• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 109
  • 52
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 290
  • 290
  • 127
  • 126
  • 115
  • 103
  • 76
  • 53
  • 52
  • 49
  • 44
  • 44
  • 40
  • 38
  • 37
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Optimizing edge-of-field water quality monitoring methods to determine the effects of best management practices on nutrient and sediment runoff

Hill, Mark 08 August 2023 (has links) (PDF)
This study investigates the impact on water quality of combined agricultural best management practices cover crop and minimum tillage, alongside an examination of techniques used to collect those samples. Edge-of-field (EOF) water quality samples were collected from 11 working farms during a two-year paired field experiment. Results showed significant reductions in nutrient concentrations, increased discharge, and mixed findings regarding nutrient mass transport post-treatment. A suite of EOF collection techniques were compared using in-situ automated water sampling systems sampling the same runoff events. Sampling protocols influenced nutrient concentrations in composite samples, but unexpected variance in velocity sensors affected measured discharge, making it challenging to confidently attribute differences in nutrient loading estimates to sampling protocol. The findings provide regionally specific evidence for mitigating on-farm nutrient enrichment in the Lower Mississippi Alluvial Valley and enhancing monitoring techniques.
142

Risk Assessment for Hazardous Materials Incident, Washington County, Tennessee: Road Transportation, Rail Transportation, and Hazardous Materials Storage.

Stagnolia, Steed Kenlee 14 August 2007 (has links) (PDF)
This study was conducted to provide a quantitative risk assessment for road transportation, railway transportation, and storage of hazardous materials in Washington County, Tennessee. A roadside survey, railroad hazardous materials survey, and a chemical inventory were conducted. It revealed an estimated 267,858 HAZMAT shipments per year on primary and secondary roadways and an estimated total of 9.4 x 109 tons of HAZMAT shipped by rail per year. There are 49 facilities that store a daily average of 33,722,700 lbs of HAZMAT. The risk of a hazardous materials incident occurring in Washington County is highest for Interstate transportation. The risk for a HAZMAT incident within the county is lower or equal to similar locations in the United States for other roadways surveyed, rail transportation, and fixed storage. Low risk does not mean there is no risk. In order to be prepared for a future incident planning, training, and research should continue.
143

SPATIAL INTERPOLATION OF HEAVY METAL CONCENTRATIONS IN SOILS OF BUMPUS COVE, TN

Magno, Melissa A, Luffman, Ingrid, Nandi, Arpita, Evanshen, Brian G 05 April 2018 (has links)
Mining processes generate waste rock, tailings, and slag that can increase heavy metal concentrations in soils. Un-reclaimed, abandoned mine sites are particularly prone to leaching these contaminants, which may accumulate and pose significant environmental and public health concerns. The characterization and spatial delineation of heavy metals of such soils is vital for risk assessment and soil reclamation. Bumpus Cove, once one of the richest mineralized districts of eastern TN, is home to at least 47 abandoned, un-reclaimed mines that were all permanently closed by the 1950s. This study evaluated 52 soil samples collected within a 0.67 km2 study area containing 6 known abandoned Pb, Zn, and Mn mines at the headwaters of Bumpus Cove Creek for heavy metal concentrations. Soil samples were analyzed for Zn, Mn, Pb, Cu, and Cd by means of microwave-assisted acid digestion and flame atomic absorption spectrometry (FAAS). Using the measured values and digital elevation model (DEM) derived from lidar data, ordinary kriging and cokriging interpolation techniques were used to predict the trend of heavy metal concentrations throughout the study area. Concentrations for Zn, Mn, and Pb show significant variability between sample sites (ranges of 12 – 1,354 mg/kg Zn, 6 – 2,574 mg/kg Mn, 33 – 2,271 mg/kg Pb). Cu and Cd were much less variable, with ranges of 1 - 65 mg/kg and 7 – 40 mg/kg, respectively. Of the measured heavy metals, only Zn and Pb exceed permissible limits in soils. Results show that ordinary kriging interpolation methods produced improved results over ordinary cokriging with and without lognormal transformations for all metals. Mn and Pb were found to transport further downhill following the natural drainage, whereas Zn, Cu and Cd concentrations exhibit localized variability without a clear transportation path. This study can provide a reference for state and local entities responsible for heavy metal monitoring in Bumpus Cove, TN.
144

Comparative Analysis of Survival and Decay of Fecal Indicator Bacteria in Bovine Feces and Freshwater Microcosms

Tariq, Reem 01 May 2018 (has links) (PDF)
Agricultural runoff can carry FIB that can pollute surface waters through the soil matrix. This study was designed to inspect the impact of temperature and matrix on the survival of FIB. The FIB were routinely enumerated over an 18-day period from fecal samples and freshwater microcosms maintained at 4oC, 22oC, and 35oC. It was found that the FIB studied underwent a primary growth of up to 1-log10 to 3-log10, highlighting the weakness of conventional FIB as indicators of pathogen contamination. The concentrations of FIB in the water phase were found to be significantly greater than those observed in the fecal phase in all FIB and their associated survivals were found to be significantly different too. Similarly, temperature was also found to be a significant factor for the survival of FIB. While the differences in the survival were significant, there was a slight variation in the patterns regarding the differences.
145

The Ecology of Fecal Indicators

Gilfillan, Dennis A 01 December 2018 (has links) (PDF)
Animal and human wastes introduce pathogens into rivers and streams, creating human health and economic burdens. While direct monitoring for pathogens is possible, it is impractical due to the sporadic distribution of pathogens, cost to identify, and health risks to laboratory workers. To overcome these issues, fecal indicator organisms are used to estimate the presence of pathogens. Although fecal indicators generally protect public health, they fall short in their utility because of difficulties in public health risk characterization, inconsistent correlations with pathogens, weak source identification, and their potential to persist in environments with no point sources of fecal pollution. This research focuses on characterizing the ecology of fecal indicators using both modeling and metabolic indicators to better understand the processes that drive fecal pollution. Fecal indicator impairment was modeled in Sinking Creek, a 303 (d) listed stream in Northeast Tennessee, using the ecological niche model, Maxent, for two different fecal indicators. While the use of Maxent has been well demonstrated at the macroscale, this study introduces its application to ecological niches at the microscale. Stream impairment seasonality was exhibited in two different indicators over multiple years and different resolutions (quarterly versus monthly sampling programs). This stresses the need for multiple year and month sampling to capture heterogeneity in fecal indicator concentrations. Although discharge is strongly associated with dissolved solutes, fecal indicator impairment was governed by other ecological factors such as populations of heterotrophic bacteria, enzyme activity, nutrient conditions, and other metabolic indicators. This research also incorporated metabolic indicators to characterize spatiotemporal variability in microbial community function, making connections to fecal and other pollution gradients. Communities differed in their ability to use a wide variety of substrates, and metabolic inhibition in sediments captured most of the interaction of aquatic and benthic communities. Sediment substrate activity was also indicative of degrees of pollution, suggesting that sediment is a potential reservoir for Escherichia coli in this stream, and there is possibility for resuspension, extended residence times, and increased duration for exposure. This research highlights the benefit of using models and other microbial indicators to better understand how environment shapes the niche of fecal indicators.
146

Satellie Monitoring of Urban Growth and Indicator-based Assessment of Environmental Impact

Furberg, Dorothy January 2014 (has links)
One of the major consequences of urbanization is the transformation of land surfaces from rural/natural environments to built-up land that supports diverse forms of human activity. These transformations impact the local geology, climate, hydrology, flora and fauna and human-life supporting ecosystem services in the region. Mapping and analysis of land use/land cover change in urban regions and tracking their environmental impact is therefore of vital importance for evaluating policy options for future growth and promoting sustainable urban development. The overall objective of this research is to investigate the extent of urban growth and/or sprawl and its potential environmental impact in the regions surrounding a few selected major cities in North America, Europe and Asia using landscape metrics and other environmental indicators to assess the landscape changes. The urban regions examined are the Greater Toronto Area (GTA) in Canada, Stockholm region and County in Sweden and Shanghai in China. The analyses are based on classificatons of optical satellite imagery (Landsat TM/ETM+ or SPOT 1/5) between 1985 and 2010. Maximum likelihood classification (MLC) under urban/rural masks, objectbased image analysis (OBIA) with rule-based classification and support vector machines (SVM) classification methods were used with grey level cooccurrence matrix (GLCM) texture features as input to help obtain higher accuracies. Based on the classification results, landscape metrics, selected environmental indicators and indices, and ecosystem service valuation were calculated and used to estimate environmental impact of urban growth. The results show that urban areas in the GTA grew by nearly 40% between 1985 and 2005. Results from the landscape metrics and urban compactness indicators show that low-density built-up areas increased significantly in the GTA between 1985 and 2005, mainly at the expense of agricultural areas. The majority of environmentally significant areas were increasingly surrounded by urban areas between 1985 and 2005, furthering their isolation from other natural areas. Urban areas in the Stockholm region increased by 10% between 1986 and 2006. The landscape metrics indicated that natural areas became more isolated or shrank whereas new small urban patches came into being. The most noticeable changes in terms of environmental impact and urban expansion were in the east and north of the study area. Large forested areas in the northeast dropped the most in terms of environmental impact ranking, while the most improved analysis units were close to the central Stockholm area. The study comparing Shanghai and Stockholm County revealed that urban areas increased ten times as much in Shanghai as they did in Stockholm, at 120% and 12% respectively. The landscape metrics results show that fragmentation in both study regions occurred mainly due to the growth of high density built-up areas in previously more natural environments, while the expansion of low density built-up areas was for the most part in conjunction with pre-existing patches. The growth in urban areas resulted in ecosystem service value losses of approximately 445 million USD in Shanghai, mostly due to the decrease in natural coastal wetlands, while in Stockholm the value of ecosystem services changed very little. This study demonstrates the utility of urban and environmental indicators derived from remote sensing data via GIS techniques in assessing both the spatio-temporal dynamics of urban growth and its environmental impact in different metropolitan regions. High accuracy classifications of optical medium resolution remote sensing data are achieved thanks in part to the incorporation of texture features for both object- and pixel-based classification methods, and to the use of urban/rural masks with the latter. The landscape metrics calculated based on the classifications are useful in quantifying urban growth trends and potential environmental impact as well as facilitating their comparison. The environmental indicator results highlight the challenges in terms of sustainable urban growth unique to each landscape, both spatially and temporally. The next phase of this PhD research will involve finding valid methods of comparing and contrasting urban growth patterns and estimated environmental impact in different regions of the world and further exploration of how to link urbanizing landscapes to changes in ecosystem services via environmental indicators. / <p>QC 20141212</p>
147

Fire Effects in Montane Meadows

Deak, Rosie 01 March 2022 (has links) (PDF)
The impact of forest fires on downstream meadow communities across California is of great ecological interest, as meadows are an important source of biodiversity in this region. Over a century of fire suppression has led to increased forest stand densities, which in turn has resulted in less water availability due to increased transpiration of densely growing trees. This potentially has left less available water for downstream plant communities in meadows. If true, then high mortality wildfires in surrounding forest are predicted to lead to an increase in available downstream moisture where obligate and facultative-wetland taxa increase and dry-adapted upland taxa decline. Here, we test this hypothesis using a dataset of 103 California montane meadows sampled before and after fire over the last 20 years. Using long term meadow monitoring data, compositional turnover is calculated for each plot from before and after fire and then evaluated against the area of 100% mortality, postfire relative-precipitation, meadow type, and proximity of the meadow to fire. We hypothesize that mortality, post-fire precipitation, and site type influence compositional turnover in meadows, regardless of proximity to the burn area. We find that compositional turnover is influenced by mortality but not by meadow type, relative precipitation, or the proximity to fire perimeter. Specifically, turnover was greater in meadows in higher mortality catchments. We then used a combination of linear models and NMDS to determine whether specific functional groups were driving higher turnover rates, expecting increases in obligate and facultative-wetland groups following high mortality fires. However we found no evidence for this. The high variation amongst meadows and their respective fire histories yielded no consistent shifts in community composition. Our findings highlight that landscape scale fire effects can interact strongly affect plant communities outside of fire perimeters, but that this does not lead to predictable shifts in wetland community composition. As fire behavior and drought are projected to become more extreme, we can expect that meadow composition will continue to change but not in predictable ways.
148

A Screening Life Cycle Analysis Of One-Way And Reusable Crate Designs – Estimating Environmental Impacts Via LCA Software

Corona, Nicolas R 01 June 2024 (has links) (PDF)
A comparison analysis conducted via COMPASS life cycle analysis software has indicated that a one-way crate design, rather than a reusable crate design, is in fact the more environmentally friendly packaging system. These results can be interpreted differently, however, as the manufacturer of said crate designs must confirm what impact indicators they would like to reference as environmental goalposts. The conducted analysis provides insight into what the environmental impacts of each packaging system look like as packaging at all three system levels has been identified as a means of reducing environmental impacts globally. As such, the manufacturer of said crate designs would like to establish a baseline understanding of what the environmental impact of their products look like. Version 3.5 of COMPASS LCA software was utilized, which references ecoinvent 3.9.1 LCA databases as well as U.S. Life Cycle Inventory (USLCI) LCA methodologies. These findings are significant as they affirm that all packaging system inputs and product life-cycle phases must be carefully considered as they impact every impact indicator score differently.
149

Aproximación metodológica al análisis integrado de la sostenibilidad urbana partiendo de las tipologías constructivas

Iborra Lucas, Milagro 28 March 2024 (has links)
[ES] Las ciudades representan un papel muy importante en el desarrollo sostenible. En general, es conocido, que el sector residencial representa unos porcentajes elevados en cuanto a consumos totales de energía y emisiones de CO2. El avance en el conocimiento ha demostrado que todo el parque edificado tiene un comportamiento energético poco efectivo y que puede ser mejorable, avanzando así en las nuevas directrices de mejora que se están imponiendo desde las administraciones. Así pues, ante un parque construido abundante y obsoleto, la rehabilitación es el gran potencial que puede contribuir a la mejora del cambio climático, a través de la propuesta de estrategias y escenarios de actuación sostenibles y adecuados a los entornos sociales, económicos y medioambientales correspondientes. La construcción sostenible se fundamenta en optimizar el impacto conjunto en el medio natural de las tres dimensiones fundamentales en cualquier actividad humana: medioambiente, economía y sociedad. Así pues, surge la necesidad de establecer un patrón de medida que permita evaluar y cuantificar la sostenibilidad de un edificio, de forma que sea objetivo y comparable, que reduzcan la complejidad de otros estándares ya existentes. La presente tesis desarrolla una sistemática de análisis del medio urbano en todas sus dimensiones, a partir de una parametrización de las distintas tipologías constructivas y de su evolución. De esta forma, se está en condiciones de conocer la evolución de los sistemas urbanos partiendo de la evolución de las variables constructivas. / [CA] Les ciutats representen un paper molt important en el desenvolupament sostenible. En general, és conegut que el sector residencial representa uns percentatges elevats quant a consums totals d'energia i emissions de CO2. L'avenç en el coneixement ha demostrat que tot el parc edificat té un comportament energètic poc efectiu i que pot ser millorable, avançant així a les noves directrius de millora que s'estan imposant des de les administracions. Així doncs, davant d'un parc construït abundant i obsolet, la rehabilitació és el gran potencial que pot contribuir a millorar el canvi climàtic, a través de la proposta d'estratègies i escenaris d'actuació sostenibles i adequats als entorns socials, econòmics i mediambientals corresponents . La construcció sostenible es fonamenta en optimitzar limpacte conjunt en el medi natural de les tres dimensions fonamentals en qualsevol activitat humana: medi ambient, economia i societat. Sorgeix, doncs, la necessitat d'establir un patró de mesura que permeti avaluar i quantificar la sostenibilitat d'un edifici, de manera que sigui objectiu i comparable, que redueixin la complexitat d'altres estàndards ja existents. Aquesta tesi desenvolupa una sistemàtica danàlisi del medi urbà en totes les seves dimensions, a partir duna parametrització de les diferents tipologies constructives i de la seva evolució. D'aquesta manera s'està en condicions de conèixer l'evolució dels sistemes urbans partint de l'evolució de les variables constructives. / [EN] Cities play a very important role in sustainable development. In general, it is well known that the residential sector represents a high percentage of total energy consumption and CO2 emissions. Advances in knowledge have shown that the entire building stock has an inefficient energy performance and that it can be improved, thus advancing in the new guidelines for improvement that are being imposed by the administrations. Thus, faced with an abundant and obsolete building stock, refurbishment is the great potential that can contribute to the improvement of climate change, through the proposal of sustainable strategies and action scenarios that are appropriate to the corresponding social, economic and environmental settings. Sustainable construction is based on optimising the joint impact on the natural environment of the three fundamental dimensions of any human activity: environment, economy and society. Thus, the need arises to establish a standard of measurement to evaluate and quantify the sustainability of a building, in a way that is objective and comparable, reducing the complexity of other existing standards. This thesis develops a systematic analysis of the urban environment in all its dimensions, based on a parameterisation of the different building typologies and their evolution. In this way, we are in a position to know the evolution of urban systems in the urban environment in all its dimensions, based on a parameterisation of the different building typologies and their evolution. / La realización de esta tesis ha derivado en la participación en un proyecto de investigación de las Comunidades Europeas: Proyecto: “Grow Green”, Contract Number 730283-2 Proyecto H2020-SCC-2016-2017 titulado GREEN CITIES FOR CLIMATE AND WATER RESILIENCE, SUSTAINABLE ECONOMIC GROWTH, HEALTHY CITIZENS AND ENVIRONMENTS. / Iborra Lucas, M. (2024). Aproximación metodológica al análisis integrado de la sostenibilidad urbana partiendo de las tipologías constructivas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203609
150

Public participation in environmental impact assessment : an effective tool for sustainable development a South African perspective (Gautrain)

Aregbeshola, Maryam Titilayo 03 1900 (has links)
The need for public participation in the development of policies, programmes or actions has been widely accepted by both government and private sectors because of the benefits of such involvement. Involving the public in the development of any policy, programme or action is, however, a daunting task. Public involvement in the development of a policy or action often leads to protest, legal litigation, criticism and delay in carrying out the project. The main objectives of this research are to examine the process of public participation in the Gautrain project and to interrogate how public involvement in the decision-making processes of environmental concerns can be improved. A quantitative study was conducted to describe and explore the process of public participation in the Gautrain environmental impact assessment procedure. The purposive sampling method was used. Thereafter, the data generated was analysed using statistical tools such as charts, tables and the Wilcoxon Mann Whitney U test to examine the similarities and differences in the response patterns of the public and the project proponent. Cronbach alpha statistical methodology was also used to test the reliability of the measurement. The findings are discussed in relation to the objectives of the study and research hypotheses. The results indicate that (1) the public were not involved early enough during the project planning and design phases; (2) adequate information was not provided to the public; and (3) public input does not have much impact on decisionmaking processes. The study does, however, indicate that the process has enhanced the participants’ learning and that the process of participation has improved in recent time as compared to the 2002-2003 periods. The study concludes by providing relevant solutions and recommendations. / Environmental Sciences / M. Sc. (Environmental Management)

Page generated in 0.0969 seconds