.; Brooks, Bryan W.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Prymnesium parvum, commonly named “golden algae,” has severely impacted fisheries in Texas, USA and other parts of the world. This study explored the environmental conditions during fish kills in Texas inland waters known to trigger P. parvum bloom formation and ecological impacts on a fish model, Pimephales promelas, a model green algae competitor, Pseudokirchinella subcapitata and a model cladoceran predator, Daphnia magna. Prymnesium parvum reduced D. magna survival and reproduction in laboratory and field studies, providing the first evidence of P. parvum impacts on cladocera. Nutrient treatment of N:P = 20 in the field decreased aquatic toxicity of P. parvum to cladocerans and fish. Whereas a potential relationship was observed between lower P. parvum related toxicity to fish, lower bacteria densities and fewer observations of P. parvum swarming behavior in laboratory studies, future studies are needed to understand the relationships among environmental conditions, grazing pressure, mixotrophy and toxin production.
The sublime and the synthetic: riparian art and industrialization.
(2009-01-07T22:25:12Z) Turner, Bradley T.; Bratton, Susan.; Environmental Science.; Baylor University. Dept. of Environmental Science.
This study proposes that traditional, American riparian artistry provided the greatest retaliation against the harsh environmental changes imposed by industry during the Gilded Age. Common environmental ethics and widespread social identification with nature established popular criteria that the American public used to determine the merits of industrialism. An eclectic mixture of local and national riparian artwork demonstrates the full influence of riparian aesthetics during the Gilded Age. Waco, Texas serves as the example of local artwork because of the city’s central riparian location and Waco’s cultural identification with the Brazos River. This thesis evaluates the extent of the natural, American sublime in direct contrast with the human synthetic to evaluate the connection between the natural and the material.
Prymnesium parvum in inland waters : comparative toxicity, microcystin allelopathy, and toxin photodegradation.
(2009-09-09T14:24:25Z) James, Susan Virginia.; Brooks, Bryan W.; Environmental Science.; Baylor University. Dept. of Environmental Science.
The harmful algal species Prymnesium parvum, a toxin-producing mixotrophic haptophyte, has caused massive fish kills in slightly saline inland Texas water bodies. In the first study, standardized aquatic test models from multiple trophic levels were simultaneously employed to compare sensitivities to P. parvum toxins. Fish mortality was the most sensitive endpoint, though adverse reproduction effects in two invertebrate species were observed; a green algal species was not adversely affected. A second study employed a probabilistic risk assessment approach and examined potential allelopathy of the cyanotoxin microcystin-LR to P. parvum. A concentration of 4,392.8 μg l⁻¹ significantly inhibited P. parvum growth over a portion of the study, which corresponded to a 9% probability of detecting this concentration in the environment. Finally, the effect of sunlight on toxicity of P. parvum cell-free filtrate was assessed. Exposure to eight hours of full or ~50% sunlight eliminated toxicity to Pimephales promelas, suggesting toxin photodegradation.
Using remote sensing to assess potential impacts of hurricanes on mosquito habitat formation : investigating the mechanisms for interrelationship between climate and the incidence of vector-borne diseases.
(2010-02-02T19:59:59Z) Naqvi, Zainab R.; White, Joseph Daniel.; Environmental Science.; Baylor University. Dept. of Environmental Science.
The present study examined the relationship between climate and the incidence of vector-borne disease. The climatological phenomenon El Niño Southern Oscillation (ENSO) was found to be significant in predicting the frequency and intensity of hurricane seasons for the Atlantic Ocean and the Yucatan Peninsula between 1985 to 2007. Satellite analysis for hurricanes that impacted the Yucatan Peninsula, specifically the country of Belize, between 1995 and 2007 determined changes in the Normalized Difference Vegetation Index (NDVI), mid-infrared range (MIR), and thermal infrared range (TIR) immediately after and one month after the hurricanes. Regression analyses found that correlations between reported cases of malaria and dengue fever for Belize and changes in the NDVI, MIR, and TIR existed between immediate and persistent impacts and disease incidence.
Hydrology of non-riverine freshwater wetlands of the upper Texas coast.
(2010-06-23T12:31:20Z) Clapp, Adam G.; Yelderman, Joe C.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Coastal Prairie Freshwater Wetlands (CPFWs) are characterized by depressions and flats that occur in the Galveston Bay area. Studies estimate that over 9,000 acres of CPFWs were lost between 1992 and 2002. The cumulative loss of water quality and flood storage function may have detrimental effects on water quality and flood attenuation. There are few quantitative data available to explain the hydrologic processes of palustrine (freshwater) wetlands. This study monitored six individual CPFWs with a combination of weirs, piezometers and rain gages; each with data loggers to record wetland, groundwater and nearby surface water levels. Data were collected for approximately 18 months with some gaps due to the effects of Hurricane Ike. Water budgets were calculated to evaluate storage volumes, discharge, and potential “nexus” with receiving waters. All the monitored wetlands discharged during the study, stored significant amounts of the annual water budget and were affected by seasons.
Assessing interactions between nutrients and aquatic toxicity : influences of nitrogen and phosphorus on ionic silver toxicity to the aquatic macrophyte Lemna gibba.
(2011-05-12T15:18:27Z) Bian, Jingyi, 1985-; Brooks, Bryan W.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Though nutrients and silver often co-occur in aquatic ecosystems, the combined effects of these environmental stressors on aquatic plants are poorly understood. Such coexposures are important because nanosilver is increasingly released to the environment, and recent studies indicate that the dissolved fraction of nanosilver appears to be more acutely toxic to aquatic life. The primary objective of this study was to understand the effects of nitrogen (N) and phosphorus (P) concentrations and N : P ratios on the toxicity of ionic silver toxicity to the model aquatic macrophyte Lemna gibba over 7-d study periods. The experimental results indicated that L. gibba were more sensitive to silver (e.g., lower EC50 values) when N and P concentrations were higher. In addition, greater ionic silver toxicity occurred under higher P-availability (e.g., lower N : P ratios) conditions. L. gibba frond number and fresh weight were also differentially affected and showed variable sensitivity to different nutrient x silver treatment combinations, which highlights the importance of considering site-specific nutrient conditions during the prospective and retrospective assessment and management of silver impacts to primary producers.
The oaks of Independence : a landscape history of the original site of Baylor University and the potential surrounding historic district.
(2011-05-12T15:23:51Z) Crumpton, Thomas William.; Bratton, Susan.; Environmental Science.; Baylor University. Dept. of Environmental Science.
The landscape in and around the village of Independence in northeastern Washington County, Texas, is characterized by dense old growth riparian zones, released old fields, open pastures, and regenerated woodlots. The results of this project signify shifts in the appearance and use of the local landscape, including an increase in general woody vegetation since the late nineteenth century, and conversion from row crop and plantation agriculture to livestock production and leisure use. Live Oak Groves of the town and surrounding properties remain a constant within the changing landscape, and many trees pre-date Anglo settlement in the area. A regression for DBH/Age relationship was created from local tree measurements, which allowed identification of thirty-four trees older than the Republic of Texas, and ninety-three trees dating to the period of Baylor University’s residence in Independence. Intensive surveys of seventeen sites helped to identify historic landscape and vegetation features within a cultural context.
Designing quantitative structure activity relationships (QSAR) to predict specific toxic endpoints for polybrominated diphenyl ethers (PBDE) in mammalian cell culture systems.
(2011-12-19) Rawat, Swati, 1984-; Bruce, Erica Dawn.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Polybrominated diphenyl ethers (PBDEs) are becoming increasingly known as effective flame retardants and have vast industrial application in products like plastics, building materials, and textiles. They are found to be structurally similar to thyroid hormones that are responsible for regulating metabolism in the body. Structural similarity with the hormones poses a threat to human health because once in the system, the PBDEs may change thyroid hormone transport and metabolism. This study is aimed at designing QSAR models for predicting toxic endpoints for PBDEs in mammalian cells. QSAR modeling uses the known chemicals’ activity, which serve as surrogates to study unknown chemicals belonging to the same family. This research is a threefold process including running in-vitro bioassays to collect data on the toxic endpoints, modeling the evaluated endpoints using QSARs and validating the models using compounds of interest from the same family (PBDEs).
Aquatic toxicology of salinity and silver in Daphnia magna : a comparative study of standardized chronic endpoints and progeny Phototaxis.
(2011-12-19) Kolkmeier, Mark A.; Brooks, Bryan W.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Behavioral bioassays with the model freshwater cladoceran Daphnia magna have the potential to serve as nontraditional but sensitive endpoints of sublethal stress in the field of ecotoxicology. However, few studies have examined the comparative sensitivity of phototaxis perturbations to standardized endpoints in chronic toxicity testing protocols. D. magna 21 d chronic toxicity studies were conducted with model stressors of salinity (NaCl) and dissolved silver (Ag+). Phototaxis assays of progeny response to relative light changes in small water columns were conducted of each brood. Results indicated predominantly decreased phototactic behavior in comparison to control brood performance at common ecotoxicological thresholds. Phototaxis assays showed effects at treatment levels below the 21-d adult reproduction LOEC value in broods 2, 3, 5 and 6 in the salinity study and broods 2, 5, and 6 in the silver study. Future refinement of robust and potentially highly ecologically relevant behavioral assays such as phototaxis in combination with traditional and nontraditional endpoints may prove useful in characterization of assessment factors.
Using in vitro to in vivo extrapolation (IVIVE) to develop toxicity metrics for human health risk assessment of polybrominated diphenyl ethers (PBDEs).
(2012-11-29) Pree, Krystal.; Bruce, Erica Dawn.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Polybrominated diphenyl ethers (PBDEs) are flame retardants found in many industrial components, such as furniture foam, consumer electronics, plastics, and textiles and levels have increased in humans over the past few decades. PBDEs demonstrate adverse neurotoxic effects in mice, are lipophilic, and bioaccumulate in fish. Consequently, PBDE biomagnification may occur, which can be transferred to humans in amounts that may present adverse health effects. This investigation uses in vitro models to calculate bioassay-based reference doses in order to develop a human health risk assessment based on the consumption of PBDE-contaminated fish, using in vitro to in vivo extrapolation (IVIVE). The toxicity effects of ten PBDE congeners were examined and compared among those developed using traditional in vivo mice studies and in vitro models in this study using rat (Clone-9), HEPG2 and zebrafish liver cells to determine the feasibility of using alternative approaches to develop toxicity metrics to evaluate human health risk.
Street Dust : implications for stormwater and air quality, and management through street sweeping.
(2013-09-24) Calvillo, Steven J.; Brooks, Bryan W.; Environmental Science.; Baylor University. Dept. of Environmental Science.
Street dust represents a source of dual potential risk to stormwater and air quality. It has been well-documented that washing of this material to local watersheds can degrade water quality. Studies have also demonstrated that as much as 85% of ambient particulate matter (PM₁₀), exposure to which is associated with several health effects, can arise from resuspension of accumulated street dust. The objectives of this study were to: (1) Critically review the available literature regarding street dust and potential impacts on stormwater and air quality, (2) Develop an understanding of available street sweeping technologies and their relative efficacy, (3) Extrapolate the relative efficacy of multiple street sweeping technologies to the context of environmental/ecological and human health risk, and (4) Provide recommendations for future research studies.
Spatial and temporal distribution of lead, copper, and zinc in sediments of East Fork Wetland, Seagoville, TX.
(2014-10-23) Acharya, Abhilasha, 1988-; Cobb, George P.
This study evaluated concentrations of three metals: lead, copper and zinc in sediments of East Fork Wetland, in Seagoville, Texas. Sediments were collected during June 2013, December 2013, and March 2014 from 138 different sites during each sampling event. Analytes were quantified using inductively coupled plasma mass spectrometry following acid digestion of samples. Average lead and zinc concentrations in interval 1 were higher than interval 3. Copper concentrations showed no seasonal variation. Average concentrations of all metals were lower than consensus based sediment quality guideline (SQG) thresholds. SQG consist of threshold effect concentration (TEC), below which harmful effects on benthic organisms are unlikely and probable effect concentration (PEC), above which adverse effects are expected to occur frequently. Approximately 98% of the individual concentrations were below TEC and 42% of data were 50% below TEC. No individual concentrations exceeded PEC levels, therefore sediments can be considered to have low toxicity.

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