Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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Subject: search.filters.subject.Water quality

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Now showing 1 - 4 of 4
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    Innovative Reuse of Baltimore Harbor Dredged Material as Vegetative Earthen Berms
    (2024) Smith, Adam; Davis, Allen P; Aydilek, Ahmet H; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Dredged material (DM) is a sediment excavated from navigable waterways, which haslimited use due to the transport and accumulation of potentially hazardous metals and organic chemicals into these waterways. DM can be used as a recycled material in place of soil, depending on its environmental and physical characteristics, and the specific use. Vegetated Earthen Berms (VEBs), used for stormwater control, is one potential beneficial application of DM. The objective of this research is to assess the environmental and geotechnical suitability of DM in VEBs. A germination study and a battery of column tests were conducted to test the innate properties of the DM and DM amended with straw and sand, as DM blends. Straw and sand were chosen to observe potential improvements to the DM’s physical and chemical parameters. A nine-week mesocosm study was performed to simulate the overall performance of DM and DM blend constructed VEBs for the plant growth and water quality criteria, determined by US EPA water quality limits. Plant cover and growth measurements along with measuring effluent water characteristics were assessed. Straw amended DM was shown to have comparable vegetative establishment parameters relative to topsoil. For the water quality, concentrations of dissolved copper and zinc were reduced relative to typical median stormwater values in DM constructed VEBs. Based on the results of these tests, DM constructed VEBs had reflected desirable qualities for potential reuse based on water quality and vegetative establishment.
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    Nutrients, chlorophyll, and emergent harmful algal bloom species of concern in coastal waters of Assateague Island National Seashore
    (2021) Ross, Morgan O; O'Neil, Judith M; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The Atlantic Ocean coastal zone of Maryland is important both ecologically and economically. Due to water quality issues, the coastal lagoons of Maryland have received considerable research attention, but little corresponding research in the coastal waters that exchange with the coastal lagoons. To better understand the linkages between the coastal ocean and the potential impacts of human activity on Maryland’s coastal zone, 5 research cruises (2018-2019) were completed to investigate concentrations of nutrients and emergent harmful algal bloom (HAB) species of concern (Dinophysis, Karenia, Pseudo-nitzschia). Nutrient and HAB species had high intra-annual variability, as well as geographic variability with relation to the inlets, coastal lagoons, and offshore discharge sites. The most significant determinants across all sampling locations, depths, and times were nitrate and ammonium. Continued eutrophication and climate change, as well as the impact of connected waterways, presents challenges for managing regional water quality issues in the coastal ocean.
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    The Impact of Private Drinking Water Wells and Animal Feeding Operations on the Incidence of Acute Gastroenteritis in Maryland: A Mixed Methods Approach
    (2019) Murray, Rianna Teresa Frederika; Wilson, Sacoby M; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    More than 44.5 million people in the United States (approximately 14% of the population) rely on private domestic wells as their primary source of drinking water. The water quality of private wells is not regulated at the state or federal level, leaving homeowners with wells responsible for the safety of their water. Meanwhile, each year, an estimated 48 million people in the U.S. are sickened, 128,000 are hospitalized, and 3,000 die of gastrointestinal (GI) illnesses caused by microorganisms that are typically transmitted through contaminated food. Given that the potential of private wells as a non-foodborne transmission pathway for these microorganisms is not well understood, my dissertation evaluated these relationships, as well as characterized the quality of private well water in Maryland. My objectives were to: 1.) Investigate the water quality of private wells in Maryland and the effect of animal feeding operations on this water quality using fecal indicator bacteria; 2.) Investigate associations between the prevalence of private wells and the incidence of campylobacteriosis in Maryland at the zip code level using data from the FoodNet active surveillance System; and 3.) Investigate associations between the prevalence of private wells and the incidence of salmonellosis in Maryland at the zip code level using FoodNet data. My findings demonstrated that 43.2% of private wells tested in Maryland did not meet at least one federal health-based drinking water standard. Additionally, my data showed that the prevalence of private wells in Maryland is a risk factor for the incidence of campylobacteriosis and salmonellosis in the coastal counties of the state. The presence of broiler chicken operations in a zip code is also a risk factor for campylobacteriosis and salmonellosis in coastal counties. These findings provide evidence for the strengthening of private well water regulations and for improving education and outreach to private well owners on proper maintenance and testing for their wells.
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    Assessment of Zero-Valent Iron Capabilities to Reduce Food-borne Pathogens via Filtration and Residual Activities in Irrigation Water
    (2017) Bradshaw, Rhodel; Sapkota, Ph.D., Amy R; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Inadequate disinfection of contaminated freshwater that is used to irrigate food crops that are eaten raw can result in foodborne illnesses. Therefore, in this study we assessed the efficacy of a low-cost, water treatment technology, zero-valent iron (ZVI), in reducing microbiological contamination of synthetic irrigation water. Specifically, we compared the capabilities of a ZVI-sand filter versus a sand filter in reducing levels of Salmonella Newport MDD314 and E. coli TVS 353 through filtration or residual disinfection. Our data showed that ZVI-sand filtration was more effective than sand filtration alone in reducing levels of both of these microorganisms. Our results also showed that, after filtration, there seemed to be no residual disinfection capabilities associated with either the ZVI-sand system or the sand system alone. Our findings suggest that ZVI-sand filtration can effectively reduce microbial contaminants in irrigation water; however, there seem to be no residual disinfection capabilities after filtration.